[0001] This application is being filed on December 15, 2017 as a PCT

International Patent Application and claims the benefit of priority to US provisional application Nos. 62/437,772, filed on December 22, 2016;

62/512,377, filed on May 30, 2017; and 62/567,835, filed on October 4, 2017, the disclosures of each herein incorporated by reference in their entireties.

FIELD OF THE INVENTION

[0002] The present invention is related to monoclonal antibodies and antigen- binding fragments thereof that bind specifically to an allergen for use in treating patients who demonstrate a sensitivity to, or an allergic reaction against an allergen.

STATEMENT OF RELATED ART

[0003] Allergens are innocuous environmental or food substances that cause an aberrant immune response resulting in allergic rhinitis, allergic asthma, food allergies, or atopic dermatitis. Upon initial allergen exposure, antigen presenting cells capture, process, and present allergen peptides to cognate T-cells. In the presence of cytokines such as IL-4 or IL-13, T-cells acquire a Type 2 phenotype, expand, and engage B cells to undergo class switch recombination resulting in polyclonal immunoglobulin subclass E (IgE) production. IgE interacts with the high affinity Fc epsilon receptor (FcsRl) on the surface of mast cells and basophils to create "allergen receptors." Allergen binding to IgE crosslinks the IgE:Fc8Rl complex triggering degranulation and release of inflammatory mediators, termed the early phase response (EPR). The EPR occurs immediately after exposure and correlates with symptoms such as nasal congestion, rhinorrhea, sneezing, and itching (Hansen, I., et al, (2004); Current Opinion in Allergy and Clinical Immunology 4 (3): 159-63). Subsequent effector cell infiltration into the tissue and continued production of IgE comprise the late phase response (LPR) occurring 4-8 hours after allergen exposure (Hansen, I., et al, (2004); Current Opinion in Allergy and Clinical Immunology 4 (3): 159-63).

[0004] Animal hair and animal dander are the source of many allergens, which pose a risk for a severe allergic response in sensitized individuals. For example, the Fel dl protein is a secreted cat protein, which belongs to the secretoglobin family of small disulfide linked heterodimeric proteins found only in mammals (Klug, J. et al. (2000), Ann. N.Y. Acad. Sci. 923:348-354). It is the major cause of cat allergies in humans (Platts-Mills, T.A., et al. (1997), J. Allergy Clin.

Immunol. 100: S2-S24). About 90-95% of patients allergic to cats have an IgE response to the Fel d 1 protein (van Ree, et al. (1999), J. Allergy Clin. Immunol. 104: 1223-1230). The symptoms in a patient who experiences an allergic response to Fel dl can range from mild rhinitis and conjunctivitis to life-threatening asthmatic responses.

[0005] The treatment for allergies includes steroids for suppressing the immune activity and bronchial dilators for relieving asthma symptoms. Desensitization therapy is also used for severely allergic patients. Peptide vaccine combinations have been tested for desensitizing individuals to particular allergens, e.g. Fel dl (See US2010/0239599A1 and EP2380591A2).

[0006] Antibodies have also been proposed as a treatment for allergies, since they may be able to block the entry of allergenic molecules into the mucosal tissues, or may bind the allergen before it has the opportunity to bind to the IgE bound to the high affinity receptor on mast cells or basophils, thus preventing the release of histamine and other inflammatory mediators from these cells. U.S. patent number 5,670,626 describes the use of monoclonal antibodies for the treatment of IgE-mediated allergic diseases such as allergic rhinitis, allergic asthma, and allergic conjunctivitis by blocking the binding of allergens to the mucosal tissue. U.S. patent number 6,849,259 describes the use of allergen- specific antibodies to inhibit allergic inflammation in an in vivo mouse model of allergy. Milk-based and egg-based antibody systems have been described. For example, US20030003133A1 discloses using milk as a carrier for allergens for inducing oral tolerance to cat dander and other allergens. Compositions and methods for reducing an allergic response in an animal to an allergen in the environment through use of a molecule that inhibits the ability of the allergen to bind to mast cells was described in US2010/0143266. Other antibodies to, for example, the Fel dl allergen, were described by de Groot et. al. (de Groot et. al, (1988), J. Allergy Clin. Immunol. 82:778-786).

[0007] Allergen-specific immunotherapy (SIT) is a treatment option for patients with allergic rhinitis triggered by aeroallergens (such as pollen, animal dander, or dust) when pharmacological therapies, such as anti-histamines, are insufficient. SIT is also an investigational treatment for food allergies. SIT is an active immunization process whereby patients are administered increasing doses of the offending allergen, followed by a maintenance dose for up to several years. The goal of SIT is to induce immunological changes, through effects on humoral and cellular immunity, which result in symptom amelioration and sustained tolerance and desensitization.

[0008] While SIT can provide long-lasting protection from allergic disease, it carries a risk of adverse reactions, has variable efficacy between patients, and can take 3-5 years to induce tolerance (Durham, M.D., et al, (1999), The New England Journal of Medicine 341 (7): 468-75, Durham, M.D., et al, (2016), Journal of Allergy and Clinical Immunology 138 (4). Elsevier Inc.: 1-12, Reismann, R.E., et al, (1992), Journal of Allergy and Clinical Immunology 90 (3 Pt 1): 335-39).

[0009] As such, there is a need in the art for a more rapid and reliable approach to treating allergies. The studies described herein address that need.

BRIEF SUMMARY OF THE INVENTION

[0010] In its broadest aspect, the invention provides methods of treating a patient who demonstrates a sensitivity to, or an allergic reaction against an allergen, or for preventing or ameliorating at least one symptom or complication associated with the allergen by administering one or more antibodies or antigen binding fragments thereof specific for the allergen (passive immunotherapy). The results described herein show that antibodies specific for an allergen, when administered to a patient suffering from an allergy, can prevent an allergen- induced allergic response. As such, it is believed that a passive immunotherapy approach such as that described herein, can be used in place of standard immunotherapy (SIT), which generally takes years of desensitization to provide effective relief to the patient, whereas positive results can be achieved in a matter of weeks by administering allergen-specific antibodies or antigen binding fragments thereof. Positive results may be measured as amelioration of at least one symptom associated with the allergy, or by improvement in one or more clinical parameters as measured by one or more of the following patient reported outcome scores: The Total Nasal Symptom Score (TNSS), the Visual Analog Score (VAS), the Peak Nasal Inspiratory Flow score (PNIF) and the titrated Skin Prick Test (SPT).

[0011] While it is believed that the therapeutic approach described herein may be effective using one or more antibodies or antigen binding fragments thereof to any allergen, the proof-of-concept studies described herein were conducted using fully human monoclonal antibodies (mAbs) and antigen-binding fragments thereof that bind specifically to the cat allergen, Fel dl. Such antibodies may be useful to bind the Fel dl allergen in vivo following exposure of a sensitized patient to the cat allergen, and as such, may act to either promote clearance of Fel dl or to block the binding of the allergen to pre-formed IgE on the surface of mast cells or basophils. By doing so, the antibodies of the invention may prevent the release of histamine or other inflammatory mediators from mast cells or basophils, thereby preventing or diminishing the untoward effects observed in patients sensitized to the cat allergen. In certain embodiments, the antibodies may be capable of reducing, minimizing, or preventing at least one symptom in a patient sensitive to the Fel dl cat allergen, such as sneezing, congestion, nasal blockage, coughing, wheezing, bronchoconstriction, rhinitis, or conjunctivitis. In certain embodiments, the antibodies may be capable of preventing even more serious in vivo complications associated with exposure to the cat allergen in sensitized individuals, such as asthmatic responses, anaphylaxis, or even death.

[0012] The antibodies of the invention can be full-length (for example, an IgGl or IgG4 antibody) or may comprise only an antigen-binding portion (for example, a Fab, F(ab')2 or scFv fragment), and may be modified to affect functionality, e.g., to eliminate residual effector functions (Reddy et al, (2000), J. Immunol. 164: 1925-1933).

[0013] A first aspect of the invention provides methods for treating a patient suffering from an allergy, or for preventing or ameliorating at least one symptom associated with allergen exposure. In embodiments, a method comprises administering one or more isolated human monoclonal antibodies or antigen- binding fragments thereof that bind specifically to the allergen.

[0014] In other embodiments, a patient can be screened to select one or more therapeutic allergen specific antibodies or antigen binding fragments thereof using the methods as described herein. In one embodiment, a method for treating a patient who demonstrates a sensitivity to, or an allergic reaction against an allergen, or for preventing or ameliorating at least one symptom or complication associated with the allergen, comprises: (a) collecting a sample of tissue or an extract thereof, or a biological fluid, or a blood sample from the patient;

(b)extracting an allergen-specific IgE, or cells containing or bound to allergen- specific IgE, from one or more of the patient samples of (a); (c)mixing the IgE, or the cells containing or bound to IgE, from the patient sample with the allergen and with one or more antibodies or antigen binding fragments thereof specific for the allergen;( d)determining if the addition of one or more antibodies or antigen binding fragments thereof specific for the allergen blocks the binding of the allergen specific IgE from step (b) to the allergen, and if the results from step (d) demonstrate effective blocking of the binding of the allergen specific IgE to the allergen with the allergen specific antibodies of step (c), administering to the patient a pharmaceutical composition comprising a therapeutically effective amount of one or more of the allergen specific antibodies or antigen binding fragments from step (c).

[0015] In yet other embodiments, a patient is monitored before and after administration of the allergen specific antibodies or antigen binding fragments thereof to determine efficacy of the treatment. In embodiments, a method comprises administering one or more therapeutically effective doses of one or more allergen-specific antibodies or antigen binding fragments thereof to the patient and measuring the severity, duration, or frequency of occurrence of one or more symptoms associated with an allergic response in a patient. In embodiments, a measurement is conducted to determine a baseline prior to administration and then at various time points post administration in order to determine the efficacy of the therapy and whether additional dosing or a change in antibodies may be required to increase efficacy.

[0016] In any of the methods described herein, the tissue sample is any tissue sample, or extract thereof, biological fluid, or blood sample containing IgE bearing cells; or the blood sample is selected from the group consisting of whole blood, serum and plasma. In embodiments, cells are isolated from the tissue sample. In specific embodiments, the cells are peripheral blood mononuclear cells (PBMC).

[0017] In any of the methods described herein, the allergen may be selected from an animal product, a food allergen, plant pollen, mold spores, house dust mites, cockroaches, perfume, detergents, household cleaners, latex, a drug product, or insect venom.

[0018] The animal product may be selected from the group consisting of animal fur, animal dander, wool, and mite excretions.

[0019] The animal product may be selected from the group consisting of cat dander, cat hair or an extract thereof, or to the Fel dl protein.

[0020] In one embodiment, the allergen is the Fel dl protein.

[0021] In certain embodiments, the animal product may contain the allergen can fl, can f2, can f3, can f4, can £5 or can f6.

[0022] In one embodiment the food allergen may be selected from the group consisting of eggs, meat, fruit, legumes, milk or other dairy products, seafood, sesame, soy, wheat, oat, barley, celery and celeriac, corn or maize and tree nuts. The legumes may be selected from the group consisting of peanuts, beans, peas and soybeans. The tree nuts may be selected from the group consisting of pecans, almonds, cashews, hazelnuts (filberts), walnuts, brazil nuts, macadamia nuts, chestnuts, pine nuts and pistachio nuts.

[0023] In one embodiment, the allergen may be selected from the group consisting of grass pollen, weed pollen and tree pollen. The tree pollen may be selected from the group consisting of birch pollen, cedar pollen, oak pollen, alder pollen, hornbeam pollen, aesculus pollen, willow pollen, poplar pollen, plantanus pollen, tilia pollen, olea pollen, Ashe juniper pollen, and Alstonia scholaris pollen.

[0024] In one embodiment, the birch pollen contains the allergen Betv 1.

[0025] In one embodiment, the cedar pollen contains the allergen Cryj 1 or Cryj2.

[0026] In one embodiment, the grass pollen is ryegrass or timothy-grass.

[0027] In one embodiment, the weed pollen is selected from the group consisting of ragweed, plantago, nettle, Artemisia vulgaris, chenopodium album and sorrel.

[0028] In one embodiment, the insect venom is produced by bees, wasps or fire ants.

[0029] In certain embodiments, the methods further comprise administering an effective amount of a second therapeutic agent useful for diminishing an allergic reaction to an allergen, wherein the second therapeutic agent is selected from the group consisting of a bronchial dilator, an antihistamine, epinephrine, a decongestant, a corticosteroid, an IL-4R antagonist, an anti-IgE antibody, or one or more different antibodies to the allergen.

[0030] In one embodiment, when a patient is screened to select one or more allergen specific antibodies, the determining step is carried out by an in vitro method selected from the group consisting of an enzyme-linked immunosorbent assay (ELISA), a radioimmunoassay (RIA), an immunoradiometric assay (IRMA), a luminescence immunoassay (LIA), an immunoblot, FACS analysis, an IgE-facilitated allergen binding (FAB) assay, a basophil activation assay (e.g. a functional phosphoflow assay, or a basophil activation test), and an assay using an engineered cell line expressing FCsRl . In other embodiments, the determining step is carried out in vivo using an allergen-specific animal model such as a passive cutaneous anaphylaxis model (PCA). In embodiments, both an in vitro and in vivo assay can be utilized.

[0031] In certain embodiments, the method further comprises administering a palliative therapy useful for reducing the severity of the allergic reaction or for ameliorating at least one symptom associated with the allergic reaction.

[0032] In one embodiment, the treating results in a lessening in severity and/or duration of at least one symptom or complication associated with the allergic reaction against the allergen, wherein the one symptom or complication associated with the allergic reaction is selected from the group consisting of sneezing, rhinorrhea, nasal itching and nasal congestion.

[0033] In one embodiment, the treating results in a reduction in allergic rhinitis, allergic conjunctivitis, rhinoconjunctivitis, allergic asthma, asthma exacerbations, or an anaphylactic response following exposure of the patient to an allergen.

[0034] In any of the methods described herein, the method provides for administering one or more antibodies that bind specifically to the allergen, e.g. Fel dl protein.

[0035] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl has an isotype selected from the group consisting of an IgGl, an IgG2 and an IgG4.

[0036] In one embodiment, the isolated human antibody or antigen-binding fragment thereof binds specifically to Fel dl with a K _D equal to or less than 10 ^"6

M. In one embodiment, the isolated human antibody or antigen-binding fragment thereof binds specifically to Fel dl with a K _D equal to or less than 1.8 nM.

[0037] In some embodiments, the antibodies or antigen binding fragments thereof specifically bind monomeric Fel dl with a K _D equal to or less than 1 x 10 ^{" 8} , lx 10 ^"9 , or 1 xlO ^"10 . In some embodiments, the antibodies or antigen binding fragments thereof specifically bind dimeric Fel dl with a K _D equal to or less than 1 x 10 ^"8 , lx 10 ^"9 , 1 xlO ^"10 , or 1 xlO ^"11 . In embodiments, the antibodies or antigen binding fragments thereof specifically bind dimeric Fel dl with a T1/2 of at least 150 min, 160 min, 170 min, 180 min, 190 min,200 mia, 210 min, 220 min., 230 min, 240 min, or 250 min. In embodiments, the antibodies or antigen binding fragments thereof specifically bind monomeric Fel dl with a T1/2 of at least 25 min, 30 min, 35 min, 40 min, 45 min, or 50 min.

[0038] In other embodiments, the antibodies or antigen binding fragments thereof block binding of the allergen to allergen specific IgE. In embodiments, one or more antibodies or antigen binding fragments thereof that block Fel dl induced basophil activation are selected that have an IC5 ₀ of about 10 pM, 20 pM,

30pM, 40 pM 50 pM, ΙΟΟρΜ, 1 nM ,or less. In an ELISA assay, one or more antibodies or antigen binding fragments thereof that block Fel dl binding to polyclonal IgE are selected that have an IC5 ₀ of about 600 pM or less. One or more antibodies or antigen binding fragments thereof that block Fel dl binding to patient IgE are selected that have an IC50 of about 500 pM or less.

[0039] In any of the methods described herein, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Feld dl comprises the three heavy chain CDRs (HCDR1, HCDR2 and HCDR3) contained within any one of the heavy chain variable region (HCVR) sequences selected from the group consisting of SEQ ID NOs: 2, 18, 34, 50, 66, 82, 98, 114, 130, 146, 162,

178, 194, 210, 226, 242, 258, 274, 290, 306, 322, 338, 354, 370 and 460; and the three light chain CDRs (LCDR1, LCDR2 and LCDR3) contained within any one of the light chain variable region (LCVR) sequences selected from the group consisting of SEQ ID NOs: 10, 26, 42, 58, 74, 90, 106, 122, 138, 154, 170, 186,

202, 218, 234, 250, 266, 282, 298, 314, 330, 346, 362, 378 and 468. Methods and techniques for identifying CDRs within HCVR and LCVR amino acid sequences are well known in the art and can be used to identify CDRs within the specified

HCVR and/or LCVR amino acid sequences disclosed herein. Exemplary conventions that can be used to identify the boundaries of CDRs include, e.g., the Kabat definition, the Chothia definition, and the AbM definition. In general terms, the Kabat definition is based on sequence variability, the Chothia definition is based on the location of the structural loop regions, and the AbM definition is a compromise between the Kabat and Chothia approaches. See, e.g. , Kabat, "Sequences of Proteins of Immunological Interest," National Institutes of Health, Bethesda, Md. (1991); Al-Lazikani et al , (1997), J. Mol. Biol. 273:927-948; and Martin et al , (1989), Proc. Natl. Acad. Sci. USA 5(5:9268-9272. Public databases are also available for identifying CDR sequences within an antibody.

[0040] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises the three heavy chain CDRs (HCDR1, HCDR2 and HCDR3) contained within any one of the heavy chain variable region (HCVR) sequences selected from the group consisting of SEQ ID NOs: 18, 66, 130, 162, 242, 306, 322, 370 and 460; and the three light chain CDRs (LCDRl, LCDR2 and LCDR3) contained within any one of the light chain variable region (LCVR) sequences selected from the group consisting of SEQ ID NOs: 26, 74, 138, 170, 250, 314, 330, 378 and 468.

[0041] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises a HCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 2, 18, 34, 50, 66, 82, 98, 114, 130, 146, 162, 178, 194, 210, 226, 242, 258, 274, 290, 306, 322, 338, 354, 370 and 460.

[0042] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises a HCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 18, 66, 130, 162, 242, 306, 322, 370 and 460.

[0043] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises a LCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 10, 26, 42, 58, 74, 90, 106, 122, 138, 154, 170, 186, 202, 218, 234, 250, 266, 282, 298, 314, 330, 346, 362, 378 and 468.

[0044] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises a LCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 26, 74, 138, 170, 250, 314, 330, 378 and 468. [0045] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises: (a) a HCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 2, 18, 34, 50, 66, 82, 98, 114, 130, 146, 162, 178, 194, 210, 226, 242, 258, 274, 290, 306, 322, 338, 354, 370 and 460; and (b) a LCVR having an amino acid sequence selected from the group consisting of SEQ ID NO: 10, 26, 42, 58, 74, 90, 106, 122, 138, 154, 170, 186, 202, 218, 234, 250, 266, 282, 298, 314, 330, 346, 362, 378 and 468.

[0046] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises: (a) a HCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 18, 66, 130, 162, 242, 306, 322, 370 and 460; and (b) a LCVR having an amino acid sequence selected from the group consisting of SEQ ID NO: 26, 74, 138, 170, 250, 314, 330, 378 and 468.

[0047] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises:

(a) a HCDR1 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 4, 20, 36, 52, 68, 84, 100, 116, 132, 148, 164, 180, 196, 212, 228, 244, 260, 276, 292, 308, 324, 340, 356, 372 and 462;

(b) a HCDR2 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 6, 22, 38, 54, 70, 86, 102, 118, 134, 150, 166, 182, 198, 214, 230, 246, 262, 278, 294, 310, 326, 342, 358, 374 and 464;

(c) a HCDR3 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 8, 24, 40, 56, 72, 88, 104, 120, 136, 152, 168, 184, 200, 216, 232,248, 264, 280, 296, 312, 328, 344, 360, 376 and 466;

(d) a LCDR1 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 12, 28, 44, 60, 76, 92, 108, 124, 140, 156, 172, 188, 204, 220, 236, 252, 268, 284, 300, 316, 332, 348, 364, 380 and 470;

(e) a LCDR2 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 14, 30, 46, 62, 78, 94, 110, 126, 142, 158, 174, 190, 206, 222, 238, 254, 270, 286, 302, 318, 334, 350, 366, 382 and 472; and

(f) a LCDR3 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176,

192, 208, 224, 240, 256, 272, 288, 304, 320, 336, 352, 368, 384 and 474. [0048] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises:

(a) a HCDR1 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 20, 68, 132, 164, 244,308, 324, 372 and 462;

(b) a HCDR2 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 22, 70, 134, 166, 246, 310, 326, 374 and 464;

(c) a HCDR3 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 24, 72, 136, 168, 248, 312, 328, 376 and 466;

(d) a LCDR1 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 28, 76, 140, 172, 252, 316, 332, 380 and 470;

(e) a LCDR2 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 30, 78, 142, 174, 254, 318, 334, 382 and 472; and

(f) a LCDR3 domain having an amino acid sequence selected from the group consisting of SEQ ID NOs: 32, 80, 144, 176, 256, 320, 336, 384 and 474.

[0049] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises a HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 2/10, 18/26, 34/42, 50/58, 66/74, 82/90, 98/106, 114/122, 130/138, 146/154, 162/170, 178/186, 194/202, 210/218, 226/234, 242/250, 258/266, 274/282, 290/298, 306/314, 322/330, 338/346, 354/362, 370/378 and 460/468.

[0050] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises a HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 18/26, 66/74, 130/138, 162/170, 242/250, 306/314, 322/330, 370/378 and 460/468.

[0051] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises a HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 18/26, 66/74, 130/138 and 162/170.

[0052] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises the HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 18/26 and 322/330.

[0053] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises the HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 18/26 and 306/314.

[0054] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises the HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 18/26 and 370/378.

[0055] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises the HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 242/250 and 306/314.

[0056] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl comprises the HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 242/250 and 322/330.

[0057] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with at least one amino acid sequence selected from the group consisting of amino acid residues ranging from about position 15 to about position 24 of SEQ ID NO: 396; amino acid residues ranging from about position 85 to about position 103 of SEQ ID NO: 396; amino acid residues ranging from about position 85 to about position 104 of SEQ ID NO: 396; amino acid residues ranging from about position 113 to about position 116 of SEQ ID NO: 396; amino acid residues ranging from about position 113 to about position 127 of SEQ ID NO: 396; and amino acid residues ranging from about position 128 to 141 of SEQ ID NO: 396. In certain embodiments, the epitopes to which the anti-Fel Dl antibodies bind are identified using hydrogen deuterium exchange (HDX).

[0058] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with amino acid residues ranging from about position 15 to about position 24 of SEQ ID NO: 396. [0059] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with amino acid residues ranging from about position 85 to about position 103 of SEQ ID NO: 396.

[0060] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with amino acid residues ranging from about position 85 to about position 104 of SEQ ID NO: 396.

[0061] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with amino acid residues ranging from about position 113 to about position 116 of SEQ ID NO: 396.

[0062] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with at least one amino acid sequence selected from the group consisting of SEQ ID NO: 402, 403, 404, 406 and 412.

[0063] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with SEQ ID NO: 402.

[0064] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with SEQ ID NO: 403.

[0065] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with SEQ ID NO: 404.

[0066] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with SEQ ID NO: 406.

[0067] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with SEQ ID NO: 412.

[0068] In one embodiment, the isolated human antibody or antigen-binding fragment thereof that binds specifically to Fel dl interacts with SEQ ID NO: 426.

[0069] In one embodiment, the isolated human antibody or antigen binding fragment thereof that interacts with SEQ ID NOs: 402, 403, 404, 406 and/or 426, comprises the three HCDRs contained in the heavy chain variable region of SEQ ID NO: 18 and the three LCDRs contained in the light chain variable region of SEQ ID NO: 26. [0070] In one embodiment, the isolated human antibody or antigen binding fragment thereof that interacts with SEQ ID NOs: 402, 403, 404, 406 and/or 426, comprises a HCDR1 of SEQ ID NO: 20; a HCDR2 of SEQ ID NO: 22; a HCDR3 of SEQ ID NO: 24; a LCDR1 of SEQ ID NO: 28; a LCDR2 of SEQ ID NO: 30 and a LCDR3 of SEQ ID NO: 32.

[0071] In one embodiment, the isolated human antibody or antigen binding fragment thereof that interacts with SEQ ID NO: 412 comprises the three HCDRs contained in the heavy chain variable region of SEQ ID NO: 306 and the three LCDRs contained in the light chain variable region of SEQ ID NO: 314.

[0072] In one embodiment, the isolated human antibody or antigen binding fragment thereof that interacts with SEQ ID NO: 412 comprises a HCDR1 of SEQ ID NO: 308; a HCDR2 of SEQ ID NO: 310; a HCDR3 of SEQ ID NO: 312; a LCDRl of SEQ ID NO: 316; a LCDR2 of SEQ ID NO: 318 and a LCDR3 of SEQ ID NO: 320.

[0073] In one embodiment, the human antibody or antigen-binding fragment thereof that binds to chain 2 of Fel d 1 interacts with amino acid residue numbers ranging from about residue 12 through residue 54 of SEQ ID NO: 396.

[0074] In one embodiment, the human antibody or antigen-binding fragment thereof that binds to chain 2 of Fel d 1 interacts with amino acid residue numbers ranging from about residue 21 through residue 47 of SEQ ID NO: 396.

[0075] In one embodiment, the human antibody or antigen-binding fragment thereof that binds to chain 2 of Fel d 1 interacts with at least one or more of the following amino acid residues in SEQ ID NO: 396: the N at position 21, the E at position 22, the L at position 23, the L at position 24, the D at position 26, the L at position 27, the T at position 30, the K at position 31, the E at position 36, the R at position 39, the K at position 43, the D at position 47.

[0076] In one embodiment, the human antibody or antigen-binding fragment thereof that binds to chain 2 of Fel d 1 binds to an epitope that comprises a plurality of the following amino acid residues from SEQ ID NO: 396: N21, E22, L23, L24, D26, L27, T30, K31, E36, R39, K43, D47.

[0077] In one embodiment, the human antibody or antigen-binding fragment thereof that interacts with at least one or more of the following amino acid residues of SEQ ID NO: 396, including the N at position 21, the E at position 22, the L at position 23, the L at position 24, the D at position 26, the L at position 27, the T at position 30, the K at position 31, the E at position 36, the R at position 39, the K at position 43, the D at position 47, comprises the HCVR/LCVR amino acid sequence pair of SEQ ID NOs: 306/314.

[0078] In certain embodiments, the epitopes to which the anti-Fel Dl antibodies bind are identified using X-ray crystallographic analysis.

[0079] In one embodiment, the human antibody or antigen binding fragment thereof that binds specifically to Fel dl comprises the HCDR1, HCDR2 and HCDR3 amino acid sequences of SEQ ID NO: 20, 22 and 24, respectively and LCDR1, LCDR2 and LCDR3 amino acid sequences of SEQ ID NO: 28, 30 and 32, respectively.

[0080] In one embodiment, the human antibody or antigen binding fragment thereof that binds specifically to Fel dl comprises the HCDR1, HCDR2 and HCDR3 amino acid sequences of SEQ ID NO: 68, 70 and 72, respectively and LCDR1, LCDR2 and LCDR3 amino acid sequences of SEQ ID NO: 76, 78 and 80, respectively.

[0081] In one embodiment, the human antibody or antigen binding fragment thereof that binds specifically to Fel dl comprises the HCDR1, HCDR2 and HCDR3 amino acid sequences of SEQ ID NO: 132, 134 and 136, respectively and LCDR1, LCDR2 and LCDR3 amino acid sequences of SEQ ID NO: 140, 142 and 144, respectively.

[0082] In one embodiment, the human antibody or antigen binding fragment thereof that binds specifically to Fel dl comprises the HCDR1, HCDR2 and HCDR3 amino acid sequences of SEQ ID NO: 164, 166 and 168, respectively and LCDR1, LCDR2 and LCDR3 amino acid sequences of SEQ ID NO: 172, 174 and 176, respectively.

[0083] In one embodiment, the human antibody or antigen binding fragment thereof that binds specifically to Fel dl comprises the HCDR1, HCDR2 and HCDR3 amino acid sequences of SEQ ID NO: 244, 246 and 248, respectively and LCDR1, LCDR2 and LCDR3 amino acid sequences of SEQ ID NO: 252, 254 and 256, respectively.

[0084] In one embodiment, the human antibody or antigen binding fragment thereof that binds specifically to Fel dl comprises the HCDR1, HCDR2 and HCDR3 amino acid sequences of SEQ ID NO: 308, 310 and 312, respectively and LCDRl, LCDR2 and LCDR3 amino acid sequences of SEQ ID NO: 316, 318 and 320, respectively.

[0085] In one embodiment, the human antibody or antigen binding fragment thereof that binds specifically to Fel dl comprises the HCDR1, HCDR2 and HCDR3 amino acid sequences of SEQ ID NO: 324, 326 and 328, respectively and LCDRl, LCDR2 and LCDR3 amino acid sequences of SEQ ID NO: 332, 334 and 336, respectively.

[0086] In one embodiment, the human antibody or antigen binding fragment thereof that binds specifically to Fel dl comprises the HCDR1, HCDR2 and HCDR3 amino acid sequences of SEQ ID NO: 372, 374 and 376 respectively and LCDRl, LCDR2 and LCDR3 amino acid sequences of SEQ ID NO: 380, 382 and 384, respectively.

[0087] In one embodiment, the invention provides a fully human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, wherein the antibody or fragment thereof exhibits one or more of the following characteristics: (i) comprises a HCVR having an amino acid sequence selected from the group consisting of SEQ ID NO: 18, 66, 130, 162, 242, 306, 322, 370 and 460, or a substantially similar sequence thereof having at least 90%, at least

95%, at least 98% or at least 99% sequence identity; (ii) comprises a LCVR having an amino acid sequence selected from the group consisting of SEQ ID

NO: 26, 74, 138, 170, 250, 314, 330, 378 and 468, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; (iii) comprises a HCDR3 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 24, 72, 136, 168,

248, 312, 328, 376 and 466, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; and a

LCDR3 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 32, 80, 144, 176, 256, 320, 336, 384 and 474, or a substantially similar sequence thereof having at least 90%, at least 95%, at least

98% or at least 99% sequence identity; (iv) comprises a HCDR1 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 20,

68, 132, 164, 244, 308, 324, 372 and 462, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; a HCDR2 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 22, 70, 134, 166, 246, 310, 326, 374 and 464, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; a LCDR1 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 28, 76, 140, 172, 252, 316, 332, 380 and 470, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; and a LCDR2 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 30, 78, 142, 174, 254, 318, 334, 382 and 472, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; (v) binds to Fel dl with a K _D equal to or less than 10 ^"6 and preferably equal to or less than 10 ^"9 ; (vi) demonstrates efficacy in at least one animal model of anaphylaxis or inflammation; or (vii) competes with a reference antibody for binding to Fel dl .

[0088] In one embodiment, a "reference antibody" may include, for example, antibodies having a combination of heavy chain and light chain amino acid sequence pairs selected from the group consisting of 18/26, 66/74, 130/138,

162/170, 242/250, 306/314, 322/330, 370/378 and 460/468.

