PSORIASIS

CROSS REFERENCE TO RELATED PATENT APPLICATION

[0001] This application claims priority to and is a continuation in part of International Application No. PCT/US18/56054 filed October 16, 2018, the contents of which are herein incorporated by reference in their entirety.

FIELD OF INVENTION

[0002] The present invention relates to injectable and topical pharmaceutical compositions comprising polymer-conjugated fumaric acid esters (FAEs), and polymer-encapsulated FAEs that are useful for prevention and treatment of autoimmune, neuro-inflammatory and neurodegenerative conditions, among others.

BACKGROUND OF THE INVENTION

[0003] Inflammation and oxidative stress are thought to promote tissue damage in multiple sclerosis and FAEs are known to exert neuroprotective effects in neuroinflammation via activation of the Nrf2 (Nuclear factor erythroid 2-related factor 2) antioxidant pathway. Linker et al., Brain. 201 1 ;134(3):678-692. Several clinical studies have shown that systemic therapy with FAEs in patients with moderate to severe psoriasis is effective and has a good long-term safety profile. Yazdi et al. Clinics in Dermatology. 2008;26(5):522-526.

[0004] Dimethyl fumarate (DMF), an FAE, is the active pharmaceutical ingredient of Tecfidera®, a delayed release capsule formulation indicated for the treatment of relapsing forms of multiple sclerosis (MS), also termed as“relapsing-remitting multiple sclerosis” (RRMS). Gold et al., Mult Scler. 2015;21 (1 ) :57-66. DMF has a very short half-life of 12 minutes after gastrointestinal absorption (Al-Jaderi et al., Front. Immunol. 2016;7:278) and is rapidly hydrolyzed by esterase in the gastrointestinal tract to monomethyl fumarate (MMF), another FAE, prior to entering systemic circulation (eq. 1). The half-life of MMF in circulation is 36 hours (Id.), with a Tmax of about 2.5 hours (Bromprezzi et al., Ther Adv Neurol Disord. 2015;8(1):20-30).

l

[0005] MMF has been shown to activate Nrf2 transcriptional pathway both in vitro and in vivo in animals and humans (Scannevin et al., J. Pharmacol. Exper. Therap. 2012;341 (1):274- 284). MMF crosses the blood brain barrier and dampens the neuro-inflammation in the central nervous system (Parodi et al., Acta Neuropathol. 2015; 130(2): 279-95). Various studies have identified similar anti-inflammatory, immunomodulatory, neuroprotective, antioxidant, anti-tumor and apoptotic effects for both DMF and MMF in various cell types (Al- Jaderi et al., 2016, Parodi et al., 2015, Linker et al., 201 1).

[0006] Although the mechanism of action of DMF and MMF may not be identical, MMF is the most bioactive metabolite of DMF and all the therapeutic effects of DMF in MS are mediated by MMF. While studies have established that both DMF and MMF can elicit an antioxidant response in human astrocytes, the assessment of cellular viability under oxidative stress determined that MMF treatment resulted in less toxicity compared to DMF (Scannevin et al., 2012). MMF does not deplete glutathione or inhibit mitochondrial and glycolytic function making MMF a better drug.

[007] Because of the anti- inflammatory, anti-oxidant, and immune modulatory properties, FAEs have also been investigated for therapy of autoimmune conditions, such as psoriasis, inflammatory lung diseases, such as asthma, neuro-inflammatory and neurodegenerative conditions, such as relapsing remitting and progressive forms of multiple sclerosis,

Parkinson’s disease, Alzheimer's disease, as well as ischemic stroke for post-ischemic recovery and retinal ischemia-reperfusion. Seidel et al., Am J Physiol Lung Cell Mol Physiol. 2009;297(2):L326-39; Strassburger-Krogias et al., Ther Adv Neurol Disord. 2014;7(5):232-8; Yao et al., Transl Stroke Res. 2016;7(6):535-547; Ahuja et al., Neurosci. 2016;36(23):6332- 51 ; Paraiso et al., J Neuroinflammation. 2018;15(1):100; Cho et al., J Neuroinflammation.

2015; 12:239. FAEs at low/ultra-low dose, which restricts availability to vascular circulation only and produces effect locally by inhibiting vascular smooth muscle cell proliferation, can be used in treatment of essential hypertension, diabetic macroangiopathy, atherosclerosis and restenosis. Hoshi S, et al., J Biol Chem. 2000;275(2):883-9.

[008] Tecfidera delayed release DMF capsules for oral administration has several deleterious side effects including, allergic reactions, progressive multifocal

leukoencephalopathy (PML, a rare brain infection leading to death or severe disability), decrease in white blood cell count, and liver problems, in turn causing exhaustion, loss of appetite, abdominal pain, dark or brown (tea color) urine, and jaundice. The most common side effects are flushing and stomach problems such as fullness, bloating, diarrhea, upper abdominal cramps, flatulence, and nausea. The Gl side effects can be severe and reached an incidence up to 38% for treatment groups in clinical trials (Bombrezzi et al., 2015). In addition, the pharmacokinetics of oral delayed release DMF capsules has several problems The Cmax and AUC variations are large (Shiekh et al., Clin Ther. 2013;35(10):1582-1594), and were also found to be undesirably variable particularly when taken after food (Litjens et al., Br J Clin Pharmacol. 2004;58(4):429-32).

