WO2015061491A1 - Mrna therapy for phenylketonuria - Google Patents

Abstract

The present invention provides, among other things, methods of treating phenylketonuria (PKU), including administering to a subject in need of treatment a composition comprising an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose and an administration interval such that at least one symptom or feature of PKU is reduced in intensity, severity, or frequency or has delayed in onset. In some embodiments, the mRNA is encapsulated in a liposome comprising one or more cationic lipids, one or more non-cationic lipids, one or more cholesterol-based lipids and one or more PEG-modified lipids

Description

MRNA THERAPY FOR PHENYLKETONURIA

RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application Serial No.

61/894,303, filed October 22, 2013, the disclosure of which is hereby incorporated by reference.

SEQUENCE LISTING

[0002] The present specification makes reference to a Sequence Listing (submitted electronically as a .txt file named "2006685-0692_SL.txt" on October 22, 2014). The .txt file was generated on October 20, 2014 and is 18,455 bytes in size. The entire contents of the Sequence Listing are herein incorporated by reference.

BACKGROUND

[0003] Phenylketonuria (PKU) is an autosomal recessive metabolic genetic disorder characterized by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase (PAH), rendering it nonfunctional. PAH is necessary to metabolize the amino acid

phenylalanine (Phe) to the amino acid tyrosine. When PAH activity is reduced, phenylalanine accumulates and is converted into phenylpyruvate (also known as phenylketone). Left untreated, PKU can result in mental retardation, seizures and other serious medical problems. Currently, there is no cure for the disease and standard of care is through management of diet, minimizing foods that contain high amounts of protein.

SUMMARY OF THE INVENTION

[0004] The present invention provides, among other things, methods and compositions for the effective treatment of phenylketonurea (PKU) base on mRNA therapy. The present invention is based, in part, on a successful animal study using a PKU disease model. For example, as described in more detail in the examples section below, administration of an mRNA encoding a human PAH protein, encapsulated within a liposome, resulted in efficient protein production in serum, liver and other clinically relevant tissues in vivo. More importantly and surprisingly, treatment of PAH knockout mice, a PKU disease model, with PAH mRNA can effectively bring down phenylalanine levels to wild type levels within six hours of dosing. Thus, the present inventors have demonstrated that mRNA therapy described herein can be highly effective in treating PKU.

[0005] In one aspect, the present invention provides methods of treating PKU including administering to a subject in need of treatment a composition comprising an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose and an administration interval such that at least one symptom or feature of PKU is reduced in intensity, severity, or frequency or has delayed in onset.

[0006] In another aspect, the present invention provides compositions for treating phenylketonuria (PKU) comprising an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose amount encapsulated within a liposome.

[0007] In some embodiments, the mRNA is encapsulated within a liposome. In some embodiments, a suitable liposome comprises one or more cationic lipids, one or more non- cationic lipids, one or more cholesterol-based lipids and one or more PEG-modified lipids.

[0008] In some embodiments, the one or more cationic lipids are selected from the group consisting of CI 2-200, MC3, DLinDMA, DLinkC2DMA, cKK-E12, ICE (Imidazol-based), HGT5000, HGT5001, DODAC, DDAB, DMRIE, DOSPA, DOGS, DODAP, DODMA and DMDMA, DODAC, DLenDMA, DMRIE, CLinDMA, CpLinDMA, DMOBA, DOcarbDAP, DLinDAP, DLincarbDAP, DLinCDAP, KLin-K-DMA, DLin-K-XTC2-DMA, HGT4003, and combinations thereof.

[0009] In some embodiments, the one or more cationic lipids comprise a compound of formula I-cl-a:

or a pharmaceutically acceptable salt thereof, wherein: each R² independently is hydrogen or Ci_₃ alkyl; each q independently is 2 to 6; each R' independently is hydrogen or Ci_₃ alkyl; and each R^L independently is C_8-12 alkyl.

[0010] In some embodiments, the one or more cationic lipids comprise cK -

[0011] In some embodiments, the one or more non-cationic lipids are selected from distearoylphosphatidylcholme (DSPC), dioleoylphosphatidylcholme (DOPC),

dipalmitoylphosphatidylcholme (DPPC), dioleoylphosphatidylglycerol (DOPG), dipalmitoylphosphatidylglycerol (DPPG), dioleoylphosphatidylethanolamine (DOPE), palmitoyloleoylphosphatidylcholine (POPC), palmitoyloleoyl-phosphatidylethanolamine (POPE), dioleoyl-phosphatidylethanolamine 4-(N-maleimidomethyl)-cyclohexane-l-carboxylate (DOPE-mal), dipalmitoyl phosphatidyl ethanolamine (DPPE), dimyristoylphosphoethanolamine (DMPE), distearoyl-phosphatidyl-ethanolamine (DSPE), 16-O-monomethyl PE, 16-O-dimethyl PE, 18-1 -trans PE, l-stearoyl-2-oleoyl-phosphatidyethanolamine (SOPE), or a mixture thereof.

[0012] In some embodiments, the one or more cholesterol-based lipids are selected from cholesterol, PEGylated cholesterol and DC-Choi (N,N-dimethyl-N- ethylcarboxamidocholesterol), l,4-bis(3-N-oleylamino-propyl)piperazine.

[0013] In some embodiments, the liposome further comprises one or more PEG-modified lipids. In some embodiments, the one or more PEG-modified lipids comprise a poly(ethylene) glycol chain of up to 5 kDa in length covalently attached to a lipid with alkyl chain(s) of C₆-C2o length. In some embodiments, a PEG-modified lipid is a derivatized ceramide such as N- Octanoyl-Sphingosine-l-[Succinyl(Methoxy Polyethylene Glycol)-2000]. In some

embodiments, a PEG-modified or PEGylated lipid is PEGylated cholesterol or

Dimyristoylglycerol (DMG) -PEG-2K.

[0014] In some embodiments, the liposome comprises cK -E12, DOPE, cholesterol, and

DMG-PEG2K.

[0015] In some embodiments, the cationic lipid (e.g., cK -E12) constitutes about 30-60

% (e.g., about 30-55%, about 30-50%, about 30-45%, about 30-40%, about 35-50%, about 35- 45%, or about 35-40%) of the liposome by molar ratio. In some embodiments, the cationic lipid (e.g., cK -E12) constitutes about 30%>, about 35%, about 40 %, about 45%, about 50%, about 55%, or about 60% of the liposome by molar ratio.

[0016] In some embodiments, the ratio of cationic lipid (e.g., cK -E12) to non-cationic lipid (e.g., DOPE) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG- PEG2K) may be between about 30-60:25-35:20-30: 1-15, respectively. In some embodiments, the ratio of cationic lipid (e.g., cK -E12) to non-cationic lipid (e.g., DOPE) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG-PEG2K) is approximately 40:30:20: 10, respectively. In some embodiments, the ratio of cationic lipid (e.g., cK -E12) to non-cationic lipid (e.g., DOPE) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG- PEG2K) is approximately 40:30:25:5, respectively. In some embodiments, the ratio of cationic lipid (e.g., cK -E12) to non-cationic lipid (e.g., DOPE) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG-PEG2K) is approximately 40:32:25:3, respectively. In some embodiments, the ratio of cationic lipid (e.g., cK -E12) to non-cationic lipid (e.g., DOPE) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG-PEG2K) is approximately 50:25:20:5.

[0017] In some embodiments, the size of a liposome is determined by the length of the largest diameter of the lipososme particle. In some embodiments, a suitable liposome has a size less than about 500nm, 400nm, 300nm, 250 nm, 200 nm, 150 nm, 100 nm, 75 nm, or 50 nm. In some embodiments, a suitable liposome has a size less than about 100 nm, 90 nm, 80 nm, 70 nm, or 60 nm.

[0018] In some embodiments, provided composition is administered intravenously. In some embodiments, provided composition is administered via pulmonary delivery. In certain embodiments, pulmonary delivery is performed by aerosolization, inhalation, nebulization or instillation. In some embodiments, provided compositions are formulated as respirable particles, nebulizable lipid, or inhalable dry powder.

[0019] In some embodiments, provided compositions are administered once daily, once a week, once every two weeks, twice a month, once a month. In some embodiments, provided compositions are administered once every 7 days, once every 10 days, once every 14 days, once every 28 days, or once every 30 days.

[0020] In some embodiments, the mRNA is administered at a dose ranging from about

0.1 - 5.0 mg /kg body weight, for example about 0.1 - 4.5, 0.1 - 4.0, 0.1 - 3.5, 0.1 - 3.0, 0.1 - 2.5, 0.1 - 2.0, 0.1 - 1.5, 0.1 - 1.0, 0.1 - 0.5, 0.1 - 0.3, 0.3 - 5.0, 0.3 - 4.5, 0.3 - 4.0, 0.3 - 3.5, 0.3

- 3.0, 0.3 - 2.5, 0.3 - 2.0, 0.3 - 1.5, 0.3 - 1.0, 0.3 - 0.5, 0.5 - 5.0, 0.5-4.5, 0.5 - 4.0, 0.5 - 3.5, 0.5

- 3.0, 0.5 - 2.5, 0.5 - 2.0, 0.5 - 1.5, or 0.5 - 1.0 mg/kg body weight. In some embodiments, the mRNA is administered at a dose of or less than about 5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.0, 0.8, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 mg/kg body weight. [0021] In some embodiments, the expression of PAH protein is detectable in liver, kidney, heart, spleen, serum, brain, skeletal muscle, lymph nodes, skin, and/or cerebrospinal fluid.

[0022] In some embodiments, administering the provided composition results in the expression of a PAH protein level at or above about 100 ng/mg, about 200 ng/mg, about 300 ng/mg, about 400 ng/mg, about 500 ng/mg, about 600 ng/mg, about 700 ng/mg, about 800 ng/mg, about 900 ng/mg, about 1000 ng/mg, about 1200 ng/mg or about 1400 ng/mg of total protein in the liver.

[0023] In some embodiments, the expression of the PAH protein is detectable 6, 12, 18,

24, 30, 36, 42, 48, 54, 60, 66, and/or 72 hours after the administration. In some embodiments, the expression of the PAH protein is detectable 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, and/or 7 days after the administration. In some embodiments, the expression of the PAH protein is detectable 1 week, 2 weeks, 3 weeks, and/or 4 weeks after the administration. In some embodiments, the expression of the PAH protein is detectable after a month after the

administration.

[0024] In some embodiments, administering provided compositions results in increased serum PAH protein levels. In some embodiments, administering provided compositions results in increased serum PAH protein levels by at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% as compared to baseline PAH protein level before treatment.

[0025] In some embodiments, administering provided compositions results in a reduced phenylalanine level in serum as compared to baseline phenylalanine level before treatment. In some embodiments, administering provided compositions results in reduction of phenylalanine levels to about 1500 μιηοΙ/L or less, about 1000 μιηοΙ/L or less, about 900 μιηοΙ/L or less, about 800 μιηοΙ/L or less, about 700 μιηοΙ/L or less, about 600 μιηοΙ/L or less, about 500 μιηοΙ/L or less, about 400 μιηοΙ/L or less, about 300 μιηοΙ/L or less, about 200 μιηοΙ/L or less, about 100 μιηοΙ/L or less or about 50 μιηοΙ/L or less in serum or plasm. In a particular embodiment, a therapeutically effective dose, when administered regularly results in reduction of phenylalanine levels to about 120 μιηοΙ/L or less in serum or plasma. [0026] In some embodiments, administering the provided composition results in reduction of phenylalanine levels in a biological sample (e.g., a serum, plasma, or urine sample) by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%), at least about 30%>, at least about 35%, at least about 40%>, at least about 45%, at least about 50%), at least about 55%, at least about 60%>, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, or at least about 95% as compared to baseline phenylalanine levels before treament.

[0027] In some embodiments, the mRNA encoding PAH is codon optimized. In some embodiments, the codon-optimized mRNA comprises SEQ ID NO: 3 (corresponding to codon- optimized human PAH mRNA sequence). In some embodiments, the mRNA comprises the 5 'UTR sequence of SEQ ID NO:4 (corresponding to 5' UTR sequence X). In some

embodiments, the mRNA comprises the 3' UTR sequence of SEQ ID NO:5 (corresponding to a 3' UTR sequence Y). In some embodiments, the mRNA comprises the 3' UTR sequence of SEQ ID NO:6 (corresponding to a 3' UTR sequence Y). In some embodiments, the codon-optimized mRNA comprises SEQ ID NO: 7 or SEQ ID NO: 8 (corresponding to codon-optimized human PAH mRNA sequence with 5' UTR and 3' UTR sequences).

[0028] In some embodiments, the mRNA comprises one or more modified nucleotides.

In some embodiments, the one or more modified nucleotides comprise pseudouridine, N-l- methyl-pseudouridine, 2-aminoadenosine, 2-thiothymidine, inosine, pyrrolo-pyrimidine, 3- methyl adenosine, 5-methylcytidine, C-5 propynyl-cytidine, C-5 propynyl-uridine, 2- aminoadenosine, C5-bromouridine, C5-fluorouridine, C5-iodouridine, C5-propynyl-uridine, C5- propynyl-cytidine, C5-methylcytidine, 2-aminoadenosine, 7-deazaadenosine, 7-deazaguanosine, 8-oxoadenosine, 8-oxoguanosine, 0(6)-methylguanine, and/or 2-thiocytidine. In some embodiments, the mRNA is unmodified.

[0029] In particular embodiments, the present invention provides compositions for treating phenylketonuria (PKU) including an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose amount encapsulated within a liposome, wherein the mRNA comprises SEQ ID NO:3, and further wherein the liposome comprises cationic or non-cationic lipid, cholesterol- based lipid and PEG-modified lipid. [0030] In particular embodiments, the present invention provides compositions for treating phenylketonuria (PKU) including an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose amount encapsulated within a liposome, wherein the mRNA comprises SEQ ID NO: 7 or SEQ ID NO: 8, and further wherein the liposome comprises cationic or non-cationic lipid, cholesterol-based lipid and PEG-modified lipid.

[0031] Other features, objects, and advantages of the present invention are apparent in the detailed description, drawings and claims that follow. It should be understood, however, that the detailed description, the drawings, and the claims, while indicating embodiments of the present invention, are given by way of illustration only, not limitation. Various changes and modifications within the scope of the invention will become apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWING

[0032] The drawings are for illustration purposes only not for limitation.

[0033] Figure 1 shows exemplary PAH protein levels in HEK293 cells after transfection with provided liposomes.

[0034] Figure 2 depicts an exemplary graph of PAH protein levels detected in the liver of wild type mice treated with provided lipid nanoparticles at various time points after administration.

[0035] Figure 3 depicts an exemplary graph of PAH protein levels detected in the liver of PAH KO mice treated with provided lipid nanoparticles at 6, 12 and 24 hours after administration as compared to untreated wild type mice and untreated PAH KO mice.

[0036] Figure 4 shows an exemplary graph of serum phenylalanine levels in PAH KO mice 6, 12, and 24 hours after treatment with provided lipid nanoparticles as compared to untreated wild type mice and untreated PAH KO mice.

[0037] Figures 5A-5I depicts in situ detection of human PAH mRNA in liver tissue from mice (A) 30 minutes, (B) 3 hours, (C) 6 hours, (D) 12 hours, (E) 24 hours, (F) 48 hours, (G) 72 hours or (H) 7 days after treatment with 1.0 mg/kg of hPAH mRNA-loaded cKK-E12-based lipid nanoparticles, or from untreated mice (I). [0038] Figure 6 depicts an exemplary graph of human PAH protein levels detected in the liver of PAH knock-out mice treated with a single dose of 0.25 mg/kg, 0.5 mg/kg, 0.75 mg/kg or 1.0 mg/kg of hPAH mRNA-loaded cKK-E12-based lipid nanoparticles, or saline.

[0039] Figure 7 depicts an exemplary graph of phenylalanine levels detected in the serum of PAH knock-out mice prior to treatment and following treatment with a single dose of 0.25 mg/kg, 0.5 mg/kg, 0.75 mg/kg or 1.0 mg/kg of hPAH mRNA-loaded cK -E12-based lipid nanoparticles, or with saline.

[0040] Figure 8 depicts an exemplary graph of human PAH protein levels detected in the liver of PAH knock-out mice treated with 0.5 mg/kg or 1.0 mg/kg of hPAH mRNA-loaded cK - E12-based lipid nanoparticles once per week for one month, or with 1.0 mg/kg of hPAH mRNA- loaded cK -E12-based lipid nanoparticles every other week for one month, or with saline.

[0041] Figure 9 depicts an exemplary graph of phenylalanine levels detected in the serum of PAH knock-out mice prior to treatment and following treatment with 0.5 mg/kg or 1.0 mg/kg of hPAH mRNA-loaded cK -E12-based lipid nanoparticles once per week for one month, or with 1.0 mg/kg of hPAH mRNA-loaded cK -E12-based lipid nanoparticles every other week for one month, or with saline.

