RELATED APPLICATIONS

[0001 ] The present application claims the benefit of priority of co-pending United States provisional patent application no. 62/756,335 filed on November 6, 2018, the contents of which are incorporated herein by reference in their entirety.

FIELD

[0002] The present application relates to combination treatments for influenza infections. In particular, the present application relates to the use of one or more neuraminidase inhibitors and one or more broadly-neutralizing antibodies (bNAbs) and compositions thereof for the prevention or treatment of influenza infections.

BACKGROUND

[0003] Influenza A viruses (IAV) cause 3-5 million serious illnesses and half a million deaths each year. Vaccination is the best way to prevent infection, but protection provided is narrow and ineffective against pandemic strains due to antigenic drift in the immunodominant hemagglutinin (HA) head domain of the influenza virus. HA is responsible for binding the influenza virus to sialic acid on host cells. Recently discovered broadly-neutralizing antibodies (bNAbs) that target the conserved HA stalk domain of the influenza virus provide great promise towards development of a“universal” influenza vaccine. These bNAbs require Fc receptor binding and effector cell function to confer maximal protection. The mechanism by which bNAbs protect against IAV propagation is incompletely understood.

[0004] It has been proposed that the main mechanism by which stalk- binding antibodies are believed to control influenza virus infections is to stimulate Fc-dependent effector functions of immune cells, which recognize virus and infected cells and control infection (Leon et al. Proc. Natl. Acad. Sci. USA, 2016, 1 13(40), E5944-E5951 , He et al. Nat Commun 2017, 8: 846). Because these antibodies target the stalk domain of HA, the head domain is free to bind to sialic acid residues. Thus, stalk-binding antibody-mediated interaction between the immune effector cell and the infected cell consists of two potential points of contact: between the antibody Fc region and Fc receptor on the immune effector cell, and between the HA head (expressed on the infected cell surface) and sialic acid residues on the Immune effector cell (Figure 1 ). The cell membrane of the infected cell is also decorated with viral neuraminidase, which can cleave sialic acid residues from the effector cells. In turn, the immune interaction is less stable with one fewer point of contact resulting in decreased effector cell activation.

[0005] Viral neuraminidases are neuraminidases (NA) found on the surface of influenza viruses that cleave sialic acid (neuramimic acid) groups from host cells, for example, host cell glycoproteins, and enables the virus to be released from the host cell. Viral neuraminidase can also cleave sialic acid groups on mucins to help viral particles penetrate the respiratory mucosa. Thus, cleavage of sialic groups allows influenza virus to replicate and spread. Neuraminidase inhibitors have been developed to block neuraminidase function as a method of treating influenza infection. Several neuraminidase inhibitors are presently in clinical use including, for example, oseltamivir, zanamivir, and peramivir. Oseltamivir, for example, is a competitive neuraminidase inhibitor used in the treatment of acute uncomplicated influenza. Laninamivir is a neuraminidase inhibitor that is currently undergoing clinical trials.

SUMMARY

[0006] Using an in vitro antibody-dependent cell cytotoxicity (ADCC) assay an in vivo mice models, the Applicants have shown that neuraminidase (NA) inhibitors, for example, oseltamivir, cause a dose-dependent increase in bNAb-mediated Fc receptor-dependent effector functions (e.g., ADCC) of influenza virus, for example, influenza A virus (IAV) infected cells. The Applicants have also shown in mouse models that the NA inhibitor (e.g., oseltamivir) / bNAb combination therapy is superior at protecting against lethal influenza virus, for example, IAV, infection compared to using either treatment alone in vivo.

[0007] The Applicants have shown that the enzymatic inhibition of NA, for example, by a neuraminidase inhibitor such as oseltamavir enhances Fc- dependent effector functions elicited by bNAbs.

[0008] Accordingly, the present application includes a method of treating or preventing an influenza infection in a subject in need thereof comprising administering, to the subject, an effective amount of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with an effective amount of one or more broadly neutralizing antibodies (bNAbs) wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs is an amount that when the bNAbs are administered alone does not treat or prevent the influenza infection.

[0009] The present application also includes a pharmaceutical composition comprising one or more broadly neutralizing antibodies (bNAbs) and one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof wherein the one or more neuraminidase inhibitors and bNAbs are present in amounts that are effective to treat an influenza infection or a disease, disorder or condition arising from an influenza infection and wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs is an amount that when the bNAbs are administered alone does not treat or prevent the influenza infection.

[0010] In some embodiments, the one or more neuraminidase inhibitors are selected from anti-neuraminidase antibodies, anti-neuraminidase proteins, anti-neuraminidase peptides, a portion of anti-neuraminidase antibodies, a portion of anti-neuraminidase proteins, and a portion of anti-neuraminidase peptides. In some embodiments, the one or more neuraminidase inhibitors are selected from oseltamivir, zanamivir, laninamivir and peramivir. In some embodiments, the neuraminidase inhibitor is oseltamivir. [001 1] Other features and advantages of the present application will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating embodiments of the application, are given by way of illustration only and the scope of the claims should not be limited by these embodiments, but should be given the broadest interpretation consistent with the description as a whole.

DRAWINGS

[0012] The embodiments of the application will now be described in greater detail with reference to the attached drawings in which:

[0013] Figure 1 is a schematic showing the stalk-binding antibodies facilitating the interaction between immune effector cells and infected cells via two points of contact. The stalk-binding antibody interacts with the HA stalk domain via its Fab portion and binds to the Fc receptor of the effector via its Fc portion (1 ). The HA head domain interacts with sialic acid residues on the effector cell (2). Although the sialic acid residues are depicted as a moiety on the Fc receptor on the effector cells, the actual location of the sialic acid residues that HA binds to in this context is not known. The lines represent enzymatic inhibition by neuraminidase on the HA head - sialic interaction, and the inhibition of oseltamivir on the neuraminidase enzymatic activity.

[0014] Figure 2 shows exemplary neuraminidase inhibitor Oseltamivir decreases both neuraminidase activity and viral replication of H1 N1 and H3N2 influenza viruses. Neuraminidase activity of influenza viruses PR8, Cal/09, and X-31 were measured in-vitro using the NA-Star Neuraminidase Kit (ThermoFisher) (Figure 2 first row). Exemplary neuraminidase inhibitor oseltamivir susceptibility of the strains were then determined using 1x10 ⁶ plaque-forming units (PFU) of the three strains using the NA-Star Neuraminidase Kit (ThermoFisher) (Figure 2 second and third rows). The ICso values are displayed to the right of the graphs. Data for the neuraminidase assays are shown as mean and SD of at least two technical replicates. Exemplary neuraminidase inhibitor oseltamivir susceptibility was also quantified using plaque assays by infecting A549 cells with the virus at a multiplicity of infection (MOI) of 5 before incubating the infected cells with indicated concentrations of oseltamivir for 18 hours (Figure 2 fourth row). N.D: not detectable. The limit of detection for the plaque assays is 25 PFU/ml.

[0015] Figure 3 shows broadly-neutralizing antibodies 6F12 and 9H10 bind specifically to A549 cells infected with an H1 N1 or H3N2 viruses respectively. A549 cells infected with PR8 or Cal/09 were stained with 6F12, and cells infected with X-31 were stained with 9H10. Uninfected A549 cells were stained using 6F12 and 9H10 as negative controls.

[0016] Figure 4 shows that exemplary neuraminidase inhibitor oseltamivir increases broadly-neutralizing antibody mediated Fc receptor activation (eg. ADCC) of influenza virus infected A549 cells. Exemplary neuraminidase inhibitor oseltamivir was found to increase the efficacy and alter the potency of ADCC induction by stalk-binding antibodies in a dose-dependent manner. In vitro ADCC assays were completed using A549 cells infected with PR8 (H1 N1 ), Cal/09 (H1 N1 ) or X-31 (H3N2) at a MOI of 5. Fold induction denotes activation above infected cells without antibody. Concentrations of exemplary neuraminidase inhibitor oseltamivir are denoted in the legend. 6F12 (Pan H1 stalk-binding antibody) was used to target PR8 and Cal/09 infected cells, while 9H10 (Group 2 HA stalk-binding antibody) was used to target X-31 infected cells. Fold induction data is shown as mean ± SD with biological triplicates. ECso values are shown as mean with SEM.

[0017] Figure 5 shows exemplary neuraminidase inhibitor oseltamivir in combination with broadly-neutralizing antibodies is superior at protecting against lethal influenza virus infections in BALB/c mice compared to using either therapeutic alone. 6-8 week old female BALB/c mice were administered intraperitoneally 1 mg/kg of 6F12 or PBS and an oral gavage of 10mg/kg of exemplary neuraminidase inhibitor oseltamivir or PBS. The mice were then infected intranasally with 500 PFU of PR8 two hours later. Mice were given oseltamivir or PBS by oral gavage twice daily for 5 days. Weight change was monitored daily (top panel), and the animals were sacrificed when they reached

*P<0.05, log-rank (Mantel-Cox) test.