SUMMARY OF THE INVENTION

[009] The present invention provides injectable and topical pharmaceutical compositions comprising polymer-conjugated FAEs, and polymer-encapsulated FAEs that are useful for treatment of diseases resulting from oxidative stress, inflammatory process and immune deregulation. The compositions of the invention offer improved chemical and pharmaceutical properties, such as superior pharmacokinetic properties, compared to DMF or MMF and require substantially reduced dosage to achieve therapeutic plasma concentration due to their structure and mode of administration. The compositions of the invention reduce adverse events and variability in pharmacokinetics, in part by avoiding local high

concentrations of the drug within the gastrointestinal tract upon oral administration and reducing gastrointestinal side effects.

[0010] In some embodiments, the present invention provides an injectable or topical pharmaceutical composition comprising a pharmaceutically effective amount of a compound of formula I

or a pharmaceutically acceptable salt thereof, wherein:

-R ₂ is a pharmaceutically acceptable polymeric moiety;

-Ri- is a linker that is capable of in vivo cleavage to form methyl or ethyl.

[0011] In other embodiments, the present invention provides an injectable or topical pharmaceutical composition comprising a pharmaceutically effective amount of a compound of formula II

or a pharmaceutically acceptable salt thereof, wherein:

-R ₂ - is a straight chain pharmaceutically acceptable polymer linked at both ends;

-Ri- and -R ₄ - are independently selected from linkers that are capable of in vivo cleavage to form

are independently selected from methyl and ethyl.

[0012] Yet other embodiments of the present invention provide an injectable or topical pharmaceutical composition comprising a pharmaceutically effective amount of a compound of formula III

or a pharmaceutically acceptable salt thereof, wherein:

R ₂ is a branched chain pharmaceutically acceptable polymer linked at one or both ends of the chain and at the end of one or more branches of the chain;

n is 2-50,

-R _x is independently selected from linkers that are capable of in vivo cleavage to form independently selected from methyl and ethyl.

[0013] Yet other embodiments of the present invention provide an injectable or topical pharmaceutical composition wherein the composition comprises micro or nano particles comprising:

the compound of formula I, II or III; and

a second pharmaceutically acceptable polymer,

wherein the compound of formula I, II or III is encapsulated in the second

pharmaceutically acceptable polymer.

[0014] Certain other embodiments of the present invention provide an injectable or topical pharmaceutical composition comprising micro or nano particles comprising:

a fumaric acid ester of formula IV

or a pharmaceutically acceptable salt thereof, wherein:

R ₆ is methoxy, ethoxy, a short chain polyethylene glycol chain having 2-6 monomers; or R ₆ together with the adjacent carbonyl constitutes a straight or branched peptide chain having 2 to 6 amino acids, an alkylene ester group, an alkenylene ester group, an alkynylene ester group, an alkylene amide group, an alkenylene amide group, an alkynylene amide group, an alkylene anhydride group, an alkenylene anhydride group, or an alkynylene anhydride group, wherein the alkylene, alkenylene or alkynylene is C _2-6 straight or branched chain, or combinations thereof,

R ₇ is methyl or ethyl; and

a pharmaceutically acceptable polymer,

wherein the fumaric acid ester is encapsulated in the pharmaceutically acceptable polymer.

[0015] In some embodiments of the invention the pharmaceutically acceptable polymer and/or the second pharmaceutically acceptable polymer is selected from the group consisting of polyethylene glycol (PEG), poly(g lycolide) (PGA), poly(lactide) (PLA), poly(caprolactone), poly(lactide-co-caprolactone), poly(lactide-co-glycolide) (PLGA), and poly(lactic acid)-butanol, poly(vinyl pyrrolidone), poly(vinyl alcohol) (PVA),

poly(ethyleneimine), poly(malic acid), poly(L-lysine), poly(L-glutamic acid), and poly ((N- hydroxyalkyl)glutamine), dextrins, hydroxyethylstarch, polysialic acid, polyacetals, N-(2- hydroxypropyl)methacrylamide copolymer, poly(amido amine) dendrimers, and mixtures, combinations and copolymers thereof. In some embodiments of the invention the pharmaceutically acceptable polymer and/or the second pharmaceutically acceptable polymer used for encapsulation is selected from the group consisting of PLA, PLGA, PVA, and combinations thereof in different proportions.

[0016] The compositions of the invention are useful for prevention or treatment of diseases resulting from oxidative stress, inflammatory process and immune deregulation, such as relapsing-remitting and progressive forms of multiple sclerosis, psoriasis, Parkinson’s disease, Alzheimer's disease, ischemic stroke, retinal ischemia-reperfusion, asthma, essential hypertension, diabetic macroangiopathy and atherosclerosis.