[0089] In one embodiment, the fully human monoclonal antibody or antigen binding fragment thereof that binds specifically to Fel dl comprises a HCDRl sequence comprising the formula X ¹ - X ² - X ³ - X ⁴ - X ⁵ - X ⁶ - X ⁷ - X ⁸ (SEQ ID

NO:386) wherein X ¹ is Gly, X ² is Phe, Tyr or Gly, X ³ is Thr or Ser, X ⁴ is Phe or

He, X ⁵ is Ser, Arg, Thr, or Asn, X ⁶ is Asn, Thr, Asp, or Ser, X ⁷ is Tyr, and X ^s is

Asn, Tyr, or Ala; a HCDR2 sequence comprising the formula X ¹ - X ² - X ³ - X ⁴ -

X ⁵ - X ⁶ - X ⁷ - X ⁸ (SEQ ID NO: 387), wherein X ¹ is He, X ² is Tyr, Ser, or Asn,

X ³ is Tyr, Ser, Gly, Pro, or Asp, X ⁴ is Asp, Arg, or Ser, X ⁵ is Gly, Val, or Ser, X ⁶ is Ser, Gly, Arg, or Tyr, X ⁷ is Tyr, Arg, Thr, Ser, or Asn, and X ^s is He, Thr, Ala,

Ser, or absent; a HCDR3 sequence comprising the formula X ¹ - X ² - X ³ - X ⁴ -

X ⁵ - X ⁶ - X ⁷ - X ⁸ - X ⁹ - X ¹⁰ - X ¹¹ - X ¹² - X ¹³ - X ¹⁴ - X ¹⁵ - X ¹⁶ (SEQ ID NO:

388), wherein X ¹ is Ala, X ² is Lys or Arg, X ³ is Arg, Gly, His, Ser, Asp, Leu, or

Thr, X ⁴ is Thr, Pro, Arg, Gly, or Glu, X ⁵ is Leu, Val, Gly, Lys, Tyr, or Asn, X ⁶ is

Ser, Arg, Thr, Ala, Tyr, Phe, or Trp, X ⁷ is Tyr, Gly, Arg, Ala, Asn, Asp, His, or

Asn, X ⁸ is Tyr, Thr, Ser, or His, X ⁹ is Val, Ser, Ala, Phe, Pro, or absent, X ¹⁰ is

Met, Gly, Asp, Pro, Val, or absent, X ¹¹ is Asp, Tyr, Ser, Gly, Phe, or absent, X ¹² is Val, Asp, Phe, or absent, X ¹³ is Phe, Asp, or absent, X ¹⁴ is Phe, Tyr, or absent, X is Asp or absent, X is Tyr or absent; a LCDR1 sequence comprising the formula X ¹ - X ² - X ³ - X ⁴ - X ⁵ - X ⁶ - X ⁷ - X ⁸ - X ⁹ - X ¹⁰ - X ¹¹ - X ¹² (SEQ ID NO: 389), wherein X ¹ is Gin, X ² is Gly, Ser, or Asp, X ³ is He or Val, X ⁴ is Ser, Leu, Asn, or Gly, X ⁵ is Asn, Tyr, Gly, or Ser, X ⁶ is Tyr, Ser, Phe, or Trp, X ⁷ is Ser or absent, X ^s is Asn or absent, X ⁹ is Asn or absent, X ¹⁰ is Lys or absent, X ¹¹ is Gin or absent, X ¹² is Tyr or absent; a LCDR2 sequence comprising the formula

X ^I - X ² - X ³ (SEQ ID NO: 390), wherein X ¹ is Ala, Trp, Asp, Tyr, Lys, Gly, or Ser, X ² is Ala or Thr, and X ³ is Ser; and a LCDR3 sequence comprising the formula X ¹ - X ² - X ³ - X ⁴ - X ⁵ - X ⁶ - X ⁷ - X ⁸ - X ⁹ (SEQ ID NO: 391), wherein X ¹ is Gin, Leu, or His, X ² is Lys, Gin, or His, X ³ is Tyr, Ser, or Leu, X ⁴ is Tyr, Asn, Gly, Asp, or Ser, X ⁵ is Ser, Asp, or Asn, X ⁶ is Leu, Ala, Tyr, Thr, or Phe, X ⁷ is Pro or Arg, X ^s is Leu, Phe, Tyr, or Thr and X ⁹ is Thr or absent.

[0090] In one embodiment, the invention features a human antibody or antigen- binding fragment specific for Fel dl, comprising a HCVR encoded by nucleotide sequence segments derived from VH, D _h and ½ germline sequences, and a LCVR encoded by nucleotide sequence segments derived from VK and JK germline sequences, with combinations as shown in Table 2.

[0091] The invention encompasses antibodies having a modified glycosylation pattern. In some applications, modification to remove undesirable glycosylation sites may be useful, or e.g., removal of a fucose moiety to increase antibody dependent cellular cytotoxicity (ADCC) function (see Shield et al. (2002) JBC 277:26733). In other applications, modification of galactosylation can be made in order to modify complement dependent cytotoxicity (CDC).

[0092] A second aspect provides an antibody or antigen binding fragment thereof that specifically binds to Fel dl for use in treating a patient suffering from a cat allergy, wherein the isolated antibody or antigen-binding fragment thereof competes for specific binding to Fel dl with an antibody or antigen-binding fragment comprising the complementarity determining regions (CDRs) of a heavy chain variable region (HCVR), wherein the HCVR has an amino acid sequence selected from the group consisting of SEQ ID NOs: 2, 18, 34, 50, 66, 82, 98, 114, 130, 146, 162, 178, 194, 210, 226, 242, 258, 274, 290, 306, 322, 338, 354, 370 and 460; and the CDRs of a light chain variable region (LCVR), wherein the LCVR has an amino acid sequence selected from the group consisting of SEQ ID NOs: 10, 26, 42, 58, 74, 90, 106, 122, 138, 154, 170, 186, 202, 218, 234, 250, 266, 282, 298, 314, 330, 346, 362, 378 and 468.

[0093] One embodiment provides an isolated antibody or antigen-binding fragment thereof that competes for specific binding to Fel dl with an antibody or antigen-binding fragment comprising the complementarity determining regions (CDRs) of a heavy chain variable region (HCVR), wherein the HCVR has an amino acid sequence selected from the group consisting of SEQ ID NOs: 18, 66, 130, 162, 242, 306, 322, 370 and 460; and the CDRs of a light chain variable region (LCVR), wherein the LCVR has an amino acid sequence selected from the group consisting of SEQ ID NOs: 26, 74, 138, 170, 250, 314, 330, 378 and 468.

[0094] In a related embodiment, the invention provides an isolated antibody or antigen-binding fragment thereof that competes for specific binding to Fel dl with an antibody or antigen-binding fragment comprising the heavy and light chain CDRs contained within heavy and light chain sequence pairs selected from the group consisting of SEQ ID NOs: 18/26, 66/74, 130/138, 162/170, 242/250, 306/314, 322/330, 370/378 and 460/468.

[0095] A third aspect provides for use of an isolated antibody or antigen- binding fragment thereof that binds the same epitope on Feld 1 as an antibody or antigen-binding fragment comprising the complementarity determining regions (CDRs) of a heavy chain variable region (HCVR), wherein the HCVR has an amino acid sequence selected from the group consisting of SEQ ID NOs: 2, 18, 34, 50, 66, 82, 98, 114, 130, 146, 162, 178, 194, 210, 226, 242, 258, 274, 290, 306, 322, 338, 354, 370 and 460; and the CDRs of a light chain variable region (LCVR), wherein the LCVR has an amino acid sequence selected from the group consisting of SEQ ID NOs: 10, 26, 42, 58, 74, 90, 106, 122, 138, 154, 170, 186, 202, 218, 234, 250, 266, 282, 298, 314, 330, 346, 362, 378 and 468.

[0096] One embodiment provides for use of an isolated antibody or antigen- binding fragment thereof that binds the same epitope on Fel dl as an antibody or antigen-binding fragment comprising the complementarity determining regions (CDRs) of a heavy chain variable region (HCVR), wherein the HCVR has an amino acid sequence selected from the group consisting of SEQ ID NOs: 18, 66, 130, 162, 242, 306, 322, 370 and 460; and the CDRs of a light chain variable region (LCVR), wherein the LCVR has an amino acid sequence selected from the group consisting of SEQ ID NOs: 10, 26, 42, 58, 74, 90, 106, 122, 138, 154, 170, 186, 202, 218, 234, 250, 266, 282, 298, 314, 330, 346, 362, 378 and 468.

[0097] In a related embodiment, the invention provides for use of an isolated antibody or antigen-binding fragment thereof that binds the same epitope on Fel dl as an antibody or antigen-binding fragment comprising the heavy and light chain CDRs contained within heavy and light chain sequence pairs selected from the group consisting of SEQ ID NOs: 18/26, 66/74, 130/138, 162/170, 242/250, 306/314, 322/330, 370/378 and 460/468.

[0098] In embodiments, a pharmaceutical composition comprises more than one antibody or antigen binding fragments that specifically bind the allergen. In certain embodiments, when more than one antibody or antigen binding fragment thereof is utilized, the antibodies do not compete with one another for binding to the allergen. In other embodiments, the antibodies or antigen binding fragments thereof specifically bind to different epitopes. In certain embodiments, one or more antibodies or antigen binding fragments thereof specifically bind to different epitopes on Fel dl . In embodiments, a pharmaceutical composition comprises one antibody or antigen binding fragment thereof that binds to an epitope comprising amino acids 15 to 54 of SEQ ID NO: 396, and a second antibody or antigen binding fragment thereof that binds to an epitope comprising amino acids 113 to 116 of SEQ ID NO:396.

[0099] A fourth aspect provides for a bi-specific antigen-binding molecule that specifically binds Fel dl, which comprises two antigen-binding domains (two arms) that comprise an HCVR amino acid sequence and a LCVR amino acid sequence from any two or more antibodies described herein.

[0100] In one embodiment, the bi-specific antigen-binding molecule comprises a first antigen-binding domain that comprises a HCVR amino acid sequence as set forth in SEQ ID NO: 370 and a LCVR amino acid sequence as set forth in SEQ ID NO: 378, and a second antigen-binding domain that comprises a HCVR amino acid sequence as set forth in SEQ ID NO: 18 and a LCVR amino acid sequence as set forth in SEQ ID NO: 378.

[0101] In one embodiment, the bi-specific antigen-binding molecule comprises a first antigen-binding domain that comprises three heavy chain complementarity determining regions (HCDR1, HCDR2 and HCDR3) consisting of the amino acid sequences as set forth in SEQ ID NOs: 372, 374 and 376, respectively, and three light chain complementarity determining regions (LCDR1, LCDR2 and LCDR3) consisting of the amino acid sequences as set forth in SEQ ID NOs: 380, 382 and 384, respectively; and wherein the second antigen-binding domain comprises three heavy chain complementarity determining regions (HCDR1, HCDR2 and HCDR3) consisting of the amino acid sequences as set forth in SEQ ID NOs: 20, 22 and 24, respectively, and three light chain complementarity determining regions (LCDR1, LCDR2 and LCDR3) consisting of the amino acid sequences as set forth in SEQ ID NOs: 380, 382 and 384, respectively.

[0102] In one embodiment, the bi-specific antigen-binding molecule comprises a first antigen-binding domain that comprises a HCVR amino acid sequence as set forth in SEQ ID NO: 306 and a LCVR amino acid sequence as set forth in SEQ ID NO: 314, and a second antigen-binding domain that comprises a HCVR amino acid sequence as set forth in SEQ ID NO: 18 and a LCVR amino acid sequence as set forth in SEQ ID NO: 314.

[0103] In one embodiment, the bi-specific antigen-binding molecule comprises three heavy chain complementarity determining regions (HCDR1, HCDR2 and HCDR3) consisting of the amino acid sequences as set forth in SEQ ID NOs: 308, 310 and 312, respectively, and three light chain complementarity determining regions (LCDR1, LCDR2 and LCDR3) consisting of the amino acid sequences as set forth in SEQ ID NOs: 316, 318 and 320, respectively; and wherein the second antigen-binding domain comprises three heavy chain complementarity determining regions (HCDR1, HCDR2 and HCDR3) consisting of the amino acid sequences as set forth in SEQ ID NOs: 20, 22 and 24, respectively, and three light chain complementarity determining regions (LCDR1, LCDR2 and LCDR3) consisting of the amino acid sequences as set forth in SEQ ID NOs: 316, 318 and 320, respectively.

[0104] In one embodiment, the invention provides for an isolated antibody specific for Fel dl, or an antigen-binding fragment thereof that competes for binding to Fel dl with any one of the bi-specific antigen-binding molecules of the invention.

[0105] In one embodiment, the invention provides for an isolated antibody specific for Fel dl, or an antigen-binding fragment thereof that binds to the same epitope on Fel dl as any of the bi-specific antigen-binding molecules of the invention. [0106] In one embodiment, the bi-specific antigen-binding molecule is an isolated human monoclonal antibody that binds specifically to Fel dl .

[0107] In one embodiment, the bi-specific antigen-binding molecule is an isolated human monoclonal antibody that binds specifically to Fel dl, wherein the human monoclonal antibody is a mono-specific antibody or a bi-specific antibody.

[0108] In one embodiment, the invention provides for a pharmaceutical composition comprising at least one bi-specific antigen-binding molecule as described herein and a pharmaceutically acceptable carrier or diluent.

[0109] In one embodiment, the invention provides for a method for treating a patient who demonstrates a sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair or an extract thereof, or to Fel dl protein, or for treating at least one symptom or complication associated with a sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair or an extract thereof, or to Fel dl protein, comprising administering an effective amount of one or more of the bi- specific antigen-binding molecules of the invention, or a pharmaceutical composition comprising an effective amount of one or more of the bi-specific antigen-binding molecules of the invention, to a patient in need thereof, wherein the patient demonstrates a reduced sensitivity to, or a diminished allergic reaction against a cat, cat dander, cat hair or an extract thereof, or to Fel dl protein, or does not experience any sensitivity to, or allergic reaction to a cat, cat dander, cat hair or an extract thereof, or to Fel dl protein, or wherein the patient demonstrates a reduction in at least one symptom or complication associated with a sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair or an extract thereof, or to Fel dl protein, or a reduction in the frequency and/or duration of at least one symptom or complication associated with a sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair or an extract thereof, or to Fel dl protein following administration of the bi-specific antigen-binding molecules or a composition comprising the bi-specific antigen-binding molecules of the invention.

[0110] In one embodiment, the invention provides for administering an effective amount of a second therapeutic agent along with at least one bi-specific antigen- binding molecule of the invention useful for diminishing an allergic reaction to a cat, cat dander, or to Fel dl protein. The second therapeutic agent may be selected from the group consisting of a corticosteroid, a bronchial dilator, an antihistamine, epinephrine, a decongestant, a corticosteroid, another different antibody to Fel dl and a peptide vaccine.

[0111] In one embodiment, the treatment with one or more bi-specific antigen- binding molecules of the invention alone, or in combination with a second therapeutic agent, may result in a reduction in allergic rhinitis, allergic conjunctivitis, allergic asthma, or an anaphylactic response following exposure of the patient to a cat, cat dander or to Fel dl protein.

[0112] In a fifth aspect, the invention provides nucleic acid molecules encoding Fel dl antibodies or fragments thereof. Recombinant expression vectors carrying the nucleic acids of the invention, and host cells into which such vectors have been introduced, are also encompassed by the invention, as are methods of producing the antibodies by culturing the host cells under conditions permitting production of the antibodies, and recovering the antibodies produced.

[0113] In one embodiment, the invention provides an antibody or fragment thereof comprising a HCVR encoded by a nucleic acid sequence selected from the group consisting of SEQ ID NO: 1, 17, 33, 49, 65, 81, 97, 113, 129, 145, 161, 177, 193, 209, 225, 241, 257, 273, 289, 305, 321, 337, 353, 369 and 459, or a substantially identical sequence having at least 90%, at least 95%, at least 98%, or at least 99% homology thereof.

[0114] In one embodiment, the HCVR is encoded by a nucleic acid sequence selected from the group consisting of SEQ ID NO: 17, 65, 129, 161, 241, 305, 321, 369 and 459.

[0115] In one embodiment, the antibody or fragment thereof further comprises a LCVR encoded by a nucleic acid sequence selected from the group consisting of SEQ ID NO: 9, 25, 41, 57, 73, 89, 105, 121, 137, 153, 169, 185, 201, 217, 233, 249, 265, 281, 297, 313, 329, 345, 361, 377 and 467 or a substantially identical sequence having at least 90%, at least 95%, at least 98%, or at least 99% homology thereof.

[0116] In one embodiment, the LCVR is encoded by a nucleic acid sequence selected from the group consisting of SEQ ID NO: 25, 73, 137, 169, 249, 313, 329, 377 and 467.

[0117] In one embodiment, the invention also provides an antibody or antigen- binding fragment of an antibody comprising a HCDR3 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO: 7, 23, 39, 55, 71, 87, 103, 119, 135, 151, 167, 183, 199, 215, 231, 247, 263, 279, 295, 311, 327, 343, 359, 375 and 465, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; and a LCDR3 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO: 15, 31, 47, 63, 79, 95, 111, 127, 143, 159, 175, 191, 207, 223, 239, 255, 271, 287, 303, 319, 335, 351, 367, 383 and 473, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

[0118] In one embodiment, the invention provides an antibody or fragment thereof further comprising a HCDR1 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO: 3, 19, 35, 51, 67, 83, 99, 115, 131, 147, 163, 179, 195, 211, 227, 243, 259, 275, 291, 307, 323, 339, 355, 371 and 461, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; a HCDR2 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO: 5, 21, 37, 53, 69, 85, 101, 117, 133, 149, 165, 181, 197, 213, 229, 245, 261, 277, 293, 309, 325, 341, 357, 373 and 463, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; a LCDR1 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO: 11, 27, 43, 59, 75, 91, 107, 123, 139, 155, 171, 187, 203, 219, 235, 251, 267, 283, 299, 315, 331, 347, 363, 379 and 469, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; and a LCDR2 domain encoded by a nucleotide sequence selected from the group consisting of SEQ ID NO: 13, 29, 45, 61, 77, 93, 109, 125, 141, 157, 173, 189, 205, 221, 237, 253, 269, 285, 301, 317, 333, 349, 365, 381 and 471, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

[0119] A sixth aspect provides a pharmaceutical composition comprising a therapeutically effective amount of one or more isolated human antibodies or antigen-binding fragments thereof that specifically bind Fel dl, together with one or more pharmaceutically acceptable excipients.

[0120] In one embodiment, the pharmaceutical composition comprises a therapeutically effective amount of two or more isolated human antibodies or antigen-binding fragments thereof that specifically bind Fel dl together with one or more pharmaceutically acceptable excipients.

[0121] In one embodiment, the pharmaceutical composition comprises:

a) an isolated first fully human monoclonal antibody, or antigen-binding fragment thereof that specifically binds Fel dl, which comprises a HCVR having an amino acid sequence as set forth is SEQ ID NO: 18; and a LCVR having an amino acid sequence as set forth is SEQ ID NO: 26; and

b) an isolated second fully human monoclonal antibody, or antigen-binding fragment thereof that specifically binds Fel dl, which comprises a HCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 66, 130, 162, 306, 322, 370 and 460; and a LCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 74, 138, 170, 314, 330, 378 and 468.

[0122] In one embodiment, the pharmaceutical composition comprises:

a) an isolated first fully human monoclonal antibody, or antigen-binding fragment thereof that specifically binds Fel dl, which comprises a HCVR having an amino acid sequence as set forth is SEQ ID NO: 242; and a LCVR having an amino acid sequence as set forth is SEQ ID NO: 250; and

b) an isolated second fully human monoclonal antibody, or antigen-binding fragment thereof that specifically binds Fel dl, which comprises a HCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 306, 322 and 460; and a LCVR having an amino acid sequence selected from the group consisting of SEQ ID NOs: 314, 330 and 468.

[0123] In one embodiment, the pharmaceutical composition comprises:

a) an isolated first fully human monoclonal antibody or antigen-binding fragment thereof that specifically binds Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 18/26; and

b) an isolated second fully human monoclonal antibody or antigen-binding fragment thereof that specifically binds Fel dl, comprising a HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 66/74, 130/138, 162/170, 306/314, 322/330 370/378 and 460/468.

[0124] In one embodiment, the pharmaceutical composition comprises: a) an isolated first human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 18/26; and

b) an isolated second human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 130/138.

[0125] In one embodiment, the pharmaceutical composition comprises:

a) an isolated first human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 18/26; and

b) an isolated second human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 322/330.

[0126] In one embodiment, the pharmaceutical composition comprises:

a) an isolated first human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 18/26; and

b) an isolated second human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 306/314.

[0127] In one embodiment, the pharmaceutical composition comprises:

a) an isolated first human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 18/26; and

b) an isolated second human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 370/378.

[0128] In one embodiment, the pharmaceutical composition comprises:

a) an isolated first fully human monoclonal antibody or antigen-binding fragment thereof that specifically binds Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 242/250; and

b) an isolated second fully human monoclonal antibody or antigen-binding fragment thereof that specifically binds Fel dl, comprising a HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 306/314 and 322/330.

[0129] In one embodiment, the pharmaceutical composition comprises

a) an isolated first human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 242/250; and

b) an isolated second human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 306/314.

[0130] In one embodiment, the pharmaceutical composition comprises

a) an isolated first human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 242/250; and

b) an isolated second human monoclonal antibody or antigen-binding fragment thereof that binds specifically to Fel dl, comprising a HCVR/LCVR amino acid sequence pair consisting of SEQ ID NOs: 322/330.

[0131] In one embodiment, the pharmaceutical composition comprises two or more isolated human monoclonal antibodies that bind specifically to Fel dl, or antigen-binding fragments thereof, comprising HCVR/LCVR amino acid sequence pairs selected from the group consisting of SEQ ID NOs: 18/26, 66/74, 130/138, 162/170, 242/250, 306/314, 322/330, 370/378 and 460/468.

[0132] In one embodiment, the pharmaceutical composition comprises four isolated human monoclonal antibodies that bind specifically to Fel dl, or antigen- binding fragments thereof, wherein the human antibodies or antigen-binding fragments thereof comprise the HCVR/LCVR amino acid sequence pairs of SEQ ID NOs: 18/26, 66/74, 130/138 and 162/170.

[0133] In one embodiment, the invention features a composition, which is a combination of a therapeutically effective amount of one or more anti-Fel dl antibodies or antigen-binding fragments thereof of the invention, and a therapeutically effective amount of a second therapeutic agent.

[0134] The second therapeutic agent may be a small molecule drug, a protein/polypeptide, an antibody, a nucleic acid molecule, such as an anti-sense molecule, or a siRNA. The second therapeutic agent may be synthetic or naturally derived. [0135] The second therapeutic agent may be any agent that is advantageously combined with an antibody or fragment thereof of the invention, for example, a second antibody other than those described herein that is capable of blocking the binding of Fel dl to IgE present on mast cells or basophils. A second therapeutic agent may also be any agent that is used as standard of care in treating an allergic response to any allergen. Such second therapeutic agent may be an antihistamine, epinephrine, a decongestant, a corticosteroid, or a peptide vaccine.

[0136] In certain embodiments, the second therapeutic agent may be an agent that helps to counteract or reduce any possible side effect(s) associated with the antibody or antigen-binding fragment of an antibody of the invention, if such side effect(s) should occur.

[0137] It will also be appreciated that the antibodies and pharmaceutically acceptable compositions of the present invention can be employed in combination therapies, that is, the antibodies and pharmaceutically acceptable compositions can be administered concurrently with, prior to, or subsequent to, one or more other desired therapeutics or medical procedures. The particular combination of therapies (therapeutics or procedures) to employ in a combination regimen will take into account compatibility of the desired therapeutics and/or procedures and the desired therapeutic effect to be achieved. It will also be appreciated that the therapies employed may achieve a desired effect for the same disorder (for example, an antibody may be administered concurrently with another agent used to treat the same disorder), or they may achieve different effects (e.g., control of any adverse effects). As used herein, additional therapeutic agents that are normally administered to treat or prevent a particular disease, or condition, are appropriate for the disease, or condition, being treated.

[0138] When multiple therapeutics are co-administered, dosages may be adjusted accordingly, as is recognized in the pertinent art.

[0139] A seventh aspect provides a method for treating a patient who demonstrates a sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein, or for preventing or ameliorating at least one symptom or complication associated with a sensitivity to, or allergic reaction against a cat, cat dander, cat hair extract, or to Fel dl protein, comprising administering an effective amount of one or more isolated human monoclonal antibodies or antigen-binding fragments thereof that bind specifically to Fel dl, or a pharmaceutical composition comprising an effective amount of one or more isolated human monoclonal antibodies or fragments thereof that binds specifically to Fel dl, or an effective amount of one or more of the bi-specific antigen-binding molecules that specifically binds Fel dl, or a pharmaceutical composition comprising an effective amount of one or more of the bi-specific antigen-binding molecules that specifically binds to Fel dl, to a patient in need thereof, wherein the sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein is either prevented, or lessened in severity and/or duration, or at least one symptom or complication associated with the sensitivity to, or allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein is prevented, or ameliorated, or that the frequency and/or duration of, or the severity of the sensitivity to or allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein is reduced following administration of one or more of the isolated human monoclonal antibodies or fragments thereof that bind specifically to Fel dl, or following administration of one or more of the bi-specific antigen-binding molecules that specifically binds Fel dl, or following administration of a composition comprising any one or more of the foregoing antibodies or bi-specific antigen-binding molecules.

[0140] In certain embodiments, the invention provides a method for reducing the severity, duration, or frequency of occurrence of one or more symptoms associated with an allergic response in a patient as measured by one or more patient reported outcome scores, the method comprises administering one or more therapeutically effective doses of one or more allergen specific monoclonal antibodies or antigen binding fragments thereof to the patient. In one embodiment, the one or more symptoms may be selected from the group consisting of nasal congestion, nasal itching, rhinorrhea and sneezing. In one embodiment, the patient reported outcome score is selected from the group consisting of a Total Nasal

Symptom Score (TNSS), a Visual Analog Scale (VAS) nasal symptoms score and an improvement in peak nasal inspiratory flow (PNIF). In one embodiment, the method is associated with a reduction in wheal diameter in an allergen skin test. In one embodiment, the allergen skin test is a titrated skin prick test (SPT), wherein there is a significant reduction in wheal diameter in a patient treated with the allergen-specific monoclonal antibodies compared to the wheal diameter observed prior to treatment of the patient with the allergen-specific monoclonal antibodies. [0141] In one embodiment, the one or more allergen-specific antibodies are administered subcutaneously, intravenously, or intranasally.

[0142] In one embodiment, the one or more allergen-specific antibodies are administered subcutaneously, each at a dose of about 10 mg to about 800 mg.

[0143] In one embodiment, the one or more allergen-specific antibodies are administered subcutaneously, each at a dose of about 600 mg.

[0144] In one embodiment, the one or more allergen-specific antibodies are administered subcutaneously, each at a dose of about 300 mg.

[0145] In one embodiment, the treatment results in at least a 20% reduction from baseline in at least one clinical parameter.

[0146] In one embodiment, the treatment results in at least a 50% reduction from baseline in at least one clinical parameter.

[0147] In one embodiment, the treatment results in an improvement in at least one patient reported outcome score by one to two weeks after administering one or more allergen-specific antibodies.

[0148] In one embodiment, the invention provides a pharmaceutical composition comprising one or more of the antibodies of the invention, or one or more of the bi-specific antigen-binding molecules that binds specifically to Fel dl for use in treating a patient who demonstrates a sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein, or for treating at least one symptom or complication associated with a sensitivity to, or allergic reaction against a cat, cat dander, cat hair extract, or to Fel dl protein, wherein the sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein is either prevented, or lessened in severity and/or duration, or at least one symptom or complication associated with the sensitivity to, or allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein is prevented, or ameliorated, or that the frequency and/or duration of, or the severity of the sensitivity to or allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein is reduced.

[0149] In one embodiment, the invention provides for use of a pharmaceutical composition comprising one or more of the antibodies of the invention, or one or more of the bi-specific antigen-binding molecules that binds specifically to Fel dl in the manufacture of a medicament for use in treating a patient who demonstrates a sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein, or for treating at least one symptom or complication associated with a sensitivity to, or allergic reaction against a cat, cat dander, cat hair extract, or to Fel dl protein, wherein the sensitivity to, or an allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein is either prevented, or lessened in severity and/or duration, or at least one symptom or complication associated with the sensitivity to, or allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein is prevented, or ameliorated, or that the frequency and/or duration of, or the severity of the sensitivity to or allergic reaction against, a cat, cat dander, cat hair extract, or to Fel dl protein is reduced.

[0150] In one embodiment, the invention provides use of a pharmaceutical composition as described above, wherein the composition is administered in combination with a second therapeutic agent useful for diminishing an allergic reaction to a cat, cat dander, cat hair extract, or to Fel dl protein. In one embodiment, the invention provides for use of the pharmaceutical composition as described above, wherein the second therapeutic agent is selected from a corticosteroid, a bronchial dilator, an antihistamine, epinephrine, a decongestant, another different antibody to Fel dl and a peptide vaccine.

[0151] In certain embodiments, the antibodies of the invention, or the bi- specific antigen-binding molecules that bind specifically to Fel dl may be capable of reducing, minimizing, or preventing at least one symptom in a patient sensitive to the Fel dl cat allergen, such as sneezing, congestion, nasal blockage, coughing, wheezing, bronchoconstriction, rhinitis, or conjunctivitis.

[0152] In one embodiment, the antibodies of the invention, or the bi-specific antigen-binding molecules that bind specifically to Fel dl, or a composition comprising one or more antibodies of the invention or one or more of the antigen- binding molecules that bind specifically to Fel dl may be used to prevent more serious in vivo complications associated with an allergy to Fel dl, including asthmatic responses, anaphylactic shock, or even death resulting from anaphylaxis.

[0153] In one embodiment, the pharmaceutical composition is administered to the patient in combination with a second therapeutic agent.

[0154] In another embodiment, the second therapeutic agent is selected from the group consisting of an antihistamine, epinephrine, a decongestant, a corticosteroid, another different antibody to Fel dl, a peptide vaccine and any other palliative therapy useful for reducing the severity of the allergic reaction or for ameliorating at least one symptom associated with the allergic reaction.

[0155] In another embodiment, a method for predicting whether a patient suffering from an allergy will respond to therapy with one or more allergen specific antibodies or antigen binding fragments thereof, or whether a patient suffering from an allergy would be a good candidate for therapy with one or more allergen specific antibodies, the method comprising:

(a) collecting a sample of tissue or an extract thereof, or a biological fluid, or a blood sample from the patient;

(b) extracting an allergen-specific IgE, or cells containing or bound to allergen-specific IgE, from one or more of the patient samples of (a);

(c) mixing the IgE, or the cells containing or bound to IgE, from the patient sample with the allergen and with one or more allergen specific antibodies or antigen binding fragments thereof; and

(d) determining if the addition of one or more allergen specific antibodies or antigen binding fragments thereof blocks the binding of the allergen specific IgE from step (b) to the allergen,

wherein the ability of the one or more allergen specific antibodies or antigen binding fragments thereof to block the binding of allergen specific IgE from step (b) to the allergen is indicative that the patient will respond to therapy with the one or more allergen specific antibodies, and/or that the patient suffering from an allergy would be a good candidate for therapy with the one or more allergen specific antibodies.

[0156] Other embodiments will become apparent from a review of the ensuing detailed description.

BRIEF DESCRIPTION OF THE FIGURES

[0157] Figure 1 shows Fel dl-specific IgG titers determined in Non-SIT and

Cat-SIT patient sera as measured by ELISA.

[0158] Figure 2 shows percent max inhibition of pErk response to 200nM nFel dl stimulation relative to control antibody as determined by flow cytometry analysis of gated basophils (CD123 ⁺ HLA-DR ^" ) from 10 cat allergic donors in the presence of REGN1908, REGN1909 or REGN1908-1909. [0159] Figure 3 shows (in the PCA model) data from Fel dl-challenged mice (n=10) expressed as ng of Evan's blue extracted per mg of ear tissue from ears sensitized with control antisera and ears sensitized with peanut antisera.

[0160] Figure 4 shows groups of mice (n=9-10) that were administered subcutaneous (SC) injections of REGN1908, REGN1909, a combination of

REGNl 908-1909 (1 : 1 ratio), or an IgG4 ^p control antibody at the indicated doses 3 days prior to initiating the PCA model. Polyclonal antiserum containing IgE generated either to Fel dl or to peanut allergen (non-relevant control, not shown) was passively administered intradermal (ID) into the ears prior to IV

administration of 0.25μg nFel dl. Data are presented as mean+/- s.e.m. Statistical significance is indicated by ****p<0.0001, ***p<0.001 or *p<0.05.

[0161] Figure 5 shows groups of mice (n=9-10) that were administered SC injections of REGN1908, REGNl 909, a combination of REGN1908-1909 (1 : 1 ratio), or an IgG4 ^p control antibody at the indicated doses 3 days prior to initiating the PCA model. Polyclonal antiserum containing IgE generated either to cat hair extract or to peanut allergen (non-relevant control, not shown) was passively administered intradermal (ID) into the ears prior to IV administration of 250 BAU cat hair extract. Data are presented as mean +/- s.e.m. Statistical significance is indicated by * *p<0.01 or *p<0.05.

[0162] Figure 6 shows groups of mice (n=9-10) that were administered SC injections of REGN1908, REGN1909, a combination of REGN1908-1909 (1 : 1 ratio), an IgG4 ^p control antibody, or concentrated Cat-SIT-IgG or Non-SIT-IgG prior to the PCA model using nFel dl . Data are expressed as ng of Evan's blue extracted per mg of ear and presented as mean +/- s.e.m. Antibody injected per mouse is noted in Table 24. Statistical significance is indicated by **p<0.01 or ^* p<0.05.

[0163] Figure 7 shows a schematic of the clinical study design.

[0164] Figure 8 shows a schematic of the Nasal Allergen Challenge procedure.

[0165] Figure 9 shows the percent change from baseline in TNSS AUC (0-lh); LS mean +/- s.e. for the full analysis set.

[0166] Figure 10 shows the percentage of subjects with >60% reduction in TNSS AUC (0-lh) at each study time point. Numbers on bars indicate number of patients represented out of total patient number LS Mean +/-s.e. for the full analysis set.