[0018] Figure 6 shows the characterization of polyclonal stalk-binding antibodies in human serum. Human serum was obtained from peripheral blood of two healthy adult donors. (A) ELISA was performed using chimeric cH6/1 protein to quantify the titers of the serum antibodies to the stalk domain of H1 hemagglutinin. Absorbance data is shown as mean ± SD with technical triplicates. (B) The area under the curve (AUC) is also shown as mean ± SEM. (C) Hemagglutinin inhibition assays using were used to test the presence of antibodies that bind to the receptor binding site on the head domain of Viet/04 H5N1 . N.D. = Not detectable. (D) In vitro ADCC assays were completed using A549 cells infected with Viet/04 (H5N1 ) at a MOI of 5. Fold induction denotes activation above infected cells without antibody. Fold induction data is shown as mean ± SD with technical triplicates.

[0019] Figure 7 shows exemplary neuraminidase inhibitor Oseltamivir is more effective at preventing influenza clinical signs when combined with serum with a higher content of polyclonal stalk-binding antibodies. 6-8 week old female BALB/c mice were administered intraperitoneally with 150ul of heat-inactivated human serum or PBS and an oral gavage of 0.1 mg/kg of exemplary neuraminidase inhibitor oseltamivir or PBS. The serum contains either a low content of polyclonal stalk-binding antibodies (A,B), or a high content of polyclonal stalk-binding antibodies (C,D) as determined by previous experiments. The mice were then infected intranasally with 200 PFU of Viet/05 two hours later. Mice were given oseltamivir or PBS by oral gavage twice daily for 5 days. Weight change was monitored daily, and the animals were sacrificed when they reached 80% of initial weight. The data is shown as percent of initial weight (A,C) and Kaplan-Meier survival curve (B,D). Data is shown as mean ± SD with n=5 unless otherwise indicated. ^* P<0.05, log-rank (Mantel-Cox) test. The No Treatment and Oseltamivir Only groups of mice are shared between the two experiments. DETAILED DESCRIPTION

I. Definitions

[0020] Unless otherwise indicated, the definitions and embodiments described in this and other sections are intended to be applicable to all embodiments and aspects of the present application herein described for which they are suitable as would be understood by a person skilled in the art.

[0021] In understanding the scope of the present application, the term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. The foregoing also applies to words having similar meanings such as the terms, “including”, “having” and their derivatives. The term“consisting” and its derivatives, as used herein, are intended to be closed terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but exclude the presence of other unstated features, elements, components, groups, integers and/or steps. The term“consisting essentially of, as used herein, is intended to specify the presence of the stated features, elements, components, groups, integers, and/or steps as well as those that do not materially affect the basic and novel characteristic(s) of features, elements, components, groups, integers, and/or steps.

[0022] Terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.

[0023] The term“and/or” as used herein means that the listed items are present, or used, individually or in combination. In effect, this term means that “at least one of” or“one or more” of the listed items is used or present. [0024] As used in this application, the singular forms“a”,“an” and“the” include plural references unless the content clearly dictates otherwise.

[0025] In embodiments comprising an “additional” or “second” component, the second component as used herein is chemically different from the other components or first component. A“third” component is different from the other, first, and second components, and further enumerated or“additional” components are similarly different.

[0026] The term“influenza infection” as used herein refers to an invasion of cells or bodily tissues by one or more foreign, undesirable influenza viruses.

[0027] The term“broadly-neutralizing antibodies (bNAb)” as used herein refers to hemagglutinin (HA) stalk-binding or HA stalk-reactive antibodies that are known to target the conserved stalk domain of HA, which may, for example, facilitate functional response such as antibody-dependent cell cytotoxicity (ADCC) in influenza-infected cells. The ability of bNAb in targeting the conserved stalk domain of HA allows it to bind to or react with the HA stalk domain of multiple influenza virus strains. The term“HA stalk-binding” or“HA stalk-reactive” as used herein means that the bNAbs bind to/ react with the stalk domain of the HA protein.

[0028] The term“neuraminidase” refers to an enzyme found, for example, in influenza viruses which cleaves sialic acid groups from glycoproteins on cells, for example, a host cell or an effector cell.

[0029] The term“neuraminidase inhibitor” refer to a compound capable of inhibiting the function of neuraminidase.

[0030] The term “oseltamivir” as used herein refers to a compound having the IUPAC name: Ethyl (3R, 4R, 5S)-4-acetamido-5-amino-3-(1 - ethylpropoxy)-1 - cyclohexene-1 -carboxylate, also known as Tamiflu ^® and having the chemical Formula:

[0031 ] The term“pharmaceutically acceptable salt” means either an acid addition salt or a base addition salt which is suitable for, or compatible with the treatment of subjects.

[0032] The term“bNAb-inducing agent” as used herein refers to any molecule or composition that produces an effective amount of one or more broadly neutralizing antibodies (bNAbs) in a subject.

[0033] As used herein “no treatment or prevention of the influenza infection” or“does not treat or prevent the influenza infection” means that there is no effective treatment or prevention of the influenza infection (for example, the desired clinical outcome is not achieved).

[0034] The term“vaccine” as used herein refers to a preparation that provides acquired immunity to a disease, for example, one caused by an infectious entity. An“influenza vaccine” in particular provides acquired immunity to influenza virus. A vaccine contains an agent that induces a subject’s immune system to recognize the agent as foreign, eliminate the agent, and to further recognize and eliminate any of the infectious entity associated with that agent that the subject’s immune system may encounter in the future. Vaccines can be prophylactic in that it prevents or ameliorates the effects of a future infection, and they can be therapeutic for remediation of health problems associated with a disease, for example, conditions arising from influenza infection.

[0035] The term“Pan H1 bNAbs” as used herein refers to bNAbs that bind to and/or react with stalk domain of H1 hemagglutinins of human influenza A viruses. An example of Pan H1 bNAbs is 6F12.

[0036] The term“Group 1 bNAbs” as used herein refers to bNAbs that bind to and/or react with stalk domain of Group 1 hemagglutinins of human influenza A viruses. Group 1 hemagglutinins include H1 , H2, H5, H6, H8, H9, H 1 1 , H12, H 13, H16, H17, and H18.

[0037] The term“Group 2 bNAbs” as used herein refers to bNAbs that bind to and/or react with stalk domain of Group 2 hemagglutinins of human influenza A viruses. Group 2 hemagglutinins include H3, H4, H7, H10, H14, and H15. [0038] An acid addition salt suitable for, or compatible with, the treatment of subjects is any non-toxic organic or inorganic acid addition salt of any basic compound.

[0039] A base addition salt suitable for, or compatible with, the treatment of subjects is any non-toxic organic or inorganic base addition salt of any acidic compound.

[0040] The term“solvate” as used herein means a compound, or a salt of a compound, wherein molecules of a suitable solvent are incorporated in the crystal lattice. A suitable solvent is physiologically tolerable at the dosage administered.

[0041] The term“prodrug” as used herein means a compound, or salt of a compound, that, after administration, is converted into an active drug.

[0042] The expression“disease, disorder or condition arising from an influenza infection” as used herein refers to any disease, disorder or condition that is directly or indirectly caused by the presence of an influenza infection in a subject.

[0043] The term“subject” as used herein includes all members of the animal kingdom.

[0044] The term“pharmaceutical composition” as used herein refers to a composition of matter for pharmaceutical use.

[0045] The term“pharmaceutically acceptable” means compatible with the treatment of subjects.

[0046] The term“parenteral” as used herein means taken into the body or administered in a manner other than through the gastrointestinal tract.

[0047] The term“administered” as used herein means administration of an effective amount of a compound to a cell either in cell culture or in a subject.

[0048] As used herein, the term “effective amount” or“therapeutically effective amount” means an amount effective, at dosages and for periods of time necessary to achieve a desired result. The terms “to treat”, “treating” and

“treatment” as used herein and as is well understood in the art, means an approach for obtaining beneficial or desired results, including clinical results. Beneficial or desired clinical results include, but are not limited to, diminishment of extent of influenza infection, stabilization (i.e. not worsening) of the state of the influenza infection, preventing spread of the influenza infection, delay or slowing of infection progression, amelioration or palliation of the influenza infectious state, diminishment of the reoccurrence of influenza infection, diminishment, stabilization, alleviation or amelioration of one or more diseases, disorders or conditions arising from the influenza infection, diminishment of the reoccurrence of one or more diseases, disorders or conditions arising from the influenza infection, and remission of the influenza infection and/or one or more symptoms or conditions arising from the influenza infection, whether partial or total, whether detectable or undetectable.“To treat”,“treating” and“treatment” can also mean prolonging survival as compared to expected survival if not receiving treatment.“To treat”,“treating” and“treatment” as used herein also include prophylactic treatment. For example, a subject with an early influenza infection is treated to prevent progression, or alternatively a subject in remission is treated to prevent recurrence.