DEFINITIONS

[0042] In order for the present invention to be more readily understood, certain terms are first defined below. Additional definitions for the following terms and other terms are set forth throughout the specification. The publications and other reference materials referenced herein to describe the background of the invention and to provide additional detail regarding its practice are hereby incorporated by reference.

[0043] Alkyl: As used herein, "alkyl" refers to a radical of a straight-chain or branched saturated hydrocarbon group having from 1 to 15 carbon atoms ("Ci_i5 alkyl"). In some embodiments, an alkyl group has 1 to 3 carbon atoms ("Ci_3 alkyl"). Examples of Ci_₃ alkyl groups include methyl (Ci), ethyl (C₂), n-propyl (C₃), and isopropyl (C₃). In some

embodiments, an alkyl group has 8 to 12 carbon atoms ("C8-i₂ alkyl"). Examples of C_8-12 alkyl groups include, without limitation, n-octyl (C₈), n-nonyl (C9), n-decyl (C₁₀), n-undecyl (Cn), n-dodecyl (C₁₂) and the like. The prefix "n-" (normal) refers to unbranched alkyl groups. For example, n-C% alkyl refers to -(CH₂)7CH₃, n-C₁₀ alkyl refers to -(CH₂)₉CH₃, etc.

[0044] Amino acid: As used herein, term "amino acid," in its broadest sense, refers to any compound and/or substance that can be incorporated into a polypeptide chain. In some embodiments, an amino acid has the general structure H₂N-C(H)(R)-COOH. In some embodiments, an amino acid is a naturally occurring amino acid. In some embodiments, an amino acid is a synthetic amino acid; in some embodiments, an amino acid is a d-amino acid; in some embodiments, an amino acid is an 1-amino acid. "Standard amino acid" refers to any of the twenty standard 1-amino acids commonly found in naturally occurring peptides. "Nonstandard amino acid" refers to any amino acid, other than the standard amino acids, regardless of whether it is prepared synthetically or obtained from a natural source. As used herein, "synthetic amino acid" encompasses chemically modified amino acids, including but not limited to salts, amino acid derivatives (such as amides), and/or substitutions. Amino acids, including carboxy- and/or amino-terminal amino acids in peptides, can be modified by methylation, amidation, acetylation, protecting groups, and/or substitution with other chemical groups that can change the peptide's circulating half-life without adversely affecting their activity. Amino acids may participate in a disulfide bond. Amino acids may comprise one or posttranslational modifications, such as association with one or more chemical entities (e.g., methyl groups, acetate groups, acetyl groups, phosphate groups, formyl moieties, isoprenoid groups, sulfate groups, polyethylene glycol moieties, lipid moieties, carbohydrate moieties, biotin moieties, etc.). The term "amino acid" is used interchangeably with "amino acid residue," and may refer to a free amino acid and/or to an amino acid residue of a peptide. It will be apparent from the context in which the term is used whether it refers to a free amino acid or a residue of a peptide.

[0045] Animal: As used herein, the term "animal" refers to any member of the animal kingdom. In some embodiments, "animal" refers to humans, at any stage of development. In some embodiments, "animal" refers to non-human animals, at any stage of development. In certain embodiments, the non-human animal is a mammal (e.g., a rodent, a mouse, a rat, a rabbit, a monkey, a dog, a cat, a sheep, cattle, a primate, and/or a pig). In some embodiments, animals include, but are not limited to, mammals, birds, reptiles, amphibians, fish, insects, and/or worms. In some embodiments, an animal may be a transgenic animal, genetically-engineered animal, and/or a clone.

[0046] Approximately or about: As used herein, the term "approximately" or "about," as applied to one or more values of interest, refers to a value that is similar to a stated reference value. In certain embodiments, the term "approximately" or "about" refers to a range of values that fall within 25%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%), 6%), 5%, 4%, 3%, 2%>, 1%), or less in either direction (greater than or less than) of the stated reference value unless otherwise stated or otherwise evident from the context (except where such number would exceed 100% of a possible value).

[0047] Biologically active: As used herein, the phrase "biologically active" refers to a characteristic of any agent that has activity in a biological system, and particularly in an organism. For instance, an agent that, when administered to an organism, has a biological effect on that organism, is considered to be biologically active.

[0048] Delivery: As used herein, the term "delivery" encompasses both local and systemic delivery. For example, delivery of mRNA encompasses situations in which an mRNA is delivered to a target tissue and the encoded protein is expressed and retained within the target tissue (aslo referred to as "local distribution" or "local delivery"), and situations in which an mRNA is delivered to a target tissue and the encoded protein is expressed and secreted into patient's circulation system (e.g., serum) and systematically distributed and taken up by other tissues (also referred to as "systemic distribution" or "systemic delivery).

[0049] Expression: As used herein, "expression" of a nucleic acid sequence refers to translation of an mRNA into a polypeptide, assemble multiple polypeptides into an intact protein (e.g., enzyme) and/or post-translational modification of a polypeptide or fully assembled protein (e.g., enzyme). In this application, the terms "expression" and "production," and grammatical equivalent, are used inter-changeably.

[0050] Functional: As used herein, a "functional" biological molecule is a biological molecule in a form in which it exhibits a property and/or activity by which it is characterized. [0051] Half-life: As used herein, the term "half-life" is the time required for a quantity such as nucleic acid or protein concentration or activity to fall to half of its value as measured at the beginning of a time period.

[0052] Improve, increase, or reduce: As used herein, the terms "improve," "increase" or

"reduce," or grammatical equivalents, indicate values that are relative to a baseline measurement, such as a measurement in the same individual prior to initiation of the treatment described herein, or a measurement in a control subject (or multiple control subject) in the absence of the treatment described herein. A "control subject" is a subject afflicted with the same form of disease as the subject being treated, who is about the same age as the subject being treated.

[0053] In Vitro: As used herein, the term "in vitro" refers to events that occur in an artificial environment, e.g., in a test tube or reaction vessel, in cell culture, etc., rather than within a multi-cellular organism.

[0054] In Vivo: As used herein, the term "in vivo" refers to events that occur within a multi-cellular organism, such as a human and a non-human animal. In the context of cell-based systems, the term may be used to refer to events that occur within a living cell (as opposed to, for example, in vitro systems).

[0055] Isolated: As used herein, the term "isolated" refers to a substance and/or entity that has been (1) separated from at least some of the components with which it was associated when initially produced (whether in nature and/or in an experimental setting), and/or (2) produced, prepared, and/or manufactured by the hand of man. Isolated substances and/or entities may be separated from about 10%, about 20%>, about 30%>, about 40%>, about 50%>, about 60%>, about 70%, about 80%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%o, about 97%, about 98%, about 99%, or more than about 99% of the other components with which they were initially associated. In some embodiments, isolated agents are about 80%, about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%o, about 98%, about 99%, or more than about 99% pure. As used herein, a substance is "pure" if it is substantially free of other components. As used herein, calculation of percent purity of isolated substances and/or entities should not include excipients {e.g., buffer, solvent, water, etc.). [0056] Local distribution or delivery: As used herein, the terms "local distribution,"

"local delivery," or grammatical equivalent, refer to tissue specific delivery or distribution.

Typically, local distribution or delivery requires a protein (e.g., enzyme) encoded by mR As be translated and expressed intracellularly or with limited secretion that avoids entering the patient's circulation system.

[0057] messenger RNA (mRNA): As used herein, the term "messenger RNA (mR A)" refers to a polynucleotide that encodes at least one polypeptide. mRNA as used herein encompasses both modified and unmodified RNA. mRNA may contain one or more coding and non-coding regions. mRNA can be purified from natural sources, produced using recombinant expression systems and optionally purified, chemically synthesized, etc. Where appropriate, e.g., in the case of chemically synthesized molecules, mRNA can comprise nucleoside analogs such as analogs having chemically modified bases or sugars, backbone modifications, etc. An mRNA sequence is presented in the 5' to 3' direction unless otherwise indicated. In some embodiments, an mRNA is or comprises natural nucleosides {e.g., adenosine, guanosine, cytidine, uridine); nucleoside analogs {e.g., 2-aminoadenosine, 2-thiothymidine, inosine, pyrrolo-pyrimidine, 3- methyl adenosine, 5-methylcytidine, C-5 propynyl-cytidine, C-5 propynyl-uridine, 2- aminoadenosine, C5-bromouridine, C5-fluorouridine, C5-iodouridine, C5-propynyl-uridine, C5- propynyl-cytidine, C5-methylcytidine, 2-aminoadenosine, 7-deazaadenosine, 7-deazaguanosine, 8-oxoadenosine, 8-oxoguanosine, 0(6)-methylguanine, and 2-thiocytidine); chemically modified bases; biologically modified bases {e.g., methylated bases); intercalated bases; modified sugars {e.g., 2'-fluororibose, ribose, 2'-deoxyribose, arabinose, and hexose); and/or modified phosphate groups {e.g., phosphorothioates and 5'-N-phosphoramidite linkages).

[0058] Nucleic acid: As used herein, the term "nucleic acid," in its broadest sense, refers to any compound and/or substance that is or can be incorporated into a polynucleotide chain. In some embodiments, a nucleic acid is a compound and/or substance that is or can be incorporated into a polynucleotide chain via a phosphodiester linkage. In some embodiments, "nucleic acid" refers to individual nucleic acid residues {e.g., nucleotides and/or nucleosides). In some embodiments, "nucleic acid" refers to a polynucleotide chain comprising individual nucleic acid residues. In some embodiments, "nucleic acid" encompasses RNA as well as single and/or double-stranded DNA and/or cDNA. [0059] Patient: As used herein, the term "patient" or "subject" refers to any organism to which a provided composition may be administered, e.g., for experimental, diagnostic, prophylactic, cosmetic, and/or therapeutic purposes. Typical patients include animals {e.g., mammals such as mice, rats, rabbits, non-human primates, and/or humans). In some

embodiments, a patient is a human. A human includes pre and post natal forms.

[0060] Pharmaceutically acceptable: The term "pharmaceutically acceptable" as used herein, refers to substances that, within the scope of sound medical judgment, are suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

[0061] Pharmaceutically acceptable salt: Pharmaceutically acceptable salts are well known in the art. For example, S. M. Berge et al., describes pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences (1977) 66: 1-19. Pharmaceutically acceptable salts of the compounds of this invention include those derived from suitable inorganic and organic acids and bases. Examples of pharmaceutically acceptable, nontoxic acid addition salts are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid or rnalonic acid or by using other methods used in the art such as ion exchange. Other pharmaceutically acceptable salts include adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2- naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like. Salts derived from appropriate bases include alkali metal, alkaline earth metal, ammonium and N⁺(C_1-4 alkyl)₄ salts. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. Further pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, sulfonate and aryl sulfonate. Further pharmaceutically acceptable salts include salts formed from the quartemization of an amine using an appropriate electrophile, e.g., an alkyl halide, to form a quarternized alkylated amino salt.

[0062] Systemic distribution or delivery: As used herein, the terms "systemic

distribution," "systemic delivery," or grammatical equivalent, refer to a delivery or distribution mechanism or approach that affect the entire body or an entire organism. Typically, systemic distribution or delivery is accomplished via body's circulation system, e.g., blood stream.

Compared to the definition of "local distribution or delivery."

[0063] Subject: As used herein, the term "subject" refers to a human or any non-human animal (e.g., mouse, rat, rabbit, dog, cat, cattle, swine, sheep, horse or primate). A human includes pre- and post-natal forms. In many embodiments, a subject is a human being. A subject can be a patient, which refers to a human presenting to a medical provider for diagnosis or treatment of a disease. The term "subject" is used herein interchangeably with "individual" or "patient." A subject can be afflicted with or is susceptible to a disease or disorder but may or may not display symptoms of the disease or disorder.

[0064] Substantially: As used herein, the term "substantially" refers to the qualitative condition of exhibiting total or near-total extent or degree of a characteristic or property of interest. One of ordinary skill in the biological arts will understand that biological and chemical phenomena rarely, if ever, go to completion and/or proceed to completeness or achieve or avoid an absolute result. The term "substantially" is therefore used herein to capture the potential lack of completeness inherent in many biological and chemical phenomena.

[0065] Target tissues: As used herein , the term "target tissues" refers to any tissue that is affected by a disease to be treated. In some embodiments, target tissues include those tissues that display disease-associated pathology, symptom, or feature.

[0066] Therapeutically effective amount: As used herein, the term "therapeutically effective amount" of a therapeutic agent means an amount that is sufficient, when administered to a subject suffering from or susceptible to a disease, disorder, and/or condition, to treat, diagnose, prevent, and/or delay the onset of the symptom(s) of the disease, disorder, and/or condition. It will be appreciated by those of ordinary skill in the art that a therapeutically effective amount is typically administered via a dosing regimen comprising at least one unit dose.

[0067] Treating: As used herein, the term "treat," "treatment," or "treating" refers to any method used to partially or completely alleviate, ameliorate, relieve, inhibit, prevent, delay onset of, reduce severity of and/or reduce incidence of one or more symptoms or features of a particular disease, disorder, and/or condition. Treatment may be administered to a subject who does not exhibit signs of a disease and/or exhibits only early signs of the disease for the purpose of decreasing the risk of developing pathology associated with the disease.

DETAILED DESCRIPTION

[0068] The present invention provides, among other things, methods and compositions for treating phenylketonuria (PKU) based on mR A therapy. In particular, the present invention provides methods for treating PKU by administering to a subject in need of treatment a composition comprising an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose and an administration interval such that at least one symptom or feature of PKU is reduced in intensity, severity, or frequency or has delayed in onset. In some embodiments, the mRNA is encapsulated within a liposome. As used herein, the term "liposome" refers to any lamellar, multilamellar, or solid lipid nanoparticle vesicle. Typically, a liposome as used herein can be formed by mixing one or more lipids or by mixing one or more lipids and polymer(s). Thus, the term "liposome" as used herein encompasses both lipid and polymer based nanoparticles. In some embodiments, a liposome suitable for the present invention contains cationic or non- cationic lipid(s), cholesterol-based lipid(s) and PEG-modified lipid(s).

Phenylketonuria (PKU)

[0069] The present invention may be used to treat a subject who is suffering from or susceptible to Phenylketonuria (PKU). PKU is an autosomal recessive metabolic genetic disorder characterized by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase (PAH), rendering it nonfunctional. PAH is necessary to metabolize the amino acid phenylalanine (Phe) to the amino acid tyrosine. When PAH activity is reduced, phenylalanine accumulates and is converted into phenylpyruvate (also known as phenylketone) which can be detected in the urine.

[0070] Phenylalanine is a large, neutral amino acid (LNAA). LNAAs compete for transport across the blood-brain barrier (BBB) via the large neutral amino acid transporter (LNAAT). Excess Phe in the blood saturates the transporter and tends to decrease the levels of other LNAAs in the brain. Because several of these other amino acids are necessary for protein and neurotransmitter synthesis, Phe buildup hinders the development of the brain, and can cause mental retardation.

[0071] In addition to hindered brain development, the disease can present clinically with a variety of symptoms including seizures, albinism hyperactivity, stunted growth, skin rashes (eczema), microcephaly, and/or a "musty" odor to the baby's sweat and urine, due to

phenylacetate, one of the ketones produced). Untreated children are typically normal at birth, but have delayed mental and social skills, have a head size significantly below normal, and often demonstrate progressive impairment of cerebral function. As the child grows and develops, additional symptoms including hyperactivity, jerking movements of the arms or legs, EEG abnormalities, skin rashes, tremors, seizures, and severe learning disabilities tend to develop. However, PKU is commonly included in the routine newborn screening panel of most countries that is typically performed 2-7 days after birth.

[0072] If PKU is diagnosed early enough, an affected newborn can grow up with relatively normal brain development, but only by managing and controlling Phe levels through diet, or a combination of diet and medication. All PKU patients must adhere to a special diet low in Phe for optimal brain development. The diet requires severely restricting or eliminating foods high in Phe, such as meat, chicken, fish, eggs, nuts, cheese, legumes, milk and other dairy products. Starchy foods, such as potatoes, bread, pasta, and corn, must be monitored. Infants may still be breastfed to provide all of the benefits of breastmilk, but the quantity must also be monitored and supplementation for missing nutrients will be required. The sweetener aspartame, present in many diet foods and soft drinks, must also be avoided, as aspartame contains phenylalanine. [0073] Throughout life, patients can use supplementary infant formulas, pills or specially formulated foods to acquire amino acids and other necessary nutrients that would otherwise be deficient in a low-phenylalanine diet. Some Phe is required for the synthesis of many proteins and is required for appropriate growth, but levels of it must be strictly controlled in PKU patients. Additionally, PKU patients must take supplements of tyrosine, which is normally derived from phenylalanine. Other supplements can include fish oil, to replace the long chain fatty acids missing from a standard Phe-free diet and improve neurological development and iron or carnitine. Another potential therapy for PKU is tetrahydrobiopterin (BH4), a cofactor for the oxidation of Phe that can reduce blood levels of Phe in certain patients. Patients who respond to BH4 therapy may also be able to increase the amount of natural protein that they can eat.