[0017] In some embodiments, the compositions of the invention may be administered parenterally, such as intravenously, intramuscularly, or subcutaneously. In certain other embodiments, the compositions of the invention may be administered topically, such as in the form of transdermal patches, creams, foams, gels, lotions, ointments, sprays, and eye drops that are applied epicutaneously, applied to the conjunctiva or through inhalation.

[0018] In some embodiments, the compositions of the invention may be administered at most twice weekly. For example, the compositions of the invention may be administered once weekly, biweekly, or once monthly.

BRIEF DESCRIPTION OF THE FIGURES

[0019] Fig. 1A shows an HPLC (High Performance Liquid Chromatography) chromatogram of MMF-PEG1000 conjugate monitored with a 210 nm UV (Ultra Violet) detector (retention time 3.53 min). The retention time of MMF is 2.11 min. PEG1000 is PEG polymer having a molecular weight of about 1000 daltons (1 kDa), which may be stated as molecular weight between approximately 950 and 1050 daltons.

[0020] Fig. 1 B shows an HPLC chromatogram of MMF-PEG2000 conjugate monitored with a 210 nm UV detector (retention time 3.10 min). The retention time of MMF is 2.1 1 min and the peak at 2.66 min is from mobile phase. PEG2000 is PEG polymer having a molecular weight of about 2000 daltons (2 kDa), which may be stated as molecular weight between approximately 1900 and 2100 daltons.

[0021] Fig. 2A shows the proton NMR (Nuclear Magnetic Resonance) spectrum of MMF- PEG1000 conjugate. Deuterated chloroform (CDCI3) was used as solvent.

[0022] Fig. 2B shows the proton NMR spectra of MMF-PEG2000 conjugate. Deuterated chloroform (CDCI3) was used as solvent.

[0023] Fig. 3A. MALDI TOF (Matrix Assisted Laser Desorption/Ionization Time-Of-Flight) mass spectrum of PEG2000 (m/z = 2080.9).

[0024] FIG. 3B. MALDI TOF mass spectrum of MMF-PEG2000 conjugate (m/z = 2192.8).

[0025] Fig. 4 shows the release kinetics of MMF-PEG conjugates (1 kDa and 2 kDa) in Phosphate Buffered Saline (PBS).

[0026] Fig. 5 shows the release kinetics of MMF-PEG conjugates (1 kDa and 2 kDa) in 80% human plasma.

[0027] Fig. 6 shows a plot of pharmacokinetics of MMF, showing plasma concentration vs. time following subcutaneous administration of MMF-PEG2000 conjugate in mice.

DETAILED DESCRIPTION

[0028] In some embodiments, in the compounds of formula I, II or III , Ri, R _x , and/or R ₄ independently, together with the adjacent carbonyl constitute an ester bond, an anhydride bond, an amide bond, a straight or branched chain peptide linker having 2 to 6 amino acids, a short chain polyethylene glycol ester group having 2-6 monomers, an alkylene ester group, an alkenylene ester group, an alkynylene ester group, an alkylene amide group, an alkenylene amide group, an alkynylene amide group, an alkylene anhydride group, an alkenylene anhydride, or an alkynylene anhydride group, wherein the alkylene, alkenylene or alkynylene is a C _2-6 straight or branched chain, or a combination thereof.

[0029] In certain embodiments, the bond between Ri and R ₂ , R ₄ and R ₂ , and/or R _x and R ₂ in the compounds of formula I, II or III is capable of in vivo cleavage. In some embodiments, Ri and R ₂ , R and R ₂ , and/or R _x and R ₂ are linked by a carbonate, ester, urethane, carbamate, disulfide, anhydride, amide, hydrazine or orthoester bond.

[0030] In some embodiments, the pharmaceutically acceptable polymer in compositions comprising compounds of formula I, II or III comprises 15-75 monomer units, 20-70 monomer units, or 25-65 monomer units. In other embodiments, the polymer has a molecular weight in the range of 1 kDa to 75 kDa, 2kDa to 60 kDa, or 3 kDa to 50 kDa. [0031] In certain other embodiments, the polymer is a branched chain PEG comprising 4- 120 monomer units, 4-75 monomer units, 4-50 monomer units, or 4-30 monomer units. In certain other embodiments, the polymer is a straight or branched chain PEG comprising 12- 120 monomer units, 12-75 monomer units, 12-75 monomer units, or 12-30 monomer units.

In some other embodiments, the polymer is a straight or branched chain PEG comprising 11-20 monomer units, 26-42 monomer units, 49-64 monomer units, or 72-1 1 1 monomer units. In certain other embodiments, the polymer is a straight or branched chain PEG having a molecular weight in the range of 0.4 kDa to 50 kDa, 0.5 kDa to 50 kDa, 0.8 kDa to 50 kDa, or 1 kDa to 50 kDa.