[0049] “Palliating” an infection, disease, disorder and/or condition means that the extent and/or undesirable clinical manifestations of an infection, disease, disorder and/or condition are lessened and/or time course of the progression is slowed or lengthened, as compared to not treating the infection, disease, disorder and/or condition.

[0050] The term“prevention” or“prophylaxis” and the like as used herein refers to a reduction in the risk or probability of a subject becoming afflicted with an influenza infection and/or a disease, disorder and/or condition arising from an influenza infection or manifesting a symptom associated with an influenza infection and/or a disease, disorder and/or condition arising from an influenza infection.

[0051] When used, for example, with respect to the methods of treatment, uses, compositions and kits of the application, a subject, for example a subject“in need thereof” is a subject who has been diagnosed with, is suspected of having, may come in to contact with, and/or was previously treated for an influenza infection or a disease, disorder or condition arising from an influenza infection.

II. Treatment methods and uses of the application

[0052] Using an in vitro antibody-dependent cell cytotoxicity (ADCC) assay and in vivo mice models, the Applicants have shown that neuraminidase (NA) inhibitors, for example, oseltamivir, causes a dose-dependent increase in bNAb-mediated Fc receptor activation (e.g. ADCC) of influenza virus, for .example, influenza A virus (IAV) infected cells. The Applicants have also shown in mouse models that the NA inhibitor (e.g., oseltamivir) / bNAb combination therapy is superior at protecting against lethal influenza virus, for example IAV, infection compared to using either treatment alone in vivo. The Applicants have shown in mouse models receiving both monoclonal and polyclonal preparations of bNAbs that neuraminidase inhibitors such as oseltamivir surprisingly work in combination and synergistically to potentiate the ability of bNAbs to induce Fc-mediated effector functions of immune cells (e.g., ADCC)

[0053] It has been demonstrated here that the potentiation of HA stalk- binding antibodies when combined with exemplary neuraminidase inhibitor oseltamivir is preserved in a polyclonal context.

[0054] The Applicants have shown that the enzymatic inhibition of NA, for example, by an neuraminidase inhibitor such as oseltamavir, enhances Fc- dependent effector functions elicited by bNAbs and therefore the NA /bNAb combination could be used to prevent or treat therapeutic resistance.

[0055] Accordingly, the present application includes a method of treating or preventing an influenza infection in a subject in need thereof comprising administering, to the subject, an effective amount of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with an effective amount of one or more broadly neutralizing antibodies (bNAbs), wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs is an amount that when the bNAbs are administered alone does not treat or prevent the influenza infection.

[0056] The present application also includes a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with an effective amount of one or more broadly neutralizing antibodies (bNAbs), for treating an influenza infection in a subject wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection; a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for preparation of a medicament for treating an influenza infection in a subject wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection; and one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for use to treat an influenza infection in a subject wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection.

[0057] In another embodiment, the present application includes a method of treating or preventing a disease, disorder or condition arising from an influenza infection in a subject comprising administering, to a subject in need thereof, an effective amount of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with an effective amount of one or more broadly neutralizing antibodies (bNAbs) wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs is an amount that when the bNAbs are administered alone does not treat or prevent the influenza infection. [0058] The present application also includes a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for treating a disease, disorder or condition arising from an influenza infection in a subject wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection; a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for preparation of a medicament for treating a disease, disorder or condition arising from an influenza infection in a subject wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection; and the use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for use to treat a disease, disorder or condition arising from an influenza infection in a subject, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection.

[0059] In another embodiment, the present application includes a method of improving the efficacy of one or more broadly neutralizing antibodies (bNAbs) for treating an influenza infection comprising administering an effective amount of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with an effective amount of one or more broadly neutralizing antibodies (bNAbs) to a subject in need thereof wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs is an amount that when the bNAbs are administered alone does not treat or prevent the influenza infection.

[0060] The present application also includes a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for improving the efficacy of the one or more broadly neutralizing antibodies (bNAbs), for treating a disease, disorder or condition arising from an influenza infection in a subject, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection; a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for the preparation of a medicament for improving the efficacy of the one or more broadly neutralizing antibodies (bNAbs) for treating an influenza infection in a subject, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection; and the use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for use to improve the efficacy of the one or more broadly neutralizing antibodies (bNAbs) for treating an influenza infection in a subject, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection..

[0061] In another embodiment, the present application includes a method of improving the efficacy of broadly neutralizing antibodies (bNAbs) for treating a disease, disorder or condition arising from an influenza infection comprising administering an effective amount of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with an effective amount of one or more broadly neutralizing antibodies (bNAbs) or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, to a subject in need thereof wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs is an amount that when the bNAbs are administered alone does not treat or prevent the influenza infection. [0062] The present application also includes a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for improving the efficacy of one or more broadly neutralizing antibodies (bNAbs), for treating a disease, disorder or condition arising from from an influenza infection in a subject, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection; a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for the preparation of a medicament for improving the efficacy of one or more broadly neutralizing antibodies (bNAbs) for treating a disease, disorder or condition arising from influenza infection in a subject wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection; and the use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with one or more broadly neutralizing antibodies (bNAbs), for use to improve the efficacy of one or more broadly neutralizing antibodies (bNAbs) for treating a disease, disorder or condition arising from influenza infection in a subject, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are used in an amount that when the bNAbs are used alone there is no treatment or prevention of the influenza infection.

[0063] In some embodiments, the influenza infection is an infection of at least one influenza virus. In some embodiments, the influenza virus is an influenza A virus or influenza B virus. In some embodiments, the influenza A virus is a hemagglutinin (“H”) or a neuraminidase (“N”) subtype. In some embodiments, the influenza A virus subtype is selected from influenza A virus subtype H1 N1 , influenza A virus subtype H1 N2, influenza A virus subtype H2N2, influenza A virus subtype H2N3, influenza A virus subtype H3N1 , influenza A virus subtype H3N2, influenza A virus subtype H3N8, influenza A virus subtype H5N1 , influenza A virus subtype H5N2, influenza A virus subtype H5N3, influenza A virus subtype H5N6, influenza A virus subtype H5N8, influenza A virus subtype H5N9, influenza A virus subtype H6N1 , influenza A virus subtype H6N2, influenza A virus subtype H7N1 , influenza A virus subtype H7N2, influenza A virus subtype H7N3, influenza A virus subtype H7N4, influenza A virus subtype H7N7, influenza A virus subtype H7N9, influenza A virus subtype H9N2 and influenza A virus subtype H10N7. In some embodiments, the influenza A virus subtype is influenza A virus subtype H5N1.

[0064] In some embodiments, the influenza A virus is an influenza A virus variant. In some embodiments, the influenza A virus variant is from avian influenza virus, human influenza virus, swine influenza virus, equine influenza virus, bat influenza virus, feline influenza virus and canine influenza virus. In some embodiments, the influenza A virus is human influenza virus.

[0065] In some embodiments, the influenza A virus is selected from PR8, Cal/09 and X-31 influenza virus A strains.

[0066] In some embodiments, the one or more bNAbs induce Fc- mediated effector function (eg. ADCC) against influenza-infected cells. In some embodiments, the one or more bNAbs are selected from Pan H1 bNAbs, Group 1 bNAbs, Pan H3 bNAbs or Group 2 bNAbs. In some embodiments, the Pan H1 bNAb is 6F12. In some embodiments, the Group 2 bNAb is 9H10

[0067] The bNAbs can be prepared using methods known in the art, for example by purification mouse hybridomas as described in Tan, GS et a. J. Virol. 2012 86(11 ):6179-88 (6F12) and Tan GS et al. J. Virol. 2014 88(23) (9H10).

[0068] In some embodiments, the one or more bNAbs are one or more exogenous bNAbs or one or more endogenous bNAbs. In some embodiments, the one or more bNAbs are one or more exogenous bNAbs. In some embodiments, the one or more bNAbs are one or more endogenous bNAbs. In some embodiments, the one or more endogenous bNAbs are produced in a subject as an antibody response to one or more bNAb-inducing agents. [0069] The one or more bNAb-inducing agents may comprise an antigen. The antigen can be, for example, a protein, a peptide, or a fragment thereof, of the conserved HA stalk domain of influenza, which is capable of inducing an immune response and thereby produces antibodies that bind to/react with the antigen and/or amino acid sequence having at least 50% similarity with the antigen. The antigen can also be part of a vaccine.