Phenylalanine Hydroxylase (PAH)

[0074] In some embodiments, the present invention provides methods and compositions for delivering mR A encoding PAH to a subject for the treatment of phenylketonuria (PKU). A suitable PAH mRNA encodes any full length, fragment or portion of a PAH protein which can be substituted for naturally-occurring PAH protein activity and/or reduce the intensity, severity, and/or frequency of one or more symptoms associated with PKU.

[0075] In some embodiments, a suitable mRNA sequence for the present invention comprises an mRNA sequence encoding human PAH protein. The naturally-occurring human PAH mRNA and the corresponding amino acid sequence are shown in Table 1 :

Table 1. Human PAH

Human CAGCUGGGGGUAAGGGGGGCGGAUUAUUCAUAUAAUUGUUAUACCAGACGG PAH UCGCAGGCUUAGUCCAAUUGCAGAGAACUCGCUUCCCAGGCUUCUGAGAGUC

(mRNA) CCGGAAGUGCCUAAACCUGUCUAAUCGACGGGGCUUGGGUGGCCCGUCGCUC

CCUGGCUUCUUCCCUUUACCCAGGGCGGGCAGCGAAGUGGUGCCUCCUGCGU CCCCCACACCCUCCCUCAGCCCCUCCCCUCCGGCCCGUCCUGGGCAGGUGACC UGGAGCAUCCGGCAGGCUGCCCUGGCCUCCUGCGUCAGGACAAGCCCACGAG GGGCGUUACUGUGCGGAGAUGCACCACGCAAGAGACACCCUUUGUAACUCUC UUCUCCUCCCUAGUGCGAGGUUAAAACCUUCAGCCCCACGUGCUGUUUGCAA ACCUGCCUGUACCUGAGGCCCUAAAAAGCCAGAGACCUCACUCCCGGGGAGC CAGCAUGUCCACUGCGGUCCUGGAAAACCCAGGCUUGGGCAGGAAACUCUCU GACUUUGGACAGGAAACAAGCUAUAUUGAAGACAACUGCAAUCAAAAUGGU GCCAUAUCACUGAUCUUCUCACUCAAAGAAGAAGUUGGUGCAUUGGCCAAA GUAUUGCGCUUAUUUGAGGAGAAUGAUGUAAACCUGACCCACAUUGAAUCU AGACCUUCUCGUUUAAAGAAAGAUGAGUAUGAAUUUUUCACCCAUUUGGAU

AAACGUAGCCUGCCUGCUCUGACAAACAUCAUCAAGAUCUUGAGGCAUGAC

AUUGGUGCCACUGUCCAUGAGCUUUCACGAGAUAAGAAGAAAGACACAGUG

CCCUGGUUCCCAAGAACCAUUCAAGAGCUGGACAGAUUUGCCAAUCAGAUUC

UCAGCUAUGGAGCGGAACUGGAUGCUGACCACCCUGGUUUUAAAGAUCCUG

UGUACCGUGCAAGACGGAAGCAGUUUGCUGACAUUGCCUACAACUACCGCCA

UGGGCAGCCCAUCCCUCGAGUGGAAUACAUGGAGGAAGAAAAGAAAACAUG

GGGCACAGUGUUCAAGACUCUGAAGUCCUUGUAUAAAACCCAUGCUUGCUA

UGAGUACAAUCACAUUUUUCCACUUCUUGAAAAGUACUGUGGCUUCCAUGA

AGAUAACAUUCCCCAGCUGGAAGACGUUUCUCAAUUCCUGCAGACUUGCACU

GGUUUCCGCCUCCGACCUGUGGCUGGCCUGCUUUCCUCUCGGGAUUUCUUGG

GUGGCCUGGCCUUCCGAGUCUUCCACUGCACACAGUACAUCAGACAUGGAUC

CAAGCCCAUGUAUACCCCCGAACCUGACAUCUGCCAUGAGCUGUUGGGACAU

GUGCCCUUGUUUUCAGAUCGCAGCUUUGCCCAGUUUUCCCAGGAAAUUGGCC

UUGCCUCUCUGGGUGCACCUGAUGAAUACAUUGAAAAGCUCGCCACAAUUU

ACUGGUUUACUGUGGAGUUUGGGCUCUGCAAACAAGGAGACUCCAUAAAGG

CAUAUGGUGCUGGGCUCCUGUCAUCCUUUGGUGAAUUACAGUACUGCUUAU

CAGAGAAGCCAAAGCUUCUCCCCCUGGAGCUGGAGAAGACAGCCAUCCAAAA

UUACACUGUCACGGAGUUCCAGCCCCUGUAUUACGUGGCAGAGAGUUUUAA

UGAUGCCAAGGAGAAAGUAAGGAACUUUGCUGCCACAAUACCUCGGCCCUU

CUCAGUUCGCUACGACCCAUACACCCAAAGGAUUGAGGUCUUGGACAAUACC

CAGCAGCUUAAGAUUUUGGCUGAUUCCAUUAACAGUGAAAUUGGAAUCCU^

UGCAGUGCCCUCCAGAAAAUAAAGUAAAGCCAUGGACAGAAUGUGGUCUGU

CAGCUGUGAAUCUGUUGAUGGAGAUCCAACUAUUUCUUUCAUCAGAAAAAG

UCCGAAAAGCAAACCUUAAUUUGAAAUAACAGCCUUAAAUCCUUUACAAGA

UGGAGAAACAACAAAUAAGUCAAAAUAAUCUGAAAUGACAGGAUAUGAGUA

CAUACUCAAGAGCAUAAUGGUAAAUCUUUUGGGGUCAUCUUUGAUUUAGAG

AUGAUAAUCCCAUACUCUCAAUUGAGUUAAAUCAGUAAUCUGUCGCAUUUC

AUCAAGAUUAAUUAAAAUUUGGGACCUGCUUCAUUCAAGCUUCAUAUAUGC

UUUGCAGAGAACUCAUAAAGGAGCAUAUAAGGCUAAAUGUAAAACACAAGA

CUGUCAUUAGAAUUGAAUUAUUGGGCUUAAUAUAAAUCGUAACCUAUGAAG

UUUAUUUUCUAUUUUAGUUAACUAUGAUUCCAAW

ACCUAAGUAAAUUUUCUUUAGGUCAGAAGCCCAUUAAAAUAGUUACAAGCA

UUGAACUUCUUUAGUAUUAUAUUAAUAUAAAAACAUUl^

UGUAAUCAUAAAUACUGCUGUAUAAGGUAAUAAAACUCUGCACCUAAUCCC

CAUAACUUCCAGUAUCAUUUUCCAAUUAAUUAUCAAGUCUGUUUUGGGAA^

CACUUUGAGGACAUUUAUGAUGCAGCAGAUGUUGACUAAAGGCUUGGUUGG

UAGAUAUUCAGGAAAUGUUCACUGAAUAAAUAAGUAAAUACAUUAUUGAAA

AGCAAAUCUGUAUAAAUGUGAAAUUUUUAUUUGUAUUAGUAAUAAAACAW

AGUAGUUUA (SEQ ID NO: 1)

Human MSTAVLENPGLGRKLSDFGQETSYIEDNCNQNGAISLIFSLKEEVGALAKVLRLFEE

PAH NDVNLTHIESRPSRLKKDEYEFFTHLDKRSLPALTNIIKILRHDIGATVHELSRDKKK

(Amino DTVPWFPRTIQELDRFANQILSYGAELDADHPGFKDPVYRARRKQFADIAYNYRH Acid Seq.) GQPIPRVEYMEEEKKTWGTVFKTLKSLYKTHACYEYNHIFPLLEKYCGFHEDNIPQ

LEDVSQFLQTCTGFRLRPVAGLLSSRDFLGGLAFRVFHCTQYIRHGSKPMYTPEPDI

CHELLGHVPLFSDRSFAQFSQEIGLASLGAPDEYIEKLATIYWFTVEFGLCKQGDSI

KAYGAGLLSSFGELQYCLSEKPKLLPLELEKTAIQNYTVTEFQPLYYVAESFNDAK

EKVRNFAATIPRPFSVRYDPYTQRIEVLDNTQQLKILADSINSEIGILCSALQKIK

(SEQ ID NO:2) [0076] In some embodiments, a suitable mR A is a wild-type hPAH mR A sequence

(SEQ ID NO: 1). In some embodiments, a suitable mRNA may be a codon optimized hPAH mRNA sequence, such as the sequence shown below:

AUGAGCACCGCCGUGCUGGAGAACCCCGGCCUGGGCCGCAAGCUGAGCGACUUCG

GCCAGGAGACCAGCUACAUCGAGGACAACUGCAACCAGAACGGCGCCAUCAGCCU

GAUCUUCAGCCUGAAGGAGGAGGUGGGCGCCCUGGCCAAGGUGCUGCGCCUGUUC

GAGGAGAACGACGUGAACCUGACCCACAUCGAGAGCCGCCCCAGCCGCCUGAAGA

AGGACGAGUACGAGUUCUUCACCCACCUGGACAAGCGCAGCCUGCCCGCCCUGAC

CAACAUCAUCAAGAUCCUGCGCCACGACAUCGGCGCCACCGUGCACGAGCUGAGC

CGCGACAAGAAGAAGGACACCGUGCCCUGGUUCCCCCGCACCAUCCAGGAGCUGG

ACCGCUUCGCCAACCAGAUCCUGAGCUACGGCGCCGAGCUGGACGCCGACCACCC

CGGCUUCAAGGACCCCGUGUACCGCGCCCGCCGCAAGCAGUUCGCCGACAUCGCC

UACAACUACCGCCACGGCCAGCCCAUCCCCCGCGUGGAGUACAUGGAGGAGGAGA

AGAAGACCUGGGGCACCGUGUUCAAGACCCUGAAGAGCCUGUACAAGACCCACGC

CUGCUACGAGUACAACCACAUCUUCCCCCUGCUGGAGAAGUACUGCGGCUUCCAC

GAGGACAACAUCCCCCAGCUGGAGGACGUGAGCCAGUUCCUGCAGACCUGCACCG

GCUUCCGCCUGCGCCCCGUGGCCGGCCUGCUGAGCAGCCGCGACUUCCUGGGCGG

CCUGGCCUUCCGCGUGUUCCACUGCACCCAGUACAUCCGCCACGGCAGCAAGCCC

AUGUACACCCCCGAGCCCGACAUCUGCCACGAGCUGCUGGGCCACGUGCCCCUGU

UCAGCGACCGCAGCUUCGCCCAGUUCAGCCAGGAGAUCGGCCUGGCCAGCCUGGG

CGCCCCCGACGAGUACAUCGAGAAGCUGGCCACCAUCUACUGGUUCACCGUGGAG

UUCGGCCUGUGCAAGCAGGGCGACAGCAUCAAGGCCUACGGCGCCGGCCUGCUGA

GCAGCUUCGGCGAGCUGCAGUACUGCCUGAGCGAGAAGCCCAAGCUGCUGCCCCU

GGAGCUGGAGAAGACCGCCAUCCAGAACUACACCGUGACCGAGUUCCAGCCCCUG

UACUACGUGGCCGAGAGCUUCAACGACGCCAAGGAGAAGGUGCGCAACUUCGCCG

CCACCAUCCCCCGCCCCUUCAGCGUGCGCUACGACCCCUACACCCAGCGCAUCGAG

GUGCUGGACAACACCCAGCAGCUGAAGAUCCUGGCCGACAGCAUCAACAGCGAGA

UCGGCAUCCUGUGCAGCGCCCUGCAGAAGAUCAAGUAA (SEQ ID NO:3)

[0077] Additional exemplary mRNA sequences are described in the Examples section, such as, SEQ ID NO:7 and SEQ ID NO:8, both of which include 5' and 3' untranslated regions framing a codon optimized mRNA sequence.

[0078] In some embodiments, a suitable mRNA sequence may be an mRNA sequence that encodes a homo log or an analog of human PAH. As used herein, a homologue or an analogue of human PAH protein may be a modified human PAH protein containing one or more amino acid substitutions, deletions, and/or insertions as compared to a wild-type or naturally- occurring human PAH protein while retaining substantial PAH protein activity. In some embodiments, an mRNA suitable for the present invention encodes an amino acid sequence at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%) or more homologous to SEQ ID NO:2. In some embodiments, an mRNA suitable for the present invention encodes a protein substantially identical to human PAH protein. In some embodiments, an mRNA suitable for the present invention encodes an amino acid sequence at least 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more identical to SEQ ID NO:2. In some embodiments, an mRNA suitable for the present invention encodes a fragment or a portion of human PAH protein. In some embodiments, an mRNA suitable for the present invention encodes a fragment or a portion of human PAH protein, wherein the fragment or portion of the protein still maintains PAH activity similar to that of the wild-type protein. In some embodiments, an mRNA suitable for the present invention has a nucleotide sequence at least 50%>, 55%, 60%>, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more identical to SEQ ID NO: l, SEQ ID NO: 3, SEQ ID NO:7 or SEQ ID NO:8.

[0079] In some embodiments, a suitable mRNA encodes a fusion protein comprising a full length, fragment or portion of a PAH protein fused to another protein (e.g., an N or C terminal fusion). In some embodiments, the protein fused to the mRNA encoding a full length, fragment or portion of a PAH protein encodes a signal or a cellular targeting sequence.

Delivery Vehicles

[0080] According to the present invention, mRNA encoding a PAH protein (e.g., a full length, fragment or portion of a PAH protein) as described herein may be delivered as naked RNA (unpackaged) or via delivery vehicles. As used herein, the terms "delivery vehicle," "transfer vehicle," "Nanoparticle" or grammatical equivalent, are used interchangeably.

[0081] In some embodiments, mRNAs encoding a PAH protein may be delivered via a single delivery vehicle. In some embodiments, mRNAs encoding a PAH protein may be delivered via one or more delivery vehicles each of a different composition. According to various embodiments, suitable delivery vehicles include, but are not limited to polymer based carriers, such as polyethyleneimine (PEI), lipid nanoparticles and liposomes, nanoliposomes, ceramide-containing nanoliposomes, proteoliposomes, both natural and synthetically-derived exosomes, natural, synthetic and semi-synthetic lamellar bodies, nanoparticulates, calcium phosphor-silicate nanoparticulates, calcium phosphate nanoparticulates, silicon dioxide nanoparticulates, nanocrystalline particulates, semiconductor nanoparticulates, poly(D-arginine), sol-gels, nanodendrimers, starch-based delivery systems, micelles, emulsions, niosomes, multi- domain-block polymers (vinyl polymers, polypropyl acrylic acid polymers, dynamic

polyconjugates), dry powder formulations, plasmids, viruses, calcium phosphate nucleotides, aptamers, peptides and other vectorial tags.

Liposomal delivery vehicles

[0082] In some embodiments, a suitable delivery vehicle is a liposomal delivery vehicle, e.g., a lipid nanoparticle. As used herein, liposomal delivery vehicles, e.g., lipid nanoparticles, are usually characterized as microscopic vesicles having an interior aqua space sequestered from an outer medium by a membrane of one or more bilayers. Bilayer membranes of liposomes are typically formed by amphiphilic molecules, such as lipids of synthetic or natural origin that comprise spatially separated hydrophilic and hydrophobic domains (Lasic, Trends BiotechnoL, 16: 307-321, 1998). Bilayer membranes of the liposomes can also be formed by amphophilic polymers and surfactants (e.g., polymerosomes, niosomes, etc.). In the context of the present invention, a liposomal delivery vehicle typically serves to transport a desired mRNA to a target cell or tissue. The process of incorporation of a desired mRNA into a liposome is often referred to as "loading". Exemplary methods are described in Lasic, et al, FEBS Lett., 312: 255-258, 1992, which is incorporated herein by reference. The liposome -incorporated nucleic acids may be completely or partially located in the interior space of the liposome, within the bilayer membrane of the liposome, or associated with the exterior surface of the liposome membrane. The incorporation of a nucleic acid into liposomes is also referred to herein as "encapsulation" wherein the nucleic acid is entirely contained within the interior space of the liposome. The purpose of incorporating a mRNA into a transfer vehicle, such as a liposome, is often to protect the nucleic acid from an environment which may contain enzymes or chemicals that degrade nucleic acids and/or systems or receptors that cause the rapid excretion of the nucleic acids. Accordingly, in some embodiments, a suitable delivery vehicle is capable of enhancing the stability of the mRNA contained therein and/or facilitate the delivery of mRNA to the target cell or tissue. Cationic Lipids

[0083] In some embodiments, liposomes may comprise one or more cationic lipids. As used herein, the phrase "cationic lipid" refers to any of a number of lipid species that have a net positive charge at a selected pH, such as physiological pH. Several cationic lipids have been described in the literature, many of which are commercially available. Particularly suitable cationic lipids for use in the compositions and methods of the invention include those described in international patent publications WO 2010/053572 (and particularly, CI 2-200 described at paragraph [00225]) and WO 2012/170930, both of which are incorporated herein by reference. In certain embodiments, the compositions and methods of the invention employ a lipid nanoparticles comprising an ionizable cationic lipid described in U.S. provisional patent application 61/617,468, filed March 29, 2012 (incorporated herein by reference), such as, e.g, (15Z, 18Z)-N,N-dimethyl-6-(9Z, 12Z)-octadeca-9, 12-dien-l -yl)tetracosa- 15,18-dien- 1 -amine (HGT5000), ( 15Z, 18Z)-N,N-dimethyl-6-((9Z, 12Z)-octadeca-9, 12-dien- 1 -yl)tetracosa- 4,15,18-trien-l -amine (HGT5001), and (15Z,18Z)-N,N-dimethyl-6-((9Z, 12Z)-octadeca-9, 12- dien- 1 -yl)tetracosa-5, 15 , 18-trien- 1 -amine (HGT5002).