[0167] Figure 11 shows the percent change from baseline in PNIF AUC(O-lh); LS mean +/- s.e. for the full analysis set.

[0168] Figure 12 shows the percent change from baseline in normalized average wheal diameter AUC from the titrated (100-33, 000SQU) cat hair extract skin prick test, read 15 minutes after administration; LS mean +/- s.e. for the safety analysis set.

DETAILED DESCRIPTION

[0169] Before the present methods are described, it is to be understood that this invention is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0170] As used herein, the term "about," when used in reference to a particular recited numerical value, means that the value may vary from the recited value by no more than 1%. For example, as used herein, the expression "about 100" includes 99 and 101 and all values in between (e.g., 99.1, 99.2, 99.3, 99.4, etc.).

[0171] Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference in their entirety.

Definitions

[0172] The term "Fel dl " or "FELD1", as used herein, refers to at least one Fel dl protein, either in natural/native form, or recombinantly produced. The Fel dl protein comprises, or alternatively consists of, chain 1 (also referred to as chain

A) of Fel dl (SEQ ID NO: 392) and chain 2 (also referred to as chain B) of Fel dl

(SEQ ID NO: 393). The natural Fel dl protein is an approximately 18 kDa heterodimeric glycoprotein composed of two chains derived from two independent genes (See Duffort, O.A. et al, (1991), Mol. Immunol. 28:301-309; Kristensen, A.K. et al, (1997), Biol. Chem. 378:899-908; Kaiser L. et al. (2003), J. Biol. Chem. 278(39):37730-37735). A recombinantly produced Fel dl protein is also shown as SEQ ID NO: 396, wherein this sequence contains amino acid residues 18 through 109 of Fel dl chain B from GenBank accession number NP_001041619.1 (without the signal sequence) fused in line with amino acid residues 19-88 of chain A of Fel dl from GenBank accession number

NP_001041618.1 (without the signal sequence and with a D27G mutation, which corresponds to the glycine at position 101 of SEQ ID NO: 396). Other recombinantly produced Fel dl constructs of the invention are exemplified in SEQ ID NOs: 385, 394, 395 and 397

[0173] ."Chain 1", or "chain A" of Fel dl is a polypeptide comprising, or alternatively consisting of, an amino acid sequence of SEQ ID NO: 392, or a homologous sequence thereof. The term homologous sequence of SEQ ID NO:392, as used herein, refers to a polypeptide that has an identity to SEQ ID NO:392 which is greater than 70%, preferably greater than 80%, more preferably greater than 90%, and even more preferably greater than 95%. The amino acid sequence of chain 1 of Fel dl is also provided in GenBank as accession number P30438, or as accession number NP_001041618.1, which also include the signal peptide which is removed in the mature protein.

[0174] "Chain 2", or "chain B" of Fel dl is a polypeptide comprising, or alternatively consisting of, an amino acid sequence of SEQ ID NO: 393, or a homologous sequence thereof. The term homologous sequence of SEQ ID NO: 393, as used herein, refers to a polypeptide that has an identity to SEQ ID NO:393 which is greater than 70%, preferably greater than 80%, more preferably greater than 90%, and even more preferably greater than 95%. The amino acid sequence of chain 2 of Fel dl is also provided in GenBank as accession number P30440, or as accession number NP_001041619.1, which include the signal peptide which is removed in the mature protein.

[0175] The term "Fel dl fragment" as used herein, refers to a polypeptide comprising or alternatively consisting of, at least one antigenic site of Fel dl . In one embodiment, the term "Fel dl fragment" as used herein, refers to a polypeptide comprising or alternatively consisting of at least two antigenic sites of Fel dl . In one embodiment, the antigenic sites are covalently linked. In one embodiment, the antigenic sites are linked by at least one peptide bond. In one embodiment, the two antigenic sites are linked by at least one peptide bond and a spacer between the antigenic sites. In one embodiment, the at least two antigenic sites derive from both chain 1 of Fel dl and from chain 2 of Fel dl. In one embodiment, the at least two antigenic sites comprise amino acid sequences 23-92 of GenBank accession number P30438 and amino acid sequences 18-109 of GenBank accession number P30440. In one embodiment, the at least two antigenic sites derive from both chain 1 of Fel dl and from chain 2 of Fel dl. In one embodiment, the at least two antigenic sites comprise amino acid sequences 19-88 of GenBank accession number NP_001041618.1 and amino acid sequences 18-109 of GenBank accession number NP 001041619.1. In one embodiment, the at least two antigenic sites comprise an amino acid sequence within any of SEQ ID NOs: 385, 394, 395, 396 or 397. In one embodiment, any of the Fel dl fragments are capable of inducing the production of antibodies in vivo that specifically bind to naturally occurring Fel dl, or to recombinantly produced Fel dl .

[0176] The term "antibody", as used herein, means any antigen-binding molecule or molecular complex comprising at least one complementarity determining region (CDR) that specifically binds to or interacts with a particular antigen (e.g. , Fel dl). The term "antibody", as used herein, is intended to refer to immunoglobulin molecules comprised of four polypeptide chains, two heavy (H) chains and two light (L) chains inter-connected by disulfide bonds (i.e. , "full antibody molecules"), as well as multimers thereof (e.g. IgM) or antigen-binding fragments thereof. Each heavy chain is comprised of a heavy chain variable region ("HCVR" or "VH") and a heavy chain constant region (comprised of domains CHT, CH2 and CH3). Each light chain is comprised of a light chain variable region ("LCVR or "VL") and a light chain constant region (CL). The VH and VL regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDR), interspersed with regions that are more conserved, termed framework regions (FR). Each VH and VL is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy -terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. In certain embodiments of the invention, the FRs of the antibody (or antigen binding fragment thereof) may be identical to the human germline sequences, or may be naturally or artificially modified. An amino acid consensus sequence may be defined based on a side-by-side analysis of two or more CDRs.

[0177] Substitution of one or more CDR residues or omission of one or more CDRs is also possible. Antibodies have been described in the scientific literature in which one or two CDRs can be dispensed with for binding. Padlan et al. (1995 FASEB J. 9: 133-139) analyzed the contact regions between antibodies and their antigens, based on published crystal structures, and concluded that only about one fifth to one third of CDR residues actually contact the antigen. Padlan also found many antibodies in which one or two CDRs had no amino acids in contact with an antigen (see also, Vajdos et al. (2002), J Mol Biol 320:415-428).

[0178] CDR residues not contacting antigen can be identified based on previous studies (for example residues H60-H65 in CDRH2 are often not required), from regions of Kabat CDRs lying outside Chothia CDRs, by molecular modeling and/or empirically. If a CDR or residue(s) thereof is omitted, it is usually substituted with an amino acid occupying the corresponding position in another human antibody sequence or a consensus of such sequences. Positions for substitution within CDRs and amino acids to substitute can also be selected empirically. Empirical substitutions can be conservative or non-conservative substitutions.

[0179] The fully human monoclonal antibodies that specifically bind to Fel dl, as disclosed herein, may comprise one or more amino acid substitutions, insertions and/or deletions in the framework and/or CDR regions of the heavy and light chain variable domains as compared to the corresponding germline sequences. Such mutations can be readily ascertained by comparing the amino acid sequences disclosed herein to germline sequences available from, for example, public antibody sequence databases. The present invention includes antibodies, and antigen-binding fragments thereof, which are derived from any of the amino acid sequences disclosed herein, wherein one or more amino acids within one or more framework and/or CDR regions are mutated to the corresponding residue(s) of the germline sequence from which the antibody was derived, or to the corresponding residue(s) of another human germline sequence, or to a conservative amino acid substitution of the corresponding germline residue(s) (such sequence changes are referred to herein collectively as "germline mutations"). A person of ordinary skill in the art, starting with the heavy and light chain variable region sequences disclosed herein, can easily produce numerous antibodies and antigen-binding fragments which comprise one or more individual germline mutations or combinations thereof. In certain embodiments, all of the framework and/or CDR residues within the VR and/or VL domains are mutated back to the residues found in the original germline sequence from which the antibody was derived. In other embodiments, only certain residues are mutated back to the original germline sequence, e.g. , only the mutated residues found within the first 8 amino acids of FR1 or within the last 8 amino acids of FR4, or only the mutated residues found within CDRl, CDR2 or CDR3. In other embodiments, one or more of the framework and/or CDR residue(s) are mutated to the corresponding residue(s) of a different germline sequence (i.e. , a germline sequence that is different from the germline sequence from which the antibody was originally derived). Furthermore, the antibodies of the present invention may contain any combination of two or more germline mutations within the framework and/or CDR regions, e.g. , wherein certain individual residues are mutated to the corresponding residue of a particular germline sequence while certain other residues that differ from the original germline sequence are maintained or are mutated to the corresponding residue of a different germline sequence. Once obtained, antibodies and antigen-binding fragments that contain one or more germline mutations can be easily tested for one or more desired property such as, improved binding specificity, increased binding affinity, improved or enhanced antagonistic or agonistic biological properties (as the case may be), reduced immunogenicity, etc. Antibodies and antigen-binding fragments obtained in this general manner are encompassed within the present invention.

[0180] The present invention also includes fully human monoclonal antibodies comprising variants of any of the HCVR, LCVR, and/or CDR amino acid sequences disclosed herein having one or more conservative substitutions. For example, the present invention includes antibodies having HCVR, LCVR, and/or

CDR amino acid sequences with, e.g., 10 or fewer, 8 or fewer, 6 or fewer, 4 or fewer, etc. conservative amino acid substitutions relative to any of the HCVR,

LCVR, and/or CDR amino acid sequences disclosed herein.

[0181] The term "human antibody", as used herein, is intended to include antibodies having variable and constant regions derived from human germline immunoglobulin sequences. The human mAbs of the invention may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo), for example in the CDRs and in particular CDR3. However, the term "human antibody", as used herein, is not intended to include mAbs in which CDR sequences derived from the germline of another mammalian species (e.g., mouse), have been grafted onto human FR sequences.

[0182] As used herein, the expression "antigen-binding molecule" means a protein, polypeptide or molecular complex comprising or consisting of at least one complementarity determining region (CDR) that alone, or in combination with one or more additional CDRs and/or framework regions (FRs), specifically binds to a particular antigen. In certain embodiments, an antigen-binding molecule is an antibody or a fragment of an antibody, as those terms are defined elsewhere herein.

[0183] As used herein, the expression "bi-specific antigen-binding molecule" means a protein, polypeptide or molecular complex comprising at least a first antigen-binding domain and a second antigen-binding domain (i.e. two arms). Each antigen-binding domain within the bi-specific antigen-binding molecule comprises at least one CDR that alone, or in combination with one or more additional CDRs and/or FRs, specifically binds to a particular antigen. In the context of the present invention, the first antigen-binding domain specifically binds a first antigen on Fel dl and the second antigen-binding domain specifically binds a second, distinct antigen on Fel dl.

[0184] The term "specifically binds," or "binds specifically to", or the like, means that an antibody or antigen-binding fragment thereof forms a complex with an antigen that is relatively stable under physiologic conditions. Specific binding can be characterized by an equilibrium dissociation constant of at least about lxlO ^"6 M or less (e.g., a smaller K _D denotes a tighter binding). Methods for determining whether two molecules specifically bind are well known in the art and include, for example, equilibrium dialysis, surface plasmon resonance, and the like. As described herein, antibodies have been identified by surface plasmon resonance, e.g., BIACORE™, which bind specifically to Fel dl . Moreover, multi- specific antibodies that bind to Fel dl and one or more additional antigens or a bi- specific that binds to two different regions of Fel dl (for example, chain 1 and/or chain 2 of Fel dl) are nonetheless considered antibodies that "specifically bind", as used herein.

[0185] The term "high affinity" antibody refers to those mAbs having a binding affinity to Fel dl, expressed as K _D , of at least 10 ^"8 M; preferably 10 ^"9 M; more preferably 10 ^"10 M, even more preferably 10 ^"11 M, even more preferably 10 ^"12 M, as measured by surface plasmon resonance, e.g., BIACORE™ or solution-affinity ELISA.

[0186] By the term "slow off rate", "Koff ' or "kd" is meant an antibody that dissociates from Fel dl, with a rate constant of 1 x 10 ^"3 s ^"1 or less, preferably 1 x 10 ^"4 s ^"1 or less, as determined by surface plasmon resonance, e.g., BIACORE™.

[0187] The terms "antigen-binding portion" of an antibody, "antigen-binding fragment" of an antibody, and the like, as used herein, include any naturally occurring, enzymatically obtainable, synthetic, or genetically engineered polypeptide or glycoprotein that specifically binds an antigen to form a complex. The terms "antigen-binding portion" of an antibody, or "antibody fragment", as used herein, refers to one or more fragments of an antibody that retain the ability to bind to the allergen, e.g. Fel dl .

[0188] The specific embodiments, antibody or antibody fragments of the invention may be conjugated to a therapeutic moiety ("immunoconjugate"), such as a corticosteroid, a second anti-allergen antibody (e.g., Fel dl), or epinephrine, a vaccine, or any other therapeutic moiety useful for treating an allergic response to an allergen, e.g. Fel dl.

[0189] An "isolated antibody", as used herein, is intended to refer to an antibody that is substantially free of other antibodies (Abs) having different antigenic specificities (e.g., an isolated antibody that specifically binds e.g. Fel dl, or a fragment thereof, is substantially free of Abs that specifically bind antigens other than Fel dl).

[0190] A "blocking antibody" or a "neutralizing antibody", as used herein (or an "antibody that neutralizes Fel dl activity"), is intended to refer to an antibody, or an antigen binding portion thereof, whose binding to Fel dl results in inhibition of at least one biological activity of Fel dl . For example, an antibody of the invention may aid in preventing the primary allergic response to Fel dl .

Alternatively, an antibody of the invention may demonstrate the ability to prevent a secondary allergic response to Fel dl, or at least one symptom of an allergic response to Fel dl, including sneezing, coughing, an asthmatic condition, or an anaphylactic response caused by Fel dl. This inhibition of the biological activity of Fel dl can be assessed by measuring one or more indicators of Fel dl biological activity by one or more of several standard in vitro or in vivo assays (such as a passive cutaneous anaphylaxis assay, as described herein) or other in vivo assays known in the art (for example, other animal models to look at protection from challenge with Fel dl following administration of one or more of the antibodies described herein).

[0191] The term "surface plasmon resonance", as used herein, refers to an optical phenomenon that allows for the analysis of real-time biomolecular interactions by detection of alterations in protein concentrations within a biosensor matrix, for example using the BIACORE™ system (Pharmacia Biosensor AB, Uppsala, Sweden and Piscataway, N.J.).

[0192] The term "K _D ", as used herein, is intended to refer to the equilibrium dissociation constant of a particular antibody-antigen interaction.

[0193] The term "epitope" refers to an antigenic determinant that interacts with a specific antigen binding site in the variable region of an antibody molecule known as a paratope. A single antigen may have more than one epitope. Thus, different antibodies may bind to different areas on an antigen and may have different biological effects. The term "epitope" also refers to a site on an antigen to which B and/or T cells respond. It also refers to a region of an antigen that is bound by an antibody. Epitopes may be either linear or conformational. A linear epitope is one produced by adjacent amino acid residues in a polypeptide chain.

A conformational epitope is produced by spatially juxtaposed amino acids from different segments of the linear polypeptide chain. In certain embodiments, epitopes may include determinants that are chemically active surface groupings of molecules such as amino acids, sugar side chains, phosphoryl groups, or sulfonyl groups, and, in certain embodiments, may have specific three-dimensional structural characteristics, and/or specific charge characteristics. Epitopes may also be defined as structural or functional. Functional epitopes are generally a subset of the structural epitopes and have those residues that directly contribute to the affinity of the interaction. Epitopes formed from contiguous amino acids are typically retained on exposure to denaturing solvents, whereas epitopes formed by tertiary folding are typically lost on treatment with denaturing solvents. An epitope typically includes at least 3, and more usually, at least 5 or 8-10 amino acids in a unique spatial conformation.

[0194] The term "substantial identity" or "substantially identical," when referring to a nucleic acid or fragment thereof, indicates that, when optimally aligned with appropriate nucleotide insertions or deletions with another nucleic acid (or its complementary strand), there is nucleotide sequence identity in at least about 90%, and more preferably at least about 95%, 96%, 97%, 98% or 99% of the nucleotide bases, as measured by any well-known algorithm of sequence identity, such as FASTA, BLAST or GAP, as discussed below. A nucleic acid molecule having substantial identity to a reference nucleic acid molecule may, in certain instances, encode a polypeptide having the same or substantially similar amino acid sequence as the polypeptide encoded by the reference nucleic acid molecule.

[0195] As applied to polypeptides, the term "substantial similarity" or

"substantially similar" means that two peptide sequences, when optimally aligned, such as by the programs GAP or BESTFIT using default gap weights, share at least 90% sequence identity, even more preferably at least 95%, 98% or 99% sequence identity. Preferably, residue positions, which are not identical, differ by conservative amino acid substitutions. A "conservative amino acid substitution" is one in which an amino acid residue is substituted by another amino acid residue having a side chain (R group) with similar chemical properties (e.g., charge or hydrophobicity). In general, a conservative amino acid substitution will not substantially change the functional properties of a protein. In cases where two or more amino acid sequences differ from each other by conservative substitutions, the percent or degree of similarity may be adjusted upwards to correct for the conservative nature of the substitution. Means for making this adjustment are well known to those of skill in the art. See, e.g., Pearson (1994) Methods Mol.

Biol. 24: 307-331, which is herein incorporated by reference. Examples of groups of amino acids that have side chains with similar chemical properties include 1) aliphatic side chains: glycine, alanine, valine, leucine and isoleucine; 2) aliphatic- hydroxyl side chains: serine and threonine; 3) amide-containing side chains: asparagine and glutamine; 4) aromatic side chains: phenylalanine, tyrosine, and tryptophan; 5) basic side chains: lysine, arginine, and histidine; 6) acidic side chains: aspartate and glutamate, and 7) sulfur-containing side chains: cysteine and methionine. Preferred conservative amino acids substitution groups are: valine- leucine-isoleucine, phenylalanine-tyrosine, lysine-arginine, alanine-valine, glutamate-aspartate, and asparagine-glutamine. Alternatively, a conservative replacement is any change having a positive value in the PAM250 log-likelihood matrix disclosed in Gonnet et al. (1992) Science 256: 1443 45, herein

incorporated by reference. A "moderately conservative" replacement is any change having a nonnegative value in the PAM250 log-likelihood matrix.

[0196] Sequence similarity for polypeptides is typically measured using sequence analysis software. Protein analysis software matches similar sequences using measures of similarity assigned to various substitutions, deletions and other modifications, including conservative amino acid substitutions. For instance, GCG software contains programs such as GAP and BESTFIT which can be used with default parameters to determine sequence homology or sequence identity between closely related polypeptides, such as homologous polypeptides from different species of organisms or between a wild type protein and a mutein thereof. See, e.g., GCG Version 6.1. Polypeptide sequences also can be compared using FASTA with default or recommended parameters; a program in GCG Version 6.1. FASTA {e.g., FASTA2 and FASTA3) provides alignments and percent sequence identity of the regions of the best overlap between the query and search sequences (Pearson (2000) supra). Another preferred algorithm when comparing a sequence of the invention to a database containing a large number of sequences from different organisms is the computer program BLAST, especially BLASTP or TBLASTN, using default parameters. See, e.g., Altschul et al. (1990) J. Mol. Biol. 215: 403 410 and (1997) Nucleic Acids Res. 25:3389 402, each of which is herein incorporated by reference.

[0197] In specific embodiments, the antibody or antibody fragment for use in the method of the invention may be mono-specific, bi-specific, or multi-specific.

Multi-specific antibodies may be specific for different epitopes of one target polypeptide or may contain antigen-binding domains specific for epitopes of more than one target polypeptide. An exemplary bi-specific antibody format that can be used in the context of the present invention involves the use of a first

immunoglobulin (Ig) CH3 domain and a second Ig CH3 domain, wherein the first and second Ig CH3 domains differ from one another by at least one amino acid, and wherein at least one amino acid difference reduces binding of the bi-specific antibody to Protein A as compared to a bi-specific antibody lacking the amino acid difference. In one embodiment, the first Ig CH3 domain binds Protein A and the second Ig CH3 domain contains a mutation that reduces or abolishes Protein A binding such as an H95R modification (by IMGT exon numbering; H435R by EU numbering). The second CH3 may further comprise an Y96F modification (by IMGT; Y436F by EU). Further modifications that may be found within the second C _H 3 include: D16E, L18M, N44S, K52N, V57M, and V82I (by IMGT; D356E, L358M, N384S, K392N, V397M, and V422I by EU) in the case of IgGl mAbs; N44S, K52N, and V82I (IMGT; N384S, K392N, and V422I by EU) in the case of IgG2 mAbs; and Q15R, N44S, K52N, V57M, R69K, E79Q, and V82I (by IMGT; Q355R, N384S, K392N, V397M, R409K, E419Q, and V422I by EU) in the case of IgG4 mAbs. Variations on the bi-specific antibody format described above are contemplated within the scope of the present invention.

[0198] By the phrase "therapeutically effective amount" is meant an amount that produces the desired effect for which it is administered. The exact amount will depend on the purpose of the treatment, and will be ascertainable by one skilled in the art using known techniques (see, for example, Lloyd (1999) The Art, Science and Technology of Pharmaceutical Compounding).

[0199] The antibodies of the invention may be used to "desensitize" a cat- sensitive individual. The term to "desensitize" is defined herein as to decrease the allergic-reactivity of a cat-sensitive individual to exposure to cats, cat dander or products thereof, e.g. Fel dl (to a level less than that which the cat-sensitive individual would otherwise experience).

[0200] The "Total Nasal Symptom Score" (TNSS); with a possible score of 0- 12, is based on assessment of 4 symptoms graded on a 0 (none) to 3 (severe) scale for congestion, itching and rhinorrhea, and 0 (none) to 3 (5 or more sneezes) for sneezing. Each of the 4 symptoms is evaluated using the following scale of 0=None, l=Mild, 2=Moderate, or 3=Severe.

[0201] A "Visual Analog Scale" (VAS) is a quantitative measure largely validated in

many diseases. These scales have been extensively used to assess the severity of rhinitis as well as the efficacy of therapeutic intervention. A VAS ranging from 0 (no nasal symptoms) to 100 cm (maximal nasal symptoms) was used to assess the severity of combined nasal symptoms.

[0202] The "Peak Nasal Inspiratory Flow" (PNIF) is an objective method, which uses a nasal spirometer for measuring nasal airflow (measured as 1/min).

[0203] The "Titrated Skin Prick Test" (SPT) is a reliable method to diagnose IgE-mediated allergic disease in patients with rhinoconjunctivitis, asthma, urticaria, anaphylaxis, atopic eczema and suspected food and drug allergy. It provides evidence for sensitization and can help to confirm the diagnosis of a suspected type I allergy. SPT interpretation utilizes the presence and degree of cutaneous reactivity as a surrogate marker for sensitization within target organs, i.e., eyes, nose, lung, gut and skin. When relevant allergens are introduced into the skin, specific IgE bound to the surface receptors on mast cells are cross- linked, mast cells degranulate, and histamine and other mediators are released. This produces a wheal and flare response, which can be quantitated. SPT results correlate with those of nasal challenge which may also be used as a surrogate to test clinically relevant sensitization. (Bousquet J, et al, (1987), Clin Allergy, 17(6):529-536).

General Description

[0204] Allergen-specific immunotherapy (SIT) has been used for over one hundred years (Noon, L., (1911), Lancet, 1 : 1572-1573) as a means of inducing immunological changes in a patient suffering from an allergy, which result in symptom amelioration and sustained tolerance and desensitization. However, the use of allergen extracts in conventional SIT presents a double-edged sword for patients— beneficial for enabling long-term disease modification through cellular and humoral immune responses to the native allergen, but detrimental to the safety profile due to cross-linking of existing allergen-specific IgE and generation of de novo IgE (Valenta, R. et al, (2016), J Allergy & Clin Immunol, 137(2):

351-357). Allergen peptide vaccines attempt to recapitulate the cellular component of SIT to induce allergen tolerance, while avoiding IgE-mediated side effects (Larche, M., et al, (2011), Immunology 6 (10): 761-71). Another approach centers on the identification and administration of short allergen peptides that correspond to major T cell epitopes, but do not bind IgE or induce an IgE or IgG humoral response (Worm, M. et al, (2011), Journal of Allergy and Clinical Immunology 127 (1): 89-97; Patel, D., et al, (2013), J Allergy & Clin Immunol, 131(1): 103-107; Couroux, P., et al, (2015), J. Brit Soc for Allergy & Clin. Immunol, 45(5):974-981). However, in a recent clinical study, this approach failed to demonstrate significant benefit, prompting reexamination of the importance of blocking IgG in successful SIT. Also in clinical development are vaccines skewed towards generating high titers of anti-allergen IgG through immunizations with longer B-cell peptides, fusion proteins, or continuous overlapping peptides (COPS) comprising the whole allergen sequence (Valenta, R. et al, (2016), J Allergy & Clin Immunol, 137(2): 351-357; Spertini, F. et al, (2016), J. Allergy & Clin. Immunol, 138(1): 162-168). However, these methods may have a low probability of producing functional blocking IgG, as observed with SIT. The studies described herein address the use of passive immunotherapy with a combination of allergen-specific antibodies for treating patients suffering from a cat allergy. The cat protein, Fel dl, was used as the allergen in these studies. As described herein, the data demonstrate that allergen (Fel dl)-specific IgE-blocking IgG antibodies are efficacious in both pre-clinical in vitro and in vivo in animal models, as well as in the clinical setting. In fact, a single subcutaneous dose of the allergen-specific antibodies reduced clinical symptoms in response to nasal provocation, with a magnitude observed at day 8 comparable to years of SIT.

Fel dl Cat Allergen

[0205] The domestic cat is a source of many indoor allergens and the severity of the symptoms in individuals who demonstrate a sensitivity to cat allergens ranges from a relatively mild rhinitis and conjunctivitis to a potentially life- threatening asthmatic condition (Lau, S. et al. (2000), Lancet 356: 1392-1397). While patients who demonstrate such a sensitivity to cats appear to be responsive to different molecules found in cat dander and pelts, the major allergen appears to be Fel dl (Felis domesticus allergen 1). It has been shown that greater than 80% of patients who are allergic to cats have IgE antibodies to this allergen (van Ree, R. et al. (1999), J. Allergy Clin. Immunol 104: 1223-1230).

[0206] The Fel dl protein is an approximately 18 kDa heterodimeric acidic glycoprotein that contains about 10-20% of N-linked carbohydrates. Each heterodimer comprises two polypeptide chains that are encoded by two separate genes (Duffort, OA, et al, (1991), Mol. Immunol. 28:301-309; Morgenstern, JP, et al, (1991), PNAS 88:9690-9694; Griffith, I.J., et al. (1992), Gene 113:263- 268). Chain 1 comprises about 70 amino acid residues and chain 2 comprises about 90-92 amino acid residues. Three interchain disulfide bonds linking the two chains in natural Fel dl have been proposed (Kristensen, A.K. et al. (1997), Biol. Chem. 378:899-908) and confirmed for recombinant Fel dl in the crystal structure (Kaiser, L. et al. (2003), J. Biol. Chem. 278:37730-37735; Kaiser, L. et al, (2007), J. Mol. Biol. 370:714-727). Although each chain is sometimes individually referred to as "Fel d 1", both chains are needed for the full protein allergen.

[0207] Fel dl is produced by sebaceous glands, squamous glands and squamous epithelial cells and is transferred to the pelt by licking and grooming (Bartholome, K. et al. (1985), J. Allergy Clin. Immunol. 76:503-506; Charpin, C. et al. (1991), J. Allergy Clin. Immunol. 88:77-82; Dabrowski, A.J. (1990), et al. J. Allergy Clin. Immunol. 86:462-465). It is also present in the salivary, perianal and lachrymal glands (Andersen, M.C., et al. (1985), J. Allergy Clin. Immunol.

76:563-569; van Milligen, F.J. et al, (1992), Int. Arch. Allergy Appl. Immunol. 92:375-378) and the principal reservoirs appear to be the skin and the fur (Mata, P. et al. (1992), Ann. Allergy 69(4):321-322).

[0208] The Fel dl protein is of an unknown function to the animal but causes an IgG or IgE reaction in sensitive humans (either as an allergic or asthmatic response). Although other cat allergens are known, including Fel d2 (albumin) and Fel d3 (cystatin), 60% to 90% of the anti-cat IgE produced is directed against Fel dl (Leitermann, K. et al, (1984), J Allergy Clin. Immunol. 74: 147-153;

Lowenstein, H. et al, (1985), Allergy 40:430-441; van Ree, R. et al, (1999), J. Allergy Clin. Immunol. 104: 1223-1230; Ichikawa, K et al, (2011), Clin. Exp. Allergy, 31 : 1279-1286).

[0209] Immunoglobulin E (IgE) is responsible for type 1 hypersensitivity, which manifests itself in allergic rhinitis, allergic conjunctivitis, hay fever, allergic asthma, bee venom allergy, and food allergies. IgE circulates in the blood and binds to high-affinity Fc receptors for IgE on basophils and mast cells. In most allergic responses, the allergens enter the body through inhalation, ingestion, or through the skin. The allergen then binds to preformed IgE already bound to the high affinity receptor on the surfaces of mast cells and basophils, resulting in cross-linking of several IgE molecules and triggering the release of histamine and other inflammatory mediators causing the various allergic symptoms.

[0210] The treatment for cat allergies includes desensitization therapy, which involves repeated injections with increasing dosages of either a crude cat dander extract, or short peptides derived from Fel dl. Using the crude extract of cat dander, Lilja et. al. demonstrated that after three years of such treatment, patients allergic to cats still exhibited systemic symptoms (Lilja, Q. et al. (1989), J. Allergy Clin. Immunol. 83:37-44 and Hedlin, et al. (1991), J. Allergy Clin. Immunol. 87:955-964). Using short peptides derived from Fel dl for

desensitization resulted in a non-significant difference between the peptide group and the placebo control group (Oldfield, W.L. et al, (2002), Lancet, 360:47-53). Efficacy was only observed when large amounts (750 ug) of the short peptide were administered to patients (Norman, P S. et al. (1996), Am. J. Respir. Crit. Care Med. 154: 1623-1628). Furthermore, asthmatic reactions have been reported in patients given both crude extracts from cat dander, as well as in patients given short Fel dl peptide treatment. Accordingly, there is a need in the field of cat allergy treatment for alternative strategies for treating patients sensitive to cat allergens, in particular Fel dl .

[0211] Antibodies have been proposed as a general treatment strategy for allergies, since they may be able to block the entry of allergenic molecules into the mucosal tissues, or may bind the allergen before it has the opportunity to bind to the IgE bound to the high affinity receptor on mast cells or basophils, thus preventing the release of histamine and other inflammatory mediators from these cells. U.S. patent number 5,670,626 describes the use of monoclonal antibodies for the treatment of IgE-mediated allergic diseases such as allergic rhinitis, allergic asthma, and allergic conjunctivitis by blocking the binding of allergens to the mucosal tissue. U.S. patent number 6,849,259 describes the use of allergen- specific antibodies to inhibit allergic inflammation in an in vivo mouse model of allergy. Milk-based and egg-based antibody systems have been described. For example, US20030003133A1 discloses using milk as a carrier for allergens for inducing oral tolerance to cat dander and other allergens. Compositions and methods for reducing an allergic response in an animal to an allergen in the environment through use of a molecule that inhibits the ability of the allergen to bind to mast cells was described in US2010/0143266. Other antibodies to Fel dl were described by de Groot et. al (de Groot et. al, (1988), J. Allergy Clin. Immunol. 82:778-786).

[0212] The fully human antibodies described herein demonstrate specific binding to Fel dl and may be useful for treating patients suffering from cat allergies, in particular, in patients who demonstrate sensitivity to the Fel dl allergen. The use of such antibodies may be an effective means of treating patients suffering from allergies to cat dander, or they may be used to prevent a heightened response to Fel dl upon secondary exposure, or the accompanying symptoms associated with the allergy, or may be used to lessen the severity and/or the duration of the allergic response associated with a primary exposure to a cat harboring the Fel dl allergen or with the recurrence of the symptoms upon secondary exposure. They may be used alone or as adjunct therapy with other therapeutic moieties or modalities known in the art for treating such allergies, such as, but not limited to, treatment with corticosteroids or epinephrine. They may be used in conjunction with a second or third different antibody specific for Fel dl . They may be used with allergen-specific immunotherapy (SIT).