[0070] In some embodiments, the one or more bNAb-inducing agents comprises an amino acid sequence of the stalk domain for a group 1 HA virus, for example the HA2 component of A/California/07/2009 H1 N1 which is: QTPKGAINTSLPFQNIHPITIGKCPKYVKSTKLRLATGLRNIPSIQSRGLFGAIA GFIEGGWTGMVDGWYGYHHQNEQGSGYAADLKSTQNAIDEITNKVNSVIEK MNTQFTAVGKEFNHLEKRIENLNKKVDDGFLDIWTYNAELLVLLENERTLDY HDSNVKNLYEKVRSQLKNNAKEIGNGCFEFYHKCDNTCMESVKNGTYDYP KYSEEAKLNREEIDGVKLESTRIYQILAIYSTVASSLVLVVSLGAISFWMCSNG SLQCRICI [SEQ ID NO: 1 ], or an amino acid sequence having at least 50% similarity with this sequence.

[0071] In some embodiments, the one or more bNAb-inducing agents comprises an amino acid sequence of the stalk domain for a group 2 HA virus, for example the HA2 component of A/Hong Kong/1/1968 H3N2 which is:

ITPNGSIPNDKPFQNVNKITYGACPKYVKQNTLKLATGMRNVPEKQTRGLFG

AKAGFIENGWEGMIDGWYGFRHQNSEGTGQAADLKSTQAAIDQINGKLNR

VIEKTNEKFHQIEKEFSEVEGRIQDLEKYVEDTKIDLWSYNAELLVALENQHTI

DLTDSEMNKLFEKTRRQLRENAEDMGNGCFKIYHKCDNACIESIRNGTYDH

DVYRDEALNNRFQIKGVELKSGYKDWILWISFAISCFLLCWLLGFIMWACQR

GNIRCNICI [SEQ ID NO:2], or an amino acid sequence having at least 50% similarity with this sequence.

[0072] Accordingly, in some embodiments, the one or more bNAb- inducing agents are one or more antigens. In some embodiments, the one or more one or more antigens are part of a vaccine.

[0073] In some embodiments, the disease, disorder or condition arising from influenza infection is selected from influenza (flu), fever, pain, cough, congestion, exhaustion, sore throat, chest discomfort, fatigue, dizziness, vomiting, pneumonia, bronchitis, dehydration, respiratory illnesses, cardiac problems, ear infections, and sinus infections.

[0074] In some embodiments, the one or more neuraminidase inhibitors are selected from anti-neuraminidase antibodies, anti-neuraminidase proteins, anti-neuraminidase peptides, a portion of anti-neuraminidase antibodies, a portion of anti-neuraminidase protein, and a portion of anti-neuraminidase peptide. In some embodiments, the one or more neuraminidase inhibitors are selected from oseltamivir, zanamivir, laninamivir and peramivir. In some embodiments, the neuraminidase inhibitor is oseltamivir.

[0075] The present application also includes a method of treating or preventing an influenza infection in a subject comprising administering, to a subject in need thereof, an effective amount of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with a bNAb-inducing agent that endogenously produces an effective amount of one or more broadly neutralizing antibodies (bNAbs) in a subject, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs that is induced is an amount that does not treat or prevent the influenza infection on its own.

[0076] The present application also includes a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with a bNAb-inducing agent that endogenously produces an effective amount of one or more broadly neutralizing antibodies

(bNAbs), for treating an influenza infection in a subject wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are induced in an amount that does not treat or prevent the influenza infection on its own; a use of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with a bNAb- inducing agent that endogenously produces an effective amount of one or more broadly neutralizing antibodies (bNAbs), for preparation of a medicament for treating an influenza infection in a subject wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are induced in an amount that does not treat or prevent the influenza infection on its own; and one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in combination with a bNAb-inducing agent that endogenously produces an effective amount of one or more broadly neutralizing antibodies (bNAbs), for use to treat an influenza infection in a subject wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are induced in an amount that does not treat or prevent the influenza infection on its own.

[0077] In some embodiments, “the bNAbs are administered or used alone there is no treatment or prevention of the influenza infection” or“when the bNAbs are administered alone does not treat or prevent the influenza infection” means when bNAbs are used alone the desired clinical outcome is not achieved.

[0078] In some embodiments, the one or more neuraminidase inhibitors are available from commercial sources or can be prepared using methods known in the art. For example, oseltamivir is marketed as Tamiflu ^® by Hoffmann la Roch, zanamivir is marketed as Relenza ^® by GlaxoSmithKline, and peramivir is marketed as Rapivab ^® by BioCryst Pharmaceuticals.

[0079] In an embodiment the pharmaceutically acceptable salt is an acid addition salt or a base addition salt. The selection of a suitable salt may be made by a person skilled in the art (see, for example, S. M. Berge, et al., "Pharmaceutical Salts," J. Pharm. Sci. 1977, 66, 1 -19).

[0080] An acid addition salt suitable for, or compatible with, the treatment of subjects is any non-toxic organic or inorganic acid addition salt of any basic compound. Basic compounds that form an acid addition salt include, for example, compounds comprising an amine group. Illustrative inorganic acids which form suitable salts include hydrochloric, hydrobromic, sulfuric, nitric and phosphoric acids, as well as acidic metal salts such as sodium monohydrogen orthophosphate and potassium hydrogen sulfate. Illustrative organic acids which form suitable salts include mono-, di- and tricarboxylic acids. Illustrative of such organic acids are, for example, acetic, trifluoroacetic, propionic, glycolic, lactic, pyruvic, malonic, succinic, glutaric, fumaric, malic, tartaric, citric, ascorbic, maleic, hydroxymaleic, benzoic, hydroxybenzoic, phenylacetic, cinnamic, mandelic, salicylic, 2-phenoxybenzoic, p-toluenesulfonic acid and other sulfonic acids such as methanesulfonic acid, ethanesulfonic acid and 2- hydroxyethanesulfonic acid. In an embodiment, the mono- or di-acid salts are formed, and such salts exist in either a hydrated, solvated or substantially anhydrous form. In general, acid addition salts are more soluble in water and various hydrophilic organic solvents, and generally demonstrate higher melting points in comparison to their free base forms. The selection criteria for the appropriate salt will be known to one skilled in the art. Other non-pharmaceutically acceptable salts such as but not limited to oxalates may be used, for example in the isolation of compounds of the application for laboratory use, or for subsequent conversion to a pharmaceutically acceptable acid addition salt.

[0081 ] A base addition salt suitable for, or compatible with, the treatment of subjects is any non-toxic organic or inorganic base addition salt of any acidic compound. Acidic compounds that form a basic addition salt include, for example, compounds comprising a carboxylic acid group. Illustrative inorganic bases which form suitable salts include lithium, sodium, potassium, calcium, magnesium or barium hydroxide as well as ammonia. Illustrative organic bases which form suitable salts include aliphatic, alicyclic or aromatic organic amines such as isopropylamine, methylamine, trimethylamine, picoline, diethylamine, triethylamine, tripropylamine, ethanolamine, 2-dimethylaminoethanol, 2- diethylaminoethanol, dicyclohexylamine, lysine, arginine, histidine, caffeine, procaine, hydrabamine, choline, betaine, ethylenediamine, glucosamine, methylglucamine, theobromine, purines, piperazine, piperidine, N- ethylpiperidine, polyamine resins, and the like. Exemplary organic bases are isopropylamine, diethylamine, ethanolamine, trimethylamine, dicyclohexylamine, choline, and caffeine. The selection of the appropriate salt may be useful, for example, so that an ester functionality, if any, elsewhere in a compound is not hydrolyzed. The selection criteria for the appropriate salt will be known to one skilled in the art. [0082] Formation of a pharmaceutically-acceptable salt may be achieved using standard techniques. For example, a neutral compound is treated with an acid or base in a suitable solvent and the formed salt is isolated by filtration, extraction or any other suitable method.

[0083] Solvates of compounds of the application include, for example, those made with solvents that are pharmaceutically acceptable. Suitable solvents are physiologically tolerable at the dosage administered.

[0084] Examples of suitable solvate solvents are ethanol, water and the like. When water is the solvent, the molecule is referred to as a“hydrate”. The formation of solvates will vary depending on the compound and the solvate. In general, solvates are formed by dissolving the compound in the appropriate solvent and isolating the solvate by cooling or using an antisolvent. The solvate is typically dried or azeotroped under ambient conditions. The selection of suitable conditions to form a particular solvate can be made by a person skilled in the art.