[0084] In some embodiments, provided liposomes include a cationic lipid described in

WO 2013063468 and in U.S. provisional application entitled "Lipid Formulations for Delivery of Messernger RNA" filed concurrently with the present application on even date, both of which are incorporated by reference herein. In some embodiments, a cationic lipid comprises a compound of formula I-cl-a:

or a pharmaceutically acceptable salt thereof, wherein: each R² independently is hydrogen or Ci_₃ alkyl; each q independently is 2 to 6; each R independently is hydrogen or Ci_₃ alkyl; and each R^L independently is C_8-12 alkyl.

[0085] In some embodiments, each R² independently is hydrogen, methyl or ethyl. In some embodiments, each R² independently is hydrogen or methyl. In some embodiments, each R² is hydrogen.

[0086] In some embodiments, each q independently is 3 to 6. In some embodiments, each q independently is 3 to 5. In some embodiments, each q is 4.

[0087] In some embodiments, each R independently is hydrogen, methyl or ethyl. In some embodiments, each R independently is hydrogen or methyl. In some embodiments, each R independently is hydrogen.

[0088] In some embodiments, each R^L independently is C_8-12 alkyl. In some embodiments, each R^L independently is «-C_8-12 alkyl. In some embodiments, each R^L independently is C9_n alkyl. In some embodiments, each R^L independently is n-Cg-n alkyl. In some embodiments, each R^L independently is C₁₀ alkyl. In some embodiments, each R^L independently is n-C₁₀ alkyl. [0089] In some embodiments, each R² independently is hydrogen or methyl; each q independently is 3 to 5; each R independently is hydrogen or methyl; and each R^L independently is C₈-i2 alkyl.

[0090] In some embodiments, each R² is hydrogen; each q independently is 3 to 5; each

R is hydrogen; and each R^L independently is C_8-12 alkyl.

[0091] In some embodiments, each R² is hydrogen; each q is 4; each R' is hydrogen; and each R^L independently is C_8-12 alkyl.

[0092] In some embodiments, a cationic lipid comprises a compound of formula I-g:

or a pharmaceutically acceptable salt thereof, wherein each R^L independently is C_8-12 alkyl. In some embodiments, each R^L independently is «-C_8-12 alkyl. In some embodiments, each R^L independently is C9_n alkyl. In some embodiments, each R^L independently is n-Cg-n alkyl. In some embodiments, each R^L independently is C₁₀ alkyl. In some embodiments, each R^L is n-C₁₀ alkyl.

[0093] In particular embodiments, provided liposomes include a cationic lipid cK -E12, or (3,6-bis(4-(bis(2-hydroxydodecyl)amino)butyl)piperazine-2,5-dione). Structure of cK -E12 is shown below:

[0094] As described in the Examples section below, the present inventors observed that liposomes based on this particular class of cationic lipids, such as, those having a structure of formula I-cl-a or formula I-g described herein (e.g., cK -E12) are unexpectedly effective in delivering mRNA and producing encoded protein in vivo. Although mRNA encoding PAH protein is used as an example in this application, it is contemplated that this class of cationic lipids having a structure of formula I-cl-a or formula I-g described herein (e.g., cK -E12) can be useful in delivering any mRNA for highly efficient and sustained production of protein (e.g., therapeutic protein) in vivo. For example, cationic lipids having a structure of formula I-cl-a or formula I-g described herein (e.g., cK -E12) can be used to deliver an mRNA that encodes one or more naturally occurring peptides or one or more modified or non-natural peptides. In some embodiments, cationic lipids having a structure of formula I-cl-a or formula I-g described herein (e.g., cK -E12) can be used to deliver an mRNA that encodes an intracellular protein including, but not limited to, a cytosolic protein (e.g., a chaperone protein, an intracellular enzyme (e.g., mRNA encoding an enzyme associated with urea cycle or lysosomal storage disorders)), a protein associated with the actin cytoskeleton, a protein associated with the plasma membrane, a perinuclear protein, a nuclear protein (e.g., a transcription factor), and any other protein involved in cellular metabolism, DNA repair, transcription and/or translation). In some embodiments, cationic lipids having a structure of formula I-cl-a or formula I-g described herein (e.g., cK - E12) can be used to deliver an mRNA that encodes a transmembrane protein, such as, an ion channel protein. In some embodiments, cationic lipids having a structure of formula I-cl-a or formula I-g described herein (e.g., cK -E12) can be used to deliver an mRNA that encodes an extracellular protein including, but not limited to, a protein associated with the extracellular matrix, a secreted protein (e.g., hormones and/or neurotransmitters).

[0095] In some embodiments, one or more cationic lipids suitable for the present invention may be N-[l-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride or

"DOTMA". (Feigner et al. (Proc. Nafl Acad. Sci. 84, 7413 (1987); U.S. Pat. No. 4,897,355). DOTMA can be formulated alone or can be combined with the neutral lipid,

dioleoylphosphatidyl-ethanolamine or "DOPE" or other cationic or non-cationic lipids into a liposomal transfer vehicle or a lipid nanoparticle, and such liposomes can be used to enhance the delivery of nucleic acids into target cells. Other suitable cationic lipids include, for example, 5- carboxyspermylglycinedioctadecylamide or "DOGS," 2,3-dioleyloxy-N-[2(spermine- carboxamido)ethyl]-N,N-dimethyl-l-propanaminium or "DOSPA" (Behr et al. Proc. Nat.'l Acad. Sci. 86, 6982 (1989); U.S. Pat. No. 5,171,678; U.S. Pat. No. 5,334,761), l,2-Dioleoyl-3- Dimethylammonium-Propane or "DODAP", l,2-Dioleoyl-3-Trimethylammonium-Propane or "DOTAP".

[0096] Additional exemplary cationic lipids also include l,2-distearyloxy-N,N-dimethyl-

3-aminopropane or "DSDMA", l,2-dioleyloxy-N,N-dimethyl-3-aminopropane or "DODMA", 1 ,2-dilinoleyloxy-N,N-dimethyl-3-aminopropane or "DLinDMA", l,2-dilinolenyloxy-N,N- dimethyl-3-aminopropane or "DLenDMA", N-dioleyl-N,N-dimethylammonium chloride or "DODAC", N,N-distearyl-N,N-dimethylarnrnonium bromide or "DDAB", N-(l,2- dimyristyloxyprop-3-yl)-N,N-dimethyl-N -hydroxy ethyl ammonium bromide or "DMRIE", 3- dimethylamino-2-(cholest-5-en-3-beta-oxybutan-4-oxy)-l-(ci s,cis-9,12- octadecadienoxy)propane or "CLinDMA", 2-[5'-(cholest-5-en-3-beta-oxy)-3'-oxapentoxy)-3- dimethy l-l-(cis,cis-9', l-2'-octadecadienoxy)propane or "CpLinDMA", N,N-dimethyl-3,4- dioleyloxybenzylamine or "DMOBA", 1 ,2-N,N'-dioleylcarbamyl-3-dimethylaminopropane or "DOcarbDAP", 2,3-Dilinoleoyloxy-N,N-dimethylpropylamine or "DLinDAP", 1,2-Ν,Ν - Dilinoleylcarbamyl-3-dimethylaminopropane or "DLincarbDAP", 1 ,2-Dilinoleoylcarbamyl-3- dimethylaminopropane or "DLinCDAP", 2,2-dilinoleyl-4-dimethylaminomethyl-[l,3]-dioxolane or "DLin- -DMA", 2,2-dilinoleyl-4-dimethylaminoethyl-[l,3]-dioxolane or "DLin-K-XTC2- DMA", and 2-(2,2-di((9Z,12Z)-octadeca-9,l 2-dien- l-yl)-l ,3-dioxolan-4-yl)-N,N- dimethylethanamine (DLin-KC2-DMA)) (see, WO 2010/042877; Semple et al, Nature Biotech. 28: 172-176 (2010)), or mixtures thereof. (Heyes, J., et al, J Controlled Release 107: 276-287 (2005); Morrissey, DV., et al, Nat. Biotechnol. 23(8): 1003-1007 (2005); PCT Publication WO2005/121348A1). In some embodiments, one or more of the cationic lipids comprise at least one of an imidazole, dialkylamino, or guanidinium moiety.

[0097] In some embodiments, the one or more cationic lipids may be chosen from XTC

(2,2-Dilinoleyl-4-dimethylaminoethyl-[l,3]-dioxolane), MC3 (((6Z,9Z,28Z,31Z)- heptatriaconta-6,9,28,31-tetraen-19-yl 4-(dimethylamino)butanoate), ALNY-100 ((3aR,5s,6aS)- N,N-dimethyl-2,2-di((9Z,12Z)-octadeca-9,12-dienyl)tetrahydro-3aH-cyclopenta[d] [1 ,3]dioxol- 5-amine)), NC98-5 (4,7, 13-tris(3-oxo-3-(undecylamino)propyl)-Nl ,N 16-diundecyl-4,7, 10,13- tetraazahexadecane-l,16-diamide), DODAP (l,2-dioleyl-3-dimethylammonium propane), HGT4003 (WO 2012/170889, the teachings of which are incorporated herein by reference in their entirety), ICE (WO 2011/068810, the teachings of which are incorporated herein by reference in their entirety), HGT5000 (U.S. Provisional Patent Application No. 61/617,468, the teachings of which are incorporated herein by reference in their entirety) or HGT5001 (cis or trans) (Provisional Patent Application No. 61/617,468), aminoalcohol lipidoids such as those disclosed in WO2010/053572, DOTAP (l,2-dioleyl-3-trimethylammonium propane), DOTMA (l,2-di-0-octadecenyl-3-trimethylammonium propane), DLinDMA (Heyes, J.; Palmer, L.;

Bremner, K.; MacLachlan, I. "Cationic lipid saturation influences intracellular delivery of encapsulated nucleic acids" J. Contr. Rel. 2005, 107, 276-287), DLin-KC2-DMA (Semple, S.C. et al. "Rational Design of Cationic Lipids for siRNA Delivery" Nature Biotech. 2010, 28, 172- 176), CI 2-200 (Love, K.T. et al. "Lipid- like materials for low-dose in vivo gene silencing" PNAS 2010, 107, 1864-1869).

[0098] In some embodiments, the percentage of cationic lipid in a liposome may be greater than 10%, greater than 20%, greater than 30%, greater than 40%, greater than 50%, greater than 60%>, or greater than 70%>. In some embodiments, cationic lipid(s) constitute(s) about 30-50 % (e.g., about 30-45%, about 30-40%, about 35-50%, about 35-45%, or about 35- 40%)) of the liposome by weight. In some embodiments, the cationic lipid (e.g., cK -E12) constitutes about 30%>, about 35%>, about 40 %>, about 45%>, or about 50%> of the liposome by molar ratio. Non-cationic/Helper Lipids

[0099] In some embodiments, provided liposomes contain one or more non-cationic

("helper") lipids. As used herein, the phrase "non-cationic lipid" refers to any neutral, zwitterionic or anionic lipid. As used herein, the phrase "anionic lipid" refers to any of a number of lipid species that carry a net negative charge at a selected H, such as physiological pH. Non- cationic lipids include, but are not limited to, distearoylphosphatidylcholine (DSPC),

dioleoylphosphatidylcholine (DOPC), dipalmitoylphosphatidylcholine (DPPC),

dioleoylphosphatidylglycerol (DOPG), dipalmitoylphosphatidylglycerol (DPPG),

dioleoylphosphatidylethanolamine (DOPE), palmitoyloleoylphosphatidylcholine (POPC), palmitoyloleoyl-phosphatidylethanolamine (POPE), dioleoyl-phosphatidylethanolamine 4-(N- maleimidomethyl)-cyclohexane-l-carboxylate (DOPE-mal), dipalmitoyl phosphatidyl ethanolamine (DPPE), dimyristoylphosphoethanolamine (DMPE), distearoyl-phosphatidyl- ethanolamine (DSPE), 16-O-monomethyl PE, 16-O-dimethyl PE, 18-1 -trans PE, l-stearoyl-2- oleoyl-phosphatidyethanolamine (SOPE), or a mixture thereof.

[0100] In some embodiments, such non-cationic lipids may be used alone, but are preferably used in combination with other excipients, for example, cationic lipids. In some embodiments, the non-cationic lipid may comprise a molar ratio of about 5% to about 90%, or about 10 % to about 70% of the total lipid present in a liposome. In some embodiments, a non- cationic lipid is a neutral lipid, i.e., a lipid that does not carry a net charge in the conditions under which the composition is formulated and/or administered. In some embodiments, the percentage of non-cationic lipid in a liposome may be greater than 5%, greater than 10%, greater than 20%, greater than 30%, or greater than 40%.

Cholesterol-based Lipids

[0101] In some embodiments, provided liposomes comprise one or more cholesterol- based lipids. For example, suitable cholesterol-based cationic lipids include, for example, DC- Choi (N,N-dimethyl-N-ethylcarboxamidocholesterol), l,4-bis(3-N-oleylamino-propyl)piperazine (Gao, et al. Biochem. Biophys. Res. Comm. 179, 280 (1991); Wolf et al. BioTechniques 23, 139 (1997); U.S. Pat. No. 5,744,335), or ICE. In some embodiments, the cholesterol-based lipid may comprise a molar ration of about 2% to about 30%, or about 5% to about 20% of the total lipid present in a liposome. In some embodiments, The percentage of cholesterol-based lipid in the lipid nanoparticle may be greater than 5, %, 10%, greater than 20%, greater than 30%, or greater than 40%.

PEGylated Lipids

[0102] In some embodiments, provided liposomes comprise one or more PEGylated lipids. For example, the use of polyethylene glycol (PEG)-modified phospholipids and derivatized lipids such as derivatized ceramides (PEG-CER), including N-Octanoyl- Sphingosine-l-[Succinyl(Methoxy Polyethylene Glycol)-2000] (C8 PEG-2000 ceramide) is also contemplated by the present invention in combination with one or more of the cationic and, in some embodiments, other lipids together which comprise the liposome. Contemplated PEG- modified lipids include, but are not limited to, a polyethylene glycol chain of up to 5 kDa in length covalently attached to a lipid with alkyl chain(s) of C6-C₂₀ length. In some embodiments, a PEG-modified or PEGylated lipid is PEGylated cholesterol or PEG-2K. The addition of such components may prevent complex aggregation and may also provide a means for increasing circulation lifetime and increasing the delivery of the lipid-nucleic acid composition to the target cell, (Klibanov et al. (1990) FEBS Letters, 268 (1): 235-237), or they may be selected to rapidly exchange out of the formulation in vivo (see U.S. Pat. No. 5,885,613).

[0103] In some embodiments, particularly useful exchangeable lipids are PEG-ceramides having shorter acyl chains (e.g., Ci₄ or Ci₈). The PEG-modified phospholipid and derivatized lipids of the present invention may comprise a molar ratio from about 0% to about 15%, about 0.5%) to about 15%), about 1%> to about 15%>, about 4%> to about 10%>, or about 2%> of the total lipid present in the liposome.

Polymers

[0104] In some embodiments, a suitable delivery vehicle is formulated using a polymer as a carrier, alone or in combination with other carriers including various lipids described herein. Thus, in some embodiments, liposomal delivery vehicles, as used herein, also encompass polymer containing nanoparticles. Suitable polymers may include, for example, polyacrylates, polyalkycyanoacrylates, polylactide, polylactide-polyglycolide copolymers, polycaprolactones, dextran, albumin, gelatin, alginate, collagen, chitosan, cyclodextrins, protamine, PEGylated protamine, PLL, PEGylated PLL and polyethylenimine (PEI). When PEI is present, it may be branched PEI of a molecular weight ranging from 10 to 40 kDA, e.g., 25 kDa branched PEI (Sigma #408727).

[0105] According to various embodiments, the selection of cationic lipids, non-cationic lipids, PEG-modified lipids and/or polymers which comprise the lipid nanoparticle, as well as the relative molar ratio of such lipids to each other, is based upon the characteristics of the selected lipid(s)/polymers, the nature of the intended target cells, the characteristics of the mR A to be delivered. Additional considerations include, for example, the saturation of the alkyl chain, as well as the size, charge, pH, pKa, fusogenicity and toxicity of the selected lipid(s). Thus the molar ratios may be adjusted accordingly.