[0213] In certain embodiments, the antibodies of the invention are obtained from mice immunized with a primary immunogen, such as natural Fel dl, which may be purchased commercially (See, for example, Indoor Biotech, #NA-FDl-2), or may be produced recombinantly. In certain embodiments, the immunogen may be either chain 1 of Fel dl, or chain 2 of Fel dl, or may be a combination of both chain 1 and chain 2 administered sequentially, or concurrently. The full-length amino acid sequence of chain 1 (also referred to as FELD1 A) is shown as SEQ

ID NO: 392. Full-length amino acid sequences for chain 1 may also be found in

GenBank accession numbers P30438 and NP 001041618.1. The full-length amino acid sequence of chain 2 (also referred to as FELD1 B) is shown as SEQ

ID NO: 393. Full-length amino acid sequences for chain 2 may also be found in

GenBank accession numbers PP30440 and NP_001041619.1.

[0214] In certain embodiments, the recombinantly produced Fel dl immunogen may be made by direct fusion of the two chains of Fel dl, as described in Kaiser et. al, to produce a fusion product that has a similar refolding partem to that of natural Fel dl (Kaiser, L. et al, (2003), J. Biol. Chem. 278(39):37730-37735). In certain embodiments, the immunogen may be a fusion protein such as that shown in the constructs of SEQ ID NOs: 385, 394, 395, 396 or 397, followed by immunization with a secondary immunogen, or with an immunogenically active fragment of the natural or recombinantly produced Fel dl .

[0215] The immunogen may be a biologically active and/or immunogenic fragment of natural or recombinantly produced Fel dl, or DNA encoding the active fragment thereof. The fragment may be derived from either the N-terminal or C-terminal of either chain 1 or chain 2, or from the N terminal or the C terminal of both chain 1 and chain 2. Fragments may be obtained from any site within chain 1 or chain 2 to be used as an immunogen for preparing antibodies to Fel dl.

[0216] In certain embodiments, the immunogen may be a fusion protein comprising any one or more of the following: i) amino acid residues 18-109 of chain 2 of Fel dl (See GenBank accession number P30440 and also SEQ ID NO: 393) fused via the C terminus directly with the N terminus of amino acid residues 23-92 of chain 1 of Fel dl (See GenBank accession number P30438 and also SEQ ID NO: 392); ii) amino acid residues 23-92 of chain 1 of Fel dl (See GenBank accession number P30438 and also SEQ ID NO: 392) fused via the C terminus to the N terminus of amino acid residues 18-109 of chain 2 of Fel dl (See GenBank accession number P30440 and also SEQ ID NO: 393); iii) amino acid residues 18- 109 of chain 2 of Fel dl (See GenBank accession number NP_001041619.1) fused via the C terminus directly with the N terminus of amino acid residues 19- 88 of chain 1 of Fel dl (See GenBank accession number NP_001041618.1), such as the construct shown in SEQ ID NO: 394 or 396; iv) amino acid residues 19-88 of chain 1 of Fel dl (See GenBank accession number NP_001041618.1) fused via the C terminus to the N terminus of amino acid residues 18-109 of chain 2 of Fel dl (See GenBank accession number NP_001041619.1). See also SEQ ID NO: 395. In certain embodiments, the fusion protein may have a tag at the C terminal end of the construct, such as a myc-myc-hexahistidine tag (See SEQ ID NOs: 385, 396 or 397 for such constructs.). In related embodiments, the fusion protein may have a mouse antibody Fc region coupled at the C terminal end of the construct (See SEQ ID NOs: 394 or 395 for such constructs.). In certain embodiments, chains 1 and 2 are coupled via a linker known to those skilled in the art, e.g. (G ₄ S) ₃ (See SEQ ID NOs: 395 and 397 for such a construct.). [0217] In certain embodiments, antibodies that bind specifically to Fel dl may be prepared using fragments of the above-noted regions, or peptides that extend beyond the designated regions by about 5 to about 20 amino acid residues from either, or both, the N or C terminal ends of the regions described herein. In certain embodiments, any combination of the above-noted regions or fragments thereof may be used in the preparation Fel dl specific antibodies. In certain embodiments, any one or more of the above-noted regions of Fel dl, or fragments thereof may be used for preparing monospecific, bispecific, or multispecific antibodies.

Antigen-Binding Fragments of Antibodies

[0218] Unless specifically indicated otherwise, the term "antibody," as used herein, shall be understood to encompass antibody molecules comprising two immunoglobulin heavy chains and two immunoglobulin light chains (i.e., "full antibody molecules") as well as antigen-binding fragments thereof. The terms

"antigen-binding portion" of an antibody, "antigen-binding fragment" of an antibody, and the like, as used herein, include any naturally occurring, enzymatically obtainable, synthetic, or genetically engineered polypeptide or glycoprotein that specifically binds an antigen to form a complex. The terms

"antigen-binding portion" of an antibody, or "antibody fragment", as used herein, refers to one or more fragments of an antibody that retain the ability to specifically bind to either chain 1 and/or chain 2 of Fel dl . An antibody fragment may include a Fab fragment, a F(ab')2 fragment, a Fv fragment, a dAb fragment, a fragment containing a CDR, or an isolated CDR. Antigen-binding fragments of an antibody may be derived, e.g. , from full antibody molecules using any suitable standard techniques such as proteolytic digestion or recombinant genetic engineering techniques involving the manipulation and expression of DNA encoding antibody variable and (optionally) constant domains. Such DNA is known and/or is readily available from, e.g. , commercial sources, DNA libraries

(including, e.g., phage-antibody libraries), or can be synthesized. The DNA may be sequenced and manipulated chemically or by using molecular biology techniques, for example, to arrange one or more variable and/or constant domains into a suitable configuration, or to introduce codons, create cysteine residues, modify, add or delete amino acids, etc. [0219] Non-limiting examples of antigen-binding fragments include: (i) Fab fragments; (ii) F(ab')2 fragments; (iii) Fd fragments; (iv) Fv fragments; (v) single-chain Fv (scFv) molecules; (vi) dAb fragments; and (vii) minimal recognition units consisting of the amino acid residues that mimic the hypervariable region of an antibody (e.g. , an isolated complementarity determining region (CDR) such as a CDR3 peptide), or a constrained FR3- CDR3-FR4 peptide. Other engineered molecules, such as domain-specific antibodies, single domain antibodies, domain-deleted antibodies, chimeric antibodies, CDR-grafted antibodies, diabodies, triabodies, tetrabodies, minibodies, nanobodies (e.g. monovalent nanobodies, bivalent nanobodies, etc.), small modular immunopharmaceuticals (SMIPs), and shark variable IgNAR domains, are also encompassed within the expression "antigen-binding fragment," as used herein.

[0220] An antigen-binding fragment of an antibody will typically comprise at least one variable domain. The variable domain may be of any size or amino acid composition and will generally comprise at least one CDR, which is adjacent to or in frame with one or more framework sequences. In antigen-binding fragments having a VH domain associated with a VL domain, the VH and VL domains may be situated relative to one another in any suitable arrangement. For example, the variable region may be dimeric and contain VH - VH, VH - VL or VL - VL dimers. Alternatively, the antigen-binding fragment of an antibody may contain a monomeric VH or VL domain.

[0221] In certain embodiments, an antigen-binding fragment of an antibody may contain at least one variable domain covalently linked to at least one constant domain. Non-limiting, exemplary configurations of variable and constant domains that may be found within an antigen-binding fragment of an antibody of the present invention include: (i) VH -CHI ; (n) VH -CH2; (iii) VH -CH3; (iv) VH -

C _H 1-C _H 2; (V) V _H -C _h 1-C _h 2-C _h 3; (VI) V _H -C _h 2-C _h 3; (v ) V _H -C _L ; (vih) V _L -C _H 1;

(ix) V _L -C _h 2; (X) V _L -C _h 3; (XI) V _L -C _H 1-C _H 2; (x ) V _L -C _H 1-C _H 2-C _H 3; (xi ) V _L -

CH2-CH3; and (xiv) VL -CL. In any configuration of variable and constant domains, including any of the exemplary configurations listed above, the variable and constant domains may be either directly linked to one another or may be linked by a full or partial hinge or linker region. A hinge region may consist of at least 2 (e.g., 5, 10, 15, 20, 40, 60 or more) amino acids, which result in a flexible or semi-flexible linkage between adjacent variable and/or constant domains in a single polypeptide molecule. Moreover, an antigen-binding fragment of an antibody of the present invention may comprise a homo-dimer or hetero-dimer (or other multimer) of any of the variable and constant domain configurations listed above in non-covalent association with one another and/or with one or more monomeric V _H or VL domain (e.g. , by disulfide bond(s)).

[0222] As with full antibody molecules, antigen-binding fragments may be mono-specific or multi-specific (e.g. , bi-specific). A multi-specific antigen- binding fragment of an antibody will typically comprise at least two different variable domains, wherein each variable domain is capable of specifically binding to a separate antigen or to a different epitope on the same antigen. Any multi- specific antibody format, including the exemplary bi-specific antibody formats disclosed herein, may be adapted for use in the context of an antigen-binding fragment of an antibody of the present invention using routine techniques available in the art.

Preparation of Human Antibodies

[0223] Methods for generating human antibodies in transgenic mice are known in the art. Any such known methods can be used in the context of the present invention to make human antibodies that specifically bind to Fel dl .

[0224] Using VELOCIMMUNE™ technology (see, for example, US

6,596,541, Regeneron Pharmaceuticals, VELOCIMMUNE®) or any other known method for generating monoclonal antibodies, high affinity chimeric antibodies to

Fel dl are initially isolated having a human variable region and a mouse constant region. The VELOCIMMUNE® technology involves generation of a transgenic mouse having a genome comprising human heavy and light chain variable regions operably linked to endogenous mouse constant region loci such that the mouse produces an antibody comprising a human variable region and a mouse constant region in response to antigenic stimulation. The DNA encoding the variable regions of the heavy and light chains of the antibody are isolated and operably linked to DNA encoding the human heavy and light chain constant regions. The

DNA is then expressed in a cell capable of expressing the fully human antibody.

[0225] Generally, a VELOCIMMUNE® mouse is challenged with the antigen of interest, and lymphatic cells (such as B-cells) are recovered from the mice that express antibodies. The lymphatic cells may be fused with a myeloma cell line to prepare immortal hybridoma cell lines, and such hybridoma cell lines are screened and selected to identify hybridoma cell lines that produce antibodies specific to the antigen of interest. DNA encoding the variable regions of the heavy chain and light chain may be isolated and linked to desirable isotypic constant regions of the heavy chain and light chain. Such an antibody protein may be produced in a cell, such as a CHO cell. Alternatively, DNA encoding the antigen-specific chimeric antibodies or the variable domains of the light and heavy chains may be isolated directly from antigen-specific lymphocytes.

[0226] Initially, high affinity chimeric antibodies are isolated having a human variable region and a mouse constant region. As in the experimental section below, the antibodies are characterized and selected for desirable characteristics, including affinity, selectivity, epitope, etc. The mouse constant regions are replaced with a desired human constant region to generate the fully human antibody of the invention, for example wild-type or modified IgGl or IgG4. While the constant region selected may vary according to specific use, high affinity antigen-binding and target specificity characteristics reside in the variable region.

[0227] In general, the antibodies of the instant invention possess very high affinities, typically possessing K _D of from about 10 ^"12 through about 10 ^"9 M, when measured by binding to antigen either immobilized on solid phase or in solution phase. The mouse constant regions are replaced with desired human constant regions to generate the fully human antibodies of the invention. While the constant region selected may vary according to specific use, high affinity antigen- binding and target specificity characteristics reside in the variable region. In some embodiments, the antibodies or antigen binding fragments thereof specifically bind monomeric Fel dl with a ¾ equal to or less than 1 x 10 ^"8 , lx 10 ^"9 , or 1 xlO ^{" 10} . In some embodiments, the antibodies or antigen binding fragments thereof specifically bind dimeric Fel dl with a K _D equal to or less than 1 x 10 ^"8 , 1 x 10 ^"9 , 1 xlO ^"10 , or 1 xlO ^"n .In embodiments, the antibodies or antigen binding fragments thereof specifically bind dimeric Fel dl with a Ti _/2 of at least 150 min, 160 min, 170 min, 180 min, 190 min,200 min., 210 min, 220 min., 230 min, 240 min, or 250 min. In embodiments, the antibodies or antigen binding fragments thereof specifically bind monomeric Fel dl with a Ti _/2 of at least 25 min, 30 min, 35 min, 40 min, 45 min, or 50 min. Bioequivalents

[0228] The anti-Fel dl antibodies and antibody fragments of the present invention encompass proteins having amino acid sequences that vary from those of the described antibodies, but that retain the ability to bind Fel dl . Such variant antibodies and antibody fragments comprise one or more additions, deletions, or substitutions of amino acids when compared to parent sequence, but exhibit biological activity that is essentially equivalent to that of the described antibodies.

Likewise, the antibody-encoding DNA sequences of the present invention encompass sequences that comprise one or more additions, deletions, or substitutions of nucleotides when compared to the disclosed sequence, but that encode an antibody or antibody fragment that is essentially bioequivalent to an antibody or antibody fragment of the invention.

[0229] Two antigen-binding proteins, or antibodies, are considered

bioequivalent if, for example, they are pharmaceutical equivalents or

pharmaceutical alternatives whose rate and extent of absorption do not show a significant difference when administered at the same molar dose under similar experimental conditions, either single does or multiple dose. Some antibodies will be considered equivalents or pharmaceutical alternatives if they are equivalent in the extent of their absorption but not in their rate of absorption and yet may be considered bioequivalent because such differences in the rate of absorption are intentional and are reflected in the labeling, are not essential to the attainment of effective body drug concentrations on, e.g., chronic use, and are considered medically insignificant for the particular drug product studied.

[0230] In one embodiment, two antigen-binding proteins are bioequivalent if there are no clinically meaningful differences in their safety, purity, and potency.

[0231] In one embodiment, two antigen-binding proteins are bioequivalent if a patient can be switched one or more times between the reference product and the biological product without an expected increase in the risk of adverse effects, including a clinically significant change in immunogenicity, or diminished effectiveness, as compared to continued therapy without such switching.

[0232] In one embodiment, two antigen-binding proteins are bioequivalent if they both act by a common mechanism or mechanisms of action for the condition or conditions of use, to the extent that such mechanisms are known.

[0233] Bioequivalence may be demonstrated by in vivo and/or in vitro methods. Bioequivalence measures include, e.g., (a) an in vivo test in humans or other mammals, in which the concentration of the antibody or its metabolites is measured in blood, plasma, serum, or other biological fluid as a function of time; (b) an in vitro test that has been correlated with and is reasonably predictive of human in vivo bioavailability data; (c) an in vivo test in humans or other mammals in which the appropriate acute pharmacological effect of the antibody (or its target) is measured as a function of time; and (d) in a well-controlled clinical trial that establishes safety, efficacy, or bioavailability or bioequivalence of an antibody.

[0234] Bioequivalent variants of the antibodies of the invention may be constructed by, for example, making various substitutions of residues or sequences or deleting terminal or internal residues or sequences not needed for biological activity. For example, cysteine residues not essential for biological activity can be deleted or replaced with other amino acids to prevent formation of unnecessary or incorrect intramolecular disulfide bridges upon renaturation. In other contexts, bioequivalent antibodies may include antibody variants comprising amino acid changes, which modify the glycosylation characteristics of the antibodies, e.g. , mutations that eliminate or remove glycosylation.

Biological Characteristics of the Antibodies

[0235] In general, the antibodies of the present invention may function by binding to/interacting with either chain 1 or to chain 2 of Fel dl, or to both chain

1 and chain 2 of Fel dl or to a fragment of either chain 1 or chain 2.

[0236] In certain embodiments, the antibodies of the present invention may bind to an epitope located in at least the C-terminal region of either chain 1 or chain 2 of Fel dl. In one embodiment, the antibodies may bind to an epitope within the N-terminal region of either chain 1 or chain 2 of Fel dl .

[0237] In certain embodiments, the antibodies of the present invention may function by blocking or inhibiting the binding of IgE to mast cells or basophils in a patient sensitive to the Fel dl allergen.

[0238] In certain embodiments, the antibodies of the present invention may function by binding to any other region or fragment of the full length chain 1 or chain 2 of the natural Fel dl protein, the amino acid sequence of which is shown in SEQ ID NO: 392 (chain 1) and SEQ ID NO: 393 (chain 2).

[0239] In certain embodiments, the antibodies of the present invention may be bi-specific antibodies. The bi-specific antibodies of the invention may bind one epitope in chain 1 and may also bind one epitope in chain 2. In certain embodiments, the bi-specific antibodies of the invention may bind two different epitopes in chain 1. In certain embodiments, the bi-specific antibodies of the invention may bind two different epitopes in chain 2. In certain embodiments, the bi-specific antibodies of the invention may bind to two different sites within the same helix on either one of chain 1 or chain 2, or may bind to the same helix on both chain 1 and chain 2. The structure of Fel dl is described in greater detail in

Kaiser et. al. (Kaiser, L. et. al. (2003), J. Biol. Chem. 278 (39):37730-37735), whereby the authors note that Fel dl consists of eight helices, H1-H4 and H5-H8, which correspond to chains 2 and 1, respectively, in natural Fel dl.

[0240] In one embodiment, the invention provides a fully human monoclonal antibody or antigen-binding fragment thereof or combination of antibodies that binds to chain 1 and/or chain 2 of Fel dl, wherein each antibody or fragment thereof exhibits one or more of the following characteristics: (i) comprises a

HCVR having an amino acid sequence selected from the group consisting of SEQ

ID NO: 2, 18, 34, 50, 66, 82, 98, 114, 130, 146, 162, 178, 194, 210, 226, 242,

258, 274, 290, 306, 322, 338, 354 and 370, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; (ii) comprises a LCVR having an amino acid sequence selected from the group consisting of SEQ ID NO: 10, 26, 42, 58, 74, 90, 106, 122, 138, 154, 170,

186, 202, 218, 234, 250, 266, 282, 298, 314, 330, 346, 362 and 378, or a substantially similar sequence thereof having at least 90%, at least 95%, at least

98% or at least 99% sequence identity; (iii) comprises a HCDR3 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 8, 24,

40, 56, 72, 88, 104, 120, 136, 152, 168, 184, 200, 216, 232,248, 264, 280, 296,

312, 328, 344, 360 and 376, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; and a

LCDR3 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192,

208, 224, 240, 256, 272, 288, 304, 320, 336, 352, 368 and 384, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; (iv) comprises a HCDR1 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 4, 20, 36, 52, 68, 84, 100, 116, 132, 148, 164, 180, 196, 212, 228, 244, 260, 276, 292, 308, 324, 340, 356 and 372, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; a HCDR2 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 6, 22, 38, 54, 70, 86, 102, 118, 134, 150, 166, 182, 198, 214, 230, 246, 262, 278, 294, 310, 326, 342, 358 and 374, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; a LCDR1 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 12, 28, 44, 60, 76, 92, 108, 124, 140, 156, 172, 188, 204, 220, 236, 252, 268, 284, 300, 316, 332, 348, 364 and 380, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; and a LCDR2 domain having an amino acid sequence selected from the group consisting of SEQ ID NO: 14, 30, 46, 62, 78, 94, 110, 126, 142, 158, 174, 190, 206, 222, 238, 254, 270, 286, 302, 318, 334, 350, 366 and 382, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity; (v) binds to chain 1 and/or chain 2 of Fel dl with a K _D equal to or less than 10 ^"9 ; (vi) does not cross-react with, or bind to, uteroglobin; or (vii) blocks dye extravasation in vivo in a passive cutaneous anaphylaxis (PCA) mouse model using Fel dl specific mouse IgE.

[0241] Non-limiting, exemplary in vitro assays for measuring binding activity are illustrated in Examples 4, herein. In Examples 4, the binding affinities and kinetic constants of human anti-Fel dl antibodies were determined by surface plasmon resonance and the measurements were conducted on a T200 Biacore instrument. Certain Fel dl antibodies of the present invention, when used alone, or in combination, are able to bind to and neutralize at least one biological effect of Fel dl, as determined by in vitro or in vivo assays. The ability of the antibodies of the invention to bind to and neutralize the activity of Fel dl may be measured using any standard method known to those skilled in the art, including binding assays, or neutralization of activity (e.g., protection from anaphylaxis) assays, as described herein. [0242] In embodiments, one or more antibodies or antigen binding fragments thereof that inhibit Fel dl induced basophil activation are selected that have an IC ₅₀ of about 10 pM, 20 pM, 30pM, 40 pM 50 pM, ΙΟΟρΜ, 1 nM , or less. In an ELISA assay, one or more antibodies or antigen binding fragments thereof that inhibit Fel dl binding to polyclonal IgE are selected that have an IC5 ₀ of about 600 pM or less. One or more antibodies or antigen binding fragments thereof that inhibit Fel dl binding to patient IgE are selected that have an IC5 ₀ of about 500 pM or less.

[0243] The Fel dl proteins or peptides may be modified to include addition or substitution of certain residues for tagging or for purposes of conjugation to carrier molecules, such as, KLH. For example, a cysteine may be added at either the N terminal or C terminal end of a peptide, or a linker sequence may be added to prepare the peptide for conjugation to, for example, KLH for immunization. The antibodies specific for Fel dl may contain no additional labels or moieties, or they may contain an N-terminal or C-terminal label or moiety. In one

embodiment, the label or moiety is biotin. In a binding assay, the location of a label (if any) may determine the orientation of the peptide relative to the surface upon which the peptide is bound. For example, if a surface is coated with avidin, a peptide containing an N-terminal biotin will be oriented such that the C-terminal portion of the peptide will be distal to the surface.

Epitope Mapping and Related Technologies

[0244] The term "epitope," as used herein, refers to an antigenic determinant that interacts with a specific antigen-binding site in the variable region of an antibody molecule known as a paratope. A single antigen may have more than one epitope. Thus, different antibodies may bind to different areas on an antigen and may have different biological effects. Epitopes may be either conformational or linear. A conformational epitope is produced by spatially juxtaposed amino acids from different segments of the linear polypeptide chain. A linear epitope is one produced by adjacent amino acid residues in a polypeptide chain. In certain circumstance, an epitope may include moieties of saccharides, phosphoryl groups, or sulfonyl groups on the antigen.

[0245] The present invention includes anti-Fel dl antibodies which interact with one or more amino acids found within one or more regions of chain 1 or chain 2 of the Fel dl molecule including, e.g., chain 1 (chain A) as shown in SEQ ID NO: 392, or chain 2 (chain B) as shown in SEQ ID NO: 393, or within comparable regions of a recombinantly produced Fel dl protein, as shown in any one of SEQ ID NOs: 385, 394, 395, 396 or 397. The epitope to which the antibodies bind may consist of a single contiguous sequence of 3 or more (e.g. , 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more) amino acids located within any of the aforementioned regions or segments of the Fel dl molecule (e.g. a linear epitope in either chain 1 or chain 2, or in a region that spans both chain 1 and chain 2). Alternatively, the epitope may consist of a plurality of non-contiguous amino acids (or amino acid sequences) located within either or both of the aforementioned regions or segments of the Fel dl molecule (e.g. a conformational epitope).

[0246] Various techniques known to persons of ordinary skill in the art can be used to determine whether an antibody "interacts with one or more amino acids" within a polypeptide or protein. Exemplary techniques include, for example, routine cross-blocking assays, such as that described in Antibodies. Harlow and

Lane (Cold Spring Harbor Press, Cold Spring Harb., NY). Other methods include alanine scanning mutational analysis, peptide blot analysis (Reineke (2004)

Methods Mol Biol 248:443-63), peptide cleavage analysis, crystallographic studies and NMR analysis. In addition, methods such as epitope excision, epitope extraction and chemical modification of antigens can be employed (Tomer (2000)

Protein Science 9: 487-496). Another method that can be used to identify the amino acids within a polypeptide with which an antibody interacts is

hydrogen/deuterium exchange detected by mass spectrometry. In general terms, the hydrogen/deuterium exchange method involves deuterium-labeling the protein of interest, followed by binding the antibody to the deuterium-labeled protein.

Next, the protein/antibody complex is transferred to water and exchangeable protons within amino acids that are protected by the antibody complex undergo deuterium-to-hydrogen back-exchange at a slower rate than exchangeable protons within amino acids that are not part of the interface. As a result, amino acids that form part of the protein/antibody interface may retain deuterium and therefore exhibit relatively higher mass compared to amino acids not included in the interface. After dissociation of the antibody, the target protein is subjected to protease cleavage and mass spectrometry analysis, thereby revealing the deuterium-labeled residues which correspond to the specific amino acids with which the antibody interacts. See, e.g., Ehring (1999) Analytical Biochemistry 267(2):252-259; Engen and Smith (2001) Anal. Chem. 73:256A-265A. X-ray crystallography of the antigen/antibody complex may also be used for epitope mapping purposes.

[0247] Modification-Assisted Profiling (MAP), also known as Antigen

Structure-based Antibody Profiling (ASAP) is a method that categorizes large numbers of monoclonal antibodies (mAbs) directed against the same antigen according to the similarities of the binding profile of each antibody to chemically or enzymatically modified antigen surfaces (US 2004/0101920, herein specifically incorporated by reference in its entirety). Each category may reflect a unique epitope either distinctly different from or partially overlapping with epitope represented by another category. This technology allows rapid filtering of genetically identical antibodies, such that characterization can be focused on genetically distinct antibodies. When applied to hybridoma screening, MAP may facilitate identification of rare hybridoma clones that produce mAbs having the desired characteristics. MAP may be used to sort the antibodies of the invention into groups of antibodies binding different epitopes.

[0248] In certain embodiments, the anti-Fel dl antibodies or antigen-binding fragments thereof bind an epitope within any one or more of the regions exemplified in chain 1 or chain 2 of Fel dl, either in natural form, as exemplified in SEQ ID NO: 392 (chain 1) and SEQ ID NO: 393 (chain 2), or recombinantly produced, as exemplified in any of SEQ ID NOS: 385, 394, 395, 396, and 397, or to a fragment thereof. In certain embodiments, the antibodies of the invention, as shown in Table 1, interact with at least one amino acid sequence selected from the group consisting of: amino acid residues ranging from about position 15 to about position 24 of SEQ ID NO: 396; amino acid residues ranging from about position 85 to about position 103 of SEQ ID NO: 396; amino acid residues ranging from about position 85 to about position 104 of SEQ ID NO: 396; amino acid residues ranging from about position 113 to about position 116 of SEQ ID NO: 396; amino acid residues ranging from about 113 to about position 127 of SEQ ID NO: 396; amino acid residues ranging from about position 128 to about position 141 of SEQ ID NO: 396. These regions are further exemplified in SEQ ID NOs: 402, 403, 404, 406, 412 and 426. [0249] In one embodiment, an antibody of the invention that interacts with/binds to an epitope within the A chain of Fel d 1 comprises the amino acid sequence pair of SEQ ID NO: 18/26.

[0250] In certain embodiments, the antibodies of the invention, as shown in Table 1, interact with one or more amino acid residues ranging from about position 12 to about position 54 of SEQ ID NO: 396.

[0251] In one embodiment, an antibody of the invention, or an antigen-binding fragment thereof that binds to chain 2 of Fel d 1 interacts with amino acid residue numbers ranging from about residue 12 through residue 54 of SEQ ID NO: 396.

[0252] In one embodiment, an antibody of the invention, or an antigen-binding fragment thereof that binds to chain 2 of Fel d 1 interacts with amino acid residue numbers ranging from about residue 15 through residue 24 of SEQ ID NO: 396.

[0253] In one embodiment, an antibody of the invention, or an antigen-binding fragment thereof that binds to chain 2 of Fel d 1 interacts with amino acid residue numbers ranging from about residue 21 through residue 47 of SEQ ID NO: 396.

[0254] In one embodiment, an antibody of the invention, or an antigen-binding fragment thereof that binds to chain 2 of Fel d 1 interacts with at least one or more of the following amino acid residues in SEQ ID NO: 396: the N at position 21, the E at position 22, the L at position 23, the L at position 24, the D at position 26, the L at position 27, the T at position 30, the K at position 31, the E at position 36, the R at position 39, the K at position 43, the D at position 47.

[0255] In one embodiment, an antibody of the invention, or an antigen-binding fragment thereof that binds to chain 2 of Fel d 1 binds to an epitope that comprises a plurality of the following amino acid residues from SEQ ID NO: 396: N21, E22, L23, L24, D26, L27, T30, K31, E36, R39, K43, D47.

[0256] In one embodiment, an antibody of the invention, or an antigen-binding fragment thereof that interacts with at least one or more of the following amino acid residues of SEQ ID NO: 396, including the N at position 21, the E at position 22, the L at position 23, the L at position 24, the D at position 26, the L at position 27, the T at position 30, the K at position 31, the E at position 36, the R at position 39, the K at position 43, the D at position 47, comprises the

HCVR/LCVR amino acid sequence pair of SEQ ID NOs: 306/314. [0257] In certain embodiments, the epitope(s) for the antibodies of the invention may be identified by either hydrogen deuterium exchange (HDX) or by X-ray crystallographic analysis.

[0258] The present invention also includes anti-Fel dl antibodies that bind to the same epitope, or a portion of the epitope, as any of the specific exemplary antibodies described herein in Table 1, or an antibody having the CDR sequences of any of the exemplary antibodies described in Table 1. Likewise, the present invention also includes anti-Fel dl antibodies that compete for binding to Fel dl or a Fel dl fragment with any of the specific exemplary antibodies described herein in Table 1, or an antibody having the CDR sequences of any of the exemplary antibodies described in Table 1.

[0259] One can easily determine whether an antibody binds to the same epitope as, or competes for binding with, a reference anti-Fel dl antibody by using routine methods known in the art. For example, to determine if a test antibody binds to the same epitope as a reference anti-Fel dl antibody of the invention, the reference antibody is allowed to bind to a Fel dl protein or peptide under saturating conditions. Next, the ability of a test antibody to bind to the Fel dl molecule is assessed. If the test antibody is able to bind to Fel dl following saturation binding with the reference anti-Fel dl antibody, it can be concluded that the test antibody binds to a different epitope than the reference anti-Fel dl antibody. On the other hand, if the test antibody is not able to bind to the Fel dl molecule following saturation binding with the reference anti-Fel dl antibody, then the test antibody may bind to the same epitope as the epitope bound by the reference anti-Fel dl antibody of the invention.

[0260] To determine if an antibody competes for binding with a reference anti- Fel dl antibody, the above-described binding methodology is performed in two orientations: In a first orientation, the reference antibody is allowed to bind to a Fel dl molecule under saturating conditions followed by assessment of binding of the test antibody to the Fel dl molecule. In a second orientation, the test antibody is allowed to bind to a Fel dl molecule under saturating conditions followed by assessment of binding of the reference antibody to the Fel dl molecule. If, in both orientations, only the first (saturating) antibody is capable of binding to the Fel dl molecule, then it is concluded that the test antibody and the reference antibody compete for binding to Fel dl . As will be appreciated by a person of ordinary skill in the art, an antibody that competes for binding with a reference antibody may not necessarily bind to the identical epitope as the reference antibody, but may sterically block binding of the reference antibody by binding an overlapping or adjacent epitope.

[0261] Two antibodies bind to the same or overlapping epitope if each competitively inhibits (blocks) binding of the other to the antigen. That is, a 1-, 5-, 10-, 20- or 100-fold excess of one antibody inhibits binding of the other by at least 50% but preferably 75%, 90% or even 99% as measured in a competitive binding assay (see, e.g., Junghans et ai, Cancer Res. 1990 50: 1495-1502).

Alternatively, two antibodies have the same epitope if essentially all amino acid mutations in the antigen that reduce or eliminate binding of one antibody reduce or eliminate binding of the other. Two antibodies have overlapping epitopes if some amino acid mutations that reduce or eliminate binding of one antibody reduce or eliminate binding of the other.

[0262] Additional routine experimentation (e.g. , peptide mutation and binding analyses) can then be carried out to confirm whether the observed lack of binding of the test antibody is in fact due to binding to the same epitope as the reference antibody or if steric blocking (or another phenomenon) is responsible for the lack of observed binding. Experiments of this sort can be performed using ELISA, RIA, surface plasmon resonance, flow cytometry or any other quantitative or qualitative antibody-binding assay available in the art.

Immunoconjugates

[0263] The invention encompasses a human anti-Fel dl monoclonal antibody conjugated to a therapeutic moiety ("immunoconjugate"), such as an agent that is capable of reducing the severity of an allergic response to the Fel dl allergen present in cat dander or on cats, or in an area of the environment where cats may reside, or to ameliorate at least one symptom associated with exposure to cats, cat dander or to the Fel dl allergen, including rhinitis, conjunctivitis, or breathing difficulties, or the severity thereof. Such an agent may be a corticosteroid, a second different antibody to Fel dl, or a vaccine. The type of therapeutic moiety that may be conjugated to the Fel dl antibody will take into account the condition to be treated and the desired therapeutic effect to be achieved. Alternatively, if the desired therapeutic effect is to treat the sequelae or symptoms associated with exposure to the Fel dl allergen, or any other condition resulting from such exposure, such as, but not limited to, rhinitis or conjunctivitis, it may be advantageous to conjugate an agent appropriate to treat the sequelae or symptoms of the condition, or to alleviate any side effects of the antibodies of the invention. Examples of suitable agents for forming immunoconjugates are known in the art, see for example, WO 05/103081.