[0032] In some embodiment, when R ₂ is H-(-0-CH2-CH2)n-, Ri is -0-, and n is 21-25, or 43-48, the compound of formula I is MMF-PEG1000 or MMF-PEG2000 conjugate, respectively. In other embodiment, n is 8-10, 65-71 , or 1 12-1 17, such that the compound of formula I is MMF-PEG400, MMF-PEG3000 or MMF-PEG5000 conjugate, respectively.

[0033] In some embodiment, the fumaric acid ester of formula IV is selected from the group consisting of monomethyl fumarate, monoethyl fumarate, dimethyl fumarate, diethyl fumarate, methylethyl fumarate, and salts and/or mixtures thereof.

[0034] The term“encapsulated” in the context of the present invention means coated by, covered by, or surrounded by, such that about 20% to about 80% of the compound of formula I, II, III, or IV is enclosed/covered/coated by the polymer. In some embodiment, the particles are in the form of liposomes or micelles.

[0035] Polymer-FAE conjugates and polymer-encapsulated FAEs may be prepared by methods known in the art, for example, Sk UH et al., Biomacromolecules. 2013;14(3):801- 10. Polymer-encapsulated FAEs may be prepared by methods known in the art. For example, Han et al., Front Pharmacol. 2016;7:185; Qutachi O et al., Acta Biomater.

2014; 10(12):5090-5098.

[0036] In some embodiments, PLGA and mixture of PLGA with other polymers, such as PLA and PVA, in different ratios are used to encapsulate compounds of the invention to form microparticles. PLGA, is a FDA approved widely used biodegradable material use for encapsulation of a broad range of therapeutic agents including hydrophilic and hydrophobic small molecule drugs, DNA, and proteins, due to its excellent biocompatibility. Other additives can be used to enhance the drug loading and efficiency in PLGA microparticles, such as PEG, poly(orthoesters), chitosan, alginate, caffeic acid, hyaluronic acid etc. PLGA can be a varying composition of PLA and PGA with a ratio from 20 to 80% PGA in PLA and vice versa. [0037] In some embodiments, PLGA microparticle can be produced by a double emulsion method from 20% (w/v) PLGA (50:50) in dichloromethane (DCM). One gram of PLGA is dissolved in 5 ml DCM for each batch of microspheres. For the primary emulsion, 250 microliter of the polymer-FAEs conjugates or free FAEs in PBS buffer is added to the PLGA/DCM, and the reaction mixture is homogenized at 9000 rpm for 5 min. The primary water in oil (w/o) emulsion is then homogenized in 0.3% PVA at 3000 rpm and the resultant water-in-oil-in-water (w/o/w) double emulsion is stirred overnight to allow DCM evaporation. The hardened microspheres are then collected using centrifugation and washed in distilled water. D-alpha-tocopheryl polyethylene glycoM OOO succinate (vitamin E) can also be used as an emulsifier to improve the drug loading.

[0038] Pharmaceutically acceptable polymers linked via in vivo cleavable linker to FAEs exert desirable effects on FAEs that may be immunoreactive or rapidly metabolized.

Pharmaceutically acceptable polymers used in the present invention may be non-toxic, non- immunogenic, non-antigenic, highly soluble in water and FDA approved. Polymer-FAE conjugates and polymer-encapsulated FAEs have several advantages: a prolonged residence in body, a decreased degradation by metabolic enzymes and a reduction or elimination of protein immunogenicity. The covalent attachment of polymer to a drug can increase its hydrodynamic size (size in solution), which prolongs its circulatory time by reducing renal clearance (Knop et al., Angew. Chemie Int. Ed. 2010;49(36):6288-6308; Veronese et al., Drug Discov Today. 2005;10(21): 1451-1458; and Harris et al., Nat Rev Drug Discov. 2003;2(3):214-221). Advantages of pharmaceutical compositions disclosed herein include, for example: increased bioavailability at lower doses; predictable drug-release profile over a defined period of time following each administration; better patient compliance; ease of application; improved systemic availability by avoidance of first-pass metabolism; reduced dosing frequency without compromising the effectiveness of the treatment;

decreased incidence of side effects; and overall cost reduction of medical care.

[0039] In some embodiments, the amount of compounds of formula I, II, III, or IV in the compositions of the invention is in the range of 25 mg to 500 mg MMF equivalents. In some other embodiments, the amount of compounds of formula I, II, III, or IV in the compositions of the invention is in the range of 100 mg to 500 mg MMF equivalents.

[0040] In some embodiments, dosage forms of the composition of the invention are adapted for administration to a patient parenterally, including subcutaneous, intramuscular, intravenous or intradermal injections. In some embodiment, the compositions of the invention further comprise one or more pharmaceutically effective carriers or excipients. Pharmaceutical compositions adapted for parenteral administration include aqueous and non-aqueous sterile injection solutions which may contain anti-oxidants, buffers, bacteriostats, and solutes that render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. The compositions may be presented in unit-dose or multidose containers, for example, sealed ampules and vials, and may be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules, and tablets.