[0085] Various polymorphic forms and salts of oseltamivir are described, for example, in W02009087062A2, the contents of which are incorporated herein by reference.

[0086] Various crystal forms of zanamivir are described, for example, in Nath et al. Cryst. Growth Des. 2014, 14, 2, 770-774, the contents of which are incorporated herein by reference.

[0087] Prodrugs of the compounds (one or more neuraminidase inhibitors, or salts and/or solvates thereof), may be prepared, for example, by acylating available hydroxy or amino groups using an activated acid in the presence of a base, and optionally, in inert solvent (e.g. an acid chloride in pyridine). Similarly, available carboxylic acid groups may be converted to ester groups using known chemistry, for example, by activation in the presence of base and reaction with suitable groups containing a nucleophile. Some common esters which have been utilized as prodrugs are phenyl esters, aliphatic (C1-C24) esters, acyloxymethyl esters, carbamates and amino acid esters. [0088] In the context of treating an influenza infection, or a disease, disorder or condition arising from an influenza infection, an effective amount of the one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof or one or more broadly neutralizing antibodies, is an amount that, for example, reduces the influenza infection compared to the influenza infection without administration of the one or more broadly neutralizing antibodies or one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof.

[0089] Further, in the context of improving the efficacy of one or more broadly neutralizing antibodies for the treatment of an influenza infection or a disease, disorder or condition arising from an influenza infection an effective amount of the one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, is, for example, an amount that, for example, reduces the influenza infection compared to the reduction of the influenza infection with administration of the one or more broadly neutralizing antibodies alone. By “reducing the infection”, it is meant, for example, reducing the amount of the infectious agent in the subject and/or reducing the symptoms of the infection. Effective amounts may vary according to factors such as the disease state, age, sex and/or weight of the subject. The amount of a given compound or composition that will correspond to such an amount will vary depending upon various factors, such as the given compound or composition, the pharmaceutical formulation, the route of administration, the type of condition, disease or disorder, the identity of the subject being treated, and the like, but can nevertheless be routinely determined by one skilled in the art.

[0090] The one or more broadly neutralizing antibodies (bNAbs) are administered to a subject, or used, in a variety of forms depending on the selected route of administration, as will be understood by those skilled in the art. In some embodiments, the one or more broadly neutralizing antibodies (bNAbs) are administered to the subject, or used, by oral (including sublingual and buccal) or parenteral (including, intravenous, intraperitoneal, subcutaneous, intramuscular, transepithelial, nasal, intrapulmonary, intrathecal, rectal, topical, patch, pump and transdermal) administration and the antibiotic formulated accordingly. Conventional procedures and ingredients for the selection and preparation of suitable compositions are described, for example, in Remington’s Pharmaceutical Sciences (2000 - 20th edition) and in The United States Pharmacopeia: The National Formulary (USP 24 NF19) published in 1999. In general, the one or more broadly neutralizing antibodies (bNAbs) are used in the form in which is it available and administered to subjects. Such forms, include, for example in the form of their pharmaceutically acceptable salts, and in an injectable or infusable suspensions.

[0091] The one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, are also administered to a subject, or used, in a variety of forms depending on the selected route of administration, as will be understood by those skilled in the art. In some embodiments, the one or more neuraminidase inhibitors are administered to the subject, or used, by oral (including sublingual and buccal) or parenteral (including, intravenous, intraperitoneal, subcutaneous, intramuscular, transepithelial, nasal, intrapulmonary, intrathecal, rectal, topical, patch, pump and transdermal) administration and the compound, salt and/or solvate, formulated accordingly. Again, conventional procedures and ingredients for the selection and preparation of suitable compositions are described, for example, in Remington’s Pharmaceutical Sciences (2000 - 20th edition) and in The United States Pharmacopeia: The National Formulary (USP 24 NF19) published in 1999.

[0092] The pharmaceutical forms suitable for injectable use include sterile aqueous solutions or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. In all cases, the form is sterile and fluid to the extent that easy syringability exists.

[0093] In some embodiments, parenteral administration is by continuous infusion over a selected period of time. Solutions suitable for parenteral administration are prepared by known methods by a person skilled in the art.

For example, the one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, is prepared in water optionally mixed with a surfactant such as hydroxypropylcellulose. Dispersions are also prepared in glycerol, liquid polyethylene glycols, DMSO and mixtures thereof with or without alcohol, and in oils. Under ordinary conditions of storage and use, these preparations contain a preservative to prevent the growth of microorganisms.

[0094] Compositions for nasal administration are conveniently formulated as aerosols, drops, gels or powders. Aerosol formulations typically comprise a solution or fine suspension of the active substance in a physiologically acceptable aqueous or non-aqueous solvent and are usually presented in single or multidose quantities in sterile form in a sealed container, which take the form of a cartridge or refill for use with an atomising device. Alternatively, the sealed container is a unitary dispensing device such as a single dose nasal inhaler or an aerosol dispenser fitted with a metering valve which is intended for disposal after use. Where the dosage form comprises an aerosol dispenser, it contains a propellant which is, for example, a compressed gas such as compressed air or an organic propellant such as fluorochlorohydrocarbon. In some embodiments, the aerosol dosage forms take the form of a pump-atomizer.

[0095] Compositions suitable for buccal or sublingual administration include tablets, lozenges, and pastilles, wherein the active ingredient is formulated with a carrier such as sugar, acacia, tragacanth, gelatin and/or glycerine. Compositions for rectal administration are conveniently in the form of suppositories containing a conventional suppository base such as cocoa butter.

[0096] In another embodiment, the one or more broadly neutralizing antibodies (bNAbs), or one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are orally administered, for example, with an inert diluent or with an assimilable edible carrier, or it is enclosed in hard or soft shell gelatin capsules, or it is compressed into tablets, or it is incorporated directly with the food of a diet. For oral administration, the one or more broadly neutralizing antibodies (bNAbs) or one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are incorporated with excipients and used in the form of, for example, ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. Oral dosage forms also include modified release, for example immediate release and timed-release, formulations. Examples of modified-release formulations include, for example, sustained-release (SR), extended-release (ER, XR, or XL), time-release or timed-release, controlled-release (CR), or continuous-release (CR or Contin), employed, for example, in the form of a coated tablet, an osmotic delivery device, a coated capsule, a microencapsulated microsphere, an agglomerated particle, e.g., molecular sieving type particles, or, a fine hollow permeable fiber bundle, or chopped hollow permeable fibers, agglomerated or held in a fibrous packet. In some embodiments, timed-release compositions are, formulated, as liposomes or those wherein the active compound is protected with differentially degradable coatings, such as by microencapsulation, multiple coatings, etc. Liposome delivery systems include, for example, small unilamellar vesicles, large unilamellar vesicles and multilamellar vesicles. In some embodiments, liposomes are formed from a variety of lipids, such as cholesterol, stearylamine or phosphatidylcholines.

[0097] It is also possible to freeze-dry the one or more broadly neutralizing antibodies (bNAbs), or one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, and use the lyophilizate obtained, for example, for the preparation of products for injection.

[0098] In some embodiments, the one or more broadly neutralizing antibodies (bNAbs), or one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are coupled with soluble polymers as targetable drug carriers. Such polymers include, for example, polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamide-phenol, polyhydroxy- ethylaspartamide-phenol, or polyethyleneoxide-polylysine substituted with palmitoyl residues. In a further embodiment, the one or more broadly neutralizing antibodies (bNAbs), or one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polylactic acid, polyglycolic acid, copolymers of polylactic and polyglycolic acid, polyepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacrylates and crosslinked or amphipathic block copolymers of hydrogels. [0099] One or more broadly neutralizing antibodies (bNAbs), or one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are used in combination with each other. One or more broadly neutralizing antibodies (bNAbs), or one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are either used or administered separately in time and/or in mode of administration (i.e. different administration routes) or they are administered together in the same pharmaceutical preparation.

[00100] In one embodiment, one or more broadly neutralizing antibodies (bNAbs), or one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are used or administered separately in time and/or in mode of administration. For example, one or more broadly neutralizing antibodies (bNAbs), are administered by injection and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are administered orally or by inhalation. In another example, one or more broadly neutralizing antibodies (bNAbs), are administered orally and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, areis administered by injection. In a further example, both one or more broadly neutralizing antibodies (bNAbs), and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are both administered orally or by injection. When one or more broadly neutralizing antibodies (bNAbs), and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are used or administered separately in time and/or in mode of administration, one or more broadly neutralizing antibodies (bNAbs), are administered, or used, either before or after administration, or use, of one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof.