Multi-specific Antibodies

[0264] The antibodies of the present invention may be mono-specific, bi- specific, or multi-specific. Multi-specific antibodies may be specific for different epitopes of one target polypeptide or may contain antigen-binding domains specific for more than one target polypeptide. See, e.g., Tutt et al, 1991, J.

Immunol. 147:60-69; Kufer et al, 2004, Trends Biotechnol. 22:238-244. The antibodies of the present invention can be linked to or co-expressed with another functional molecule, e.g., another peptide or protein. For example, an antibody or fragment thereof can be functionally linked (e.g., by chemical coupling, genetic fusion, noncovalent association or otherwise) to one or more other molecular entities, such as another antibody or antibody fragment to produce a bi-specific or a multi-specific antibody with a second binding specificity. For example, the present invention includes bi-specific antibodies wherein one arm of an immunoglobulin may be specific for chain 1 of Fel dl, or a fragment thereof, and the other arm of the immunoglobulin may be specific for chain 2 of Fel dl, or a second therapeutic target, or may be conjugated to a therapeutic moiety.

[0265] Certain exemplary embodiments of the present invention include a bi- specific antigen-binding molecule, which is a bi-specific antibody. Each antigen- binding domain of a bi-specific antibody comprises a heavy chain variable domain (HCVR) and a light chain variable domain (LCVR). The HCVR may also be referred to as a V _H region, and the LCVR may also be referred to as a VL region. Typically, each HCVR and LCVR comprises three CDRs interspersed with four FRs, arranged from amino-terminus to carboxy -terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The three CDRs within an HCVR may be referred to herein as HCDR1, HCDR2 and HCDR3; while the three CDRs within an LCVR may be referred to herein as LCDR1 , LCDR2 and LCDR3. [0266] In the bi-specific antigen-binding molecules of the present invention, each antigen-binding domain may comprise or consist of a full antibody molecule or an antigen-binding fragment of an antibody. The terms "antigen-binding portion" of an antibody, "antigen-binding fragment" of an antibody, and the like, as used herein, include any naturally occurring, enzymatically obtainable, synthetic, or genetically engineered polypeptide or glycoprotein that specifically binds an antigen to form a complex. Antigen-binding fragments of an antibody may be derived, e.g. , from full antibody molecules using any suitable standard techniques such as proteolytic digestion or recombinant genetic engineering techniques involving the manipulation and expression of DNA encoding antibody variable and optionally constant domains. Such DNA is known and/or is readily available from, e.g. , commercial sources, DNA libraries (including, e.g., phage- antibody libraries), or can be synthesized. The DNA may be sequenced and manipulated chemically or by using molecular biology techniques, for example, to arrange one or more variable and/or constant domains into a suitable configuration, or to introduce codons, create cysteine residues, modify, add or delete amino acids, etc.

[0267] Non-limiting examples of antigen-binding fragments that may be included in the bi-specific antigen-binding molecules of the present invention include: (i) Fab fragments; (ii) F(ab')2 fragments; (iii) Fd fragments; (iv) Fv fragments; (v) single-chain Fv (scFv) molecules; (vi) dAb fragments; and (vii) minimal recognition units consisting of the amino acid residues that mimic the hypervariable region of an antibody. Other engineered molecules, such as domain-specific antibodies, single domain antibodies, domain-deleted antibodies, chimeric antibodies, CDR-grafted antibodies, diabodies, triabodies, tetrabodies, minibodies, nanobodies (e.g. monovalent nanobodies, bivalent nanobodies, etc.), small modular immunopharmaceuticals (SMIPs), and shark variable IgNAR domains, are also encompassed within the expression "antigen-binding fragment," as used herein.

[0268] An antigen-binding fragment of an antibody will typically comprise at least one variable domain. The variable domain may be of any size or amino acid composition and will generally comprise at least one CDR, which is adjacent to or in frame with one or more framework sequences. In antigen-binding fragments having a VH domain associated with a VL domain, the VH and VL domains may be situated relative to one another in any suitable arrangement. For example, the variable region may be dimeric and contain VH-VH, VH-VL or VL-VL dimers. Alternatively, the antigen-binding fragment of an antibody may contain a monomeric VH or VL domain.

[0269] In certain embodiments, an antigen-binding fragment of a bi-specific antigen-binding molecule may contain at least one variable domain covalently linked to at least one constant domain. Non-limiting, exemplary configurations of variable and constant domains that may be found within an antigen-binding domain of a bi-specific antigen-binding molecule may include: (i) VH-CH1; (n) VH-C _h 2; (hi) V _H -C _H 3; (iv) V _H -C _H 1-C _H 2; (v) VH-C _h 1-CH2-C _h 3; (VI) V _H -C _H 2-C _H 3; (vh) VH-C _l ; (vih) V _L -CH1; (ix) V _L -C _H 2; (x) V _L -C _H 3; (xi) V _L -C _H 1-C _H 2; (x ) V _L - CH1-CH2-CH3; (xiii) VL-CH2-CH3; and (xiv) VL-CL. In any configuration of variable and constant domains, including any of the exemplary configurations listed above, the variable and constant domains may be either directly linked to one another or may be linked by a full or partial hinge or linker region. A hinge region may consist of at least 2 (e.g. , 5, 10, 15, 20, 40, 60 or more) amino acids, which result in a flexible or semi -flexible linkage between adjacent variable and/or constant domains in a single polypeptide molecule. Moreover, an antigen- binding domain of a bi-specific antigen-binding molecule may comprise a homo- dimer or hetero-dimer (or other multimer) of any of the variable and constant domain configurations listed above in non-covalent association with one another and/or with one or more monomeric V _H or VL domain (e.g., by disulfide bond(s)).

[0270] The first antigen-binding domain and the second antigen-binding domain may be directly or indirectly connected to one another to form a bi- specific antigen-binding molecule. Alternatively, the first antigen-binding domain and the second antigen-binding domain may each be connected to a separate multimerizing domain. The association of one multimerizing domain with another multimerizing domain facilitates the association between the two antigen-binding domains, thereby forming a bispecific antigen-binding molecule. As used herein, a "multimerizing domain" is any macromolecule, protein, polypeptide, peptide, or amino acid that has the ability to associate with a second multimerizing domain of the same or similar structure or constitution. For example, a multimerizing domain may be a polypeptide comprising an immunoglobulin CH3 domain. A non-limiting example of a multimerizing component is an Fc portion of an immunoglobulin, e.g. , an Fc domain of an IgG selected from the isotypes IgGl, IgG2, IgG3, and IgG4, as well as any allotype within each isotype group. In certain embodiments, the multimerizing domain may be an Fc fragment or an amino acid sequence of 1 to about 200 amino acids in length containing at least one cysteine residues. In other embodiments, the multimerizing domain may be a cysteine residue, or a short cysteine-containing peptide. Other multimerizing domains include peptides or polypeptides comprising or consisting of a leucine zipper, a helix-loop motif, or a coiled-coil motif.

[0271] Any bi-specific antibody format or technology may be used to make the bi-specific antigen-binding molecules of the present invention. For example, an antibody or fragment thereof having a first antigen binding specificity can be functionally linked (e.g., by chemical coupling, genetic fusion, noncovalent association or otherwise) to one or more other molecular entities, such as another antibody or antibody fragment having a second antigen-binding specificity to produce a bi-specific antigen-binding molecule.

[0272] An exemplary bi-specific antibody format that can be used in the context of the present invention involves the use of a first immunoglobulin (Ig) CH3 domain and a second Ig CH3 domain, wherein the first and second Ig CH3 domains differ from one another by at least one amino acid, and wherein at least one amino acid difference reduces binding of the bi-specific antibody to Protein A as compared to a bi-specific antibody lacking the amino acid difference. In one embodiment, the first Ig CH3 domain binds Protein A and the second Ig CH3 domain contains a mutation that reduces or abolishes Protein A binding such as an

H95R modification (by IMGT exon numbering; H435R by EU numbering). The second CH3 may further comprise a Y96F modification (by IMGT; Y436F by

EU). Further modifications that may be found within the second CH3 include:

D16E, L18M, N44S, K52N, V57M, and V82I (by IMGT; D356E, L358M,

N384S, K392N, V397M, and V422I by EU) in the case of IgGl antibodies;

N44S, K52N, and V82I (IMGT; N384S, K392N, and V422I by EU) in the case of

IgG2 antibodies; and Q15R, N44S, K52N, V57M, R69K, E79Q, and V82I (by

IMGT; Q355R, N384S, K392N, V397M, R409K, E419Q, and V422I by EU) in the case of IgG4 antibodies. Variations on the bi-specific antibody format described above are contemplated within the scope of the present invention. [0273] Other exemplary bi-specific formats that can be used in the context of the present invention include, without limitation, e.g. , scFv-based or diabody bispecific formats, IgG-scFv fusions, dual variable domain (DVD)-Ig, Quadroma, knobs-into-holes, common light chain (e.g. , common light chain with knobs-into- holes, etc.), CrossMab, CrossFab, (SEED)body, leucine zipper, Duobody, IgGl/IgG2, dual acting Fab (DAF)-IgG, and Mab ² bispecific formats (see, e.g. , Klein et al. 2012, mAbs 4:6, 1-11, and references cited therein, for a review of the foregoing formats). Bi-specific antibodies can also be constructed using peptide/nucleic acid conjugation, e.g. , wherein unnatural amino acids with orthogonal chemical reactivity are used to generate site-specific antibody - oligonucleotide conjugates which then self-assemble into multimeric complexes with defined composition, valency and geometry. (See, e.g. , Kazane et al., J. Am. Chem. Soc. [Epub: Dec. 4, 2012]).

Selection of Allergen Specific Antibodies

[0274] Any of the allergen specific antibodies or antigen binding fragments thereof described herein can be evaluated for the ability to bind to and/or inhibit one or more actions of allergen specific IgE, especially allergen specific IgE obtained from the patient. In one embodiment, the method for treating a patient who demonstrates a sensitivity to, or an allergic reaction against an allergen, or for preventing or ameliorating at least one symptom or complication associated with the allergen, comprises (:a) collecting a sample of tissue or an extract thereof, or a biological fluid, or a blood sample from the patient; (b)extracting an allergen-specific IgE, or cells containing or bound to allergen-specific IgE, from one or more of the patient samples of (a); (c)mixing the IgE, or the cells containing or bound to IgE, from the patient sample with the allergen and with one or more antibodies or antigen binding fragments thereof specific for the allergen; (d)determining if the addition of one or more antibodies or antigen binding fragments thereof specific for the allergen blocks the binding of the allergen specific IgE from step (b) to the allergen, and if the results from step (d) demonstrate effective blocking of the binding of the allergen specific IgE to the allergen with the allergen specific antibodies of step (c), administering to the patient a pharmaceutical composition comprising a therapeutically effective amount of one or more of the allergen specific antibodies or antigen binding fragments from step (c).

[0275] The tissue sample is any tissue sample, or extract thereof, biological fluid, or blood sample containing IgE bearing cells; or the blood sample is selected from the group consisting of whole blood, serum and plasma. In embodiments, cells are isolated from the tissue sample. In specific embodiments, the cells are peripheral blood mononuclear cells.

[0276] In one embodiment the determining step is carried out by an in vitro method selected from the group consisting of an enzyme-linked immunosorbent assay (ELISA), a radioimmunoassay (RIA), an immunoradiometric assay (IRMA), a luminescence immunoassay (LIA), an immunoblot, FACS analysis, an IgE-facilitated allergen binding (FAB) assay, a basophil activation assay (e.g. a functional phosphoflow assay, or a basophil activation test as described in Example 10), and an assay using an engineered cell line expressing FCsRl .

[0277] In one embodiment, the determining step is carried out in vivo using an allergen-specific animal model. In embodiments, the mixture of the IgE or the cells containing or bound to IgE from the patient sample, the allergen, and the one or more antibodies or antigen binding fragments thereof specific for the allergen is injected into the animal model. The allergen-specific animal model is a mouse model of Passive Cutaneous Anaphylaxis (PCA) wherein the model further comprises the following steps:

(a) injecting the animal with allergen-specific IgE, or antiserum containing allergen-specific IgE, intradermally at one skin site and injecting the animal with non-allergen-specific IgE or antiserum containing non-allergen-specific IgE intradermally at a second skin site;

(b) injecting the animal systemically with the allergen, along with a dye; and

(c) assessing the extent of dye extravasation at the site of allergen injection; wherein the amount of dye extravasated into the tissue is directly related to the amount of mast cell activation in the animal and wherein a change in the amount of dye extravasated into the tissue as compared to an animal injected with allergen specific IgG is indicative of a projected positive treatment outcome in the patient.

[0278] In another embodiment, the one or more antibodies or antigen binding fragments thereof specific for the allergen blocks the binding of the allergen specific IgE to the allergen is carried out in vivo using an allergen-specific animal model. In this embodiment, the one or more allergen specific antibodies or antigen binding fragments are injected into mice. Allergen specific IgE, optionally allergen specific IgE from the patient, is injected intradermally into one ear and control IgE is injected intradermally into another ear. The mice are challenged with allergen and injected with a dye. A decrease in dye extravasation in animals receiving one or more allergen specific antibodies or antigen binding fragments is indicative that the antibodies inhibit mast cell degranulation induced by allergen specific IgE.

[0279] In certain embodiments, the patient sample may be analyzed first in vitro using the methods and diagnostic tests described above, followed by a confirmatory analysis in the in vivo animal model, such as the PCA model described herein. In embodiments, allergen specific antibodies or antigen binding fragments thereof are selected that inhibit the binding of allergen to allergen specific IgE, or inhibit mast cell degranulation induced by allergen specific IgE, especially allergen specific IgE obtained from the patient.

Therapeutic Administration and Formulations

[0280] The invention provides therapeutic compositions comprising the anti-Fel dl antibodies or antigen-binding fragments thereof of the present invention. The administration of therapeutic compositions in accordance with the invention will be administered via a suitable route including, but not limited to, intravenously, subcutaneously, intramuscularly, intranasally, with suitable carriers, excipients, and other agents that are incorporated into formulations to provide improved transfer, delivery, tolerance, and the like. A multitude of appropriate formulations can be found in the formulary known to all pharmaceutical chemists: Remington's

Pharmaceutical Sciences, Mack Publishing Company, Easton, PA. These formulations include, for example, powders, pastes, ointments, jellies, waxes, oils, lipids, lipid (cationic or anionic) containing vesicles (such as LIPOFECTIN™),

DNA conjugates, anhydrous absorption pastes, oil-in-water and water-in-oil emulsions, emulsions carbowax (polyethylene glycols of various molecular weights), semi-solid gels, and semi-solid mixtures containing carbowax. See also

Powell et al. "Compendium of excipients for parenteral formulations" PDA

(1998) J Pharm Sci Technol 52:238-311. [0281] The dose of antibody may vary depending upon the age and the size of a subject to be administered, target disease, conditions, route of administration, and the like. When the antibody of the present invention is used for treating the rhinitis or conjunctivitis associated with exposure to a cat, or to cat dander in an individual having a sensitivity to Fel dl, or for preventing an anaphylactic response to the cat allergen, or for lessening the severity of the allergic response, it is advantageous to intravenously administer the antibody of the present invention normally at a single dose of about 0.01 to about 30 mg/kg body weight, more preferably about 0.02 to about 7, about 0.03 to about 5, or about 0.05 to about 3 mg/kg body weight. Depending on the severity of the condition, the frequency and the duration of the treatment can be adjusted. In certain

embodiments, the antibody or antigen-binding fragment thereof of the invention can be administered as an initial dose of at least about 0.1 mg to about 800 mg, about 1 to about 600 mg, about 5 to about 300 mg, or about 10 to about 200 mg, to about 100 mg, or to about 50 mg. In certain embodiments, the initial dose may be followed by administration of a second or a plurality of subsequent doses of the antibody or antigen-binding fragment thereof in an amount that can be approximately the same or less than that of the initial dose, wherein the subsequent doses are separated by at least 1 day to 3 days; at least one week, at least 2 weeks; at least 3 weeks; at least 4 weeks; at least 5 weeks; at least 6 weeks; at least 7 weeks; at least 8 weeks; at least 9 weeks; at least 10 weeks; at least 12 weeks; or at least 14 weeks.

[0282] Various delivery systems are known and can be used to administer the pharmaceutical composition of the invention, e.g., encapsulation in liposomes, microparticles, microcapsules, recombinant cells capable of expressing the mutant viruses, receptor mediated endocytosis (see, e.g., Wu et al. (1987) J. Biol. Chem. 262:4429-4432). Methods of introduction include, but are not limited to, intradermal, transdermal, intramuscular, intraperitoneal, intravenous,

subcutaneous, intranasal, epidural and oral routes. The composition may be administered by any convenient route, for example by infusion or bolus injection, by absorption through epithelial or mucocutaneous linings (e.g., oral mucosa, rectal and intestinal mucosa, etc.) and may be administered together with other biologically active agents. Administration can be systemic or local. [0283] The pharmaceutical composition can be also delivered in a vesicle, in particular a liposome (see, for example, Langer (1990) Science 249: 1527-1533).

[0284] In certain situations, the pharmaceutical composition can be delivered in a controlled release system. In one embodiment, a pump may be used. In another embodiment, polymeric materials can be used. In yet another embodiment, a controlled release system can be placed in proximity of the composition's target, thus requiring only a fraction of the systemic dose.

[0285] The injectable preparations may include dosage forms for intravenous, subcutaneous, intracutaneous and intramuscular injections, drip infusions, etc.

These injectable preparations may be prepared by methods publicly known. For example, the injectable preparations may be prepared, e.g. , by dissolving, suspending or emulsifying the antibody or its salt described above in a sterile aqueous medium or an oily medium conventionally used for injections. As the aqueous medium for injections, there are, for example, physiological saline, an isotonic solution containing glucose and other auxiliary agents, etc., which may be used in combination with an appropriate solubilizing agent such as an alcohol

(e.g., ethanol), a polyalcohol (e.g., propylene glycol, polyethylene glycol), a nonionic surfactant [e.g., polysorbate 80, HCO-50 (polyoxy ethylene (50 mol) adduct of hydrogenated castor oil)], etc. As the oily medium, there are employed, e.g., sesame oil, soybean oil, etc., which may be used in combination with a solubilizing agent such as benzyl benzoate, benzyl alcohol, etc. The injection thus prepared is preferably filled in an appropriate ampoule.

[0286] A pharmaceutical composition of the present invention can be delivered subcutaneously or intravenously with a standard needle and syringe. In addition, with respect to subcutaneous delivery, a pen delivery device readily has applications in delivering a pharmaceutical composition of the present invention.

Such a pen delivery device can be reusable or disposable. A reusable pen delivery device generally utilizes a replaceable cartridge that contains a pharmaceutical composition. Once all of the pharmaceutical composition within the cartridge has been administered and the cartridge is empty, the empty cartridge can readily be discarded and replaced with a new cartridge that contains the pharmaceutical composition. The pen delivery device can then be reused. In a disposable pen delivery device, there is no replaceable cartridge. Rather, the disposable pen delivery device comes prefilled with the pharmaceutical composition held in a reservoir within the device. Once the reservoir is emptied of the pharmaceutical composition, the entire device is discarded.

[0287] Numerous reusable pen and autoinjector delivery devices have applications in the subcutaneous delivery of a pharmaceutical composition of the present invention. Examples include, but certainly are not limited to

AUTOPEN™ (Owen Mumford, Inc., Woodstock, UK), DISETRONIC™ pen (Disetronic Medical Systems, Burghdorf, Switzerland), HUMALOG MIX 75/25™ pen, HUMALOG™ pen, HUMALIN 70/30™ pen (Eli Lilly and Co., Indianapolis, IN), NOVOPEN™ I, II and III (Novo Nordisk, Copenhagen, Denmark), NOVOPEN JUNIOR™ (Novo Nordisk, Copenhagen, Denmark), BD™ pen (Becton Dickinson, Franklin Lakes, NJ), OPTIPEN™, OPTIPEN PRO™, OPTIPEN STARLET™, and OPTICLIK™ (sanofi-aventis, Frankfurt, Germany), to name only a few. Examples of disposable pen delivery devices having applications in subcutaneous delivery of a pharmaceutical composition of the present invention include, but certainly are not limited to the SOLOSTAR™ pen (sanofi-aventis), the FLEXPEN™ (Novo Nordisk), and the KWIKPEN™ (Eli Lilly), the SURECLICK™ Autoinjector (Amgen, Thousands Oaks, CA), the PENLET™ (Haselmeier, Stuttgart, Germany), the EPIPEN (Dey, L.P.) and the HUMIRA™ Pen (Abbott Labs, Abbott Park, IL), to name only a few.

[0288] Advantageously, the pharmaceutical compositions for oral or parenteral use described above are prepared into dosage forms in a unit dose suited to fit a dose of the active ingredients. Such dosage forms in a unit dose include, for example, tablets, pills, capsules, injections (ampoules), suppositories, etc. The amount of the aforesaid antibody contained is generally about 5 to about 500 mg per dosage form in a unit dose; especially in the form of injection, it is preferred that the aforesaid antibody is contained in about 5 to about 100 mg and in about 10 to about 250 mg for the other dosage forms.

Therapeutic Uses of the Antibodies

[0289] Due to their interaction with Fel dl, the present antibodies are useful for treating the primary response following exposure of an individual to a cat, cat dander or to an environment containing the Fel dl protein, or at least one symptom associated with the allergic response, such as itchy eyes, conjunctivitis, rhinitis, wheezing, breathing difficulties, or for preventing a secondary response to the Fel dl allergen, including a more serious anaphylactic response, or for lessening the severity, duration, and/or frequency of symptoms following reexposure to the cat allergen. Accordingly, it is envisioned that the antibodies of the present invention may be used prophylactically or therapeutically.

[0290] In yet a further embodiment of the invention the present antibodies are used for the preparation of a pharmaceutical composition for treating patients suffering from a sensitivity to cats, cat dander, cat hair or an extract thereof, and/or the Fel dl protein. In yet another embodiment of the invention the present antibodies are used for the preparation of a pharmaceutical composition for reducing the severity of primary exposure to Fel dl, or for reducing the severity, duration of, and/or number of allergic responses to Fel dl. In a further embodiment of the invention the present antibodies are used as adjunct therapy with any other agent useful for treating cat allergens, including corticosteroids, vaccines, allergen specific immunotherapy (SIT), or any other palliative therapy known to those skilled in the art.

[0291] In embodiments, a pharmaceutical composition comprises more than one antibody or antigen binding fragments that specifically bind the allergen. In certain embodiments, when more than one antibody or antigen binding fragment thereof is utilized, the antibodies do not compete with one another for binding to the allergen. In other embodiments, the antibodies or antigen binding fragments thereof specifically bind to different epitopes. In certain embodiments, one or more antibodies or antigen binding fragments thereof specifically bind to different epitopes on Fel dl. In embodiments, a pharmaceutical composition comprises one antibody or antigen binding fragment thereof binds to an epitope comprising amino acids 15 to 54 of SEQ ID NO:396, and a second antibody or antigen binding fragment thereof binds to an epitope comprising amino acids 113 to 116 of SEQ ID NO:396.

[0292] Methods are provided herein for monitoring the efficacy of the allergen specific antibodies or antigen binding fragments thereof. In embodiments, a method for reducing the severity, duration, or frequency of occurrence of one or more symptoms associated with an allergic response in a patient as measured by one or more patient reported outcome scores, the method comprising

administering one or more therapeutically effective doses of one or more allergen-specific monoclonal antibodies or antigen binding fragments thereof to the patient and measuring the severity, duration, or frequency of occurrence of one or more symptoms associated with an allergic response in a patient. In embodiments, a measurement is conducted to determine a baseline prior to administration and then at least one time point post administration in order to determine the efficacy of the therapy and whether additional dosing or a change in antibodies may be required to increase efficacy.

[0293] In embodiments, measurements are conducted prior to therapy, and post administration of the one or more allergen specific monoclonal antibodies or antigen binding fragments thereof to the patient upon exposure to the allergen. In embodiments, measurements are conducted at one or more time points post administration such as at one week post administration, at one month post administration, at two months post administration, at three months post administration, at 6 months post administration, at 12 months post administration, and/or at 24 months post administration. If the measurements show that post administration of the allergen-specific monoclonal antibodies or antigen binding fragments thereof to the patient the severity, duration, or frequency of occurrence of one or more symptoms associated with an allergic response in a patient is decreased as compared to the measurements prior to therapy, treatment is continued or may be discontinued until symptoms return to pre administration levels. If the measurements show that post administration of the allergen-specific monoclonal antibodies or antigen binding fragments thereof to the patient the severity, duration, or frequency of occurrence of one or more symptoms associated with an allergic response in a patient is not decreased as compared to the measurements prior to therapy, treatment may be discontinued, the dosage of the allergen specific antibody or antigen binding fragment thereof may be changed, or a different antibody or antigen binding fragment or combinations thereof may be utilized.

[0294] In one embodiment, the one or more symptoms may be selected from the group consisting of nasal congestion, nasal itching, rhinorrhea and sneezing.

In one embodiment, the patient reported outcome score is selected from the group consisting of a Total Nasal Symptom Score (TNSS), a Visual Analog Scale

(VAS) nasal symptoms score and an improvement in peak nasal inspiratory flow

(PNIF). In one embodiment, the method is associated with a reduction in wheal diameter in an allergen skin test. In one embodiment, the allergen skin test is a titrated skin prick test (SPT), wherein there is a significant reduction in wheal diameter in a patient treated with the allergen-specific monoclonal antibodies compared to the wheal diameter observed prior to treatment of the patient with the allergen-specific monoclonal antibodies.

[0295] In embodiments, the treatment is monitored by a determination of one or more efficacy end points. An example of an efficacy endpoint is to determine change in TNSS area under the curve (AUC) between pretreatment and day 8 after nasal allergen challenge (NAC) over the first hour of challenge (0 hour to 1 hour, early phase allergic response). Other endpoints include percent change in TNSS AUC from pretreatment to day 8 NAC over the first hour; change and percent change in TNSS AUC from pretreatment NAC to days 29, 57, and 85 over the first hour; and change and percent change in TNSS AUC from hours 1 to 8 post-challenge (LPR) ) from pretreatment NAC to days 8, 29, 57, and 85. In yet other embodiments, endpoints include change and percent change from pretreatment NAC to days 8, 29, 57, and 85 in peak TNSS, peak VAS nasal symptoms score, and peak PNIF; as well as VAS nasal symptoms score AUC and PNIF AUC from 0-1 hr, and 1 to 8 hours.

[0296] In embodiments, one or more doses of the allergen specific antibodies are administered depending on whether the severity, duration, and/or frequency of occurrence of one or more symptoms associated with an allergic response in a patient post administration are decreased or increased as compared to the severity, duration, and/or frequency of occurrence of one or more symptoms associated with an allergic response in a patient prior to administration. In certain embodiments, if the patient exhibits at least a 30%, at least 40%, or at least 50% decrease in the severity, duration, and/or frequency of occurrence of one or more symptoms associated with an allergic response in a patient at a measured time point as compared to measurements prior administration (i.e. baseline score), no additional doses of the allergen specific antibodies may be necessary. In other embodiments, if the patient exhibits a reduction in the area under the curve(AUC) for TNSS of at least 30%, at least 40%, at least 50% or at least 60% ,at a measured time point as compared to the AUC for TNSS prior to

administration(i.e. baseline score), no further doses may be necessary Combination Therapies

[0297] Combination therapies may include an anti-Fel dl antibody of the invention and any additional therapeutic agent that may be advantageously combined with an antibody of the invention, or with a biologically active fragment of an antibody of the invention.

[0298] For example, a second therapeutic agent may be employed to aid in reducing the allergic symptoms following exposure to a cat, cat dander, cat hair or an extract thereof, or Fel dl, or being exposed to an environment in which a cat resides, such as a corticosteroid. The antibodies may also be used in conjunction with other therapies, such as a vaccine specific for the Fel dl allergen. The additional therapeutically active component(s) may be administered prior to, concurrent with, or after the administration of the anti-Fel dl antibody of the present invention. For purposes of the present disclosure, such administration regimens are considered the administration of an anti-Fel dl antibody "in combination with" a second therapeutically active component.

Administration Regimens

[0299] According to certain embodiments of the present invention, multiple doses of one or more anti-Fel dl antibodies (an antibody combination) or a bi- specific antigen-binding molecule may be administered to a subject over a defined time course. The methods according to this aspect of the invention comprise sequentially administering to a subject multiple doses of an antibody, antibody combination, or a bi-specific antigen-binding molecule of the invention. As used herein, "sequentially administering" means that each dose of an antibody, antibody combination, or a bi-specific antigen-binding molecule is administered to the subject at a different point in time, e.g. , on different days separated by a predetermined interval (e.g. , hours, days, weeks or months). The present invention includes methods, which comprise sequentially administering to the patient a single initial dose of an antibody, antibody combination, or a bi-specific antigen-binding molecule, followed by one or more secondary doses of the antibody, and optionally followed by one or more tertiary doses of the antibody.

[0300] The terms "initial dose," "secondary doses," and "tertiary doses," refer to the temporal sequence of administration of an antibody, antibody combination, or a bi-specific antigen-binding molecule of the invention. Thus, the "initial dose" is the dose which is administered at the beginning of the treatment regimen (also referred to as the "baseline dose"); the "secondary doses" are the doses which are administered after the initial dose; and the "tertiary doses" are the doses which are administered after the secondary doses. The initial, secondary, and tertiary doses may all contain the same amount of an antibody, antibody combination, or a bi- specific antigen-binding molecule, but generally may differ from one another in terms of frequency of administration. In certain embodiments, however, the amount of an antibody, antibody combination, or a bi-specific antigen-binding molecule contained in the initial, secondary and/or tertiary doses varies from one another (e.g. , adjusted up or down as appropriate) during the course of treatment. In certain embodiments, two or more (e.g., 2, 3, 4, or 5) doses are administered at the beginning of the treatment regimen as "loading doses" followed by subsequent doses that are administered on a less frequent basis (e.g. , "maintenance doses").

[0301] In one exemplary embodiment of the present invention, each secondary and/or tertiary dose is administered 1 to 26 (e.g. , 1, 1 ½, 2, 2½, 3, 3½, 4, 4½, 5, 5½, 6, 6½, 7, 7½, 8, 8½, 9, 9½, 10, 10½, 11, 11 ½, 12, 12½, 13, 13½, 14, 14½, 15, 15½, 16, 16½, 17, 17½, 18, 18½, 19, 19½, 20, 20½, 21, 21 ½, 22, 22½, 23, 23½, 24, 24½, 25, 25 ½, 26, 26½, or more) weeks after the immediately preceding dose. The phrase "the immediately preceding dose," as used herein, means, in a sequence of multiple administrations, the dose of an antibody, antibody combination, or a bi-specific antigen-binding molecule, which is administered to a patient prior to the administration of the very next dose in the sequence with no intervening doses.

[0302] The methods according to this aspect of the invention may comprise administering to a patient any number of secondary and/or tertiary doses of an antibody, antibody combination, or a bi-specific antigen-binding molecule that specifically binds Fel dl. For example, in certain embodiments, only a single secondary dose is administered to the patient. In other embodiments, two or more (e.g., 2, 3, 4, 5, 6, 7, 8, or more) secondary doses are administered to the patient. Likewise, in certain embodiments, only a single tertiary dose is administered to the patient. In other embodiments, two or more (e.g. , 2, 3, 4, 5, 6, 7, 8, or more) tertiary doses are administered to the patient.

[0303] In embodiments involving multiple secondary doses, each secondary dose may be administered at the same frequency as the other secondary doses. For example, each secondary dose may be administered to the patient 1 to 2 weeks after the immediately preceding dose. Similarly, in embodiments involving multiple tertiary doses, each tertiary dose may be administered at the same frequency as the other tertiary doses. For example, each tertiary dose may be administered to the patient 2 to 4 weeks after the immediately preceding dose. Alternatively, the frequency at which the secondary and/or tertiary doses are administered to a patient can vary over the course of the treatment regimen. The frequency of administration may also be adjusted during the course of treatment by a physician depending on the needs of the individual patient following clinical examination.

[0304] In embodiments, one or more doses of an allergen specific antibody or antigen binding fragment thereof is administered depending on whether the severity, duration, and/or frequency of occurrence of one or more symptoms associated with an allergic response in a patient post administration are decreased or increased as compared to the severity, duration, and/or frequency of occurrence of one or more symptoms associated with an allergic response in a patient prior to administration. In certain embodiments, if the patient exhibits at least a 30%, at least 40%, or at least 50% decrease in the severity, duration, and/or frequency of occurrence of one or more symptoms associated with an allergic response in a patient at a measured time point post administration as compared to a

measurement prior administration (i.e. baseline score), no additional doses of the allergen specific antibodies may be necessary. In other embodiments, if the patient exhibits a reduction in the area under the curve(AUC) for TNSS of at least 30%, at least 40%, at least 50% or at least 60%, at a measured time point post administration as compared to the AUC for TNSS prior to administration(i.e. baseline score), no further doses may be necessary.