EXAMPLES

Preparation of monomethyl fumarate-PEG conjugates

[0041] The synthetic route for preparation of monomethyl fumarate-polyethylene glycol (MMF-PEG) conjugates is shown in eq. 2.

MMF-PEG 1000; n - 22-23

MMF PEG2000; n - 45*47

The PEG conjugates were produced by a coupling reaction between PEGs and MMF in presence of N-(3-Dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride (EDC) and dimethyl amino pyridine (DMAP) (see experimental section). Following purification, the products were confirmed by proton NMR and mass spectroscopic analysis.

[0042] The purity of the final MMF-PEG conjugates was confirmed by reverse-phase HPLC monitored at 210 and 260 nm, where no such significant amounts of starting material as well as impurities were present (Figs. 1A and 1 B). The percentage purity of the MMF-PEG conjugates was 97.7% (1.0 kDa PEG, retention time 3.53 min) and 96.5% (2.0 kDa PEG, retention time 3.10 min) at 210 nm. The retention time of MMF is 2.1 1 min and the absence of MMF peak at 260 nm confirmed the formation of the conjugates in both cases.

[0043] In the ¹ H NMR of MMF-PEG1000 conjugate shown in Fig. 2A, the presence of a characteristic peak at 4.35 ppm for OCH2 group of PEG confirmed the formation of ester bond between MMF and PEG. Additionally, other peaks related to both chemical entities are present such as singlet at 3.79 ppm for methoxy group of MMF, singlet at 3.33 ppm for methoxy group of PEG, multiplets at 3.44-3.75 for the backbone OCH2 groups of PEG, and a singlet at 6.87 ppm for two protons (CH=CH) of MMF confirmed the formation of the conjugate. In a similar manner, the structure of MMF-PEG2000 conjugate was established shown in Fig. 2B. [0044] The molecular weight of both MMF-conjugates was evaluated using MALDI TOF mass spectroscopy. The molecular weight of the MMF-PEG1000 conjugate was 1223.5 g/mol. The average molecular weight of PEG1000 is 1039.4 g/mol which implies that there are 22-23 OCH2-CH2 repeating units present in the PEG chain. Based on molecular weights of PEG1000 and corresponding conjugate, it was determined that one MMF molecule attached to the PEG. This finding is in good agreement with the NMR analysis of the conjugate. In a similar way the structure of MMF-PEG2000 conjugate (m/z = 2192.8 g/mol) was established. Representative MALDI TOF spectra of PEG2000 and MMF-PEG2000 conjugates are shown in Figs. 3A and 3B respectively. From both proton NMR and in MALDI TOF mass, it was established that approximately one molecule of MMF reacted with the corresponding PEG molecules.

In-vitro drug release study of the MMF-PEG conjugates

[0045] In vitro MMF release characteristics of the inventive MMF-PEG conjugates were studied to investigate their stability in physiologically relevant solutions such as PBS (pH 7.4) and in human plasma. 80% Human plasma was used in the study to simulate the biological conditions of intravenous (IV) as well as subcutaneous (SC) injection.

[0046] Drug Release Study in PBS; A drug release study of the MMF-PEG conjugates was performed in 0.1 M phosphate buffer (pH 7.4) at 37 °C. A concentration of 3 mg/mL of the conjugate was placed in a water bath and the temperature of the bath was maintained at 37 °C with constant mixing. Samples were collected at appropriate time points and lyophilized using liquid nitrogen. The MMF-PEG conjugates along with released MMF were extracted from the lyophilized powder using acetonitrile and the samples were analyzed in reverse- phase HPLC. The peaks of MMF-PEG conjugates and MMF were monitored at 210 and 260 nm respectively. Since the MMF also further degrades, peak area of MMF-PEG conjugate was used for the analysis.

[0047] The results of the study of MMF-PEG1000 and 2000 conjugates in PBS is shown in Fig. 4. In PBS, both the conjugates released the drug in a steady manner and the release pattern is nearly zero order. Approximately 90% of the drug payload was released in 7 days in both cases with no initial burst. The drug from PEG 1000 conjugate was released much slower than from PEG2000 conjugate. The released MMF was monitored at 260 nm by HPLC. After 4 days, the ester bond of MMF started degrading resulting in a fumaric acid.

[0048] Drug Release Study in Plasma: Another MMF release study from the MMF- PEG1000 and 2000 conjugates (3 mg/mL) was performed using human pooled plasma diluted to 80% with 0.1 M PBS in a water bath (Dual-action shaker; Polyscience) at 37 °C, collecting 200 pL aliquot samples at appropriate intervals. The protein was precipitated using 2 M trichloroacetic acid, cold acetonitrile was added, centrifuged, filtered, and stored at -80 °C for HPLC analysis. Different solvents were used to extract the drug conjugates as well as the released drug from the plasma solution. Each sample was analyzed using HPLC, and the drug release was calculated using a calibration graph. DMF was used as the reference drug for this study.