[00101 ] In another embodiment, one or more broadly neutralizing antibodies (bNAbs), and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are administered contemporaneously. As used herein, “contemporaneous administration” of two substances to a subject means providing one or more broadly neutralizing antibodies (bNAbs), and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, so that they are both biologically active in the subject at the same time. The exact details of the administration will depend on the pharmacokinetics of the one or more broadly neutralizing antibodies (bNAbs), and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, in the presence of each other, and can include administering one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, within a few hours of each other, or even administering one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, within 24 hours or greater of administration of the other, if the pharmacokinetics are suitable. Design of suitable dosing regimens is routine for one skilled in the art.

[00102] In some embodiments, one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors or a salt, prodrug and/or solvate thereof, are administered to a subject in a single composition or formulation.

[00103] In another embodiment of the present application, one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are administered to a subject in a non- contemporaneous fashion.

[00104] In a further embodiment of the present application, one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are administered to the subject in a contemporaneous fashion followed by, or alternating with, administration in a non-contemporaneous fashion. In some embodiments, one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors or a salt, prodrug and/or solvate thereof, are administered to a subject in a contemporaneous fashion.

[00105] Treatment methods comprise administering to a subject one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, and optionally consists of a single administration, or alternatively comprises a series of administrations. The length of the treatment period depends on a variety of factors, such as the severity of the disease, disorder or condition, the age of the subject, the dosage of one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, the activity of one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, and/or a combination thereof.

[00106] It is an embodiment that one or more broadly neutralizing antibodies, are administered or used according to treatment protocol that is known for the broadly neutralizing antibodies in the treatment in influenza infections.

[00107] It is also an embodiment that one or more neuraminidase inhibitors, are administered or used according to treatment protocol that is known for the neuraminidase inhibitor in the treatment in influenza infections.

[00108] In some embodiments, one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are administered or used as soon as possible after exposure to the influenza virus. In some embodiments, one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are administered or used until treatment of the influenza infection is achieved. For example, until complete elimination of the influenza virus is achieved, or until the number of influenza viruses has been reduced to the point where the subject’s defenses are no longer overwhelmed and can kill any remaining influenza viruses.

[00109] In some embodiments, one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, are administered or used as soon as possible before an expected exposure to the influenza virus.

[001 10] The dosage of the one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, varies depending on many factors such as the pharmacodynamic properties thereof, the mode of administration, the age, health and weight of the subject, the nature and extent of the symptoms, the frequency of the treatment and the type of concurrent treatment, if any, and the clearance rate in the subject to be treated. One of skill in the art can determine the appropriate dosage based on the above factors. One or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, may be administered initially in a suitable dosage that may be adjusted as required, depending on the clinical response.

[001 1 1 ] In some embodiments, the dosage of the one or more broadly neutralizing antibodies, and one or more neuraminidase inhibitors, or a salt, prodrug and/or solvate thereof, is equal to or less than the dosage of such agents when used alone. Such dosages are known to or readily determined by those skilled in the art.

[001 12] In In some embodiments, the one or more broadly neutralizing antibody (bNAb)-inducing agents are administered to a subject, or used, in a variety of forms as described herein for when one or more broadly neutralizing antibodies are used. The dosages of the one or more broadly neutralizing antibody (bNAb)-inducing agents can also be readily determined by those skilled in the art.

[001 13] In some embodiments, the effective amount of the one or more neuraminidase inhibitors is about 0.1 mg/kg to about 100 mg/kg, about 0.1 mg/kg to about 75mg/kg, 0.1 mg/kg to about 50 mg/kg, about 1 mg/kg to about 50 mg/kg, or about 1 mg/kg to about 3 mg/kg.

[001 14] In some embodiments, the effective amount of the one or more broadly neutralizing antibodies (bNAbs) is about 0.1 mg/kg to about 50 mg/kg, about 1 mg/kg to about 40 mg/kg, about 1 mg/kg to about 30 mg/kg or about 1 mg/kg to about 25 mg/kg.

III. Compositions and Kits of the application

[001 15] The present application also includes a pharmaceutical combination, packaged together in a kit or a single composition, comprising one or more broadly neutralizing antibodies (bNAbs) and one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof wherein the one or more neuraminidase inhibitors and bNAbs are present in amounts that are effective to treat an influenza infection or a disease, disorder or condition arising from an influenza infection and wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs is an amount that when the bNAbs are administered or used alone there is no treatment or prevention of the influenza infection.

[001 16] The present application also includes a pharmaceutical combination, packaged together in a kit or a single composition, comprising one or more broadly neutralizing antibodies (bNAbs) and one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof wherein the one or more neuraminidase inhibitors and bNAbs are present in amounts that are effective for improving the efficacy of the one or more bNAbs to treat an influenza infection or a disease, disorder or condition arising from an influenza infection, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs is an amount that when the bNAbs are administered or used alone there is no treatment or prevention of the influenza infection.

[001 17] In some embodiments, the disease, disorder or condition arising from influenza infection is influenza (flu).

[001 18] The present application also includes a kit for the treatment of an influenza infection or a disease, disorder or condition arising from an influenza infection, the kit comprising one or more broadly neutralizing antibodies (bNAbs) and one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof and optionally instructions for administration of the one or more bNAbs and one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt and/or solvate thereof, to a subject in need thereof, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are administered or used in an amount that when the one or more bNAbs are administered or used alone there is no treatment or prevention the influenza infection. [001 19] The present application also includes a kit for the treatment of an influenza infection, or a disease, disorder or condition arising from an influenza infection, the kit comprising: one or more neuraminidase inhibitors or a pharmaceutically acceptable salt and/or solvate thereof; and instructions for administration of one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt and/or solvate thereof, to a subject being administered one or more bNAbs for an influenza infection or a disease, disorder or condition arising from an influenza infection wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are administered or used in an amount that when the one or more bNAbs are administered or used alone there is no treatment or prevention the influenza infection.

[00120] The present application also includes a kit for improving the efficacy of one or more bNAbs for the treatment of an influenza infection or a disease, disorder or condition arising from an influenza infection, the kit comprising one or more broadly neutralizing antibodies (bNAbs) and one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof; and optionally instructions for administration of the one or more broadly neutralizing antibodies (bNAbs) and one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, to a subject in need thereof wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are administered or used in an amount that when the one or more bNAbs are administered or used alone there is no treatment or prevention the influenza infection.

[00121 ] The present application also includes a kit for improving the efficacy of one or more bNAbs for the treatment of an influenza infection, or a disease, disorder or condition arising from an influenza infection, the kit comprising one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt and/or solvate thereof; and instructions for administration one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt and/or solvate thereof, to a subject being administered one or more bNAbs for the treatment of an influenza infection or a disease, disorder or condition arising from an influenza infection wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs and the one or more bNAbs are administered or used in an amount that when the one or more bNAbs are administered or used alone there is no treatment or prevention the influenza infection.

[00122] In some embodiments, one or more broadly neutralizing antibodies (bNAbs) and one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof, in the compositions and kits of the present application are formulated as separate pharmaceutical compositions, for separate administration to, or use in, subjects. In this embodiment, the separate pharmaceutical compositions are formulated independently of each other and in accordance with the desired mode of administration for each active.

[00123] In some embodiments, the one or more broadly neutralizing antibodies (bNAbs) are formulated for administration, or use, by oral delivery or for delivery by injection. In another embodiment, one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt and/or solvate thereof is formulated for administration, or use, by oral delivery, for delivery by injection. In another embodiment, one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt and/or solvate thereof is formulated for administration, or use, by oral delivery or for delivery by inhalation.

[00124] In some embodiments, one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt and/or solvate thereof, and the one or more broadly neutralizing antibodies (bNAbs) in the compositions and kits of the present application are formulated as a single pharmaceutical composition, for combined, simultaneous administration to, or use in, subjects. In some embodiments, the single pharmaceutical composition is formulated for administration, or use, by oral delivery or by injection. In some embodiments, the single pharmaceutical composition is formulated for administration, or use, by injection.