[0305] In embodiments, an allergen specific antibody or antigen binding fragment thereof is administered once a month, once every two months, once every three months, once every 6 months, or once very year. In embodiments, administration frequency is determined by whether the patient exhibits at least a

30%, at least 40%, or at least 50% decrease in the severity, duration, and/or frequency of occurrence of one or more symptoms associated with an allergic response in a patient at a measured time point post administration as compared to a measurement prior to administration (i.e. baseline score). If the severity, duration, and/or frequency of occurrence of one or more symptoms associated with an allergic response is decreased more than 50%, the patient may no longer need administration of the allergen specific antibody or antigen binding fragment thereof. If the symptoms are not reduced or recur after a reduction, administration of the allergen specific antibody or antigen binding fragment thereof may resume until the desired level of symptom reduction is obtained.

Diagnostic Uses of the Antibodies

[0306] The anti-Fel dl antibodies of the present invention may also be used to detect and/or measure Fel dl in a sample, e.g., for diagnostic purposes. It is envisioned that confirmation of an allergic response thought to be caused by Fel dl may be made by measuring the presence of either Fel dl through use of any one or more of the antibodies of the invention. Exemplary diagnostic assays for Fel dl may comprise, e.g. , contacting a sample, obtained from a patient, with an anti-Fel dl antibody of the invention, wherein the anti-Fel dl antibody is labeled with a detectable label or reporter molecule or used as a capture ligand to selectively isolate Fel dl protein from patient samples. Alternatively, an unlabeled anti-Fel dl antibody can be used in diagnostic applications in combination with a secondary antibody which is itself detectably labeled. The detectable label or reporter molecule can be a radioisotope, such as H, ¹⁴ C, ² P, 5S, or ¹²⁵ I; a fluorescent or chemiluminescent moiety such as fluorescein isothiocyanate, or rhodamine; or an enzyme such as alkaline phosphatase, β- galactosidase, horseradish peroxidase, or luciferase. Specific exemplary assays that can be used to detect or measure Fel dl in a sample include enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), and fluorescence- activated cell sorting (FACS).

[0307] Samples that can be used in Fel dl diagnostic assays according to the present invention include any tissue or fluid sample obtainable from a patient, which contains detectable quantities of Fel dl protein, or fragments thereof, under normal or pathological conditions. Generally, levels of Fel dl in a particular sample obtained from a healthy/non-allergic patient (e.g. , a patient not afflicted with a sensitivity associated with the presence of Fel dl) will be measured to initially establish a baseline, or standard, level of Fel dl. This baseline level of

Fel dl can then be compared against the levels of Fel dl measured in samples obtained from individuals suspected of having a sensitivity to Fel dl in cat dander, or symptoms associated with such condition.

EXAMPLES

[0308] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the methods and compositions of the invention, and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.) but some experimental errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, molecular weight is average molecular weight, temperature is in degrees Centigrade, and pressure is at or near atmospheric.

Example 1. Generation of Human Antibodies to Fel dl

[0309] An immunogen comprising any one of the following can be used to generate antibodies to Fel dl. In certain embodiments, the antibodies of the invention are obtained from mice immunized with a primary immunogen, such as full length natural Fel dl (nFel dl), which may be purchased commercially (e.g., from Indoor Biotechnologies, # LTN-FDl-1), or isolated from cat hair or dander by multi-step column chromatography (See, for example, Chapman MD, et al.

(1988), J. Immunol. 140: 812-818), or which may be produced recombinantly (See

GenBank accession numbers P30438, or NP_001041618.1 for the full length amino acid sequence of chain 1 of Fel dl (also referred to as chain A or FELD1

A; also see SEQ ID NO: 392) and GenBank accession number P30440, or

NP_001041619.1 for the full length amino acid sequence of chain 2 of Fel dl

(also referred to as chain B or FELD B; also see SEQ ID NO: 393), or fragments of either chain 1 or chain 2, or fragments from both chain 1 and chain 2 of the Fel dl protein, followed by immunization with a secondary immunogen, or with an immunogenically active fragment of the natural protein. Animals may be immunized with either chain 1 protein alone or chain 2 protein alone, or with both chain 1 and chain 2 proteins, administered sequentially, or concurrently. Various constructs may be prepared using portions of chain 1 and chain 2 along with various linking or spacer strategies known to those skilled in the art. These constructs may be used alone, or in various combinations to elicit antibody responses in vivo. For example, recombinant Fel dl constructs, such as those exemplified in SEQ ID NOs: 385, 394, 395, 396 or 397, or fragments thereof, may be used as immunogens.

[0310] In certain embodiments, the antibodies of the invention are obtained from mice immunized with a primary immunogen, such as a biologically active and/or immunogenic fragment of natural Fel dl, or DNA encoding the active fragment thereof. The fragment may be derived from the N-terminal or C-terminal domain of either chain 1 and/or chain 2 of Fel dl .

[0311] In certain embodiments, the recombinantly produced Fel dl immunogen may be made by direct fusion of the two chains of Fel dl, as described in Kaiser et. al, to produce a fusion product that has a similar refolding partem to that of natural Fel dl (Kaiser, L. et al, (2003), J. Biol. Chem. 278(39):37730-37735). In certain embodiments, the immunogen may be a fusion protein such as that shown in the constructs of SEQ ID NOs: 385, 394, 395, 396 or 397, followed by immunization with a secondary immunogen, or with an immunogenically active fragment of the natural or recombinantly produced Fel dl .

[0312] In certain embodiments, the recombinant Fel dl protein constructs used in the studies described herein are comprised of either i) Fel dl B chain (chain 2) and Fel dl A chain (chain 1) linked as a continuous, in-line fusion (with Fel dl B chain at the N-terminus) or ii) a continuous, in-line fusion with Fel dl A chain at the N-terminus followed by a flexible linker [(Gly4Ser) ₃ ] followed by Fel dl B.

These constructs may also include a C-terminal tag (myc-myc-His6 or mouse

IgG2a Fc region), as indicated below. The proteins were expressed in Chinese hamster ovary (CHO) cells. An exogenous signal sequence used to promote expression in CHO cells is not included in the sequence listings.

[0313] In certain embodiments, the immunogen may be a fusion protein comprising any one or more of the following: i) amino acid residues 18-109 of chain 2 of Fel dl (See GenBank accession number P30440 and also SEQ ID NO:

393) fused via the C terminus directly with the N terminus of amino acid residues

23-92 of chain 1 of Fel dl (See GenBank accession number P30438 and also SEQ

ID NO: 392); ii) amino acid residues 23-92 of chain 1 of Fel dl (See GenBank accession number P30438 and also SEQ ID NO: 392) fused via the C terminus to the N terminus of amino acid residues 18-109 of chain 2 of Fel dl (See GenBank accession number P30440 and also SEQ ID NO: 393); iii) amino acid residues 18- 109 of chain 2 of Fel dl (See GenBank accession number NP_001041619.1) fused via the C terminus directly with the N terminus of amino acid residues 19- 88 of chain 1 of Fel dl (See GenBank accession number NP_001041618.), such as the construct shown in SEQ ID NO: 394 or 396; iv) amino acid residues 19-88 of chain 1 of Fel dl (See GenBank accession number NP_001041618.1) fused via the C terminus to the N terminus of amino acid residues 18-109 of chain 2 of Fel dl (See GenBank accession number NP_001041619.1). See also SEQ ID NO: 395). In certain embodiments, the fusion protein may have a tag at the C terminal end of the construct, such as a myc-myc-hexahistidine tag (See SEQ ID NOs: 385, 396 or 397 for such constructs.). In related embodiments, the fusion protein may have a mouse Fc coupled at the C terminal end of the construct (See SEQ ID NOs: 394 or 395 for such constructs.). In certain embodiments, chains 1 and 2 are coupled via a linker known to those skilled in the art, e.g. (G ₄ S)3 (See SEQ ID NOs: 395 and 397 for such a construct.).

[0314] In certain embodiments, antibodies that bind specifically to Fel dl may be prepared using fragments of the above-noted regions, or peptides that extend beyond the designated regions by about 5 to about 20 amino acid residues from either, or both, the N or C terminal ends of the regions described herein. In certain embodiments, any combination of the above-noted regions or fragments thereof may be used in the preparation of Fel dl specific antibodies. In certain embodiments, any one or more of the above-noted regions of Fel dl, or fragments thereof may be used for preparing monospecific, bispecific, or multispecific antibodies.

[0315] The full length proteins, or fragments thereof, that were used as immunogens, as noted above, were administered directly, with an adjuvant to stimulate the immune response, to a VELOCIMMUNE ^® mouse comprising DNA encoding human Immunoglobulin heavy and kappa light chain variable regions.

The antibody immune response was monitored by a Fel dl -specific immunoassay.

When a desired immune response was achieved splenocytes were harvested and fused with mouse myeloma cells to preserve their viability and form hybridoma cell lines. The hybridoma cell lines were screened and selected to identify cell lines that produce Fel dl specific antibodies. Using this technique, and the various immunogens described above, several anti-Fel dl, chimeric antibodies (i.e. , antibodies possessing human variable domains and mouse constant domains) were obtained; certain exemplary antibodies generated in this manner were designated as H1M1230N, H1M1234N, H1M1241N, H2M1233N, H2M1236N, H2M1237N, and H2M1242N.

[0316] Anti-Fel dl antibodies were also isolated directly from antigen-positive B cells without fusion to myeloma cells, as described in U.S. 2007/0280945 Al, herein specifically incorporated by reference in its entirety. Using this method, several fully human anti-Fel dlantibodies (i.e., antibodies possessing human variable domains and human constant domains) were obtained; exemplary antibodies generated in this manner were designated as follows: H4H2574P, H4H2590S, H4H2592B, H4H2594S, H4H2597P, H4H2606B, H4H2607B, H4H2608B, H4H2636P, H4H2645P, H4H2793P, H4H2797P and H4H2864P.

[0317] The biological properties of the exemplary antibodies generated in accordance with the methods of this Example are described in detail in the Examples set forth below.

Example 2. Heavy and Light Chain Variable Region Amino Acid Sequences

[0318] Table 1 sets forth the heavy and light chain variable region amino acid sequence pairs of selected antibodies specific for Fel dl and their corresponding antibody identifiers. Antibodies are typically referred to herein according to the following nomenclature: Fc prefix (e.g. "H4H", "HIM, "H2M"), followed by a numerical identifier (e.g. "1232" as shown in Table 1), followed by a "P" or "N" suffix. Thus, according to this nomenclature, an antibody may be referred to as, e.g. "H1M1232N". The H4H, HIM, and H2M prefixes on the antibody designations used herein indicate the particular Fc region of the antibody. For example, an "H2M" antibody has a mouse IgG2 Fc, whereas an "H4H" antibody has a human IgG4 Fc. As will be appreciated by a person of ordinary skill in the art, an HIM or H2M antibody can be converted to an H4H antibody, and vice versa, but in any event, the variable domains (including the CDRs), which are indicated by the numerical identifiers shown in Table 1, will remain the same.

Antibodies having the same numerical antibody designation, but differing by a letter suffix of N, B, S or P refer to antibodies having heavy and light chains with identical CDR sequences but with sequence variations in regions that fall outside of the CDR sequences (i.e., in the framework regions). Thus, N, B, S and P variants of a particular antibody have identical CDR sequences within their heavy and light chain variable regions but differ from one another within their framework regions.

Table 1

H4H2645P 322 324 326 328 330 332 334 336

H4H2793P 338 340 342 344 346 348 350 352

H4H2797P 354 356 358 360 362 364 366 368

H4H2864P 370 372 374 376 378 380 382 384

H4H2574B 428 430 432 434 436 438 440 442

H4H2597B 444 446 448 450 452 454 456 458

H4H2636B 460 462 464 466 468 470 472 474

H4H2645B 476 478 480 482 484 486 488 490

Example 3. Variable Gene Utilization Analysis

[0319] To analyze the structure of antibodies produced, the nucleic acids encoding antibody variable regions were cloned and sequenced. From the nucleic acid sequence and predicted amino acid sequence of the antibodies, gene usage (VH, D, J _H , VK, or J _K ) was identified for each Heavy Chain Variable Region (HCVR) and Light Chain Variable Region (LCVR). Table 2 sets forth the gene usage for selected antibodies in accordance with the invention.

Table 2

H4H2594S 226/234 3-11 6-6 4 1-16 4

H4H2597P 242/250 3-11 6-6 4 6-21 1

H4H2606B 258/266 3-11 3-9 4 6-21 1

H4H2607B 274/282 3-11 1-26 4 1-17 2

H4H2608B 290/298 3-11 1-26 4 6-21 1

H4H2636P 306/314 3-23 1-1 4 1-5 4

H4H2645P 322/330 3-23 ND 1 1-16 3

H4H2793P 338/346 3-7 3-16 4 1-12 1

H4H2797P 354/362 3-33 5-12 3 1-16 3

H4H2864P 370/378 3-23 1-7 4 1-9 3

Example 4. Antibody Binding to Fel dl as Determined by Surface Plasmon Resonance

[0320] Binding associative and dissociative rate constants (k _a and k _& , respectively) and calculated equilibrium dissociation constants and dissociative half-lives (Κ _Ό and tm, respectively) for antigen binding to anti-Fel dl monoclonal antibodies were determined using a real-time surface plasmon resonance biosensor (Biacore T200 or Biacore 2000) assay. The Biacore sensor surface was derivatized with either polyclonal rabbit anti-mouse antibody (GE Healthcare, # BR- 1008-38) or with monoclonal mouse anti -human Fc antibody (GE Healthcare, # BR-1008-39) to capture anti-Fel dl antibodies, expressed with mouse Fc (antibody ID prefix HIM, H2M, H2aM, H2bM) or human IgG4 Fc (antibody ID prefix H4H), respectively. For kinetic fits, at least two different concentrations (ranging from 390 pM to 67nM) of natural Fel dl (Indoor Biotech, # NA-FD1-2) or a recombinant version of the protein, Fel dl (B-A)-mmH (SEQ ID NO: 396) were injected over the anti-Fel dl monoclonal antibody-captured surface at 25°C at a flow rate of 50μ1/ιηίη in running buffer (lOmM HEPES, 150mM NaCl, 0.05% P20, 3mM MgCl ₂ , 3mM CaCl ₂ ). Fel dl (B-A)-mmH was expressed in Chinese hamster ovary (CHO) cells and is comprised of amino acids 18-109 of Fel dl B (accession #P30440) fused in-line with amino acids 23-92 of Fel dl A (accession #P30438) with a C-terminal myc-myc-hexahistidine tag. Antibody- antigen association was monitored for 3 to 5 minutes, and the dissociation of antigen from the captured monoclonal antibody (in running buffer alone at 25°C) was monitored for 10 or 15 minutes. Kinetic association (k _a ) and dissociation (k _& ) rate constants were determined by processing and fitting the data to a 1 : 1 binding model using Scrubber 2.0 curve fitting software. Binding dissociation equilibrium constants (Κ _Ό ) and dissociative half-lives (tm) were calculated from the kinetic rate constants as: Κ _Ό = k k _a and t = 1η(2)Λ¾· Binding parameters for different anti-Fel dl monoclonal antibodies are tabulated in Table 3 and Table 4. Table 3 shows the Biacore affinities at 25°C for natural Fel dl binding to captured anti- Fel dl monoclonal antibodies and Table 4 shows the Biacore affinities at 25°C for recombinant Fel dl binding to captured anti-Fel dl monoclonal antibodies.

[0321] As shown in Table 3, 10 of the 25 antibodies tested exhibited Κ _Ό values below InM for binding to natural Fel dl, ranging from 207 pM to 982 pM. As shown in Table 4, 17 of the 25 antibodies tested exhibited Κ _Ό values below InM for binding to recombinant Fel dl, ranging from 144 pM to 924 pM. Two of the antibodies, H4H2574B and H4H2793P, bound to recombinant, but not natural Fel dl under these experimental conditions

Table 3

of recombinant Fel dl (67nM, 200nM, and 600nM) were used for this sample Table 4

*Because of the lower observed binding affinity, higher injected concentrations of recombinant Fel dl (67nM, 200nM, and 600nM) were used for this sample

Example 5. Cross Competition of anti-Fel dl Antibodies for Binding to Natural (n) Fel dl

[0322] A binding experiment was performed using an Octet Red biosensor system (Fortebio Inc.) to determine cross-competition for a panel of 8 anti-Fel dl antibodies binding to natural Fel dl (nFel dl; Indoor Biotechnologies, #NA-FD1- 2). The experiment was performed at 25°C in HBST buffer (0.01 M HEPES pH7.4, 0.15M NaCl, 3 mM EDTA, 0.05% v/v Surfactant P20) containing 0. lmg/mL BSA. A washing step with the HBST buffer was performed between each binding step, and plates were agitated during the binding and washing steps using an orbital plate shaker at lOOOrpm. A first anti-Fel dl antibody (niAb-1) was captured for 2 minutes onto the anti-hFc biosensor surface from stock solutions of antibody at lOug/mL (final capture levels ~1.5nm response units). The coated sensor tips were then blocked for 5 minutes with a l OOug/mL solution of an irrelevant antibody. Sensor tips were then submerged into wells containing 500nM of nFel dl for 5 minutes, and then into wells containing 50 ug/mL solutions of a second anti-Fel dl antibody (mAb-2). The mAb-2 solutions were supplemented with l OOug/mL of an irrelevant antibody to minimize non-specific binding. The binding responses for mAb-2 binding to nFel dl pre-complexed with mAb-1 were measured for the 8x8 antibody matrix (Table 5). Each binding value for mAb-2 binding to a different mAb-l/Fel dl capture surface (down a column in Table 5) was subtracted by the mAb-l/Fel dl/mAb-2 self-competition value (where mAb-1 = mAb-2; across the diagonal in Table 5). Values below O. lOnm indicate cross-competition of mAb-1 and mAb-2 to a common binding site on Fel dl .

[0323] Four antibodies, H4H2636P, H4H1616N, H4H2645P, and H4H2864P, bi-directionally compete with each other for binding to nFel dl, but do not compete with any of the other anti- Fel dl antibodies. Two antibodies,

H4H1232N and H4H2597P, bi-directionally compete with each other for binding to nFel dl . Both H4H1232N and H4H2597P uni-directionally compete with H4H1300N. Bi-directional competition with H4H1300N could not be determined because H4H1300N did not pre-complex with nFel dl . H4H1238N did not compete with any of the anti- Fel dl antibodies for binding to nFel dl .

Table 5

Example 6. Effect of anti-Fel dl Antibodies in a Passive Cutaneous Anaphylaxis (PCA) in vivo Model

[0324] The passive cutaneous anaphylaxis (PCA) in vivo model was used to assess in vivo mast cell degranulation. The model involves intradermal injection of an allergen-specific antiserum into a local area on the skin followed by intravenous injection of an antigen along

with a dye. The allergic reaction causes capillary dilatation and increased vascular permeability at the site of sensitization, resulting in preferential accumulation of dye at this site. The dye can be extracted from the tissue and quantitated spectrophotometrically. Dye extravasation into tissue sensitized with test antiserum is compared to extravasation into tissue sensitized with a non- relevant antiserum. [0325] Antisera were generated by immunizing Balb/c mice with 5 μg natural

Fel dl protein purified from cat hair extract (Indoor Biotechnologies, # LTN-

FDl-1), 5 μg of crude peanut allergen extract (Greer Laboratories, #

XPF171D3A25), or 1250 of Bioequivalent allergy units (BAU) of standardized cat hair extract (Greer Laboratories, #GTE3A01) in a solution of lmg/ml of alum

(Pierce, # 77161) in IX phosphate buffered saline. Two weeks later (day 14) sensitized mice were boosted with doses of allergen identical to those used for the initial immunization. Two weeks after the boost (day 28), mice were sacrificed and serum was collected. Total IgE concentration in the isolated antisera was determined by ELISA. The final concentration of antiserum was diluted to

2400ng/mL IgE in IX phosphate buffered saline.

[0326] To determine the effect of anti-Fel dl antibodies on mast cell degranulation in the PCA model, prior to ear sensitization with antiserum generated as described above, groups of Balb/c mice were first injected subcutaneously with either a human IgG4 isotype control antibody, an anti-Fel dl antibody, or a combination of anti-Fel dl antibodies at doses of 5mg/kg (total antibody dose, 2.5mg/kg of each antibody) for single point experiments unless otherwise indicated or at concentrations ranging from 0.06mg/kg to 2mg/kg for dose-ranging experiments. Three days after pre-treatment with antibodies, one group of mice ("natural Fel dl group") was sensitized by intradermal injection with ΙΟμΙ of natural Fel dl -derived antiserum or ΙΟμΙ of peanut-derived antiserum

(negative control) into the right and left ears, respectively, of each mouse. A second group of mice ("cat extract group") was sensitized with 20μ1. of cat hair extract-derived antiserum or 20μ1. of peanut-derived antiserum (negative control) into the right and left ears, respectively, of each mouse. Twenty-four hours after sensitization, mice in the natural Fel dl group were challenged by intravenous injection (100 μΐ. per mouse) of a solution of 0.25 μg/mL natural Fel dl (Indoor

Biotechnologies, # LTN-FDl-1) dissolved in IX phosphate buffered saline containing 0.5% (w/v) Evan's blue dye (Sigma, # E2129). Similarly, 24 hours after sensitization, mice in the cat extract group were challenged with 250BAU of standardized cat hair extract [standardized cat hair extract (Greer Laboratories,

#GTE3A01)] dissolved in IX phosphate buffered saline containing 0.5% (w/v)

Evan's blue dye (Sigma, # E2129). One hour after antigen challenge, mice were sacrificed, ears were excised and placed in 1 mL formamide and incubated for 3 days at 56 C to extract the Evan's blue dye from the tissue. Ear tissue was then removed from the formamide, blotted to remove excess liquid and weighed. Two hundred microliter aliquots of each formamide extract were transferred to 96 well plates in duplicate. Absorbance of the resulting supernatants was measured at 620nm. The OD was converted to Evan's blue dye concentration using a standard curve. The average concentration of Evan's blue dye extravasated into the tissue of the antisera-sensitized ear (normalized by ear tissue weight) was calculated for the group treated with the isotype control antibody and defined as F(isotype,avg). The reduction in Evan's blue dye extravasation resulting from antibody pre- treatment was calculated per mouse by subtracting the amount of Evan's blue dye for the antibody-treated group's Fel dl or extract sensitized ear, defined as F(mAb,i), from F(isotype,avg). This number was then divided by the difference between F(isotype,avg) and the dye amount for the antibody-treated group's peanut sensitized ear [P(mAb,i)] and multiplied by 100 to give the overall percent reduction in dye extravasation for each mouse (% Reduction).

[0327] % Reduction (per mouse) = 100*[F(isotype,avg) - F(mAb,i)]/[F(isotype,avg) - P(mAb,i)]

[0328] The average percent reduction in dye leakage was then calculated for each antibody group. Results, expressed as (mean ± SD) of percent Evan's blue reduction are shown in Table 6 and Table 7 for the natural Fel dl group and in Table 8 for the cat hair extract group.

[0329] As shown in Table 6, seven groups of mice from the natural Fel dl group, when treated with specific combinations of anti-Fel dl antibodies at fixed concentrations, exhibited reductions in dye extravasations ranging from 79% to 103% compared to mice receiving control antibody. Mice treated with

H4H2590S/H4H1238N, H4H2590S/H4H2574P, or H4H1232N/H4H1616N pairwise antibody combinations exhibited less than 3% reduction in dye extravasation compared to mice receiving control antibody, demonstrating that not all anti-Fel dl antibodies tested in this model were efficacious.

[0330] In addition, dose-ranging experiments were performed with mice from the natural Fel dl group, as shown in Table 7. Single antibodies were not as effective at reducing dye extravasation as the anti-Fel dl antibody combinations at the tested doses. [0331] A specific pair of anti-Fel dl antibodies (H4H2636P and H4H1232N) at multiple dose levels, as well as each of these anti-Fel dl antibodies alone at a single (highest) dose level, was further tested in the PCA model using mice that were sensitized and challenged with cat hair extract as shown in Table 8. At 2mg/kg, these single anti-Fel dl antibodies alone were not as efficacious at reducing dye extravasation as a combination of the two antibodies. The combination of H4H2636P and H4H1232N at both 2mg/kg and lmg/kg reduced dye extravasation by more than 90% as compared with the isotype control in the PCA model using cat hair extract as the antigen.

[0332] All reductions that were statistically significant (p<0.05) compared to isotype control as determined by two-way ANOVA with Bonferroni's post-test are noted with an asterisk (*). The number of mice used per group (n) is noted within parentheses in the tables.

Table 6

§10mg/kg total antibody concentration; **0.5mg/kg total antibody concentration Table 7

0±49

H4H2597P (n=5)

28±51

H4H2636P (n=5)

Studv 6

64±41* 27±25 18±39 0±16

H4H2597P+H4H2645P (n=10) (n=5) (n=5) (n=5)

7±31

H4H2597P (n=5)

0±26

H4H2645P (n=5)

Table 8

Example 7. Effect of anti-Fel dl antibodies in a lung inflammation in vivo model

[0333] The lung inflammation in vivo mouse model is used to assess allergen induced lung inflammation and mucus accumulation that could be associated with asthma or rhinoconjuctivitis. The model involves repeated intranasal

administration of an allergen into previously allergen-sensitized mice. The allergen-associated inflammation can cause increases in lung mucus

accumulation, eosinophil migration into the lung, serum total IgE, and allergen specific IgGl levels.

[0334] Balb/c mice were intraperitoneally immunized with lug of natural Fel d 1 protein purified from cat hair extract (Indoor Biotechnologies, #LTN-FD1-1) in a solution of Img/mL of alum (Pierce, # 77161) in IX phosphate buffered saline. Seven days later, sensitized mice were boosted intraperitoneally with 1 ug of natural Fel d 1 in a solution of lmg/mL alum in IX phosphate buffered saline. On days 17, 21, and 25, groups of mice (n=5) were injected subcutaneously with a human IgG4 isotype control antibody or a 1 : 1 combination of anti- Fel d 1 antibodies, H4H1232N and H4H2636P, at 20mg/kg (total antibody dose). On days 20, 24, and 28, mice were intranasally challenged with 0.05 ug of natural Fel d 1 diluted in 20 uL of IX phosphate buffered saline. Control mice were challenged with 20 uL of IX phosphate buffered saline on the same days. On day 32, all mice were sacrificed and their lungs were harvested. Experimental dosing and treatment protocol for groups of mice are shown in Table 9.

[0335] To determine circulating total IgE and Fel d 1 specific IgGl in the serum of the mice, serum samples were collected for each mouse via terminal cardiac puncture using a 27G1/2 1 mL TB syringe (Becton Dickinson, #309306) with a needle attached. Blood samples were placed into BD microtainer® serum separator tubes (Becton Dickinson, #365956), centrifuged, and then the serum was transferred to a fresh tube for storage until analysis.

[0336] To determine the total IgE concentration in the serum samples for each mouse, a sandwich ELISA OPTEIA kit (BD Biosciences, #555248) was used according to the manufacturer's instructions. Serum samples were diluted and incubated with anti-IgE capture antibody coated on 96-well plates. Total IgE was detected by biotinylated anti-mouse IgE secondary antibody. Purified horseradish peroxidase (HRP)-labeled mouse IgE was used as a standard. The chromagen 3,3',5,5'-tetramethylbenzidine (TMB) (BD OPTEIA substrate reagent set, BD, #555214) was used to detect HRP activity. A stop solution of 1M sulfuric acid was then added, and absorbance at 450nm was measured on a Molecular Devices SpectraMax M5 plate reader. Data analysis was performed using Prism™ software. The mean amounts of circulating IgE levels in serum for each experimental group are expressed as ng/mL (± SEM) as shown in Table 10. Mice challenged with Fel d 1 intranasally when treated with the combination of anti- Fel d 1 antibodies exhibited a significant decrease in the amount of circulating IgE [6683 (±1394) ng/mL] compared to mice receiving isotype control antibody [14080 (±1505) ng/mL].

[0337] To determine the Fel d 1 specific IgGl levels in the serum samples from each mouse, an ELISA was utilized. Fel d 1 coated plates were incubated with serially diluted mouse serum samples, followed by incubation with anti-mouse IgGl-HRP conjugated antibody (BD Biosciences, # 559626). All samples were developed with a TMB solution and analyzed as described above. Relative levels of circulating IgGl in serum were represented as titer units (titer units were calculated by multiplying the measured OD by a dilution factor required to achieve OD450 that was greater than two times background). The mean circulating Fel d 1 -specific IgGl levels in serum for each experimental group are expressed as titer x 10 ³ (±SEM) as shown in Table 11. Mice challenged with Fel d 1 intranasally when treated with the combination of anti- Fel d 1 antibodies exhibited a significant decrease in the amount of Fel d 1 -specific IgGl levels in serum [titer of 105.3 (±31.33) xlO ³ ] when compared to mice receiving isotype control antibody [titer of 526.1 (±144.0) xlO ³ ].

Lung harvest for cell infiltrate analysis:

[0338] After exsanguination, the right lung from each mouse was removed and placed into a small petri dish containing Dulbecco's Modified Eagle Medium

(DMEM) (Irvine Scientific, #9033) and chopped into cubes that were

approximately 2 to 3 mm in size. The cubes were then transferred to a tube containing a solution of 20 μg/mL DNAse (Roche, #10104159001) and 0.7 U/mL

Liberase TH (Roche, #05401151001) diluted in Hank's Balanced Salt Solution

(HBSS) (Gibco, #14025) and placed into a 37°C water bath for 20 minutes with vortexing every 5 minutes. This reaction was then stopped by adding

ethylenediaminetetraacetic acid (EDTA) (Gibco, #15575) at a final concentration of lOmM. Each lung was mashed, filtered through a 70 μιτι filter, centrifuged, and then lung pellet was resuspended in 4 mL of ACK lysing buffer (Gibco, #10492) to remove red blood cells. After a 3 minute room temperature incubation, DMEM was added to deactivate the ACK buffer. The cell suspensions were centrifuged, and the cell pellets were then resuspended into 10 mL of MACS buffer solution [a mixture of Miltenyi auto MACS Rinsing Solution (Militenyi Biotec, #130-091-

222) and MACS BSA (Militenyi Biotec, #130-091-376)]. The resuspended samples were filtered through a 70 μιτι filter and lxlO ⁶ cells were plated into a 96- well V-bottom plate. Cells were then centrifuged and the pellets were

resuspended in purified rat anti-mouse CD16/CD32 Fc Block, (BD Biosciences

Clone: 2.4G2, #553142) diluted in MACS Buffer for 15 minutes at 40°C. The cells were washed twice and were then incubated in the appropriate antibody mixture (described in Table 12) diluted in MACS buffer for 30 minutes at 4°C protected from light. After antibody incubation, the cells were washed twice in MACS buffer and resuspended in BD cytofix (BD Biosciences, #554655) for 15 minutes at 4°C while being protected from light. The cells were washed, resuspended in MACS buffer and were then transferred to BD FACS tubes (BD Biosciences, #352235) for analysis of eosinophils by flow cytometry. Eosinophils were defined as cells that were CD45 ⁺ , GR1 ^" , CD1 lc'°, SiglecF". Data are expressed as frequency of eosinophils in CD45 ⁺ cells (± SEM) in Table 13.

[0339] Mice challenged with Fel d 1 intranasally when treated with the combination of anti- Fel d 1 antibodies exhibited a significant decrease in the frequency of eosinophils in the CD45 ⁺ cell population as compared to mice receiving no antibody (67% decrease) or receiving isotype control antibody (46% decrease) as shown in Table 13.

Lung harvest for histological analysis:

[0340] After exsanguination, the left lungs were removed and placed into tubes containing a 5 mL solution of 4% (w/v) paraformaldehyde (Boston Bioproducts, # BM-155) in IX phosphate buffered saline and stored at room temperature for 3 days. Lung samples were then blotted dry and transferred to tubes containing 70% ethanol for histological analysis. The samples were sent to Histoserv, Inc (Germantown, MD) for sectioning and periodic acid Schiff (PAS) staining.

[0341] Approximately 35 digital images across the full area of each PAS- stained lung section were acquired using a Zeiss Axioplan 2 Imaging light microscope with a Zeiss AxioCam MRc camera. A whole lung image was then constructed from the smaller images and analyzed using ImageJ software with the aid of a color threshold plugin. The regions of mucus accumulation in the bronchial lumen were identified and quantitated through a user-chosen color threshold and normalized to the total area of the lumen that was identified and quantitated by a separate color threshold setting. Percentage of the bronchial lumen occupied by mucus accumulation for each lung was expressed as [(mucus area/lumen area) x 100] and was calculated for each treatment group. Results, expressed as mean percent lung obstruction (± SEM) are shown in Table 14. [0342] Mice treated with the combination of anti- Fel d 1 antibodies exhibited a trend towards reduced mucus accumulation in the lung bronchi (5.21+/-0.81 % mucus accumulation) compared to mice receiving control antibody (10.81+/- 1.13% mucus accumulation) in the lung inflammation model as shown in Table 14.. No differences were observed in bronchial lumen size or overall lung size between the groups of mice.