[0049] The results of the plasma study are shown in Fig. 5. In human plasma, the extent of release was relatively higher for both MMF-PEG conjugates, compared to PBS at the same time point. This type of release pattern is expected because of the presence of enzymes (e.g. esterase) in human plasma which can specifically cleave the ester bond much faster than in case of PBS. Both conjugates were very similar, with the PEG 1000 conjugate showing slightly faster release during the initial time points. There were burst release of MMF in case of plasma in initial point (31 % at 0 h in case of 2 kDa and 39% at 0 h in case of 1 kDa). Similar to PBS release, the drug started degrading after the 4th day, the peak for the degradation product was very prominent compared to the drug peak. The peak area corresponding to the degraded product was included in the calculation. Based on the plasma release profile, a slow release of the drug from the conjugates in vivo is expected.

Pharmacokinetics in Mice

[0050] A pilot pharmacokinetics study was done to determine the route of administration and best possible corresponding dose to get the therapeutic level of MMF in blood. MMF conjugates (500 pg of MMF equivalent) were injected intravenously and subcutaneously in 5-6 weeks old BALB-NeuT mice (inbred BALB/c female mice transgenic for the rat neu (Her- 2/neu, ErbB-2) oncogene; BALB/c is an albino, laboratory-bred strain of the house mouse) and MMF concentration was determined with HPLC up to day 7. The MMF concentration increased from 1 h to 24h and roughly 10% of the MMF was detected in blood plasma at 24h in both cases. The drug concentration steadily decreased until day 7 in both cases, and peak MMF concentration in plasma was in the range of 1 1-18 pg/mL in both SC and IV routes of administration. The MMF concentrations in the plasma were higher in case of MMF- PEG2000 as compared to MMF-PEG1000 in both SC and IV routes. The peak plasma concentrations of MMF were higher following SC route compared to IV route of injection at all time points. Data in the pharmacology section of the New Drug Application for Tecfidera ^® (NDA 204063) indicates that oral administration of 25 mg/kg dose of Tecfidera® (500 pg of MMF equivalent) achieves an average Cmax of 1 1.05 pg/mL (9.4 pg/mL in male mice and 12.7pg/mL in female mice). This is the concentration range seen on day 7 following 25 mg/kg (500 pg of MMF equivalent) of MMF-PEG 1000 and 2000 conjugates. In this pilot study, the observed Cmax was 53 pg/mL for MMF-PEG1000 and 67 pg/mL for MMF- PEG2000 at 24 hrs upon subcutaneous administration. The observed C _max was 62 pg/mL for MMF-PEG1000 and 52 pg/mL for MMF-PEG2000 at 24 hrs upon intravenous administration.

[0051] Since the MMF concentration in blood is reported for Tecfidera ^® (Tecfidera ^® label), the objective was to match the same drug concentration in the blood in mice. The average Cmax value of MMF in blood was reported as 2.74 pg/mL (360 mg single dose) and 2.15 pg/mL (240 mg single dose) when Tecfidera ^® was administered to healthy volunteers (Pharmacology Review, Drug Master File filed with Food & Drug Administration (FDA)). Dosing MS patients with 240 mg twice daily of Tecfidera ^® results in a mean Cmax of 1.87 pg/mL and the AUC of 8.21 mg.hr/L (Tecfidera ^® label). The pharmacokinetics of Tecfidera ^® showed high inter-subject variability with respect to the Cmax value.

[0052] To achieve the required MMF concentration in the blood, 150 pg MMF equivalent of MMF-PEG2000 conjugate was injected via IV and SC routes and blood samples were collected up to day-10 and MMF concentrations were analyzed. The MMF levels were highest at day-1 in both cases and gradually decreased till day-7. No MMF was observed at 240 h (day 10) in either route of administration. At day-7 the MMF concentrations were 2.00 pg/mL (IV) and 2.36 pg/mL (SC). The above observed MMF concentration were comparative to those observed with therapeutic dose of oral Tecfidera ^® 240 mg twice daily.

[0053] A full-scale pharmacokinetics study was done using MMF-PEG2000 conjugate via SC route of administration. Two dose strengths of the MMF conjugate were injected (100 and 150 pg MMF equivalents) subcutaneously in 5 weeks BALB/c mice (n=5) and the MMF concentrations were determined up to Day 10. The objective of the study was to determine the pharmacokinetics of active drug, MMF, following subcutaneous injection, with the goal of achieving plasma concentrations in the 1-10 pg/mL range. The MMF concentration was determined with HPLC and PK parameters such as ti/2, Cmax, Tmax, AUC, CL (clearance), and Vd (volume of distribution) were calculated.