[00125] The present application also includes a pharmaceutical combination, packaged together in a kit or a single composition, comprising one or more broadly neutralizing antibody (bNAb)-inducing agents that endogenously produce an effective amount of one or more broadly neutralizing antibodies (bNAbs) in a subject and one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof wherein the one or more neuraminidase inhibitors and bNAbs are present in amounts that are effective to treat an influenza infection or a disease, disorder or condition arising from an influenza infection and wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the amount of the one or more bNAbs is an amount that when the bNAbs are administered or used alone there is no treatment or prevention of the influenza infection

[00126] The present application also includes a kit for the treatment of an influenza infection or a disease, disorder or condition arising from an influenza infection, the kit comprising one or more broadly neutralizing antibody (bNAb)- inducing agents that endogenously produce an effective amount of one or more broadly neutralizing antibodies (bNAbs) in a subject and one or more neuraminidase inhibitors or a pharmaceutically acceptable salt, prodrug and/or solvate thereof and optionally instructions for administration of the one or more bNAb-inducing agents and one or more neuraminidase inhibitors, or a pharmaceutically acceptable salt and/or solvate thereof, to a subject in need thereof, wherein the bNAbs bind to the stalk domain of hemagglutinin (HA) and the one or more bNAbs are administered or used in an amount that when the one or more bNAbs are administered or used alone there is no treatment or prevention the influenza infection.

EXAMPLES

[00127] The following non-limiting examples are illustrative of the present application:

Example 1 : Inhibition of viral replication using a neuraminidase inhibitor

[00128] Neuraminidase activity of 6x10 ⁶ PFU of PR8 and X-31 and 6x10 ⁵ PFU of Cal/09 were measured using the Neuraminidase Assay Kit from Sigma- Adrich (MAK121 ) per manufacturer’s protocol. Specifically, influenza virus strains PR8 (A/Puerto Rico/8/1934 H1 N1 ); Cal/09 (A/California/7/2009 H1 N1 ); and X-31 , a reassortant virus with HA and NA from A/Hong Kong/1 /1968 H3N2 in the PR8 backbone (Fig. 2 first panel). Approximately 1x10 ⁴ PFU of virus was required before NA activity was detectable by the assay. The NA activity was within in the linear range of the assay until approximately 1x10 ⁶ PFU for all viruses. The oseltamivir acid susceptibility of these viruses using the same kit using 1x10 ⁶ PFU of each strain (Fig. 2 second and third panel) was measured. All three viruses displayed similar levels of oseltamivir acid susceptibility as shown by the ICso values, with PR8 being the most susceptible and X-31 being the least susceptible. Viruses were incubated with exemplary neuraminidase inhibitor oseltamivir acid for 30 minutes at room temperature before measurements were taken. ^* p<0.05, one-way ANOVA with Dunnett’s multiple comparisons test.

[00129] In Figure 2 (fourth panel) Viral replication of PR8, Cal/09, and X- 31 were measured using plaque assays. A549 cells were infected with PR8, Cal/09, or X-31 at a multiplicity of infection (MOI) of 5. After infection, the media was changed to include stated concentrations of oseltamivir acid. The supernatant was then collected 12 hours (Ibars 1 to 4) or 18 hours (bars 5 to 8) after infection, and the titer was measured by completing plaque assays using MDCK cells. N=3, error bars represent SD, ^* p<0.05 compared to OmM oseltamivir acid, one-way ANOVA with Dunnett’s multiple comparisons test. N.D = Not Detected.

[00130] Exemplary neuraminidase inhibitor oseltamivir acid decreased both neuraminidase activity and viral replication of H1 N1 and H3N2 influenza viruses linfluenza virus strains PR8, Cal/09, and X-31 were used. This experiment verified that oseltamivir carboxylate was indeed active against the neuraminidase proteins on influenza virus particles. It was also found that increasing concentrations of oseltamivir acid also inhibits the ability of influenza viruses to replicate in a dose-dependent manner in cell culture of A549 cells. That is, higher concentrations of oseltamivir acid induced appreciable decreases in viral replication. Surprisingly, exemplary neuraminidase inhibitor oseltamivir acid induced the greatest decline in viral replication for X-31 , while PR8 and Cal/09 showed more modest declines in titer. Overall, it was shown that oseltamivir acid can be used as a chemical inhibitor of neuraminidase in subsequent experiments.

Example 2: Broadly neutralizing antibodies bind infected cells

[00131 ] Immunofluorescent staining of PR8, Cal/09, and X-31 infected A549 cells were completed using 6F12 and 9H10 antibodies as shown in Figure 3 (U.l. = Uninfected cells. Scale bars represent 400pm). The broadly- neutralizing antibodies 6F12 and 9H10 bound specifically to A549 cells infected with an H1 N1 or H3N2 viruses respectively. Accordingly, it was shown that the broadly-neutralizing antibodies used were specific to the viruses used to infect the target cells. These antibodies did not react with cells that were uninfected (U.I.). This demonstrated that the antibodies were indeed interacting with the targets of interest. This was important for the next experiment, which relied on these broadly-neutralizing antibodies to bind to and activate modified Jurkat effector cells in the antibody-dependent cell cytotoxicity (ADCC) assays.

Example 3: Neuraminidase inhibitor increases broadly-neutralizing antibody mediated ADCC of influenza virus infected A549 cells

Figure 1 shows how stalk-binding antibodies facilitate the interaction between immune effector cells and infected cells via two points of contact .The stalk- binding antibody interacts with the HA stalk domain via its Fab portion, and binds to the Fc receptor of the effector via its Fc portion(1 ). The HA head domain interacts with sialic acid residues on the effector cell (2). Although the sialic acid residues are depicted as a moiety on the Fc receptor on the effector cells, the actual location of the sialic acid residues that HA binds to in this context is not known.

[00132] To determine the role of neuraminidase on stalk-binding antibody mediated activation of immune effector cells, a series of ADCC assays was performed. A549 cells were infected with PR8, Cal/09, or X-31. As shown in Figure 4, ADCC of PR8, Cal/09, or X-31 infected A549 cells were measured using a luciferase-based system. A549 cells were seeded onto 96-well plates and infected 24 hours later with PR8, Cal/09, or X-31 at an MOI of 5. 18 hours after infection, the media was changed and indicated concentrations of exemplary neuraminidase inhibitor oseltamivir acid (OSLT) and 6F12 or 9H10 antibodies were added. Therefore, the infected cells were incubated with exemplary neuraminidase inhibitor oseltamivir acid and monoclonal stalk- binding antibodies 6F12 for cells infected with PR8 and Cal/09, and 9H10 for cells infected with X-31 . 6F12 is a Pan H1 stalk-binding antibody, while 9H10 is a group 2 HA stalk-binding antibody. Jurkat reporter cells were then added and incubated for 6 hours before luciferase activity was measured by ADCC (Figure 4). Data represents fold induction of luciferase activity over a 10pg/ml IgG negative control. N=3, error bars represent SD. U.l = uninfected cells. Addition of exemplary neuraminidase inhibitor oseltamivir acid resulted in a dose- dependent increase in efficacy (higher maximal fold induction) and potency (decreased EC50) of 6F12 in PR8 and Cal/09 infected cells. Cells infected with X-31 showed different results: the efficacy of ADCC induction by 6F12 increased with the addition of exemplary neuraminidase inhibitor oseltamivir, acid but the potency surprisingly decreased with 1 mM concentration of exemplary neuraminidase inhibitor oseltamivir acid compared to the control and low oseltamivir acid condition. As described in Example 2, the interactions between 6F12 to PR8 and Cal/09 infected cells, and 9H10 to X-31 infected cells were verified using immunofluorescent staining of infected A549 cells (Figure 3).

[00133] Therefore, exemplary neuraminidase inhibitor oseltamivir acid increased broadly-neutralizing antibody mediated ADCC of influenza virus infected A549 cells. Accordingly, it was found that exemplary neuraminidase inhibitor oseltamivir acid had a cooperative effect with broadly-neutralizing antibodies in causing ADCC of influenza virus infected cells. Increasing antibody concentrations with no exemplary neuraminidase inhibitor oseltamivir added (▲ in Figure 4), there was increased fold induction of ADCC of our infected target (A549) cells. The fold induction was compared to cells that did not have antibody added to it. Upon addition of exemplary neuraminidase inhibitor oseltamivir in various concentrations, it was found that the ADCC potency increased (decreased ECso) in PR8 and Cal/09 infected cells, and the efficacy (fold induction) increased in all three viruses tested. The increase in potency and efficacy was also dose-dependent on the amount of oseltamivir that was added. Therefore, it was found that exemplary neuraminidase inhibitor oseltamivir cooperates with broadly-neutralizing antibodies to facilitate ADCC of influenza virus infected cells.

Example 4: Exemplary neuraminidase inhibitor oseltamivir in combination with broadly-neutralizing antibodies is superior at protecting against lethal influenza virus infections compared to using either therapeutic alone.