Table 9: Experimental dosing and treatment protocol for groups of Balb/c

Table 10: Total Circulating IgE levels in Mouse Serum

Table 11: Circulating Fel d 1-specific IgGl in Mouse Serum

Table 12: Antibodies Used for Flow Cytometry Analysis

Table 13: Frequency of eosinophils in CD45 cells as determined by flow cytometry

Table 14: Lung Obstruction (mucus area/lumen area,

Example 8. Epitope Mapping by Hydrogen-Deuterium Exchange

[0343] In order to determine the epitopes of Fel dl (a heterodimeric protein comprised of Fel dl chain A and FELD1 chain B) recognized by two anti-Fel dl antibodies, studies were done using hydrogen-deuterium (H/D) exchange.

[0344] Studies were performed for each antibody co-complexed with Fel dl . Prior to the H/D exchange experiments, CHO cell-expressed recombinant Fel dl comprised of amino acids 18-109 of Feld 1 chain B (GenBank accession number NP 001041619.1) fused in-line with amino acids 19-88 of FELD1 A (GenBank accession #NP_001041618.1) expressed with a C-terminal myc-myc- hexahistidine tag and with a D27G mutation (Fel dlB-A-mmH; SEQ ID: 396) was deglycosylated at 37°C for 4 hours under native conditions using PNGase F (New England BioLabs, #0704). For this study, two anti-FELDl antibodies (H4H1232N and H4H2636P) were covalently attached to N-hydroxysuccinimide (NHS) agarose beads (GE Lifescience, #17-0906-01) according to the manufacturer's protocol.

[0345] To map the Fel dlB-A-mmH binding epitope recognized by

H4H1232N, two sets of H/D exchange experiments were carried out (all binding and exchange reactions carried out at room temperature). The first experiment used an 'on-solution/off-beads' format (on-exchange in solution followed by off- exchange on beads). For the on-exchange, the deglycosylated Fel dlB-A-mmH protein was deuterated for 5 and 10 minutes (in two separate sub-experiments) in PBS buffer at pH 7.4 prepared with D ₂ 0 (PBS-D) and was then bound to the H4H1232N beads during a 2-minute incubation in PBS-D. The co-complex of Fel dlB-A-mmH-bound to H4H1232N beads was then washed with PBS buffer at pH 7.4 prepared with H ₂ 0 (PBS-H) and incubated in PBS-H for half of the on- exchange time (off-exchange), allowing only the epitopes on Fel dlB-A-mmH protected by the binding of the H4H1232N antibody to remain deuterated. After the off-exchange, the bound Fel dlB-A-mmH was eluted from the beads using an ice-cold 0.1% aqueous trifluoroacetic acid (TFA) solution. The eluted Fel dlB-A- mmH was then digested with immobilized pepsin (Thermo Scientific, #20343) for 5 minutes at 4°C. The resulting peptides were desalted at 4°C using ZipTip chromatographic pipette tips (Millipore, #ZTC18S096) according to the manufacturer's protocol and then immediately analyzed on an UltrafleXtreme matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometer (MS).

[0346] The second experiment is referred to as the 'on-beads/off-beads' (on- exchange on beads followed by off-exchange on beads). For this experiment, the deglycosylated Fel dlB-A-mmH was first bound to the H4H1232N beads, and then incubated for 5 or 10 minutes (in separate sub-experiments) in PBS-D to allow on-exchange. The following steps (off-exchange, pepsin digestion, and MS analysis) were carried out as described for the Όη-solution/off-beads' procedure above. The centroid values or average mass-to-charge ratios (m/z) of all the detected peptides were calculated and compared between the on-solution/off- beads and on-beads/off-beads experiments. Peptides exhibiting increased mass after the on-solution/off-beads procedure compared to the on-beads/off-beads procedure include amino acids within the Fel dl protein protected from exchange as a result of antibody binding and therefore reveal binding epitope regions.

[0347] The H/D exchange experiment for Fel dlB-A-mmH binding to the anti- Fel dl antibody H4H2636P was performed using the same procedure described above for H4H1232N, but with H4H2636P beads replacing the H4H1232N beads.

[0348] A comparison of the centroid m/z values for all the peptides detected in the H/D exchange experiment of Fel dlB-A-mmH with H4H1232N are shown in Table 15. These peptides were identified by liquid chromatography -matrix assisted laser desorption ionization (LC-MALDI) MS. Most peptic peptides gave similar centroid values (differences < 0.3 m/z units) for both the on-solution/off- beads and on-beads/off-beads protocols, for each of two different on-exchange and off-exchange times. However, three peptides with amino acids spanning from 85-103, 85-104, and 113-127 of Fel dlB-A-mmH (SEQ ID NO: 396) had differences in m/z centroid values > 0.3 in both the 5 minute and 10 minute experiments. The differences between these centroid values from the on- solution/off-beads and on-beads/off-beads protocol are highlighted in bold in Table 15. Since another peptide, amino acids 117-127 of SEQ ID NO: 396, did not show deuteron retention after off-exchange, the region of protection from exchange in the 113-127 peptide can be reduced to residues 113-116 of SEQ ID NO: 396. The two regions, residues 85-104 (SEQ ID NO: 403) and 113-116 (SEQ ID NO: 426), are protected from full off-exchange as a result of H4H1232N binding to Fel dlB-A-mmH after on-exchange. Therefore, these two segments are defined by the H/D exchange method as a discontinuous epitope for antibody H4H1232N binding to the Fel dlB-A-mmH protein.

[0349] Comparisons of the centroid m/z values for the peptides detected in the H/D exchange experiment of Fel dlB-A-mmH complexed with H4H2636P are shown in Table 16. Only one peptide, amino acids 15-24 of FELDlB-A-mmH, exhibited an increase in the centroid m/z values > 0.3 m/z for the on-solution/off- beads condition compared to the on-beads/off-beads condition, indicating that this segment was protected from full off-exchange by the binding of H4H2636P. The centroid value differences greater than 0.3 m/z are highlighted in bold in Table 16. Therefore, amino acids within this 15-24 region (SEQ ID NO: 412) based on the H/D exchange method include an epitope for antibody H4H2636P binding to the Fel dlB-A-mmH protein.

Table 15: The Effect on H/D Exchange of H4H1232N Binding to Fel dlB-A- mrnH as Measured by Centroid m/z Values of Peptic Peptides

LDKIYTSPLC

GPGGEQKL

153-170 1920.33 1920.25 0.09 1920.37 1920.38 -0.01

(SEQ ID NO: 407)

ISEEDLSGH

183-196 1672.54 1672.59 -0.04 1672.54 1672.51 0.03 HHHHH (SEQ

ID NO: 408)

ISEEDLSGH HHHHHSSG

183-199 1903.91 1903.95 -0.03 1903.95 1903.92 0.03

(SEQ ID NO: 409)

EDLSGHHHH

186-199 1574.44 1574.44 0.01 1574.44 1574.47 -0.03 HHSSG (SEQ

ID NO: 410)

Table 16: The Effect on H/D Exchange of H4H2636P Binding to Fel dlB-A- mrnH as Measured by Centroid m/z Values of Peptic Peptides

LKLNTLGRE

ICPAVKRGV

85-103 2083.63 2083.63 0 2083.67 2083.62 0.04

D (SEQ ID NO: 416)

LKLNTLGRE ICPAVKRGV

85-104 2196.67 2196.74 -0.07 2196.8 2196.78 0.02

DL (SEQ ID NO: 417)

YVEQVAQY KALPVVL

113-127 1721.28 1721.27 0.01 1721.19 1721.21 -0.02

(SEQ ID NO: 418)

VAQYKALP

117-127 1201.55 1201.53 0.02 1201.55 1201.59 -0.04 WL (SEQ ID

NO: 419)

YKALPVVL

120-127 903.18 903.12 0.06 903.14 903.14 -0.01 (SEQ ID NO:

420)

ENARILKNC VDAKM

128-141 1606.41 1606.34 0.08 1606.57 1606.46 0.11

(SEQ ID NO: 421)

LDKIYTSPLC GPGGEQKL

153-170 1920.29 1920.23 0.06 1920.24 1920.36 -0.13

(SEQ ID NO: 422)

ISEEDLSGH

183-196 1672.56 1672.59 -0.02 1672.58 1672.54 0.04 HHHHH (SEQ

ID NO: 423)

ISEEDLSGH HHHHHSSG

183-199 1903.9 1903.89 0.01 1903.94 1903.93 0.02

(SEQ ID NO: 424)

EDLSGHHHH

186-199 1574.4 1574.37 0.03 1574.41 1574.37 0.04 HHSSG (SEQ

ID NO: 425) Example 9. Generation of Bi-specific Antibodies

Description of the Fel d 1 Bispecific Antibodies Produced

[0350] Bi-specific antibodies comprising heavy and light chain binding domains from pairs of certain of the anti-Fel dl antibodies described in the present invention were constructed using standard methodologies. The ant-Fel dl antibodies used to construct the bi-specific antibodies of this example were obtained by immunizing a Veloclmmune® mouse with a primary immunogen, such as full length natural Fel dl, which may be purchased commercially (e.g., from Indoor Biotechnologies, # LTN-FDl-1), or isolated from cat hair or dander by multi-step column chromatography (See, for example, Chapman MD, et al. (1988), J. Immunol. 140:812-818), or which may be produced recombinantly (See GenBank accession numbers P30438, or NP_001041618.1 for the full length amino acid sequence of chain 1 of Fel dl (also referred to as chain A or FELD1 A; also see SEQ ID NO: 392) and GenBank accession number P30440, or

NP_001041619.1 for the full length amino acid sequence of chain 2 of Fel dl (also referred to as chain B or FELD B; also see SEQ ID NO: 393), or fragments of either chain 1 or chain 2, or fragments from both chain 1 and chain 2 of the Fel dl protein, followed by immunization with a secondary immunogen, or with an immunogenically active fragment of the natural protein. In one embodiment, the immunogen used is exemplified in SEQ ID NO: 394 (in line fusion of Fel dl Chain2 -Chainl-mFc) or SEQ ID NO: 395 (fusion of Fel dl Chain 1 using a linker and Chain 2 -mFc).

[0351] The bi-specific antibodies produced in accordance with the present Example comprise two antigen-binding domains (i.e. "binding arms 1 and 2").

[0352] One of the bi-specific antibodies, designated H4H3467D comprises a common kappa light chain on both Fab arms, derived from the antibody

H4H2864P (SEQ ID NO: 378). One Fab arm of H4H3467D utilizes the heavy chain variable region (V _H ) from the antibody H4H2864P (SEQ ID NO: 370), while the other Fab arm utilizes the V _H region from H4H1232N (SEQ ID NO: 18).

[0353] A second bi-specific antibody of the invention, designated H4H8751D, comprises a common kappa light chain on both Fab arms, derived from the antibody H4H2636P (SEQ ID NO: 314). One Fab arm of H4H8751D utilizes the V _H region from H4H2636P (SEQ ID NO: 306), while the other Fab arm utilizes the V _H region from H4H1232N (SEQ ID NO: 18).

[0354] Table 17 below provides the component parts of the antigen-binding domains of the two bi-specific antibodies made in accordance with Example 9. The amino acid sequence identifiers for the various heavy chain and light chain variable regions that were derived from the parental antibodies (used to prepare the bi-specific antibodies) are also provided in Table 17.

Table 17. Component parts of the two arms of the bi-specific antibodies produced

[0355] Tables 18A and 18B below set forth the amino acid sequence identifiers for the various heavy chain variable regions (Table 18A) and the light chain variable regions (Table 18B) and their corresponding complementarity determining region sequences (CDRs) for the two bi-specific antibodies described herein.

Table 18A. HCVR and HCDR Sequence Identifiers for bi-specific antibodies produced

H4H8751D H4H2636P 306 308 310 312 (Arm 1)

H4H1232N 18 20 22 24 (Arm 2)

Table 18B. LCVR and LCDR Sequence Identifiers for bi-specific antibodies produced

Biacore Analysis of Bi-specific Antibodies to Determine Association and Dissociation Values

[0356] Binding association and dissociation rate constants (k _a and k _& , respectively), equilibrium dissociation constants and dissociation half-lives (Κ _Ό and ti/2, respectively) for natural Fel d 1 (subsequently referred to as nFel d 1) binding to purified anti-Fel d 1 monospecific and bispecific antibodies were determined using a real-time surface plasmon resonance biosensor assay on a

Biacore 2000 instrument. On a CM5 chip, using the EDC-NHS chemistry, the

Biacore sensor surface was derivatized with a monoclonal mouse anti-human Fc antibody (GE, # BR-1008-39) to capture anti-Fel d 1 monospecific and bispecific antibodies. All the Biacore binding studies were performed at 25°C in HBSP+ running buffer (0.01M HEPES pH 7.4, 0.15M NaCl, 3mM CaCl ₂ , 3mM MgCl ₂ ,

0.05% v/v Surfactant P20). Different concentrations of nFel d 1 (Indoor Biotech, #

NA-FDl-2) (ranging from 600nM to 2.34nM, 6-fold dilutions) prepared in HBSP+ running buffer were injected over the anti-Fel d 1 antibody captured surface at a flow rate of 50μΕ/ιηίη. Association of nFel d 1 to the captured monoclonal antibodies was monitored for 4 minutes and the dissociation of nFel d 1 in HBSP+ running buffer was monitored for 7 minutes. Kinetic association (k _a ) and dissociation (¾) rate constants were determined by fitting the real-time sensorgrams to a 1 : 1 binding model with mass transport limitation using Scrubber 2.0c curve fitting software. Binding dissociation equilibrium constants (¾) and dissociative half-lives (ti/2) were then calculated from the kinetic rate constants as: Κ _Ό (M) = k _d I k _a and t _½ (min) = [1η2/(60*λ¾)].

[0357] Binding kinetics of nFel dl binding to different anti-Fel d 1 monospecific and bi-specific antibodies at 25°C are shown in Table 19. The three monospecific anti-Fel d 1 antibodies bound to nFel dl with Κ _Ό values ranging from 155pM to 1.6nM. The two bi-specific anti-Fel dl antibodies, H4H3467D and H4H8751D, bound to nFel dl with : _D values of 250pM and 347pM respectively.

Table 19: Binding Kinetics of anti-Fel dl mono-specific and bi-specific antibodies binding to nFel d 1 at 25°C.

[0358] To determine the in vivo efficacy of the anti-Fel d 1 bi-specifics compared with their mono-specific parental antibodies, these antibodies along with an isotype control antibody were tested in the PCA in vivo model using natural Fel d 1 for both sensitization and challenging, which was previously described (see Example 6). Antibodies in this study were administered at a concentration of lmg/kg total antibody (0.5mg/kg of each antibody was used when two antibodies were administered simultaneously) using 8 mice per experimental group. The data for each experimental group expressed as percent reduction in dye extravasation ± SD are shown in Table 20. [0359] The mono-specific antibodies H4H1232N and H4H2864P caused a 67 (± 26)% and an 81 (± 26)% reduction in dye extravasation, respectively. The combination of the mono-specific antibodies, H4H1232N and H4H2864P, caused a 98 (± 3.5)% reduction in dye extravasation, while the bi-specific, H4H3467D, composed of the mono-specific antibodies, H4H1232N and H4H2864P, caused a 93 (± 11)% reduction in dye extravasation.

[0360] The mono-specific antibodies H4H1232N and H4H2636P caused a 64 (± 33)% and an 8.7 (± 79)% reduction in dye extravasation, respectively, in another experiment. The combination of the mono-specific antibodies, H4H1232N and H4H2636P, caused a 90 (± 15)% reduction in dye extravasation, while the bi- specific, H4H8751D, composed of the mono-specific antibodies, H4H1232N and H4H2636P, caused a 77 (± 20)% reduction in dye extravasation.

Table 20: Effect of anti-Fel d 1 bispecific antibodies and their parental monospecific antibodies in the passive cutaneous anaphylaxis (PCA) in vivo model

EXAMPLE 10: Targeting Allergens by Passive Immunotherapy with

Monoclonal Antibodies for the Treatment of Allergy

Materials and Methods

Generation of REGN1908 (H4H1232N) and REGN1909 (H4H2636P):

[0361] REGN1908 and REGN1909 were produced as described in Example 1 above. REGN1908 is also referred to as H4H1232N and comprises a heavy chain variable region (HCVR) amino acid sequence of SEQ D NO: 18 and a light chain variable region (LCVR) amino acid sequence of SEQ ID NO: 26. REGN1908 also has the following heavy and light chain complementarity determining region (HCDRs and LCDRs, respectively) amino acid sequences: HCDR1, 2 and 3: SEQ ID NOs: 20, 22 and 24; LCDR1, 2 and 3: SEQ ID NOs: 28, 30 and 32.

REGN1909 is also referred to as H4H2636P and comprises a heavy chain variable region (HCVR) amino acid sequence of SEQ D NO:306 and a light chain variable region (LCVR) amino acid sequence of SEQ ID NO: 314. REGN1909 also has the following heavy and light chain complementarity determining region (HCDRs and LCDRs, respectively) amino acid sequences: HCDR1, 2 and 3: SEQ ID NOs: 308, 310 and 312; LCDR1, 2 and 3: SEQ ID NOs: 316, 318 and 320. Both natural Fel dl (nFel dl ; obtained from Indoor Biotech) and recombinant Fel dl (rFel dl) were used in in vitro assays. Recombinant Fel dl was produced following the design of Kaiser et al. (Kaiser, L. et al, (2003), The Journal of Biological Chemistry 278 (39): 37730-35) who showed that single-chain fusions were structurally and functionally equivalent to the natural Fel dl heterodimer. The Regeneron-produced recombinant proteins include amino acids 18-109 of Fel dl Chain 2 (NP_001041619.1) at the N-terminus fused directly in-line to amino acids 23-92 of Fel dl Chain 1 (NP_001041618.1) with a D27G mutation and a C-term Myc-Myc-6xHis tag. The proteins were expressed in Chinese Hamster Ovary (CHO) cells and made with either a monomeric (myc-myc-hexahistidine) or a dimeric (mouse IgG2a Fc) C-terminal tag (rFel dl-mmH and rFel dl-mFc, respectively). The dimeric Fc fusion FcsRla was generated to support development of the ELISA-based competition assay. Isolation and concentration of IgG from patient sera:

[0362] Serum from cat-allergic patients who underwent physician determined (determined by allergy skin prick test and clinical symptoms) successful immunotherapy (Cat-SIT) and cat allergic control patients (Non-SIT) was first separated from donor blood by centrifugation at 3000rpm. Serum was later passed through 0.22μπι filter and after overnight incubation with 50mL of Protein G sepharose beads at 4°C was poured into column and SIT IgG was eluted with Pierce IgG elution buffer. After neutralization of the eluate with 1M Tris, pH 8.5, samples were dialyzed against PBS, pH 7.2. All the samples were concentrated approximately 10-fold using an Amicon Ultracel with a 50k MW cut off.

Quantitation of total and Fel dl specific IgG in sera from patients undergoing SIT:

[0363] Total and Fel dl -specific IgG levels were quantitated in sera samples from human patients undergoing SIT therapy using a standard ELISA. Ninety-six- well microtiter plates (Thermo Scientific) were coated with 2 μg/mL of either natural Fel dl (LoTox Indoor Biotechnologies) or anti-human IgG (Jackson Immunoresearch) in phosphate-buffered saline (PBS, Irvine Scientific) overnight at 4°C. The next day, plates were washed with PBS containing 0.05% Tween 20 (PBS-T, Sigma- Aldrich) four times using a plate washer (Molecular Devices). Plates were then blocked by incubation for 1 hour at room temperature (RT) with 250 of 0.5% bovine serum albumin (BSA, Sigma-Aldrich) in PBS. Sera or purified IgG from human patients undergoing SIT were serially diluted three-fold in 0.5% BSA-PBS starting at 1 : 1000 (for Fel dl specific IgG) and 1 :27000 (for total IgG), added to the blocked plates in duplicate, and then incubated for 1 hour at RT. The last two wells were left blank to be used as a secondary antibody alone control (background control). For total IgG quantitation, a standard curve was generated using human IgG (Thermo Scientific, # 31154) starting at 1 μg/mL and diluted 3-fold across the plate. For Fel dl-specific IgG quantitation, a standard curve was generated using an anti-Fel dl monoclonal antibody (H4H1238N) also starting at 1 μg/mL and diluted 3-fold across the plate. Goat anti-human IgG-Fc- Horse Radish Peroxidase (HRP) conjugated secondary antibody (Jackson

Immunoresearch) was then added to the plates at 1 :5000 dilution and incubated for

1 hour at room temperature (RT). Plates were washed with PBS-T in between each step of the protocol. To develop the colorimetric reaction, TMB/H2O2 substrate was added to the plates and incubated for 20 minutes. The reaction was stopped using 2 N sulfuric acid (H2SO4, VWR). Absorbance was subsequently measured on a spectrophotometer (Victor, Perkin Elmer) at 450 nm. Total and Fel dl specific IgG were computed from the respective standard curve plots using Graphpad PRISM software.

Blocking ELISA for Fel dl binding to allergen-specific IgE by anti-Fel dl IgG antibodies:

[0364] The ability of anti-Fel dl monoclonal antibodies or purified IgG from SIT patient serum to block Fel dl binding to plate-captured IgE from allergic human donor plasma/sera was determined using a blocking ELISA. Microtiter plates were coated overnight at 4°C with human FcsRla (the high affinity receptor for IgE) extracellular domain protein with a C-terminal mouse Fc tag (hFc DRla- mFc). Plates were blocked with 0.5% BSA (w/v) for 1 hour at room temperature (RT). Plasma from allergic donors was diluted 5-fold and total IgE was captured over the receptor-coated surface. A constant amount of recombinant Fel dl-mmH (0.7 nM) was pre-mixed with serial dilutions of anti-Fel dl monoclonal antibodies and Fel dl specific SIT IgG starting from 10 μg/ml each in 3-fold serial dilution and incubated for 1 hour at RT to allow Fel dl -antibody interaction to reach equilibrium. The antibody-Fel dl mixture was then added to the IgE-coated plate for 1 hour. Plates were subsequently washed and the amount of free Fel dl-mmH bound to plate was detected using an anti-myc antibody (clone 9E10 produced in- house as a human IgGl isotype) conjugated to HRP, and incubated at a 1 : 10,000 dilution, by incubating for 1 hour at RT. Plates were washed with PBS-T between each step of the protocol. To develop the colorimetric reaction, TMB/H2O2 substrate was added to the plates and incubated for 20 minutes at room

temperature (RT). The reaction was stopped using 2 N sulfuric acid (H2SO4; VWR, # BDH3500-1). Absorbance was subsequently measured on a

spectrophotometer (Victor, Perkin Elmer) at 450 nm. The concentration of antibody required to inhibit the signal of a constant concentration of Fel dl by 50% (IC5 ₀ ) was determined using Prism software. Mouse Experiments

[0365] Female, 7-8 week old Balb/c mice from Jackson Laboratories were used for all mouse studies. For the entire duration of the experiment, animals remained housed in the Regeneron animal facility under standard conditions, and were allowed to acclimate for at least 7 days prior to being placed on study. All animal experiments were performed in accordance with the guidelines for the Institutional Animal Care and Use Committee at Regeneron. For preclinical mouse studies, no statistical methods were used to predetermine sample size. Mice were randomly assigned to treatment groups without predefined criteria and blinding was not able to be performed due to obvious color change of the ear.

Passive Cutaneous Anaphylaxis Mouse model:

[0366] Antisera used for passive intradermal (ID) administration were previously generated by immunizing Balb/c mice with either Fel dl, standardized cat hair extract, or crude peanut allergen extract (irrelevant control antisera) using alum adjuvant. Sera from 10-20 mice were pooled and used for passive administration. On day 1, Balb/c mice received a SC injection of REGN1908, REGN1909, REGN1908-1909, concentrated Cat-SIT IgG or non-SIT IgG, or an IgG4 ^p isotype control antibody. Three days later, antisera generated to Fel dl or cat hair extract, or peanut (negative control) was injected ID into the right and left ears, respectively, allowing allergen-specific IgE to bind FcsR on mast cells. Each anti-serum was standardized to contain l-25ng IgE per injection (depending on experiment). Twenty-four hours after local administration of allergen-specific antisera, mice were challenged by intravenous (IV) injection of 0.250μg-lμg Fel dl or 250 Bioequivalent allergy units (BAU) cat hair extract diluted in PBS containing 0.5% Evans blue dye (Sigma). One hour after allergen challenge, mice were sacrificed. Evans blue dye was extracted from ear tissue and

spectrophotometrically quantitated using a standard curve. Ears were then dried and weighed.

Cat-SIT IgG binding studies:

[0367] Cat-SIT-IgG binding studies were performed on Octet HTX biosensor and all the samples were prepared in buffer containing lOmM HEPES, 500mM NaCl, lmg/mL BSA, 0.02% sodium azide, 0.05% surfactant Tween-20, pH 7.4 (HBS-BT). HIS1K Octet biosensors were first dipped in wells containing 2μg/mL of rFel dl .mmh for 60 seconds to capture 0.05nm of rFel dl .mmh followed by dipping Octet biosensors in wells containing lOOnM of Fel dl specific IgG present in different Protein G purified Cat-SIT IgG samples. The specific binding sensorgrams were generated by a double referencing procedure by subtracting any interaction of Cat-SIT IgG over the reference surface (blank HIS IK Octet biosensor) from the Cat-SIT IgG binding to the Fel dl.mmh captured surface; thereby removing any observed non-specific binding signal. In addition, rFel dl.mmh captured biosensors were dipped in HBS-BT buffer to allow subtraction of signal changes resulting from the natural dissociation of captured rFel dl .mmh from the HIS IK biosensor. Octet binding data was double reference subtracted and binding kinetic parameters were measured by fitting the data to a 1 : 1 binding model with mass transport limitation using Scrubber 2.0c.

Intracellular staining of phosphorylated Erk using basophils from cat allergic patients:

[0368] Blood drawn from allergic patients was shipped at room temperature for same-day delivery by Bioreclamation IVT. PBMCs were purified by centrifugation on a Ficoll layer, washed three times in pre-warmed RPMI media (Gibco), resuspended in pre-warmed serum-free X-Vivo 15 media (Lonza) and plated on a 96-well plate. The cells were then incubated at 37°C for 30 minutes. In parallel, a 2X stimulation plate was prepared that included a dose response of purified nFel dl as well as dose responses of anti-Fel dl antibodies mixed with a constant dose (final concentration 200pM) of purified natural Fel dl (Indoor Biotechnologies). The stimulation plate was also incubated for 30 minutes at 37°. The cells were then stimulated at 37°C using a 96-well multichannel pipette, and the stimulation was stopped after precisely 5 minutes by adding 1 volume of pre-warmed Cytofix (BD). After 15 minutes of fixation, the cells were washed twice in MACS buffer and made permeable by resuspending and storing them in ice-cold methanol overnight at -20 degrees. The cells were then washed three times with MACS buffer, resuspended for 10 minutes in human Fc blocker (ebioscience) and then stained with an antibody cocktail containing pErk-Alexa 488 (Cell Signaling), CD123-BUV395 (BD) and HLA-DR-APC (BD) antibodies for 30 minutes. Cells were washed twice with MACS buffer, incubated for 15 minutes with Cytofix (BD) diluted 1:4 in PBS to fix the stain, resuspended in MACS buffer and acquired in an LSR-Fortessa instrument. Data was analyzed by calculating the MFI of phosphorylated Erk staining within the basophil gate. Percent Max Inhibition was calculated as

100 - (100 X Maximum Antibody Response)/Isotype Response Maximum antibody response was the average Median Fluorescence Intensity (MFI) of phosphorylated Erk in the top three doses of Fel dl antibody in the dose response curve (plateau of the curve) minus the baseline MFI (average of replicate unstimulated samples), and isotype response is the average of all the MFI values in the dose response of an IgG4 isotype control antibody minus the baseline MFI.

Basophil activation tests using cat allergic patient basophils:

[0369] To evaluate antibody-mediated inhibition of basophil activation, a 20pM final constant concentration of Fel dl (Indoor Biotechnologies) was pre-incubated for 30 minutes at 37°C with REGN1908, REGN1909, REGN1908-1909 combo, or IgG4 ^p isotype control antibody at final concentrations ranging from 0.8fM to Ι.ΟμΜ. Concurrently with the Fel dl and antibody pre-incubation, PBMC

(BioreclamationlVT) were purified from fresh whole blood from allergic donors by Ficoll density gradient centrifugation. The purified PBMC were washed, resuspended in X-VIVO 15 media (Lonza), and plated in duplicate columns in a v- bottom, polypropylene, 96-well plate (approximately 5x105 cells/well). To prime the basophils contained in the overall PBMC population for activation, hIL-3 (R&D Systems, 0.3nM) was added to the cell suspension and the plate was incubated at 37°C for 10 minutes. The pre-incubated antibodies and Fel dl were then added to the primed PBMC. Cells without the addition of antibody were included as negative control samples and a dose response of Fel dl ranging from final concentrations of 7.8aM to ΙΟ.ΟηΜ was included as a positive control. The cells were then incubated at 37°C for 20 minutes to facilitate basophil activation. Activation was subsequently stopped by incubation at 4°C for 5 minutes. Basophil activation was then evaluated by flow cytometry. The cells were stained at 4°C for 20 minutes with either an antibody cocktail containing anti-HLA-DR-FITC (Beckman Coulter, Catalog #IM0463U, clone B8.12.2), anti-CD123-APC (BD, clone 7G3, Catalog #560087), and anti-CD203c-PE (Beckman Coulter, Catalog #IM3575, clone 97A6) or a cocktail containing anti-HLA-DR-PE-Cy7 (Biolegend, Catalog #307616, clone L243), anti-CD123-APC (BD, Catalog #560087,clone 7G3), and anti-CD63-FITC (Beckman Coulter Catalog #IM1165U clone

CLBGran/12). After staining, the cells were washed in a 1 :20 dilution of MACS BSA Stock Solution (Miltenyi Biotec) in autoMACS Rinsing Solution (Miltenyi Biotec), fixed in Cytofix (BD) diluted 1 :4 in Dulbecco's phosphate buffered saline (Gibco), and analyzed on a flow cytometer (BD LSRFortessa X-20). The gating strategy was used to identify basophils within the larger population of PBMC and to determine levels of basophil activation. Samples were run to collect

approximately 1000 events determined to be basophils. Basophils were defined as singlet, lymphoid, HLA-DR-, and CD123+. Activated basophils were further defined as CD203c ^Hl or CD63 ^Hl . To specify a baseline level of activation, gates were set so that 10% of basophil events from hIL-3-primed, unstimulated samples (no Fel d 1) were positive for activation (CD203c ^Hl or CDeS^). These gates were then applied to all other experimental conditions to determine the relative level of basophil activation.

Determination of kinetic binding parameters of REGN1908 and REGN1909 interaction with Fel dl

[0370] The entire coupling procedure was performed using filtered and degassed lOmM HEPES, 150mM NaCl, 0.05% (v/v) Surfactant P20 using standard amine-coupling chemistry. The CM5 sensor surface was activated by injecting a 1 : 1 (by volume) mixture of 0.2M l-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and 0.05M N hydroxy succinimide at a flow rate of ΙΟμΕ/ ώ ΐΐε for 7 minutes, followed by injecting 50 μg/mL of goat anti-human Fey (prepared in 0.01M acetate coupling buffer, pH 5.0) until a resonance unit (RU) signal of about 8600RU was obtained. Remaining active groups on the CM5 chip surface were later blocked by injecting 1M ethanolamine, pH8.0 over the surface for 7 minutes at a flow rate of ΙΟμΕ/ ώ ΐΐε. The coupled chip surfaces and the reference surface were then washed and treated with lOmM glycine-HCl, pH 1.5 to remove uncoupled residual proteins. [0371] Binding kinetics studies for REGN1908 and REGN1909 were performed on Biacore T200 using lOmM HEPES, 150mM NaCl, 3mM MgCl ₂ , 3mM CaCl ₂ , 0.05% (v/v) Surfactant P20, pH 7.4 (HBSP++) as running buffer at a flow rate of 50pIJminute. Around 94-163 RU of REGN1908 or REGN1909 was first captured on different flow cells using the goat anti-human Fey coupled sensor surface. Different concentrations of nFel dl or rFel dl .mmh, serially diluted by 2- fold in HBSP++ buffer were later injected over the antibody captured surfaces for 2.5 minutes followed by 15 minutes dissociation phase. Specific Biacore binding sensorgrams were obtained by a double referencing procedure by first subtracting any interaction of nFel dl or rFel dl .mmh over the reference surface (goat anti- human Fey coupled surface only) from the nFel dl or rFel dl .mmh binding signal to REGN1908 or REGN1909 captured surfaces; thereby removing any refractive index changes. In addition, injections of HBSP++ buffer were performed to allow subtraction of RU signal changes resulting from the natural dissociation of captured REGN1908 or REGN1909 from the goat anti-human Fey coupled surface. The binding kinetic parameters were obtained by globally fitting the double reference subtracted data to a 1 : 1 binding model with mass transport limitation using Biacore T200 Evaluation Software, version 1.0.