[0054] The pharmacokinetics results are shown in Fig. 6. It was observed that the 100 pg MMF equivalent of the conjugate dose resulted in MMF plasma concentrations ranging from 7.7 pg/mL (6 h) to 1 pg/mL (day 7) with Cmax concentration at 12 h (9.4 pg/mL). In case of 150 pg equivalent of MMF, the plasma concentrations ranged from 15.5 to 1.67 pg/mL from 6h to day-7. The MMF was not detected at day-10 in either dose groups. The results suggest that there is a good correlation between administered dose and plasma concentrations, at least in the dose range used. Other pharmacokinetic non-dose dependent parameters, such as the volume of distribution, clearance and half-life showed good concordance for the two doses.

Materials and methods [0055] Materials: N-(3-Dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride (EDC), 4- (Dimethylamino) pyridine (DMAP) were purchased from Sigma-Aldrich (St. Louis, MO, USA). mPEG-OH (one side methoxy (OCH3)-capped polyethylene glycol, 1 kDa and 2 kDa) were procured from Creative PEGworks (Chapel Hill, NC, USA). ACS grade dimethylformamide (DMF), DCM, chloroform and methanol were obtained from Fisher Scientific. Regenerated cellulose (RC) dialysis membrane with molecular weight cut-off 1000 Da was obtained from Spectrum Laboratories, Inc. (Rancho Dominguez, CA, USA). Deuterated chloroform (CDCh) was purchased from Cambridge Isotope Laboratories, Inc. (Andover, MA, USA).

[0056] Preparation of MMF-PEG 1000 conjugate: Monomethyl fumarate (0.7 gm, 5.52 mmol) was dissolved in 30 mL of DCM/dry dimethylformamide (9:1 , v/v) in a 100 mL two neck flask under nitrogen environment and EDC (1.4 gm, 9.2 mmol) and DMAP (0.03 g, 0.27 mmol) were added to it and the reaction mixture stirred for half an hour in an ice bath. Finally, the mPEG-OH (1 kDa, 1.0 g, 0.92 mmol) was dissolved in 10mL of dry DCM and added to the reaction mixture and the mixture stirred for 24h at room temperature. The solvent was evaporated at room temperature under vacuum. The crude product was purified using column chromatography over silica gel (60-120 mesh). The mixture of solvents (0.75% methanol in dichloromethane) used as eluent afforded 0.52 g of MMF-PEG1000 conjugate (47% yield and Retention factor (Rf) = 0.6, in 5% methanol and 95% DCM). The final MMF- PEG1000 conjugate was characterized by reverse-phase HPLC, proton NMR and MALDI- TOF mass spectroscopy. iH NMR (400 MHz, CDCIs): d 3.33 (s, 3H, OCHs of mPEG), 3.44- 3.75 (m, backbone OCH2CH2O of mPEG), 3.79 (s, 3H, OCHs of MMF), 4.35 (m, 2H, OCHs of mPEG adjacent to MMF), 6.87 (m, 2H, -CH=CH- of MMF).

[0057 Preparation of MMF-PEG2000 conjugate: Monomethyl fumarate (0.35 g, 2.74 mmol) was dissolved in 30 mL of dry DCM/dry Dimethylformamide (9:1 , v/v) under nitrogen condition in an ice bath; and EDC (0.69 g, 4.5 mmol) and DMAP (0.01 g, 0.13 mmol) were added to it. The reaction mixture was stirred for 30 min and mPEG-OH (2 kDa, 1 g, 0.45 mmol) dissolved in 10 mL of dry DCM was added to the reaction mixture. The resulting reaction mixture was stirred for 24h at room temperature. The solvent was removed under reduced pressure at room temperature and the obtained crude product was dialyzed in Dl water using dialysis membrane (MWCO 1 kDa) for 36 h. The obtained solution was lyophilized to get 0.72 g of MMF-PEG2000 conjugate (68% yield). The final MMF-PEG2000 conjugate was characterized by HPLC, ¹ H NMR and MALDI-TOF mass spectroscopy. ¹ H NMR (400 MHz, CDCIs): d 6.87 (s, 2H, -CH=CH- of MMF), 4.35 (m, 2H, OCHs of mPEG adjacent to MMF), 3.81 (s, 3H, OCHs of MMF) 3.43-3.76 (m, backbone OCH2CH2O of mPEG), 3.36 (s, 3H, OCHs of PEG). [0058] NMR Spectroscopy: NMR spectra of final conjugates, as well as starting materials was recorded on a Varian Spectrometer (400 MHz). Tetramethylsilane (TMS) was used as internal standard and deuterated chloroform (CDCta) was used as solvent to dissolve the conjugates.

[0059] MALDI-TOF Mass Spectrometry: MALDI-TOF mass spectra was recorded in a AB- Sciex 5800 MALDI/TOF-MS instrument operating in the reflector mode. 2,5

Dihydroxybenzoic acid (DHB) was used as matrix and cytochrome c (MW 12361 g/mol) was used as external standard. The matrix solution was prepared by dissolving 20 mg of matrix in 1 mL of deionized water/ ACN (0.1 % TFA; 1 :1). Samples were prepared by mixing 10 pL of conjugates (2 mg/ml_ in methanol) with 100 pl_ of matrix solution, and 1 mI_ of sample mixture was placed onto the MALDI plate. The samples were allowed to air-dry at room temperature and used for analysis.