[0106] In some embodiments, the cationic lipids, non-cationic lipids, cholesterol, and/or

PEG-modified lipids can be combined at various relative molar ratios. For example, the ratio of cationic lipid (e.g., cK -E12, C12-200, etc.) to non-cationic lipid (e.g., DOPE, etc.) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG-PEG2K) may be between about 30-60:25-35:20-30: 1-15, respectively. In some embodiments, the ratio of cationic lipid (e.g., cK -E12, C12-200, etc.) to non-cationic lipid (e.g., DOPE, etc.) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG-PEG2K) is approximately 40:30:20: 10, respectively. In some embodiments, the ratio of cationic lipid (e.g., cK -E12, C12-200, etc.) to non-cationic lipid (e.g., DOPE, etc.) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG-PEG2K) is approximately 40:30:25:5, respectively. In some embodiments, the ratio of cationic lipid (e.g., cK -E12, C12-200, etc.) to non-cationic lipid (e.g., DOPE, etc.) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG-PEG2K) is

approximately 40:32:25:3, respectively. In some embodiments, the ratio of cationic lipid (e.g., cK -E12, C12-200, etc.) to non-cationic lipid (e.g., DOPE, etc.) to cholesterol-based lipid (e.g., cholesterol) to PEGylated lipid (e.g., DMG-PEG2K) is approximately 50:25:20:5. Synthesis of mRNA

[0107] mRNAs according to the present invention may be synthesized according to any of a variety of known methods. For example, mRNAs according to the present invention may be synthesized via in vitro transcription (IVT). Briefly, IVT is typically performed with a linear or circular DNA template containing a promoter, a pool of ribonucleotide triphosphates, a buffer system that may include DTT and magnesium ions, and an appropriate RNA polymerase (e.g., T3, T7 or SP6 RNA polymerase), DNAse I, pyrophosphatase, and/or RNAse inhibitor. The exact conditions will vary according to the specific application.

[0108] In some embodiments, for the preparation of mRNA according to the invention, a

DNA template is transcribed in vitro. A suitable DNA template typically has a promoter, for example a T3, T7 or SP6 promoter, for in vitro transcription, followed by desired nucleotide sequence for desired mRNA and a termination signal.

[0109] Desired mRNA sequence(s) according to the invention may be determined and incorporated into a DNA template using standard methods. For example, starting from a desired amino acid sequence (e.g., an enzyme sequence), a virtual reverse translation is carried out based on the degenerated genetic code. Optimization algorithms may then be used for selection of suitable codons. Typically, the G/C content can be optimized to achieve the highest possible G/C content on one hand, taking into the best possible account the frequency of the tRNAs according to codon usage on the other hand. The optimized RNA sequence can be established and displayed, for example, with the aid of an appropriate display device and compared with the original (wild-type) sequence. A secondary structure can also be analyzed to calculate stabilizing and destabilizing properties or, respectively, regions of the RNA.

Modified mRNA

[0110] In some embodiments, mRNA according to the present invention may be synthesized as unmodified or modified mRNA. Typically, mRNAs are modified to enhance stability. Modifications of mRNA can include, for example, modifications of the nucleotides of the RNA. An modified mRNA according to the invention can thus include, for example, backbone modifications, sugar modifications or base modifications. In some embodiments, mRNAs may be synthesized from naturally occurring nucleotides and/or nucleotide analogues (modified nucleotides) including, but not limited to, purines (adenine (A), guanine (G)) or pyrimidines (thymine (T), cytosine (C), uracil (U)), and as modified nucleotides analogues or derivatives of purines and pyrimidines, such as e.g. 1-methyl-adenine, 2-methyl-adenine, 2- methylthio-N-6-isopentenyl-adenine, N6-methyl-adenine, N6-isopentenyl-adenine, 2-thio- cytosine, 3-methyl-cytosine, 4-acetyl-cytosine, 5-methyl-cytosine, 2,6-diaminopurine, 1-methyl- guanine, 2-methyl-guanine, 2,2-dimethyl-guanine, 7-methyl-guanine, inosine, 1-methyl-inosine, pseudouracil (5-uracil), dihydro-uracil, 2-thio-uracil, 4-thio-uracil, 5- carboxymethylaminomethyl-2-thio-uracil, 5-(carboxyhydroxymethyl)-uracil, 5-fluoro-uracil, 5- bromo-uracil, 5-carboxymethylaminomethyl-uracil, 5-methyl-2-thio-uracil, 5-methyl-uracil, N- uracil-5-oxyacetic acid methyl ester, 5-methylaminomethyl-uracil, 5-methoxyaminomethyl-2- thio-uracil, 5'-methoxycarbonylmethyl-uracil, 5-methoxy-uracil, uracil-5-oxyacetic acid methyl ester, uracil-5-oxyacetic acid (v), 1-methyl-pseudouracil, queosine, .beta.-D-mannosyl-queosine, wybutoxosine, and phosphoramidates, phosphorothioates, peptide nucleotides,

methylphosphonates, 7-deazaguanosine, 5-methylcytosine and inosine. The preparation of such analogues is known to a person skilled in the art e.g. from the U.S. Pat. No. 4,373,071 , U.S. Pat. No. 4,401 ,796, U.S. Pat. No. 4,415,732, U.S. Pat. No. 4,458,066, U.S. Pat. No. 4,500,707, U.S. Pat. No. 4,668,777, U.S. Pat. No. 4,973,679, U.S. Pat. No. 5,047,524, U.S. Pat. No. 5, 132,418, U.S. Pat. No. 5, 153,319, U.S. Pat. Nos. 5,262,530 and 5,700,642, the disclosures of which are incorporated by reference in their entirety.

[0111] In some embodiments, mRNAs (e.g., PAH-encoding mRNAs) may contain RNA backbone modifications. Typically, a backbone modification is a modification in which the phosphates of the backbone of the nucleotides contained in the RNA are modified chemically. Exemplary backbone modifications typically include, but are not limited to, modifications from the group consisting of methylphosphonates, methylphosphoramidates, phosphoramidates, phosphorothioates (e.g. cytidine 5'-0-(l-thiophosphate)), boranophosphates, positively charged guanidinium groups etc., which means by replacing the phosphodiester linkage by other anionic, cationic or neutral groups.

[0112] In some embodiments, mRNAs (e.g., PAH-encoding mRNAs) may contain sugar modifications. A typical sugar modification is a chemical modification of the sugar of the nucleotides it contains including, but not limited to, sugar modifications chosen from the group consisting of 2'-deoxy-2'-fluoro-oligoribonucleotide (2'-fluoro-2'-deoxycytidine 5 '-triphosphate, 2'-fluoro-2'-deoxyuridine 5 '-triphosphate), 2'-deoxy-2'-deamine-oligoribonucleotide (2'-amino-2'- deoxycytidine 5 '-triphosphate, 2'-amino-2'-deoxyuridine 5 '-triphosphate), 2'-0- alkyloligoribonucleotide, 2'-deoxy-2'-C-alkyloligoribonucleotide (2'-0-methylcytidine 5'- triphosphate, 2'-methyluridine 5'-triphosphate), 2'-C-alkyloligoribonucleotide, and isomers thereof (2'-aracytidine 5 '-triphosphate, 2'-arauridine 5 '-triphosphate), or azidotriphosphates (2'- azido-2'-deoxycytidine 5 '-triphosphate, 2'-azido-2'-deoxyuridine 5 '-triphosphate).

[0113] In some embodiments, mRNAs (e.g., PAH-encoding mRNAs) may contain modifications of the bases of the nucleotides (base modifications). A modified nucleotide which contains a base modification is also called a base-modified nucleotide. Exemples of such base- modified nucleotides include, but are not limited to, 2-amino-6-chloropurine riboside 5'- triphosphate, 2-aminoadenosine 5 '-triphosphate, 2-thiocytidine 5 '-triphosphate, 2-thiouridine 5'- triphosphate, 4-thiouridine 5 '-triphosphate, 5-aminoallylcytidine 5 '-triphosphate, 5- aminoallyluridine 5'-triphosphate, 5-bromocytidine 5 '-triphosphate, 5-bromouridine 5'- triphosphate, 5-iodocytidine 5 '-triphosphate, 5-iodouridine 5 '-triphosphate, 5-methylcytidine 5'- triphosphate, 5-methyluridine 5 '-triphosphate, 6-azacytidine 5'-triphosphate, 6-azauridine 5'- triphosphate, 6-chloropurine riboside 5 '-triphosphate, 7-deazaadenosine 5 '-triphosphate, 7- deazaguanosine 5 '-triphosphate, 8-azaadenosine 5 '-triphosphate, 8-azidoadenosine 5'- triphosphate, benzimidazole riboside 5 '-triphosphate, Nl-methyladenosine 5 '-triphosphate, Nl- methylguanosine 5 '-triphosphate, N6-methyladenosine 5 '-triphosphate, 06-methylguanosine 5'- triphosphate, pseudouridine 5 '-triphosphate, puromycin 5 '-triphosphate or xanthosine 5'- triphosphate.

[0114] Typically, mRNA synthesis includes the addition of a "cap" on the N-terminal

(5 ') end, and a "tail" on the C-terminal (3 ') end. The presence of the cap is important in providing resistance to nucleases found in most eukaryotic cells. The presence of a "tail" serves to protect the mRNA from exonuclease degradation.

[0115] Thus, in some embodiments, mRNAs (e.g., PAH-encoding mRNAs) include a 5 ' cap structure. A 5 ' cap is typically added as follows: first, an RNA terminal phosphatase removes one of the terminal phosphate groups from the 5 ' nucleotide, leaving two terminal phosphates; guanosine triphosphate (GTP) is then added to the terminal phosphates via a guanylyl transferase, producing a 5 '5 '5 triphosphate linkage; and the 7-nitrogen of guanine is then methylated by a methyltransferase. Examples of cap structures include, but are not limited to, m7G(5*)ppp (5*(A,G(5*)ppp(5*)A and G(5*)ppp(5*)G.

[0116] In some embodiments, mRNAs (e.g., PAH-encoding mR As) include a 3 ' poly(A) tail structure. A poly- A tail on the 3' terminus of mR A typically includes about 10 to 300 adenosine nucleotides (SEQ ID NO:9) (e.g., about 10 to 200 adenosine nucleotides, about 10 to 150 adenosine nucleotides, about 10 to 100 adenosine nucleotides, about 20 to 70 adenosine nucleotides, or about 20 to 60 adenosine nucleotides). In some embodiments, mRNAs include a 3 ' poly(C) tail structure. A suitable poly-C tail on the 3' terminus of mRNA typically include about 10 to 200 cytosine nucleotides (SEQ ID NO: 10) (e.g., about 10 to 150 cytosine

nucleotides, about 10 to 100 cytosine nucleotides, about 20 to 70 cytosine nucleotides, about 20 to 60 cytosine nucleotides, or about 10 to 40 cytosine nucleotides). The poly-C tail may be added to the poly-A tail or may substitute the poly-A tail.

[0117] In some embodiments, mRNAs include a 5 ' and/or 3 ' untranslated region. In some embodiments, a 5 ' untranslated region includes one or more elements that affect an mRNA's stability or translation, for example, an iron responsive element. In some

embodiments, a 5 ' untranslated region may be between about 50 and 500 nucleotides in length.

[0118] In some embodiments, a 3 ' untranslated region includes one or more of a polyadenylation signal, a binding site for proteins that affect an mRNA's stability of location in a cell, or one or more binding sites for miRNAs. In some embodiments, a 3 ' untranslated region may be between 50 and 500 nucleotides in length or longer.

Cap structure

[0119] In some embodiments, mRNAs include a 5 ' cap structure. A 5 ' cap is typically added as follows: first, an RNA terminal phosphatase removes one of the terminal phosphate groups from the 5 ' nucleotide, leaving two terminal phosphates; guanosine triphosphate (GTP) is then added to the terminal phosphates via a guanylyl transferase, producing a 5 '5 '5 triphosphate linkage; and the 7-nitrogen of guanine is then methylated by a methyltransferase. Examples of cap structures include, but are not limited to, m7G(5')ppp (5'(A,G(5')ppp(5')A and G(5')ppp(5')G. [0120] Naturally occurring cap structures comprise a 7-methyl guanosine that is linked via a triphosphate bridge to the 5 '-end of the first transcribed nucleotide, resulting in a dinucleotide cap of m⁷G(5')ppp(5')N, where N is any nucleoside. In vivo, the cap is added enzymatically. The cap is added in the nucleus and is catalyzed by the enzyme guanylyl transferase. The addition of the cap to the 5' terminal end of RNA occurs immediately after initiation of transcription. The terminal nucleoside is typically a guanosine, and is in the reverse orientation to all the other nucleotides, i.e., G(5')ppp(5')GpNpNp.

[0121] A common cap for mRNA produced by in vitro transcription is m⁷G(5')ppp(5')G, which has been used as the dinucleotide cap in transcription with T7 or SP6 RNA polymerase in vitro to obtain RNAs having a cap structure in their 5'-termini. The prevailing method for the in vitro synthesis of capped mRNA employs a pre-formed dinucleotide of the form

m⁷G(5')ppp(5')G ("m⁷GpppG") as an initiator of transcription.

[0122] To date, a usual form of a synthetic dinucleotide cap used in in vitro translation experiments is the Anti-Reverse Cap Analog ("ARCA") or modified ARCA, which is generally a modified cap analog in which the 2' or 3' OH group is replaced with -OCH3.

[0123] Additional cap analogs include, but are not limited to, a chemical structures selected from the group consisting of m⁷GpppG, m⁷GpppA, m⁷GpppC; unmethylated cap analogs (e.g., GpppG); dimethylated cap analog (e.g., m²'⁷GpppG), trimethylated cap analog

2 2 7 7 7

(e.g., m ' ' GpppG), dimethylated symmetrical cap analogs (e.g., m Gpppm G), or anti reverse cap analogs (e.g., ARCA; m⁷,^2'0meGpppG, m^72'dGpppG, m⁷'^3'0meGpppG, m⁷'^3'dGpppG and their tetraphosphate derivatives) (see, e.g., Jemielity, J. et al, "Novel 'anti-reverse ' cap analogs with superior translational properties^'" , RNA, 9: 1108-1122 (2003)).

[0124] In some embodiments, a suitable cap is a 7-methyl guanylate ("m⁷G") linked via a triphosphate bridge to the 5 '-end of the first transcribed nucleotide, resulting in m⁷G(5')ppp(5')N, where N is any nucleoside. A preferred embodiment of a m⁷G cap utilized in embodiments of the invention is m⁷G(5')ppp(5')G.

[0125] In some embodiments, the cap is a CapO structure. CapO structures lack a 2'-0- methyl residue of the ribose attached to bases 1 and 2. In some embodiments, the cap is a Capl structure. Ca l structures have a 2'-0-methyl residue at base 2. In some embodiments, the cap is a Cap2 structure. Cap2 structures have a 2'-0-methyl residue attached to both bases 2 and 3.

[0126] A variety of m⁷G cap analogs are known in the art, many of which are

commercially available. These include the m⁷GpppG described above, as well as the ARCA 3'- OCH₃ and 2^*-OCH₃ cap analogs (Jemielity, J. et al, RNA, 9: 1108-1122 (2003)). Additional cap analogs for use in embodiments of the invention include N7-benzylated dinucleoside tetraphosphate analogs (described in Grudzien, E. et al, RNA, 10: 1479-1487 (2004)), phosphorothioate cap analogs (described in Grudzien-Nogalska, E., et al, RNA, 13: 1745-1755 (2007)), and cap analogs (including biotinylated cap analogs) described in U.S. Patent Nos. 8,093,367 and 8,304,529, incorporated by reference herein.

Tail structure

[0127] Typically, the presence of a "tail" serves to protect the mRNA from exonuclease degradation. The poly A tail is thought to stabilize natural messengers and synthetic sense RNA. Therefore, in certain embodiments a long poly A tail can be added to an mRNA molecule thus rendering the RNA more stable. Poly A tails can be added using a variety of art-recognized techniques. For example, long poly A tails can be added to synthetic or in vitro transcribed RNA using poly A polymerase (Yokoe, et al. Nature Biotechnology. 1996; 14: 1252-1256). A transcription vector can also encode long poly A tails. In addition, poly A tails can be added by transcription directly from PCR products. Poly A may also be ligated to the 3' end of a sense RNA with RNA ligase (see, e.g., Molecular Cloning A Laboratory Manual, 2nd Ed., ed. by Sambrook, Fritsch and Maniatis (Cold Spring Harbor Laboratory Press: 1991 edition)).

[0128] In some embodiments, mRNAs include a 3' poly(A) tail structure. Typically, the length of the poly A tail can be at least about 10, 50, 100, 200, 300, 400 at least 500 nucleotides (SEQ ID NO: 11). In some embodiments, a poly- A tail on the 3' terminus of mRNA typically includes about 10 to 300 adenosine nucleotides (SEQ ID NO: 9) {e.g., about 10 to 200 adenosine nucleotides, about 10 to 150 adenosine nucleotides, about 10 to 100 adenosine nucleotides, about 20 to 70 adenosine nucleotides, or about 20 to 60 adenosine nucleotides). In some embodiments, mRNAs include a 3' poly(C) tail structure. A suitable poly-C tail on the 3' terminus of mRNA typically include about 10 to 200 cytosine nucleotides (SEQ ID NO: 10) (e.g., about 10 to 150 cytosine nucleotides, about 10 to 100 cytosine nucleotides, about 20 to 70 cytosine nucleotides, about 20 to 60 cytosine nucleotides, or about 10 to 40 cytosine nucleotides). The poly-C tail may be added to the poly-A tail or may substitute the poly-A tail.