[00134] The relevance of the in-vitro findings in an in-vivo model was tested. As shown in Figure 5, 6-8 week old female BALB/c mice were given an intraperitoneal injection of 1 mg/kg 6F12 anti-stalk antibody or control IgG and oral gavage of 10mg/kg of exemplary neuraminidase inhibitor oseltamivir phosphate (OSLT) or phosphate-buffered saline (PBS). The mice were then infected intranasally two hours later with 5X LD50 (500PFU) of IAV strain PR8. Mice were then given 10mg/kg OSLT or PBS twice daily by oral gavage for 5 consecutive days (Figure 5). Mice were monitored twice daily for body weight and IAV infection clinical signs. Data is shown in Figure 5 as percent weight (a) and percent survival (b). N=5 per group, error bars represent SD, ^* p<0.05, log- rank test. Mice that received exemplary neuraminidase inhibitor oseltamivir phosphate all experienced significant weight loss, and 3/5 mice recovered. Mice that received both exemplary neuraminidase inhibitor oseltamivir phosphate and 6F12 all maintained weight at above 90% throughout the experimental period, with no mouse reaching endpoint.

[00135] Therefore, exemplary neuraminidase inhibitor oseltamivir phosphate in combination with broadly-neutralizing antibodies was superior at protecting against lethal influenza virus infections in BALB/c mice compared to using either therapeutic alone. This experiment shows that the results from the previous in vitro ADCC experiments translates to better in vivo protection. It was demonstrated that the cooperative interaction between exemplary neuraminidase inhibitor oseltamivir and broadly-neutralizing antibodies in eliciting ADCC of influenza-virus infected cells resulted in better protection of mice that were infected with the same virus strain. Mice that received both oseltamivir phosphate and 6F12 displayed fewer clinical signs (less weight loss and fewer reached endpoint) compared to mice that received only oseltamivir, only 6F12, or neither. Therefore, combining oseltamivir phosphate and broadly- neutralizing antibodies as a prophylaxis worked better than using either of the two therapeutics by themselves.

Example 5: The cooperative effect of exemplary neuraminidase inhibitor oseltamivir phosphate and stalk-binding antibodies at preventing clinical signs of influenza virus infections is maintained in a polyclonal antibody context.

[00136] The previous results demonstrate that exemplary neuraminidase inhibitor oseltamivir phosphate cooperates with monoclonal stalk-binding antibodies to protect against clinical signs of influenza virus infections by enhancing antibody-mediated immune effector cell activation. It was next investigated if these findings persist in the more natural context of polyclonal human serum.

[00137] Serum was first purified from peripheral blood of two healthy donors. ELISAs were then performed on the serum samples using a chimeric cH6/1 hemagglutinin protein, where the head domain is derived from A/Mallard/Sweden/81 /02 and the stalk domain is derived from A/Puerto Rico/8/1934 (Figure 6A, B). The cH6/1 chimera was chosen to quantify antibodies that specifically bind to the group 1 stalk domain. A/Vietnam/1203/2004 HAIo (Viet/04), which is a low pathogenicity human H5N1 virus, was chosen for the downstream experiments. Viet/04 strain was chosen for its high pathogenicity in mice, relevance as a pandemic threat to humans, and the expected cross-reactivity of group 1 stalk-binding antibodies with the hemagglutinin stalk of Viet/04. T o ensure that the serum samples do not contain neutralizing antibodies that bind to the head domain of Viet/04, a hemagglutinin inhibition assay was conducted(Figure 6C). Both serum samples exhibited undetectable levels of HA inhibition, indicating that both donors were naive to this virus. ADCC assays were then conducted, which showed that the serum sample with greater titer of stalk binding antibodies elicited stronger ADCC as determined using Jurkat reporter cells (Figure 6D).

[00138] The protective effects of these serum samples against Viet/04 H5N1 challenge in Balb/c mice both alone and in combination with exemplary neuraminidase inhibitor oseltamivir phosphate was next assessed. Six groups of 6-8 week old BALB/c mice were first either administered 150ul of serum low in stalk-binding antibodies, 150ul of serum high in stalk-binding antibodies, or 150ul of PBS. The mice were then given either 10mg/kg exemplary neuraminidase inhibitor oseltamivir phosphate or PBS by oral gavage. Two hours after the treatments were given, the mice were infected with 5LDso of Viet/04 H5N1 (200PFU) intranasally. The mice continued to receive either 10mg/kg exemplary neuraminidase inhibitor oseltamivir phosphate or PBS twice daily by oral gavage for 5 days. The mice were monitored for 14 days and sacrificed when they reached 80% of their initial body weight. The data is shown as two sets of graphs with shared negative control groups to separate mice that received serum low and high in stalk-binding antibodies (Figure 7). All the mice that received either serum low or high in stalk-binding antibodies or exemplary neuraminidase inhibitor oseltamivir phosphate alone demonstrated significant weight loss and mortality, with 4/5 mice reaching endpoint before day 14 in most treatment groups. When exemplary neuraminidase inhibitor oseltamivir phosphate was combined with serum containing low stalk antibody, the mortality of the mice improved to only 1/5 mice reaching endpoint by day 14. However, the morbidity of the mice remained similar to serum low or high in stalk-binding antibodies alone or exemplary neuraminidase inhibitor oseltamivir phosphate alone. Exemplary neuraminidase inhibitor oseltamivir phosphate combined with serum containing high stalk antibody showed the greatest improvement in morbidity and mortality. Importantly, this group displayed markedly improved mortality and morbidity with minimal weight loss compared to the other combination therapy group.

[00139] It has been demonstrated here that the potentiation of stalk- binding antibodies when combined with exemplary neuraminidase inhibitor oseltamivir phosphate is preserved in a polyclonal context. The hemagglutinin stalk domain is an attractive target for universal influenza vaccine design, as antibodies against this domain are effective against multiple strains of influenza virus. Recipients of the universal vaccine are thus expected to maintain higher serum titers of anti-stalk antibody. These results suggest that universal vaccines should also attempt to elicit high titers of antibodies that inhibit neuraminidase activity in order to enhance vaccine effectiveness.

Example 6: The cooperative effect of combining exemplary neuraminidase inhibitor oseltamivir and stalk-binding antibodies is preserved when used to treat acute influenza virus infections

[00140] While it the superiority of NA/bnAb combination treatment has been demonstrated in a prophylactic setting, it is intuitive that this combination should also be effective therapeutically.

The experimental design to demonstrate this is similar to the previous experiments, except that 6-8 week old BALB/c mice would be infected with 5LD50 of PR8 before starting treatment at various times post-infection (eg. 24, 48 , 72hpi). Various doses of bnAb would be tested (eg. 1 mg/kg, 5mg/kg, 10mg/kg) since administration post-infection is likely to require a higher dose to achieve protection than prophylactic treatment. Mice would be monitored for 14 days post-infection and sacrificed when weight dropped below 80% of pre- infection body weight. The combination of bnAb+NA would be deemed superior than either drug alone if it results in less morbidity (as measured by weight loss) or mortality.

[00141 ] As shown in the above examples, the use of serum with low amounts of stalk-binding antibodies, serum with high amounts of stalk-binding antibodies or exemplary neuraminidase inhibitor oseltamivir alone was not able to treat mice infected with an influenza virus. Stalk-binding antibodies can inhibit influenza virus from initiating infection, inhibit budding, inhibit HA cleavage/maturation, and/or can induce Fc-mediated effector functions (eg. ADCC) Therefore, the stalk-binding antibodies alone or neuraminidase alone working by their own distinct mechanisms alone, for example, neuraminidase inhibitors are known to protect against influenza infection by inhibiting budding, were not effective at treating mice infected with an influenza virus. The use of serum with low amounts of stalk-binding antibodies in combination with an exemplary neuraminidase inhibitor only offered considerable improvement in survival, but more moderate improvement in morbidity. It was only when exemplary neuraminidase inhibitor oseltamivir was combined with serum containing high stalk antibody that improvement in morbidity and mortality was observed. While not wishing to be limited by theory, the data presented herein suggests that neuraminidase inhibitors such as oseltamivir and bnAbs surprisingly work in combination and synergistically to increase the potency of Fc-mediated effector function of immune cells (eg. ADCC mechanism), and not by working by their own distinct mechanisms alone. This combined mechanism of action is consistent with the“2 point of contact” model of how bnAbs induce ADCC/Fc effector functions as shown in Figure 1. The neuraminidase inhibitors and bnAbs work cooperatively to stabilize HA:sialic acid interactions (which NA generally cleaves). The lines in Figure 1 represent enzymatic inhibition by neuraminidase on the HA head - sialic interaction, and the inhibition of exemplary neuraminidase inhibitor oseltamivir on the neuraminidase enzymatic activity.

[00142] While the present application has been described with reference to examples, it is to be understood that the scope of the claims should not be limited by the embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

[00143] All publications, patents and patent applications are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety. Where a term in the present application is found to be defined differently in a document incorporated herein by reference, the definition provided herein is to serve as the definition for the term.