[0060] HPLC: The MMF-PEG conjugates were analyzed by system gold HPLC instrument (Beckman Coulter, Inc. Brea, CA) equipped with binary pump, UV detector, and autosampler interfaced with 32 Karat software. Acetonitrile:phosphate buffer pH 6.8 (75:25, v/v) in gradient flow (1 mL/min) was used as the mobile phase and chromatograms were monitored at 210 nm. Supelcosil LC-18 column with 5 pm particle size, 25 cm length, 4.6 mm internal diameter was used for the analysis.

[0061] Drug Release Study in PBS: The drug release study of the MMF-PEG conjugates was performed in 0.1 M phosphate buffer (pH 7.4) at 37 °C. A concentration of 3 mg/ml_ of the conjugate was placed in a water bath and the temperature of the bath was maintained at 37 °C with constant mixing. Samples were collected at appropriate time points and lyophilized using liquid nitrogen. The MMF-PEG conjugates along with released MMF were extracted from the

lyophilized powder using acetonitrile and the samples were analyzed in reverse-phase HPLC. The peaks of MMF-PEG conjugates and MMF were monitored at 210 and 260 nm respectively. Since the MMF further degrades, peak area of MMF-PEG conjugate was used for the analysis.

[0062] Drug Release Study in Plasma: The MMF-PEG conjugates (3 mg/mL) were incubated in human pooled plasma diluted to 80% with 0.1 M PBS with constant mixing in water bath at 37 °C. The plasma samples were collected at periodic intervals and lyophilized using liquid nitrogen. Both MMF-PEG conjugates and released MMF were extracted from the lyophilized samples using methanol. The samples were analyzed by reverse-phase HPLC using acetonitrile:phosphate buffer pH 6.8 (75:25) as mobile phase at 210 and 260 nm. The peak area of MMF was used for the analysis. [0063] To obtain a standard plot, MMF was accurately weighed and spiked in blank plasma. Stock solution of 5000 pg/mL was prepared and was further diluted to 250, 125, 62.5, 31.25, 15.6, 7.8, 3.9, 1.9 and 0.9 pg/mL (n = 2). A standard plot was obtained with regression equation y = 260748x + 371377 (Correlation coefficient = 0.9976). Proteins were precipitated using 2M trichloroacetic acid and centrifuged at 3000 rpm at 4 °C for 10 min. The supernatant was transferred into a fresh 1.5 ml tubes and freeze dried. MMF was extracted from freeze dried samples using acetonitrile and centrifuged at 3000 rpm at room

temperature for 10 min. Supernatant was analyzed by HPLC using acetonitrile:phosphate buffer pH 6.8; 75:25, as a mobile phase. The calibration plots were constructed between the absorbance values and the respective concentration values. MMF peak was monitored at 210 nm.

[0064] Dose and route determination studies of the MMF conjugates in mice. A pharmacokinetic pilot study was performed with five to six-week-old BALB-NeuT mice (n =

2). Each animal was injected intravenously or subcutaneously with a single dose of MMF- PEG conjugates (500 pg and 150 pg of MMF equivalent conjugates) in a total 200 pL of PBS. Mice were euthanized at different time intervals post-injection and blood samples were withdrawn via cardiac puncture. Plasma were collected from the samples by centrifugation at 3000 rpm at 4 °C for 20 min. The proteins were precipitated using 2M trichloroacetic acid and centrifuged at 3000 rpm at 4 °C for 10 min. The supernatant was transferred into fresh 1.5 ml tubes and freeze dried. The drug was extracted using acetonitrile and centrifuged at 3000 rpm at room temperature for 10 min. Supernatant was analyzed by HPLC using acetonitrile:phosphate buffer pH 6.8; 75:25, as a mobile phase. Peak area of MMF was used for the analysis.

[0065] A full-scale pharmacokinetic study was performed with 5-week old BALB/c mice (n = 5). Each animal was injected subcutaneously with a single dose of MMF-PEG2000 conjugate (100 pg and 150 pg MMF equivalent) in a total 200 pL of PBS. Mice were euthanized at 6, 12, 24, 72, 120, 168, and 240 h post-injection and blood samples were withdrawn via cardiac puncture. Plasma were collected from the samples by centrifugation at 3000 rpm at 4 °C for 20 min. The proteins were precipitated using 2M trichloroacetic acid and centrifuged at 3000 rpm at 4 °C for 10 min. The supernatant was transferred into fresh 1.5 ml tubes and freeze dried. The drug was extracted using acetonitrile and centrifuged at 3000 rpm at room temperature for 10 min. Supernatant was analyzed by HPLC using acetonitrile:phosphate buffer pH 6.8; 75:25, as a mobile phase. Peak area of MMF was used for the analysis.