[0129] In some embodiments, the length of the poly A or poly C tail is adjusted to control the stability of a modified sense mRNA molecule of the invention and, thus, the transcription of protein. For example, since the length of the poly A tail can influence the half- life of a sense mRNA molecule, the length of the poly A tail can be adjusted to modify the level of resistance of the mRNA to nucleases and thereby control the time course of polynucleotide expression and/or polypeptide production in a target cell.

5 ' and 3 ' Untranslated Region

[0130] In some embodiments, mRNAs include a 5 ' and/or 3 ' untranslated region. In some embodiments, a 5 ' untranslated region includes one or more elements that affect an mRNA's stability or translation, for example, an iron responsive element. In some

embodiments, a 5 ' untranslated region may be between about 50 and 500 nucleotides in length.

[0131] In some embodiments, a 3 ' untranslated region includes one or more of a polyadenylation signal, a binding site for proteins that affect an mRNA's stability of location in a cell, or one or more binding sites for miRNAs. In some embodiments, a 3 ' untranslated region may be between 50 and 500 nucleotides in length or longer.

[0132] Exemplary 3' and/or 5' UTR sequences can be derived from mRNA molecules which are stable (e.g., globin, actin, GAPDH, tubulin, histone, or citric acid cycle enzymes) to increase the stability of the sense mRNA molecule. For example, a 5 ' UTR sequence may include a partial sequence of a CMV immediate-early 1 (IE1) gene, or a fragment thereof to improve the nuclease resistance and/or improve the half-life of the polynucleotide. Also contemplated is the inclusion of a sequence encoding human growth hormone (hGH), or a fragment thereof to the 3 ' end or untranslated region of the polynucleotide (e.g., mRNA) to further stabilize the polynucleotide. Generally, these modifications improve the stability and/or pharmacokinetic properties (e.g., half-life) of the polynucleotide relative to their unmodified counterparts, and include, for example modifications made to improve such polynucleotides' resistance to in vivo nuclease digestion.

Formation of Liposomes

[0133] The liposomal transfer vehicles for use in the present invention can be prepared by various techniques which are presently known in the art. The liposomes for use in provided compositions can be prepared by various techniques which are presently known in the art. For example, multilamellar vesicles (MLV) may be prepared according to conventional techniques, such as by depositing a selected lipid on the inside wall of a suitable container or vessel by dissolving the lipid in an appropriate solvent, and then evaporating the solvent to leave a thin film on the inside of the vessel or by spray drying. An aqueous phase may then added to the vessel with a vortexing motion which results in the formation of MLVs. Uni-lamellar vesicles (ULV) can then be formed by homogenization, sonication or extrusion of the multi-lamellar vesicles. In addition, unilamellar vesicles can be formed by detergent removal techniques.

[0134] In certain embodiments, provided compositions comprise a liposome wherein the mR A is associated on both the surface of the liposome and encapsulated within the same liposome. For example, during preparation of the compositions of the present invention, cationic liposomes may associate with the mRNA through electrostatic interactions.

[0135] In some embodiments, the compositions and methods of the invention comprise mRNA encapsulated in a liposome. In some embodiments, the one or more mRNA species may be encapsulated in the same liposome. In some embodiments, the one or more mRNA species may be encapsulated in different liposomes. In some embodiments, the mRNA is encapsulated in one or more liposomes, which differ in their lipid composition, molar ratio of lipid

components, size, charge (Zeta potential), targeting ligands and/or combinations thereof. In some embodiments, the one or more liposome may have a different composition of cationic lipids, neutral lipid, PEG-modified lipid and/or combinations thereof. In some embodiments the one or more lipisomes may have a different molar ratio of cationic lipid, neutral lipid, cholesterol and PEG-modified lipid used to create the liposome. [0136] The process of incorporation of a desired mRNA into a liposome is often referred to as "loading". Exemplary methods are described in Lasic, et al, FEBS Lett., 312: 255-258, 1992, which is incorporated herein by reference. The liposome -incorporated nucleic acids may be completely or partially located in the interior space of the liposome, within the bilayer membrane of the liposome, or associated with the exterior surface of the liposome membrane. The incorporation of a nucleic acid into liposomes is also referred to herein as "encapsulation" wherein the nucleic acid is entirely contained within the interior space of the liposome. The purpose of incorporating a mRNA into a transfer vehicle, such as a liposome, is often to protect the nucleic acid from an environment which may contain enzymes or chemicals that degrade nucleic acids and/or systems or receptors that cause the rapid excretion of the nucleic acids. Accordingly, in some embodiments, a suitable delivery vehicle is capable of enhancing the stability of the mRNA contained therein and/or facilitate the delivery of mRNA to the target cell or tissue.

Liposome Size

[0137] Suitable liposomes in accordance with the present invention may be made in various sizes. In some embodiments, provided liposomes may be made smaller than previously known mRNA encapsulating liposomes. In some embodiments, decreased size of liposomes is associated with more efficient delivery of mRNA. Selection of an appropriate liposome size may take into consideration the site of the target cell or tissue and to some extent the application for which the liposome is being made.

[0138] In some embodiments, an appropriate size of liposome is selected to facilitate systemic distribution of PKU protein encoded by the mRNA. In some embodiments, it may be desirable to limit transfection of the mRNA to certain cells or tissues. For example, to target hepatocytes a liposome may be sized such that its dimensions are smaller than the fenestrations of the endothelial layer lining hepatic sinusoids in the liver; in such cases the liposome could readily penetrate such endothelial fenestrations to reach the target hepatocytes.

[0139] Alternatively or additionally, a liposome may be sized such that the dimensions of the liposome are of a sufficient diameter to limit or expressly avoid distribution into certain cells or tissues. For example, a liposome may be sized such that its dimensions are larger than the fenestrations of the endothelial layer lining hepatic sinusoids to thereby limit distribution of the liposomes to hepatocytes.

[0140] In some embodiments, the size of a liposome is determined by the length of the largest diameter of the lipososme particle. In some embodiments, a suitable liposome has a size no greater than about 250 nm (e.g., no greater than about 225 nm, 200 nm, 175 nm, 150 nm, 125 nm, 100 nm, 75 nm, or 50 nm). In some embodiments, a suitable liposome has a size ranging from about 10 - 250 nm (e.g., ranging from about 10 - 225 nm, 10 - 200 nm, 10 - 175 nm, 10 - 150 nm, 10 - 125 nm, 10 - 100 nm, 10 - 75 nm, or 10 - 50 nm). In some embodiments, a suitable liposome has a size ranging from about 100 - 250 nm (e.g., ranging from about 100— 225 nm, 100 - 200 nm, 100 - 175 nm, 100 - 150 nm). In some embodiments, a suitable liposome has a size ranging from about 10 - 100 nm (e.g., ranging from about 10 - 90 nm, 10 - 80 nm, 10 - 70 nm, 10 - 60 nm, or 10 - 5 nm).

[0141] A variety of alternative methods known in the art are available for sizing of a population of liposomes. One such sizing method is described in U.S. Pat. No. 4,737,323, incorporated herein by reference. Sonicating a liposome suspension either by bath or probe sonication produces a progressive size reduction down to small ULV less than about 0.05 microns in diameter. Homogenization is another method that relies on shearing energy to fragment large liposomes into smaller ones. In a typical homogenization procedure, MLV are recirculated through a standard emulsion homogenizer until selected liposome sizes, typically between about 0.1 and 0.5 microns, are observed. The size of the liposomes may be determined by quasi-electric light scattering (QELS) as described in Bloomfield, Ann. Rev. Biophys.

Bioeng., 10:421-150 (1981), incorporated herein by reference. Average liposome diameter may be reduced by sonication of formed liposomes. Intermittent sonication cycles may be alternated with QELS assessment to guide efficient liposome synthesis.

Pharmaceutical Compositions

[0142] To facilitate expression of mRNA in vivo, delivery vehicles such as liposomes can be formulated in combination with one or more additional nucleic acids, carriers, targeting ligands or stabilizing reagents, or in pharmacological compositions where it is mixed with suitable excipients. Techniques for formulation and administration of drugs may be found in "Remington's Pharmaceutical Sciences," Mack Publishing Co., Easton, Pa., latest edition.

[0143] Provided liposomally-encapsulated or associated mRNAs, and compositions containing the same, may be administered and dosed in accordance with current medical practice, taking into account the clinical condition of the subject, the site and method of administration, the scheduling of administration, the subject's age, sex, body weight and other factors relevant to clinicians of ordinary skill in the art. The "effective amount" for the purposes herein may be determined by such relevant considerations as are known to those of ordinary skill in experimental clinical research, pharmacological, clinical and medical arts. In some

embodiments, the amount administered is effective to achieve at least some stabilization, improvement or elimination of symptoms and other indicators as are selected as appropriate measures of disease progress, regression or improvement by those of skill in the art. For example, a suitable amount and dosing regimen is one that causes at least transient protein (e.g. , enzyme) production.

[0144] Suitable routes of administration include, for example, oral, rectal, vaginal, transmucosal, pulmonary including intratracheal or inhaled, or intestinal administration;

parenteral delivery, including intradermal, transdermal (topical), intramuscular, subcutaneous, intramedullary injections, as well as intrathecal, direct intraventricular, intravenous,

intraperitoneal, or intranasal.

[0145] Alternately or additionally, liposomally encapsulated mRNAs and compositions of the invention may be administered in a local rather than systemic manner, for example, via injection of the pharmaceutical composition directly into a targeted tissue, preferably in a sustained release formulation. Local delivery can be affected in various ways, depending on the tissue to be targeted. For example, aerosols containing compositions of the present invention can be inhaled (for nasal, tracheal, or bronchial delivery); compositions of the present invention can be injected into the site of injury, disease manifestation, or pain, for example; compositions can be provided in lozenges for oral, tracheal, or esophageal application; can be supplied in liquid, tablet or capsule form for administration to the stomach or intestines, can be supplied in suppository form for rectal or vaginal application; or can even be delivered to the eye by use of creams, drops, or even injection. Formulations containing provided compositions complexed with therapeutic molecules or ligands can even be surgically administered, for example in association with a polymer or other structure or substance that can allow the compositions to diffuse from the site of implantation to surrounding cells. Alternatively, they can be applied surgically without the use of polymers or supports.

[0146] Provided methods of the present invention contemplate single as well as multiple administrations of a therapeutically effective amount of the therapeutic agents (e.g. , mR A encoding a PAH protein) described herein. Therapeutic agents can be administered at regular intervals, depending on the nature, severity and extent of the subject's condition (e.g., PKU). In some embodiments, a therapeutically effective amount of the therapeutic agents (e.g., mRNA encoding a PAH protein) of the present invention may be administered intrathecally periodically at regular intervals (e.g., once every year, once every six months, once every five months, once every three months, bimonthly (e.g., once every two months), monthly (e.g., once every month), biweekly (e.g., once every two weeks, every other week), weekly, daily or continuously)

[0147] In some embodiments, provided liposomes and/or compositions are formulated such that they are suitable for extended-release of the mRNA contained therein. Such extended- release compositions may be conveniently administered to a subject at extended dosing intervals. For example, in one embodiment, the compositions of the present invention are administered to a subject twice day, daily or every other day. In a preferred embodiment, the compositions of the present invention are administered to a subject twice a week, once a week, every 7 days, every 10 days, every 14 days, every 28 days, every 30 days, every two weeks (e.g., every other week), every three weeks, or more preferably every four weeks, once a month, every six weeks, every eight weeks, every other month, every three months, every four months, every six months, every eight months, every nine months or annually. Also contemplated are compositions and liposomes which are formulated for depot administration (e.g. , intramuscularly, subcutaneously) to either deliver or release a mRNA over extended periods of time. Preferably, the extended-release means employed are combined with modifications made to the mRNA to enhance stability

[0148] As used herein, the term "therapeutically effective amount" is largely determined based on the total amount of the therapeutic agent contained in the pharmaceutical compositions of the present invention. Generally, a therapeutically effective amount is sufficient to achieve a meaningful benefit to the subject (e.g., treating, modulating, curing, preventing and/or ameliorating PKU). For example, a therapeutically effective amount may be an amount sufficient to achieve a desired therapeutic and/or prophylactic effect. Generally, the amount of a therapeutic agent (e.g., mR A encoding a PAH protein) administered to a subject in need thereof will depend upon the characteristics of the subject. Such characteristics include the condition, disease severity, general health, age, sex and body weight of the subject. One of ordinary skill in the art will be readily able to determine appropriate dosages depending on these and other related factors. In addition, both objective and subjective assays may optionally be employed to identify optimal dosage ranges.

[0149] A therapeutically effective amount is commonly administered in a dosing regimen that may comprise multiple unit doses. For any particular therapeutic protein, a therapeutically effective amount (and/or an appropriate unit dose within an effective dosing regimen) may vary, for example, depending on route of administration, on combination with other pharmaceutical agents. Also, the specific therapeutically effective amount (and/or unit dose) for any particular patient may depend upon a variety of factors including the disorder being treated and the severity of the disorder; the activity of the specific pharmaceutical agent employed; the specific composition employed; the age, body weight, general health, sex and diet of the patient; the time of administration, route of administration, and/or rate of excretion or metabolism of the specific protein employed; the duration of the treatment; and like factors as is well known in the medical arts.

[0150] According to the present invention, a therapeutically effective dose of the provided composition, when administered regularly, results in increased expression of hepatic PAH protein as compared to baseline levels before treament. In some embodiments,

administering the provided composition results in the expression of a PAH protein level at or above about 100 ng/mg, about 200 ng/mg, about 300 ng/mg, about 400 ng/mg, about 500 ng/mg, about 600 ng/mg, about 700 ng/mg, about 800 ng/mg, about 900 ng/mg, about 1000 ng/mg, about 1200 ng/mg or about 1400 ng/mg of total protein in the liver.

[0151] In some embodiments, administering provided compositions results in increased serum PAH protein levels. In some embodiments, administering provided compositions results in increased serum PAH protein levels by at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% as compared to baseline PAH protein level before treatment. Typically, baseline PAH protein level in serum is measured immediately before treatment.

[0152] In some embodiments, administering the provided composition results in reduced phenylalanine levels in a biological sample. Suitable biological samples include, for example, whole blood, plasma, serum, urine or cerebral spinal fluid. In some embodiments, administering the provided composition results in reduction of phenylalanine levels in a biological sample (e.g., a serum, plasma or urine sample) by at least about 5%, at least about 10%>, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%), at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, or at least about 95% as compared to baseline level before treatment. Typically, baseline phenylalanine level is measured immediately before treatment.

[0153] In some embodiments, a therapeutically effective dose of the provided

composition, when administered regularly, results in a reduced phenylalanine level in serum or plasma as compared to the baseline phenylalanine level immediately before treatment. In some embodiments, a therapeutically effective dose of the provided composition, when administered regularly, results in a reduced phenylalanine level in serum or plasma as compared to the baseline phenylalanine level in subjects who are not treated. In some embodiments, a

therapeutically effective dose of the provided composition, when administered regularly, results in reduction of phenylalanine levels to about 1500 μιηοΙ/L or less, about 1000 μιηοΙ/L or less, about 900 μιηοΙ/L or less, about 800 μιηοΙ/L or less, about 700 μιηοΙ/L or less, about 600 μιηοΙ/L or less, about 500 μιηοΙ/L or less, about 400 μιηοΙ/L or less, about 300 μιηοΙ/L or less, about 200 μιηοΙ/L or less, about 100 μιηοΙ/L or less, or about 50 μιηοΙ/L in serum or plasma. In a particular embodiment, a therapeutically effective dose, when administered regularly results in reduction of phenylalanine levels to about 120 μιηοΙ/L or less in serum or plasma.

[0154] In some embodiments, administering the provided composition results in reduced levels of phenylalanine and or metabolites of phenylalanine (e.g., phenylketone, phenylpyruvate) in the urine.

[0155] In some embodiments, one or more neuropsychiatric tests may be used to determine a therapeutically effective dose. In some embodiments, an improvement on one or more neuropsychiatric tests of at least 10%, 20%, 30%>, 40%> or 50%> as compared to either the individual before treatment, or an untreated control individual, indicates that a particular dose is a therapeutically effective amount. In some embodiments, a suitable neuropsychiatric test may be the Inattentive portion of the Attention Deficit and Hyperactivity Disorder Rating Scale (ADHD-RS) and/or the Profile of Mood States (POMS).