Evaluation of Nonexclusive Binding of REGN1908 and REGN1909 to Fel dl

[0372] The ability of REGN1908 and REGN1909 to bind Fel dl simultaneously was examined using Biacore T200 in an assay format of injecting one antibody over Fel dl protein captured by another antibody on the sensor surface. Similar to described above, surface density ranged from 4682 to 6683 RU of REGN1908 and REGN1909 were immobilized over separate flow cells of a CM5 sensor chip using standard amine-coupling chemistry reported earlier. Freshly prepared and degassed HBS-P buffer (lOmM HEPES, 150mM NaCl, 0.05% Surfactant P20), pH7.4 was used as running buffer during the entire coupling steps. The coupled chip surface was then washed and treated with lOmM glycine-HCl, pH 1.5 to remove uncoupled residual proteins. 200nM nFel dl was first injected over the sensor surface coupled with REGN1908 or REGN1909 for lOminutes followed by individual injections of REGN1908 and REGN1909 (25 g mL). The entire experiment was performed using HBS-P++ running buffer at a flow rate of 10pL/rninute. Preclinical statistics:

[0373] Statistical analysis was assessed using GraphPad Prism 6. Analysis of the differences between two groups was assessed using the Student's paired or Student's unpaired two-tailed t test. For multiple group animal studies, normality of the data was evaluated using the Shapiro-Wilk if n>7 or the Kolmogorov- Smirnov test if n<7. If data passed the normality test, and standard deviations of the different groups were not statistically different from each other as assessed by the Brown-Forsythe test, results were interpreted by one-way analysis of variance (ANOVA) followed by the Tukey post hoc test for multiple comparisons. If data failed to pass the normality test, or standard deviations were significantly different, results were interpreted using the Kruskal-Wallis test followed by the Dunn's post hoc test for multiple comparisons. Differences were considered to be statistically significant when p < 0.05

RESULTS

Allergen-specific IgG Induced by SIT shows inter-patient variability in binding profile and potency

[0374] To characterize the IgGs induced by SIT, sera from cat-allergic patients who underwent successful SIT with cat-hair extract (Cat-SIT) (range: 13-86 months with median of 33 months) or sera from cat-allergic control patients (Non- SIT), was used to confirm by ELISA that Cat-SIT patients had a higher percentage of Fel dl-specific IgG compared to Non-SIT cat-allergic patients, though it constituted less than 0.2% of total IgG (Fig. 1). Using a real-time kinetic binding assay, the apparent binding affinity of polyclonal Fel dl -specific IgG (Cat-SIT- IgG) was determined by injecting 9 purified Cat-SIT IgG samples each containing ΙΟΟηΜ Fel dl-specific IgG over a recombinant Feldl .mmh (rFel dl.mmh)-coated Octet biosensor. All Cat-SIT IgGs bound Fel dl, with apparent KD values ranging from 0.36nM to 9.8nM and an ~30-fold difference in the dissociation rate constant. The ability of purified Cat-SIT-IgG to block Fel dl binding to cat-allergic patient- derived IgE was also examined in a blocking ELISA. Purified Cat-SIT-IgG blocks Feldl .mmh binding to IgE, however the blocking potency is low (IC5 ₀ values ranging from 0.18μΜ to 2.3μΜ) (Fig. 1). There was no correlation with duration of Cat-SIT (Table 21) with Fel dl-specific titers, affinity, or potency. Collectively, these data suggest that Cat-SIT induces an increase in circulating Fel dl -specific IgG, which can bind to Fel dl with varying kinetics, but as a whole, Cat-SIT-IgG inefficiently blocks Fel dl binding to polyclonal patient IgE.

Table 21

REGN1908 and REGN1909 simultaneously bind Fel dl and prevent Fel dl binding to polyclonal Fel dl-specific patient IgE

[0375] To determine whether monoclonal antibodies could block allergen binding to IgE as well or better than those naturally produced during SIT, we generated Fel dl-specific fully human monoclonal antibodies using Regeneron's

Veloclmmune® human antibody mouse platform (Macdonald, L. et al, (2014), Proceedings of the National Academy of Sciences of the United States of America 111 (14): 5147-52; Murphy, A., et al, (2014), Proceedings of the National Academy of Sciences of the United States of America 111 (14): 5153-58). Given the polyclonality of allergen-specific IgE response, we hypothesized that multiple epitopes on the allergen would need to be blocked to prevent IgE-mediated effector cell activation. Therefore, two antibodies with optimal binding profiles, REGN1908 and REGN1909, were selected for development. Surface Plasmon Resonance (SPR)-Biacore binding studies demonstrated that REGN1908 and REGN1909 each bound with subnanomolar affinity to recombinant and native Fel dl protein (rFel d 1 and nFel dl , respectively) (Table 22), and sequential binding assays confirmed independent, non-competitive binding to nFel dl (Table 23).

Table 22

Binding kinetics table for the interaction of REGN1908 and REGN1909 with nFel d 1 and rFel d l .mmH or rFel d l.mFc. nFel dl : Natural Fel dl. rFel dl-mmH: Recombinant Fel dl with a myc-myc-hexahistidine tag. k _a : association rate constant. k _d : dissociation rate constant. Κ _Ό : equilibrium dissociation constant. ti _/2 : dissociative half-life.

Table 23

200nM of nFel d 1 was first injected over the CM5 sensor surface immobilized with REGN1908 (left panel) or REGN1909 (right panel) followed by the injection of 25 μg/ml of REGN1908 (light blue line) or REGN1909 (dark blue line); nFel dl : Natural Fel dl. rFel dl-mmH: Recombinant Fel dl with a myc- myc-hexahistidine tag. k _a : association rate constant. k _& . dissociation rate constant. Κ _Ό : equilibrium dissociation constant, tm dissociative half-life.

[0376] REGN1908 and REGN1909 were next evaluated individually and in combination for the ability to block Fel dl binding to cat allergen-specific polyclonal human IgE. In a blocking ELISA each antibody partially blocked nFel dl binding to IgE with a maximum blockade of 51%, whereas the combination of REGN1908 and REGN1909 (REGN1908-1909) blocked Fel dl binding to patient-derived IgE more potently: The maximum blockade increased to 83% with an IC50 value of 0.45nM. Next, we tested the ability of REGN1908-1909 to block Fel dl-induced activation of human basophils from cat-allergic donors using two different assays. To assess FcsR engagement and activation, basophils were tested in a functional phosphoflow assay that measures phosphorylation of the kinase ERK, a proximal readout of basophil activation and degranulation (Liu, Y., et cil, (2007), The Journal of Experimental Medicine 204 (1): 93-103 ;Zhu, M., et al, (2012), The Journal of Biological Chemistry 287 (11): 8135-43).

Basophils from all 10 cat-allergic donors responded to Fel dl stimulation with varying intensities (data not shown). REGN1908-1909 inhibited at least 80% of basophil activation in 7/10 donors, while a single antibody (REGN1908) achieved the same level of inhibition in only 3/7 donors (Fig. 2). In the basophil activation test (BAT), which measures allergen-induced upregulation of the basophil activation markers, CD203c and CD63 by flow cytometry (Sturm, E.M., et al, (2010), Cytometry Part B: Clinical Cytometry 78B (5): 308-18; Ocmant, A., et αί, (2007), Journal of Immunological Methods 320 (1-2): 40-48), REGN1908- 1909 potently blocked Fel dl-induced basophil activation (IC ₅₀ values of 55pM and ΙΟρΜ, respectively).

[0377] These data establish that REGN1908 and REGN1909 each bind with high affinity, simultaneously, and in a non-competing fashion to Fel dl, and are more effective in combination when blocking Fel dl binding to polyclonal IgE from cat-allergic subjects.

REGN1908-1909 combination synergistically inhibits cat allergen-induced mast cell degranulation in mice

[0378] The potency of REGN1908 and REGN1909 was evaluated in vivo using the passive cutaneous anaphylaxis (PCA) mouse model with nFel dl or cat hair extract, which contains a heterogeneous mixture of cat proteins including Fel dl . The PCA model assesses type 1 hypersensitivity and measures local mast cell activation-induced vascular permeability in ear tissue (Bradley, B.L., et al, (1991), J Allergy Clin Immunol 1991 ;88(4):661-74.). After passive sensitization with nFel dl mouse antisera or control antisera, Fel dl challenge induced significant mast cell degranulation only in the nFel dl sensitized ear (Fig. 3), validating the model and confirming specificity of the allergic response. The combination of REGN1908-1909 significantly blocked nFel dl-induced mast cell degranulation at a dose of 1 mg/kg (total antibody; 1 : 1 ratio). Notably, the combination demonstrated a synergistic effect- only 0.5 mg/kg of each antibody was required to significantly block degranulation, whereas 1 mg/kg of each antibody alone had a minimal effect (Fig. 4). Similarly, REGN1908-1909 also blocked cutaneous anaphylaxis induced by cat hair extract (Fig. 5), demonstrating that Fel dl is the major driver of cat hair extract-induced mast cell degranulation in this model. These data reveal that REGN1908 and REGN1909 should be administered together in order to achieve efficacy in the PCA model, demonstrating that multiple Fel dl epitopes must be bound to prevent Fel dl- induced crosslinking of polyclonal IgE and subsequent effector cell activation. Passive immunotherapy with REGN1908-1909 blocks mast cell

degranulation in vivo more efficiently than natural IgGs from Cat-SIT patients

[0379] To compare the ability of REGN1908-1909 or Cat-SIT IgG to inhibit Fel dl from binding to polyclonal IgE, both a blocking ELISA and the PCA mouse model were used. Both REGN1908-1909 and Cat-SIT-IgG blocked Fel dl binding to donor polyclonal cat-allergic IgE. Cat-SIT-IgG blocked binding to baseline, however a high IgG concentration was required (IC ₅₀ range: 0.309μΜ to 23.15μΜ). In contrast, REGN1908-1909 demonstrated 5 orders of magnitude higher potency than Cat-SIT-IgG with an IC5 ₀ of ~580pM.

[0380] In the PCA model, purified Cat-SIT-IgG from 3 donors, or Non-SIT IgG, was concentrated and injected subcutaneously into mice to reconstitute the circulating IgG level present in each individual SIT donor. The amount of antibody injected per mouse is noted in Table 24. The donors selected represented varying lengths of SIT treatment (13, 20, and 35 months), and included the donor with the highest Fel dl -specific IgG titer, which showed the greatest potency in vitro (Donor 10, See Table 25). While Non-SIT IgG did not prevent degranulation, REGN1908-1909 inhibited degranulation as well as or better than purified Cat-SIT-IgG (Fig. 6). The degree of protection conferred by Cat-SIT-IgG was proportional to the amount of Fel dl -specific IgG in the individual samples, and, notably, approximately 5-fold more Fel dl -specific IgG from Cat-SIT-IgG samples (or 1000-fold more total IgG) was needed per mouse to achieve the same blocking efficacy as REGN1908-1909 [(Fel dl-specific IgG: 0.02mg/mouse for REGN1908-1909 vs 0.092mg/mouse for SIT Donor 10 (Fig. 6). These data show that REGN1908-1909 blocks mast cell degranulation in vivo more efficiently than Cat-SIT patient polyclonal Fel dl -specific IgGs, naturally generated after years of SIT, and support the concept that the majority of IgG generated by SIT are not functional blockers. Table 24

The table shows th amount of antibody injected into mi ce in Figure 6.

Table 25

Characteristics of patients whose sera was used in the PCA model, Figure 6. indicates returning donors

EXAMPLE 11: REGN1908-1909 Significantly Reduces Clinical Symptoms in Response to Nasal Allergen Challenge in Cat-allergic Human Subjects: A Single Dose Study of the Efficacy, Safety, Tolerability and Pharmacokinetics of REGN1908-1909 in Allergic Rhinitis Subjects Challenged Intranasally with Allergen Extract Clinical study design:

[0381] A multicenter phase lb, randomized, double-blind, placebo-controlled, single subcutaneous dose, proof-of-mechanism study was conducted in 6 study centers in Europe and Asia-Pacific.

[0382] Subjects eligible for randomization were stratified in 2 blocks: the London site (Quintiles Phase I Unit), and all other study sites combined, implemented through a central interactive voice response system. Subjects were randomized 1 : 1 on day 1 to receive a single SC dose of REGN1908-1909 (600 mg total, 1 : 1 antibody ratio; n=37) or placebo (n=36).

[0383] The protocol was approved by the appropriate ethics

committees/institutional review boards, and each patient gave written consent at screening visit 1. The study was conducted in compliance with institutional review board regulations, the International Conference on Harmonization Guidelines for Good Clinical Practice, and the Declaration of Helsinki.

Patient population:

[0384] Eligible subjects were 18-55 years of age with cat-induced allergic rhinitis and cat sensitization confirmed at screening. To confirm cat-sensitization, subjects underwent screening at two visits, day -28 and day -14 (+/- 2 days). At screening visit 1, subjects were screened for allergen-specific IgE, underwent a skin prick test with cat hair extract (cat-SPT, Aquagen©, ALK-Abello) and other allergen extracts, and were tested for lung function (FEV1). Subjects were eligible for screening visit 2 based on IgE titers specific for Fel d 1 and cat hair extract >0.35kAU/l each, cat-SPT mean wheal diameter of >3mm compared to a negative control SPT, and normal lung function. Subjects were excluded if they had prior history of SIT or vaccination with cat allergen, or anti-IgE therapy; SIT to other allergens within 3 months prior to screening; or were living with or chronically exposed to a cat.

[0385] At screening visit 2, a single nasal allergen challenge (NAC) was performed using increasing doses of cat hair extracts (100-33,000 SQ-U/ml).

Briefly, cat hair extract was applied intranasally every 10 min for 1 hour, or until a total nasal symptom score (TNSS) >7 was reached. TNSS (measured on a 0-12 scale) is a composite patient symptom assessment of congestion, itching, and rhinorrhea (each graded on 0-3 scale, 3 being severe), and sneezing (3 being >5 sneezes). Cat-sensitized subjects were eligible for enrollment based on having a TNSS<2 prior to the screening NAC (time 0), and peak TNSS>7 within one hour of NAC initiation.

[0386] Eligible subjects were randomized to receive study drug or placebo on study day 1 (14 days after screening visit 2). On study days 8, 29, 57, and 85, subjects underwent NAC using the same allergen titration required for each individual subject to reach TNSS>7 at their 2 ^nd screening visit, not to exceed the maximum dose established in the screening visit, regardless of whether TNSS>7 was reached. At each study visit, TNSS, as well as VAS nasal symptoms score (0 to 100 scale) and peak nasal inspiratory flow (PNIF, measured in nasal patency, 1/min) were measured, were measured pre-NAC, then at 10, 30, and 60min during the first hour , and once per hour for 8 hours to measure the late phase response (LPR). Serum samples were collected at each study visit, and a repeat cat-SPT was performed on study days 29 and 85.

Efficacy endpoints:

[0387] The primary efficacy endpoint was change in TNSS AUC between pretreatment and day 8 NAC over the first hour of challenge (0 hour to 1 hour, early phase allergic response). Secondary endpoints were percent change in TNSS AUC from pretreatment to day 8 NAC over the first hour; change and percent change in TNSS AUC from pretreatment NAC to days 29, 57, and 85 over the first hour; and change and percent change in TNSS AUC from hours 1 to 8 post-challenge (LPR) from pretreatment NAC to days 8, 29, 57, and 85.

Exploratory endpoints included change and percent change from pretreatment NAC to days 8, 29, 57, and 85 in peak TNSS, peak VAS nasal symptoms score, and peak PNIF; as well as VAS nasal symptoms score AUC and PNIF AUC from 0-1 hr, and 1 to 8 hours. Responder analysis was performed ad-hoc.

Pharmacokinetic parameters were also measured.

[0388] Percent change from baseline to day 29 or day 85 in mean wheal diameter AUC for the titrated cat hair extract skin prick test (100-33,000 SQ-

U/ml) measured 15 min post-application was an additional exploratory endpoint.

The test was performed with duplicate serial dilutions of Aquagen (ALK-Abello) cat hair extract using six dose titrations ranging from 100 - 33,000 SQ-U/ml.

Single probes with a negative control solution (saline) and a positive histamine control were administered in duplicate simultaneously with cat hair extract probes on the opposite arm. 15 minutes after application, the wheal diameters were recorded. Mean wheal diameters were calculated by adding the longest diameter to the longest orthogonal diameter and dividing by 2. For each of the duplicate skin prick tests, the longest and longest orthogonal diameters should be recorded, and the mean diameter of each wheal calculated to two decimal places. The mean wheal diameters from the duplicate skin pricks were then averaged.

For the titrated cat skin prick test, the formula used to calculate the normalized average wheal diameter AUC was:

[(tl - tO)(Dl + D0)/2 + (t2 - tl)(D2 + Dl)/2 + (t3 - t2)(D3 + D2)/2+ (t4 - t3)(D4 + D3)/2+ (t5 - t4)(D5 + D4)/2] /(t5 - tO)

in which:

ti is the concentration (in SQU/ml) for which Di is measured;

tO = 100, tl = 330, t2 = 1000, t3 = 3300, t4 = 10000, and t5 = 33000

Di is the average wheal diameter obtained at concentration ti.

The negative control was not subtracted from this value.

Safety:

[0389] Safety assessments included rates of treatment-emergent adverse events (TEAEs) or serious AEs (SAEs) through day 85 as reported by investigators, along with vital signs and laboratory tests. Adverse events were described at the Medical Dictionary for Regulatory Activities (MedDRA; version 17.0) to lowest level terms.

Clinical Statistical analysis:

[0390] A sample size of approximately 70 cat-allergic subjects was needed to provide at least 90% power to detect the expected mean differences in primary endpoint between the two treatment groups, with an assumption of a TNSS AUC mean value of 5 for the placebo group and 3 for the treatment group during the course of 0-1 -hour post-challenge. The assumed standard deviation of 2.43 is consistent with the effect of topical nasal corticosteroids (Wu et al. (2013),

Allergy Asthma Proc May -June 34(3):283-291, Nicholson, et al, (2011), J.

Allergy Clin. Immunol, 128:800-807). Primary efficacy analyses were conducted in the full analysis set (FAS) which includes all randomized subjects who received any study drug on day 1 and had TNSS evaluation results on day 8 (n=36 and n=34, for placebo and REGN1908-1909 groups, respectively). Efficacy endpoints were analyzed using analysis-of-covariance (ANCOVA) model with treatment group as a factor and baseline value as a covariate. The results of the ANCOVA model included the summary of least-squares (LS) mean for each treatment group with corresponding standard error (SE), the LS mean difference between treatment group with corresponding SE and 95% confidence interval (CI), and the p-value corresponding to the between-treatment-group difference. Sensitivity analyses were performed for all efficacy analyses by excluding 4 subjects from a study site terminated early due to non-compliance, as determined by the investigator/sponsor, and for the primary efficacy endpoint by imputing three missing TNSS AUC(O-lh) values at Day 8 with baseline values. Secondary and exploratory efficacy endpoints were analyzed using the same ANCOVA model as the primary analysis; no control for multiplicity was performed for secondary and exploratory endpoints, therefore p values are considered nominal. The safety analysis set included all randomized subjects who received any study drug on day 1, based on treatment received.

RESULTS

REG 1908-1909 blocks the early phase allergic response to nasal allergen challenge in cat-allergic patients

[0391] To determine whether the preclinical protection afforded by

REGN1908-1909 could translate into clinical efficacy, a Phaselb, randomized, double-blind, placebo-controlled proof-of-mechanism (POM) study was conducted to evaluate if a single subcutaneous (SC) dose of REGN1908-1909

(600 mg; 1 : 1 ratio) could inhibit cat hair extract-induced allergic symptoms in cat-allergic subjects (Fig. 7). A Nasal Allergen Challenge (NAC) with cat hair extract was selected for POM as a reliable, reproducible, and controlled method of measuring allergy symptoms (Fig. 8A and 8B). Intranasal instillation of allergen causes local allergic symptoms, such as nasal congestion, itching, sneezing and rhinorrhea, which are associated with IgE-mediated mast cell and basophil degranulation and peak within the EPR (Durham, M.D., et al, (2016),

Journal of Allergy and Clinical Immunology 138 (4). Elsevier Inc.: 1-

12;Scadding, G, et al, (2015), Clinical and Experimental Allergy: Journal of the British Society for Allergy and Clinical Immunology 45 (3): 613-23). Therefore, the primary efficacy analysis was change in Total Nasal Symptom Score (TNSS) area under the curve (AUC) over the first hour after a NAC [TNSS AUC(O-lh)] from pretreatment to day 8 challenge.

[0392] Seventy -three subjects were randomized and received the intended study drug (placebo=37 subjects; REGN1908-1909=36 subjects). Baseline characteristics were generally balanced between groups, and the majority of subjects were poly allergic. Sixty-eight subjects completed the study (34 per group); 4 subjects were removed from the study due to noncompliance of a study site and 1 subject in the treatment group withdrew consent.

[0393] The change in clinical symptoms [TNSS AUC(O-lh)] from baseline to day 8 NAC was significantly reduced in patients receiving a single SC dose of

REGN1908-1909 (600mg) compared to placebo (LS mean difference -1.771, p=0.0003; 95% CI[-2.704,-0.838]) (Table 26). Sensitivity analyses of the primary endpoint showed a similar result (Table 27). No effect on clinical endpoints was due to an individual study site (p=0.5518). Neither baseline Cat-dander IgE nor

Fel d 1 IgE titers correlated with percent change from baseline in TNSS AUC(0- lh) (p=0.4492, p=0.8157, respectively). Though the NAC model does not robustly induce a late phase response, TNSS AUC(l-8h) was reduced in

REGN1908-1909-treated subjects compared to placebo at days 8 and 29

(p=0.0094, and p=0.0074, respectively. Component analysis of TNSS revealed that REGN1908-1909 had the greatest impact on two of TNSS components,

"Nasal Congestion" and "Rhinorrhea", which contributed to 34% and 39% improvement on the primary endpoint total score, respectively.

[0394] The effect of REGN1908-1909 was maintained for at least a month after the first dose, with evidence suggesting efficacy throughout the 85-day study.

REGN1908-1909 treatment led to sustained and clinically meaningful improvement in symptoms (commonly defined as >20% reduction in total symptom score compared to placebo): REGN1908-1909 treatment reduced TNSS

AUC(O-lh) by 56%, 61%, 51%, and 51% on days 8, 29, 57, and 85 respectively; resulting in 29%, 33%, 14,%, and 23% reduction versus placebo and achieving nominal statistical significance versus placebo at every timepoint except day 57

(p=0.0005, 0.0004, 0.1321, 0.0187, respectively) (Table 26, Fig. 9). In addition, responder analysis showed that at least 50% of patients receiving REGN1908- 1909 achieved >60% reduction in TNSS AUC(O-lh) at every study day, compared to placebo (Fig. 10) and only 4 patients receiving REGN1908-1909 did not achieve > 30% response at any timepoint. The duration and magnitude of the TNSS results were reflected in another patient reported symptom score, visual analog score (VAS) (data not shown) and also in the objective measure of nasal congestion and the Peak Nasal Inspiratory Flow (PNIF) (Fig. 11), with 39% improvement at days 8 and 85.

[0395] REGN1908-1909 treatment also reduced the hypersensitivity response to cat hair extract delivered to the skin in a titrated skin prick test (cat-SPT) (Fig. 12). This skin test is much less subjective than patient-reported allergic symptomology, as reflected by the lack of a placebo response, and may be the best pharmacodynamic measure of the blockade of IgE-driven response. In contrast to subjects receiving placebo, where no change in wheal diameter was observed, REGN1908-1909 treatment resulted in a 52% reduction compared to baseline at Day 29, with the magnitude of the effect unchanged at day 85. These data further support that REGN1908-1909 suppresses the early phase allergic response (EPR), and further show that the mechanism of action for REGN1908- 1909 elucidated in the mouse PC A model, translates to cat-allergic humans. Taken together, for all three measures (TNSS, PNIF, and Cat-SPT) the similar magnitude in efficacy observed on day 8, when total study drug concentration was >75mg/L (Cmax), and at day 85, when levels were ~5mg/L, supports that very low levels of potent blocking antibodies may prevent allergen-induced allergic response.

[0396] Overall, REGN1908-1909 was safe and well-tolerated. A total of 107 AEs were observed and were generally balanced between groups. Two AEs were categorized as severe, but determined to be unrelated to treatment by investigator assessment (1 appendicitis in the placebo group, and 1 pyelonephritis in the REGN1908-1909 group). At least one AE was observed in 23 (63.9%) of subjects in the REGN1908-1909 group and 23 (62.2%) in the placebo group. The most frequent AE was headache in both groups (6 in the REGN1908-1909 group; 5 in the placebo group). Two mild injection site reactions were observed, one in each group. No subject discontinued due to AE, and there were no deaths in the study. SUMMARY

[0397] While SIT therapy has been used for over 100 years to treat allergies, the use of heterogeneous allergen extracts in conventional SIT present a double-edge sword for patients. In some patients the treatment requires frequent injections over many years and carries the risk of inducing allergic reactions to the injections. Other approaches have attempted to recapitulate the protective effect of SIT by using minimally protective components by focusing on either cellular or humoral responses, while avoiding IgE-mediated side effects. Certain allergen T-cell peptide vaccines have been tested but have failed to demonstrate significant benefit, while other peptide vaccines have demonstrated efficacy in birch or grass allergy.

[0398] In contrast to peptide vaccines, the approach described herein allows selection of the most potent combination of blocking antibodies generated in response to whole allergens naturally and agnostically by genetically humanized Veloclmmune® mice (Macdonald, L. E. et al. Precise and in situ genetic humanization of 6 Mb of mouse immunoglobulin genes. Proceedings of the National Academy of Sciences of the United States of America 111, 5147-5152, (2014); Murphy, A. J. et al. Mice with megabase humanization of their immunoglobulin genes generate antibodies as efficiently as normal mice.

Proceedings of the National Academy of Sciences of the United States of America 111, 5153-5158, (2014). Interestingly, REGN1908 and REGN1909, the two most potent blocking antibodies, bind to conformational Fel d 1 epitopes. Furthermore, passive administration enables direct delivery of high, uniform concentrations of two blocking antibodies (>75mg/L total) with a single dose, avoiding the need for repeated allergen or peptide administrations, adjuvants, and subsequent patient immune response to generate high antibody titers.

[0399] Furthermore, the studies described herein demonstrated proof-of- principle that direct administration of allergen-specific monoclonal antibodies provides a well-tolerated, rapid and effective approach to reducing allergic symptoms. Using Fel dl, the dominant cat allergen for proof-of-principle, it was systematically demonstrated that the combination of two high-affinity, non- competing Fel dl-specific IgG4 monoclonal antibodies, REGN1908 and

REGN1909, blocks Fel dl binding to cat-allergic polyclonal IgE in vitro and prevents mast cell degranulation in vivo, more efficiently than IgG purified from patients who underwent successful cat-SIT. This preclinical approach translated to clinical efficacy in which a single SC dose of REGN1908-1909 in cat-allergic subjects resulted in a clinically meaningful and sustained reduction in total nasal symptoms by blocking the early allergic response to nasal challenge with cat allergen.

[0400] More specifically, this clinical proof-of-principle study examined the potential of passive immunotherapy with monoclonal antibodies to Fel d 1 to block acute allergic symptoms triggered by nasal provocation with cat extract. The majority of subjects receiving REGN1908-1909 experienced symptom amelioration with at least 50% of subjects achieving 60% improvement in TNSS at every timepoint, clinically establishing the immunodominance of Fel d 1 as the driver of cat allergy symptoms. While not all patients achieved a clinical response, similar interpatient variability was observed preclinically in a functional ex vivo basophil assay: 80% inhibition of basophil activation was observed in 7/10 donors. The variability observed both preclinically and clinically suggests that REGN1908-1909 does not block Fel d 1 binding to a proportion of patients' IgE repertoire or that Fel d 1 is not the main driver of cat allergic symptoms for these patients. However, unique to a passive immunization approach, these data also suggest a potential mechanism to predict patient response to REGN1908- 1909 therapy: Since ex vivo basophil activation tests have been shown to correlate with nasal response to allergen challenge (Paterniti, M. et al. Cat allergen-induced blood basophil reactivity in vitro predicts acute human nasal allergen challenge responses in vivo. Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology 41, 963-969, (2011)), it may be possible to determine whether pre-testing the ability of REGN1908- 1909 to block Fel d 1 from cross-linking patient IgE in an ex vivo functional basophil bioassay can target therapy to patients who will receive maximal benefit.

[0401] Taken together, our data support the hypothesis that high-quality anti- allergen blocking antibodies are sufficient to drive the symptom reduction afforded by SIT therapy (Flicker, S. et al., (2011), Current Topics in

Microbiology and Immunology 352: 141-59). Relative improvement in symptom reduction at Day 8 in this study was numerically superior to that reported for patients completing 1-2 years of grass subcutaneous immunotherapy (Durham, S. unpublished). Furthermore, the improvement observed in this study may be 4- to 8-fold more effective than nasal steroids and antihistamines, respectively (Durham, S. et al, (2016), J. of Allergy & Clin. Immunol. 138(4): 1-12).

[0402] This study validates a new paradigm for anti-allergen antibody development: Preclinical selection of potent, fully human anti-allergen antibodies that block allergen binding to a majority of allergen-specific IgEs results in clinical efficacy. Applying this novel, systematic approach to other allergens may enable development of a repertoire of anti-allergen therapeutics for personalized allergy management.

Table 26

LS mean difference vs placebo (SE) (-42.935, -4.050) 0.0187 95%CI

Analyses are based on ANCOVA model with treatment group as a factor and baseline as a covariate. For secondary efficacy endpoints no control for multiplicity was performed, therefore p values are considered nominal. NAC = Nasal allergen challenge; TNSS = Total nasal symptom score; AUC(O-lh) = Area under the curve (hour 0 to hour 1). SD = Standard deviation; LS Mean = Least squares mean, SE = Standard error of the LS Mean; CI = Confidence interval.

Table 27

Example 12. Determination of the Binding Site(s) for H4H2636P on Chain 2 of Fel d 1 by X-Ray Crystallography

[0403] A study was done to determine the binding site(s) for H4H2636P on Chain 2 of Fel d 1 by X-Ray Crystallography. In this study, a Fab fragment of H4H2636P was cloned and expressed in HEK293 cells, then purified by Protein A affinity chromatography. Recombinant Fel dl (chain 2(N50A) - chain

1(G31D), with a C-terminal myc-myc-His6 affinity tag) was purified as described above (See Example 8). rFel dl and H4H2636P Fab were mixed in

approximately a 1 : 1 molar ratio and incubated at room temperature for 1 hour. The complex was then separated from a slight excess of Fab by size exclusion chromatography. The rFel dl - Fab complex was concentrated to 20 mg/ml in HEPES -buffered saline, then crystallized against a reservoir solution of 0.2 M calcium acetate, 0.1 M sodium cacodylate pH 6.5, 40% (v/v) polyethylene glycol 300. Crystals were harvested directly from the mother liquor and frozen in liquid nitrogen.

[0404] Diffraction data to 2.9 A were collected on a rFel dl - Fab crystal at beamline 5.0.2 of the Advanced Light Source, Lawrence Berkeley National Laboratory. The structure was solved by molecular replacement using Phaser, with PDB code 1PUO as the search model for the Fel dl component, and PDB code 2R8S for the Fab component. The structure was refined using refmac5, and rebuilt using coot. Coordinates for the final rFel dl - Fab structure have been deposited in the RCSB Protein Data Bank with accession code 5VYF.

[0405] An X-ray crystal structure of the Fab fragment of H4H2636P bound to Fel dl showed that multiple residues in the HDX-protected peptide contact H4H2636P. In particular, within the HDX protected peptide, which spans from residue 15 through residue 24 of SEQ ID NO: 396, X-ray crystallographic analysis shows binding at residues N21, E22, L23 and L24 of SEQ ID NO: 396. X-ray crystallographic analysis also shows several additional contacts are made by Fel dl residues in a Chain 2 peptide not detected by HDX. These include the following residues: D26, L27, T30, K31, E36, R39, K43 and D47 of SEQ ID NO: 396. Together these data, combined with that shown in Example 8, support a model in which H4H1232N and H4H2636P bind simultaneously and non- competitively to conformational epitopes at opposing regions of the surface of the Fel dl heterodimer.