[0156] In some embodiments, the therapeutically effective dose ranges from about 0.005 to 500 mg/kg body weight, e.g., from about 0.005 to 400 mg/kg body weight, from about 0.005 to 300 mg/kg body weight, from about 0.005 to 200 mg/kg body weight, from about 0.005 to 100 mg/kg body weight, from about 0.005 to 90 mg/kg body weight, from about 0.005 to 80 mg/kg body weight, from about 0.005 to 70 mg/kg body weight, from about 0.005 to 60 mg/kg body weight, from about 0.005 to 50 mg/kg body weight, from about 0.005 to 40 mg/kg body weight, from about 0.005 to 30 mg/kg body weight, from about 0.005 to 25 mg/kg body weight, from about 0.005 to 20 mg/kg body weight, from about 0.005 to 15 mg/kg body weight, from about 0.005 to 10 mg/kg body weight. In some embodiments, the mRNA is administered at a dose ranging from about 0.1 - 5.0 mg /kg body weight, for example about 0.1 - 4.5, 0.1 - 4.0, 0.1 - 3.5, 0.1 - 3.0, 0.1 - 2.5, 0.1 - 2.0, 0.1 - 1.5, 0.1 - 1.0, 0.1 - 0.5, 0.1 - 0.3, 0.3 - 5.0, 0.3 - 4.5, 0.3 - 4.0, 0.3 - 3.5, 0.3 - 3.0, 0.3 - 2.5, 0.3 - 2.0, 0.3 - 1.5, 0.3 - 1.0, 0.3 - 0.5, 0.5 - 5.0, 0.5 - 4.5, 0.5 - 4.0, 0.5 - 3.5, 0.5 - 3.0, 0.5 - 2.5, 0.5 - 2.0, 0.5 - 1.5, or 0.5 - 1.0 mg/kg body weight.

[0157] In some embodiments, the therapeutically effective dose is or greater than about

0.1 mg/kg body weight, about 0.5 mg/kg body weight, about 1.0 mg/kg body weight, about 3 mg/kg body weight, about 5 mg/kg body weight, about 10 mg/kg body weight, about 15 mg/kg body weight, about 20 mg/kg body weight, about 30 mg/kg body weight, about 40 mg/kg body weight, about 50 mg/kg body weight, about 60 mg/kg body weight, about 70 mg/kg body weight, about 80 mg/kg body weight, about 90 mg/kg body weight, about 100 mg/kg body weight, about 150 mg/kg body weight, about 200 mg/kg body weight, about 250 mg/kg body weight, about 300 mg/kg body weight, about 350 mg/kg body weight, about 400 mg/kg body weight, about 450 mg/kg body weight, or about 500 mg/kg body weight. In some embodiments, the therapeutically effective dose is administered at a dose of or less than about 5.0, 4.5, 4.0, 3.5, 3.0, 2.5, 2.0, 1.5, 1.0, 0.8, 0.6, 0.5, 0.4, 0.3, 0.2, or 0.1 mg/kg body weight. [0158] Also contemplated herein are lyophilized pharmaceutical compositions comprising one or more of the liposomes disclosed herein and related methods for the use of such compositions as disclosed for example, in United States Provisional Application No.

61/494,882, filed June 8, 2011, the teachings of which are incorporated herein by reference in their entirety. For example, lyophilized pharmaceutical compositions according to the invention may be reconstituted prior to administration or can be reconstituted in vivo. For example, a lyophilized pharmaceutical composition can be formulated in an appropriate dosage form (e.g., an intradermal dosage form such as a disk, rod or membrane) and administered such that the dosage form is rehydrated over time in vivo by the individual's bodily fluids.

[0159] Provided liposomes and compositions may be administered to any desired tissue.

In some embodiments, the mRNA delivered by provided liposomes or compositions is expressed in the tissue in which the liposomes and/or compositions were administered. In some

embodiments, the mRNA delivered is expressed in a tissue different from the tissue in which the liposomes and/or compositions were administered Exemplary tissues in which delivered mRNA may be delivered and/or expressed include, but are not limited to the liver, kidney, heart, spleen, serum, brain, skeletal muscle, lymph nodes, skin, and/or cerebrospinal fluid.

[0160] According to various embodiments, the timing of expression of delivered mRNAs can be tuned to suit a particular medical need. In some embodiments, the expression of the PAH protein encoded by delivered mRNA is detectable 1, 2, 3, 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, and/or 72 hours in serum or target tissues after a single administration of provided liposomes or compositions. In some embodiments, the expression of the PAH protein encoded by the mRNA is detectable 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, and/or 7 days in serum or target tissues after a single administration of provided liposomes or compositions. In some embodiments, the expression of the PAH protein encoded by the mRNA is detectable 1 week, 2 weeks, 3 weeks, and/or 4 weeks in serum or target tissues after a single administration of provided liposomes or compositions. In some embodiments, the expression of the protein encoded by the mRNA is detectable after a month or longer after a single administration of provided liposomes or compositions. EXAMPLES

[0161] While certain compounds, compositions and methods of the present invention have been described with specificity in accordance with certain embodiments, the following examples serve only to illustrate the compounds of the invention and are not intended to limit the same.

Example 1. Exemplary Liposome Formulations for hP AH mRNA Delivery and Expression

[0162] This example provides exemplary liposome formulations for effective delivery and expression of hPAH mRNA in vivo.

Lipid Materials

[0163] The formulations described in the following Examples, unless otherwise specified, contain a multi-component lipid mixture of varying ratios employing one or more cationic lipids, helper lipids (e.g., non-cationic lipids and/or cholesterol lipids) and PEGylated lipids designed to encapsulate phenylalanine hydroxylase (PAH) mRNA. Unless otherwise specified, the multi-component lipid mixture used in the following Examples were ethanolic solutions of cKK-E12 (cationic lipid), DOPE (non-cationic lipid), cholesterol and DMG-PEG2K.

Messenger RNA Material

[0164] Codon-optimized human phenylalanine hydroxylase (PAH) messenger RNA was synthesized by in vitro transcription from a plasmid DNA template encoding the gene, which was followed by the addition of a 5' cap structure (Cap 1) (Fechter, P.; Brownlee, G.G.

"Recognition of mRNA cap structures by viral and cellular proteins" J. Gen. Virology 2005, 86, 1239-1249) and a 3' poly(A) tail of approximately 250 nucleotides in length (SEQ ID NO: 12) as determined by gel electrophoresis. 5' and 3' untranslated regions present in each mRNA product are represented as X and Y, respectively, and defined as stated (vide infra).

Codon-Optimized Human Phenylalanine Hydroxylase (PAH) mRNA:

X - SEQ ID NO:3 - Y

5 ' and 3 ' UTR Sequences

X (5' UTR Sequence) = GGACAGAUCGCCUGGAGACGCCAUCCACGCUGUUUUGACCUCCAUAGAAGACACC GGGACCGAUCCAGCCUCCGCGGCCGGGAACGGUGCAUUGGAACGCGGAUUCCCCG UGCCAAGAGUGACUCACCGUCCUUGACACG [SEQ ID NO.:4]

Y (3' UTR Sequence) =

GGGUGGCAUCCCUGUGACCCCUCCCCAGUGCCUCUCCUGGCCCUGGAAGUUGCCA CUCCAGUGCCCACCAGCCUUGUCCUAAUAAAAUUAAGUUGCAUCAAAGCU [SEQ ID NO.:5]

OR

CGGGUGGCAUCCCUGUGACCCCUCCCCAGUGCCUCUCCUGGCCCUGGAAGUUGCC ACUCCAGUGCCCACCAGCCUUGUCCUAAUAAAAUUAAGUUGCAUCAAGCU (SEQ ID NO.:6)

[0165] For example, the codon-optimized human PAH messenger RNA comprised:

GGACAGAUCGCCUGGAGACGCCAUCCACGCUGUUUUGACCUCCAUAGAAGACACC

GGGACCGAUCCAGCCUCCGCGGCCGGGAACGGUGCAUUGGAACGCGGAUUCCCCG

UGC C AAG AGUG ACUC AC CGUC CUUG AC AC G AUG AGC AC CGC CGUGCUGG AG AAC C

CCGGCCUGGGCCGCAAGCUGAGCGACUUCGGCCAGGAGACCAGCUACAUCGAGGA

CAACUGCAACCAGAACGGCGCCAUCAGCCUGAUCUUCAGCCUGAAGGAGGAGGUG

GGCGCCCUGGCCAAGGUGCUGCGCCUGUUCGAGGAGAACGACGUGAACCUGACCC

ACAUCGAGAGCCGCCCCAGCCGCCUGAAGAAGGACGAGUACGAGUUCUUCACCCA

CCUGGACAAGCGCAGCCUGCCCGCCCUGACCAACAUCAUCAAGAUCCUGCGCCAC

GACAUCGGCGCCACCGUGCACGAGCUGAGCCGCGACAAGAAGAAGGACACCGUGC

CCUGGUUCCCCCGCACCAUCCAGGAGCUGGACCGCUUCGCCAACCAGAUCCUGAG

CUACGGCGCCGAGCUGGACGCCGACCACCCCGGCUUCAAGGACCCCGUGUACCGC

GCCCGCCGCAAGCAGUUCGCCGACAUCGCCUACAACUACCGCCACGGCCAGCCCA

UCCCCCGCGUGGAGUACAUGGAGGAGGAGAAGAAGACCUGGGGCACCGUGUUCA

AGACCCUGAAGAGCCUGUACAAGACCCACGCCUGCUACGAGUACAACCACAUCUU

CCCCCUGCUGGAGAAGUACUGCGGCUUCCACGAGGACAACAUCCCCCAGCUGGAG

GACGUGAGCCAGUUCCUGCAGACCUGCACCGGCUUCCGCCUGCGCCCCGUGGCCG

GCCUGCUGAGCAGCCGCGACUUCCUGGGCGGCCUGGCCUUCCGCGUGUUCCACUG

CACCCAGUACAUCCGCCACGGCAGCAAGCCCAUGUACACCCCCGAGCCCGACAUC

UGCCACGAGCUGCUGGGCCACGUGCCCCUGUUCAGCGACCGCAGCUUCGCCCAGU

UCAGCCAGGAGAUCGGCCUGGCCAGCCUGGGCGCCCCCGACGAGUACAUCGAGAA

GCUGGCCACCAUCUACUGGUUCACCGUGGAGUUCGGCCUGUGCAAGCAGGGCGAC

AGCAUCAAGGCCUACGGCGCCGGCCUGCUGAGCAGCUUCGGCGAGCUGCAGUACU

GCCUGAGCGAGAAGCCCAAGCUGCUGCCCCUGGAGCUGGAGAAGACCGCCAUCCA

GAACUACACCGUGACCGAGUUCCAGCCCCUGUACUACGUGGCCGAGAGCUUCAAC

GACGCCAAGGAGAAGGUGCGCAACUUCGCCGCCACCAUCCCCCGCCCCUUCAGCG

UGCGCUACGACCCCUACACCCAGCGCAUCGAGGUGCUGGACAACACCCAGCAGCU

GAAGAUCCUGGCCGACAGCAUCAACAGCGAGAUCGGCAUCCUGUGCAGCGCCCUG

CAGAAGAUCAAGUAAGGGUGGCAUCCCUGUGACCCCUCCCCAGUGCCUCUCCUGG CCCUGGAAGUUGCCACUCCAGUGCCCACCAGCCUUGUCCUAAUAAAAUUAAGUUG CAUCAAAGCU (SEQ ID NO:7)

[0166] In another example, the codon-optimized human PAH messenger RNA comprised:

GGACAGAUCGCCUGGAGACGCCAUCCACGCUGUUUUGACCUCCAUAGAAGACACC

GGGACCGAUCCAGCCUCCGCGGCCGGGAACGGUGCAUUGGAACGCGGAUUCCCCG

UGC C AAG AGUG ACUC AC CGUC CUUG AC AC G AUG AGC AC CGC CGUGCUGG AG AAC C

CCGGCCUGGGCCGCAAGCUGAGCGACUUCGGCCAGGAGACCAGCUACAUCGAGGA

CAACUGCAACCAGAACGGCGCCAUCAGCCUGAUCUUCAGCCUGAAGGAGGAGGUG

GGCGCCCUGGCCAAGGUGCUGCGCCUGUUCGAGGAGAACGACGUGAACCUGACCC

ACAUCGAGAGCCGCCCCAGCCGCCUGAAGAAGGACGAGUACGAGUUCUUCACCCA

CCUGGACAAGCGCAGCCUGCCCGCCCUGACCAACAUCAUCAAGAUCCUGCGCCAC

GACAUCGGCGCCACCGUGCACGAGCUGAGCCGCGACAAGAAGAAGGACACCGUGC

CCUGGUUCCCCCGCACCAUCCAGGAGCUGGACCGCUUCGCCAACCAGAUCCUGAG

CUACGGCGCCGAGCUGGACGCCGACCACCCCGGCUUCAAGGACCCCGUGUACCGC

GCCCGCCGCAAGCAGUUCGCCGACAUCGCCUACAACUACCGCCACGGCCAGCCCA

UCCCCCGCGUGGAGUACAUGGAGGAGGAGAAGAAGACCUGGGGCACCGUGUUCA

AGACCCUGAAGAGCCUGUACAAGACCCACGCCUGCUACGAGUACAACCACAUCUU

CCCCCUGCUGGAGAAGUACUGCGGCUUCCACGAGGACAACAUCCCCCAGCUGGAG

GACGUGAGCCAGUUCCUGCAGACCUGCACCGGCUUCCGCCUGCGCCCCGUGGCCG

GCCUGCUGAGCAGCCGCGACUUCCUGGGCGGCCUGGCCUUCCGCGUGUUCCACUG

CACCCAGUACAUCCGCCACGGCAGCAAGCCCAUGUACACCCCCGAGCCCGACAUC

UGCCACGAGCUGCUGGGCCACGUGCCCCUGUUCAGCGACCGCAGCUUCGCCCAGU

UCAGCCAGGAGAUCGGCCUGGCCAGCCUGGGCGCCCCCGACGAGUACAUCGAGAA

GCUGGCCACCAUCUACUGGUUCACCGUGGAGUUCGGCCUGUGCAAGCAGGGCGAC

AGCAUCAAGGCCUACGGCGCCGGCCUGCUGAGCAGCUUCGGCGAGCUGCAGUACU

GCCUGAGCGAGAAGCCCAAGCUGCUGCCCCUGGAGCUGGAGAAGACCGCCAUCCA

GAACUACACCGUGACCGAGUUCCAGCCCCUGUACUACGUGGCCGAGAGCUUCAAC

GACGCCAAGGAGAAGGUGCGCAACUUCGCCGCCACCAUCCCCCGCCCCUUCAGCG

UGCGCUACGACCCCUACACCCAGCGCAUCGAGGUGCUGGACAACACCCAGCAGCU

GAAGAUCCUGGCCGACAGCAUCAACAGCGAGAUCGGCAUCCUGUGCAGCGCCCUG

CAGAAGAUCAAGUAACGGGUGGCAUCCCUGUGACCCCUCCCCAGUGCCUCUCCUG

GCCCUGGAAGUUGCCACUCCAGUGCCCACCAGCCUUGUCCUAAUAAAAUUAAGUU

GCAUCAAGCU (SEQ ID NO: 8)

[0167] Synthetic codon-optimized human PAH mRNA was transfected into HEK293T cells and analyzed 24 hours later. Upon cell lysis and processing, human PAH was successfully detected via western blot analysis (see Figure 1).

Formulation Protocol

[0168] Aliquots of 50 mg/mL ethanolic solutions of cK -E12, DOPE, cholesterol and

DMG-PEG2K were mixed and diluted with ethanol to 3 mL final volume. Separately, an aqueous buffered solution (10 mM citrate/150 mM NaCl, pH 4.5) of PAH mRNA was prepared from a 1 mg/mL stock. The lipid solution was injected rapidly into the aqueous mRNA solution and shaken to yield a final suspension in 20% ethanol. The resulting nanoparticle suspension was filtered, diafiltrated with lx PBS (pH 7.4), concentrated and stored at 2-8°C. Final concentration = 1.28 mg/mL PAH mRNA (encapsulated). Z_ave = 79 nm; PDI = 0.12.

Example 2. Administration of hPAH mRNA-loaded Liposome Nanoparticles

[0169] This example illustrates exemplary methods of administering hPAH mRNA- loaded liposome nanoparticles and methods for analyzing delivered mRNA and subsequently expressed hPAH protein in various target tissues in vivo.

[0170] All studies were performed using male CD-I mice or PAH knockout mice of approximately 6-8 weeks of age at the beginning of each experiment. Samples were introduced by a single bolus tail-vein injection of an equivalent total dose of 1.0 mg/kg (or otherwise specified) of encapsulated PAH mRNA. Mice were sacrificed and perfused with saline at the designated time points.

Isolation of organ tissues for analysis

[0171] The liver, spleen, kidney and heart of each mouse was harvested, apportioned into separate parts, and stored in either 10% neutral buffered formalin or snap-frozen and stored at - 80°C for analysis.

Isolation of plasma for analysis

[0172] All animals were euthanized by C0₂ asphyxiation at designated time points post dose administration (± 5%) followed by thoracotomy and terminal cardiac blood collection. Whole blood (maximal obtainable volume) was collected via cardiac puncture on euthanized animals into serum separator tubes, allowed to clot at room temperature for at least 30 minutes, centrifuged at 22°C ± 5°C at 9300 g for 10 minutes, and the serum was extracted. For interim blood collections, approximately 40-50μί of whole blood was collected via facial vein puncture or tail snip. Samples collected from non-treatment animals were used as baseline phenylalanine levels for comparison to study animals. Phenylalanine Analysis

[0173] Phenylalanine levels were measured using a commercially available kit

(BioAssay Systems EPHE-100) and by following the manufacturer's protocol.

Enzyme-Linked Immunosorbent Assay (ELISA) Analysis - hPAH ELISA

[0174] Standard ELISA procedures were followed employing goat polyclonal anti-hPAH antibody (Novus NBP 1-52084) as the capture antibody with rabbit anti-hPAH polyclonal antibody (Sigma (HPA02807) as the secondary (detection) antibody. Horseradish peroxidase (HRP)-conjugated goat anti-rabbit IgG was used for activation of the 3,3',5,5'- tetramethylbenzidine (TMB) substrate solution. The reaction was quenched using 2N H₂SO₄ after 20 minutes. Detection was monitored via absorption (450 nm) on a Molecular Device Flex Station instrument. Untreated mouse liver and human hPAH protein were used as negative and positive controls, respectively.

Example 3. In vivo protein production and clinical efficacy

[0175] This example demonstrates that administration of hPAH mR A results in successful protein production and clinical efficacy in vivo.

[0176] In order to determine if delivered mRNA was successfully translated into protein in vivo, quantification of human PAH protein detected in treated mouse livers was achieved via ELISA-based methods (Figure 2). Figure 3 further shows that a clear production of human PAH protein was observed with no cross reactivity with the mouse homolog as confirmed via untreated wild type mouse livers. Between 6 and 12 hours after administration, approximately 300 ng of hPAH protein was detected per mg of total protein in a sample (see Figure 3).

[0177] To determine clinical efficacy, we evaluate the effect of mRNA delivery in serum phenylalanine levels in PAH knockout mice, a PKU disease model. Phenylalanine levels in untreated PAH knockout mice were extremely elevated as compared to wild type mice (-1450 uM vs -50 uM). As shown in Figure 4, upon treatment of these knockout mice with PAH mRNA, phenylalanine levels were brought down to wild type levels within six hours of dosing. This data demonstrate that hPAH mRNA therapy is highly effective in treating PKU. Example 4. Detection of hPAH mRNA in vivo

[0178] This example demonstrates that following administration of hPAH mRNA, the

PAH mRNA is detectable in the liver of mice for at least 72 hours.

[0179] Mice were administered a single dose (1.0 mg/kg) of hPAH mRNA-loaded cK -

E12-based lipid nanoparticles, or saline (i.e., control) as described above in Example 2. Mice were sacrificed 30 minutes, 3 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours and 7 days following administration of the hPAH mRNA and the livers were collected. In situ hybridization of the livers was performed to detect the presence of the hPAH mRNA (Figures 5A-5I). The presence of hPAH mRNA was observable for at least 72 hours post-administration (Figures 5 A- 5G). The hPAH mRNA was detectable in sinusoidal cells as well as in hepatocytes. These data demonstrate that hPAH mRNA can be detected in the liver for at least 72 hours post- administration.

Example 5. Human PAH protein levels and serum phenylalanine levels in PAH knockout mice after dose response treatment with hPAH mRNA

[0180] This example demonstrates a dose response between the amount of hPAH mRNA administered and the amount of both human PAH protein expressed in the liver and serum phenylalanine levels.

[0181] PAH knockout mice were administered a single dose of 0.25 mg/kg, 0.50 mg/kg,

0.75 mg/kg or 1.0 mg/kg of hPAH mRNA-loaded cK -E12-based lipid nanoparticles or saline (i.e., control) as described above in Example 2. A serum sample was collected from the mice prior to the dose (i.e., pre-dose) and 6 hours after the dose (i.e., post-dose). Mice were sacrificed 6 hours post-administration and the livers were collected.

[0182] Human PAH protein levels in the livers were measured by ELISA. These data demonstrate that at all doses, increased levels of hPAH protein were detected relative to the control (Figure 6). These data also demonstrate a dose response between the amount of hPAH mRNA administered and the amount of PAH protein expressed in the liver. For example, mice administered 1.0 mg/kg of hPAH mRNA expressed approximately 1000 ng of PAH/mg of total protein while mice administered 0.25 mg/kg of hPAH mRNA expressed approximately 200 ng of PAH/mg of total protein.

[0183] The serum level of phenylalanine was quantified in the pre- and post- treatment samples (Figure 7). These data demonstrate a reduction in serum phenylalanine at all treatment doses relative to the pre-dose control, as well as a dose response. For example, mice

administered 1.0 mg/kg of hPAH mRNA demonstrated lower levels of phenylalanine (i.e., less than 500 μΜ) than those administered 0.25 mg/kg (i.e., less than 1500 μΜ).

Example 6. Human PAH protein and serum phenylalanine levels in PAH knockout mice after treatment with hPAH mRNA for one month

[0184] This example demonstrates that treatment with hPAH mRNA over one month results in increased levels of hPAH protein in the liver and decreased levels of serum

phenylalanine.

[0185] PAH knockout mice were administered a single dose of 0. 5 mg/kg or 1.0 mg/kg of hPAH mRNA- loaded cK -E12-based lipid nanoparticles once per week for one month or 1.0 mg/kg of hPAH mRNA- loaded cK -E12-based lipid nanoparticles once every other week for one month, or saline (i.e., control) as described above in Example 2. Serum was collected from the mice prior to the first dose (i.e., pre-dose) and six hours after each dose. Mice were sacrificed 6 hours after administration of the final dose on day 29 and the livers were collected.

[0186] Human PAH protein levels in the liver were measured by ELISA. These data demonstrate that at all doses, increased levels of hPAH protein were detected relative to the control (Figure 8).

[0187] The serum level of phenylalanine was quantified in the pre- and post- treatment samples (Figure 9). These data demonstrate a reduction in serum phenylalanine at all treatment doses relative to the pre-dose control sample. These data also demonstrate that the higher dose (i.e., 1.0 mg/kg) resulted in lower levels of serum phenylalanine, even when the hPAH mRNA was administered every other week. EQUIVALENTS

[0188] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. The scope of the present invention is not intended to be limited to the above Description, but rather is as set forth in the following claims:

Claims

CLAIMS We claim:

1. A method of treating phenylketonuria (PKU), comprising administering to a subject in need of treatment a composition comprising an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose and an administration interval such that at least one symptom or feature of PKU is reduced in intensity, severity, or frequency or has delayed in onset.

2. The method of claim 1 , wherein the mRNA is encapsulated within a liposome.

3. The method of claim 2, wherein the liposome comprises one or more cationic lipids, one or more non-cationic lipids, one or more cholesterol-based lipids and one or more PEG-modified lipids.

4. The method of claim 3, wherein the one or more cationic lipids are selected from the group consisting of C12-200, MC3, DLinDMA, DLinkC2DMA, cKK-E12, ICE (Imidazol- based), HGT5000, HGT5001, DODAC, DDAB, DMRIE, DOSPA, DOGS, DODAP, DODMA and DMDMA, DODAC, DLenDMA, DMRIE, CLinDMA, CpLinDMA, DMOBA, DOcarbDAP, DLinDAP, DLincarbDAP, DLinCDAP, KLin-K-DMA, DLin-K-XTC2-DMA, HGT4003, and combinations thereof.

5. The method of claim 4, wherein the one or more cationic lipids comprise cKK-E12:

6. The method of any one of claims 3-5, wherein the one or more non-cationic lipids are selected from DSPC (l,2-distearoyl-sn-glycero-3-phosphocholine), DPPC (1,2-dipalmitoyl-sn- glycero-3-phosphocholine), DOPE (l,2-dioleyl-sn-glycero-3-phosphoethanolamine), DOPC

(1 ,2-dioleyl-sn-glycero-3-phosphotidylcholine) DPPE (1 ,2-dipalmitoyl-sn-glycero-3- phosphoethanolamine), DMPE (l,2-dimyristoyl-sn-glycero-3-phosphoethanolamine), DOPG (,2- dioleoyl-5/7-glycero-3-phospho-(l'-rac-glycerol)).

7. The method of any one of claims 3-6, wherein the one or more cholesterol-based lipids is cholesterol or PEGylated cholesterol.

8. The method of any one of claims 3-7, wherein the one or more PEG-modified lipids comprise a poly(ethylene) glycol chain of up to 5 kDa in length covalently attached to a lipid with alkyl chain(s) of C₆-C₂o length.

9. The method of any one of the preceding claims, wherein the cationic lipid constitutes about 30-60 % of the liposome by molar ratio.

10. The method of claim 9, wherein the cationic lipid constitutes about 30%, 40 %, 50%>, or 60% of the liposome by molar ratio.

11. The method of any one of the preceding claims, wherein the ratio of cationic lipids:non- cationic lipids: cholesterol lipids: PEGylated lipids is approximately 40:30:20: 10 by molar ratio.

12. The method of any one of the preceding claims, wherein the ratio of cationic lipids:non- cationic lipids: cholesterol lipids: PEGylated lipids is approximately 40:30:25:5 by molar ratio.

13. The method of any one of the preceding claims, wherein the ratio of cationic lipids:non- cationic lipids: cholesterol lipids: PEGylated lipids is approximately 40:32:25:3 by molar ratio.

14. The method of any one of the preceding claims, wherein the ratio of cationic lipids:non- cationic lipids: cholesterol lipids: PEGylated lipids is approximately 50:25:20:5 by molar ratio.

15. The method of any one of the preceding claims, wherein the liposome comprises cK - E12, DOPE, cholesterol and DMG-PEG2K.

16. The method of any one of claims 2-15, wherein the liposome has a size less than about 100 nm.

17. The method of any one of the preceding claims, wherein the mRNA is administered at the effective dose ranging from about 0.1 - 3.0 mg/kg body weight.

18. The method of any one of the preceding claims, wherein the mRNA is administered at the effective dose ranging from about 0.1 - 1.0 mg/kg body weight.

19. The method of any one of the preceding claims, wherein the composition is administered intravenously.

20. The method of any one of the preceding claims, wherein the composition is administered once a week.

21. The method of any one of claima 1-19, wherein the composition is administered once every two weeks.

22. The method of any one of claims 1-19, wherein the composition is administered twice a month.

23. The method of any one of claims 1-19, wherein the composition is administered once a month.

24. The method of any one of the preceding claims, wherein the administering of the composition results in the expression of the PAH protein detectable in liver, kidney, spleen, muscle, and serum.

25. The method of any one of the preceding claims, wherein the administering of the composition results in the expression of a PAH protein level at or above about 100 ng/mg of total protein in the liver.

26. The method of any one of the preceding claims, wherein the administering of the composition results in increased serum PAH protein level.

27. The method of any one of the preceding claims, wherein the administering of the composition results in reduced phenylalanine level in the serum as compared to the baseline phenylalanine level before the treatment.

28. The method of any one of the preceding claims, wherein the administering of the composition results in reduction of phenylalanine levels to about 1000 μιηοΙ/L or less in the serum.

29. The method of any one of the preceding claims, wherein the administering of the composition results in reduction of phenylalanine levels to about 500 μιηοΙ/L or less in the serum.

30. The method of any one of the preceding claims, wherein the administering of the composition results in reduction of phenylalanine levels to about 120 μιηοΙ/L or less in the serum.

31. The method of any one of the preceding claims, wherein the mRNA is codon optimized.

32. The method of claim 31 , wherein the codon-optimized mRNA comprises SEQ ID NO:3, SEQ ID NO:7 or SEQ ID NO:8.

33. The method of claim 31, wherein the codon-optimized mRNA comprises SEQ ID NO:3.

34. The method of claim 33, wherein the mRNA comprises the 5' UTR sequence of SEQ ID NO:4.

35. The method of claim 33, wherein the mRNA comprises the 3' UTR sequence of SEQ ID NO:5 or SEQ ID NO:6.

36. The method of any one of the preceding claims, wherein the mRNA comprises one or more modified nucleotides.

37. The method of claim 36, wherein the one or more modified nucleotides comprise pseudouridine, N-l-methyl-pseudouridine, 2-aminoadenosine, 2-thiothymidine, inosine, pyrrolo- pyrimidine, 3-methyl adenosine, 5-methylcytidine, C-5 propynyl-cytidine, C-5 propynyl-uridine, 2-aminoadenosine, C5-bromouridine, C5-fluorouridine, C5-iodouridine, C5-propynyl-uridine, C5 -propynyl-cytidine, C5-methylcytidine, 2-aminoadenosine, 7-deazaadenosine, 7- deazaguanosine, 8-oxoadenosine, 8-oxoguanosine, 0(6)-methylguanine, and/or 2-thiocytidine.

38. The method of any one of claims 1-35, wherein the mR A is unmodified.

39. A composition for treating phenylketonuria (PKU), comprising an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose amount encapsulated within a liposome.

40. The composition of claim 39, wherein the liposome comprises one or more cationic lipids, one or more non-cationic lipids, one or more cholesterol-based lipids and one or more PEG-modified lipids.

41. The composition of claim 40, wherein the one or more cationic lipids are selected from the group consisting of CI 2-200, DLinDMA, DLinkC2DMA, cK -E12, ICE (Imidazol-based), DODAC, DDAB, DMPJE, DOSPA, DOGS, DODAP, DODMA and DMDMA, DODAC, DLenDMA, DMPJE, CLinDMA, CpLinDMA, DMOBA, DOcarbDAP, DLinDAP,

DLincarbDAP, DLinCDAP, KLin-K-DMA, DLin-K-XTC2-DMA, HGT4003, and combinations thereof.

42. The composition of claim 40 or 41, wherein the one or more cationic lipids comprise CK -E12:

43. The composition of any one of claims 39-42, wherein the one or more non-cationic lipids are selected from DSPC (l,2-distearoyl-sn-glycero-3-phosphocholine), DPPC (1,2-dipalmitoyl- sn-glycero-3-phosphocholine), DOPE (l,2-dioleyl-sn-glycero-3-phosphoethanolamine), DOPC (1 ,2-dioleyl-sn-glycero-3-phosphotidylcholine) DPPE (1 ,2-dipalmitoyl-sn-glycero-3- phosphoethanolamine), DMPE (l,2-dimyristoyl-sn-glycero-3-phosphoethanolamine), and DOPG (,2-dioleoyl-5/7-glycero-3-phospho-(l'-rac-glycerol)).

44. The composition of any one of claims 39-43, wherein the one or more cholesterol-based lipids is cholesterol.

45. The composition of any one of claims 39-44, wherein the one or more PEG-modified lipids comprise a poly(ethylene) glycol chain of up to 5 kDa in length covalently attached to a lipid with alkyl chain(s) of C6-C20 length.

46. The method of any one of claims 39-45, wherein the ratio of cationic lipids :non-cationic lipids: cholesterol-based lipids: PEG-modified lipids is approximately 40:30:20: 10.

47. The method of any one of claims 39-45, wherein the ratio of cationic lipids :non-cationic lipids: cholesterol-based lipids: PEG-modified lipids is approximately 40:30:25:5.

48. The method of any one of claims 39-45, wherein the ratio of cationic lipids :non-cationic lipids: cholesterol-based lipids: PEG-modified lipids is approximately 40:32:25:3.

49. The method of any one of claims 39-45, wherein the ratio of cationic lipids :non-cationic lipids: cholesterol-based lipids: PEG-modified lipids is approximately 50:25 :20:5.

50. The composition of any one of claims 39-49, wherein the liposome comprises cK -E12, DOPE, cholesterol, and DMG-PEG2K.

51. The composition of any one of claims 39-50, wherein the liposome has a size less than about 100 nm.

52. The composition of any one of claims 39-51 , wherein the composition is formulated for intravenous administration.

53. The composition of any one of claims 39-52, wherein the mRNA comprises SEQ ID NO:3, SEQ ID NO:7 or SEQ ID NO:8.

54. The method of any one of claims 39-52, wherein the mRNA comprises SEQ ID NO:3.

55. The composition of claim 54, wherein the mRNA comprises the 5' UTR sequence of SEQ ID NO:4.

56. The composition of claim 54, wherein the mRNA comprises the 3' UTR sequence of SEQ ID NO:5 or SEQ ID NO:6.

57. A composition for treating phenylketonuria (PKU), comprising an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose amount encapsulated within a liposome, wherein the mRNA comprises SEQ ID NO:3, and

further wherein the liposome comprises cationic or non-cationic lipid, cholesterol-based lipid and PEG-modified lipid.

58. A composition for treating phenylketonuria (PKU), comprising an mRNA encoding phenylalanine hydroxylase (PAH) at an effective dose amount encapsulated within a liposome, wherein the mRNA comprises SEQ ID NO: 7 or SEQ ID NO:8, and further wherein the liposome comprises cationic or non-cationic lipid, cholesterol-based lipid and PEG-modified lipid.