Viral vectors encoding recombinant FVIII variants with increased expression for gene therapy of hemophilia A

Abstract

Among other aspects, the present disclosure provides codon-modified polynucleotides encoding Factor VIII variants for expression in mammalian cells. In some embodiments, the present disclosure also provides mammalian gene therapy vectors and methods for treating hemophilia A.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 793,058, filed January 16, 2019, the entire disclosure of which is incorporated herein by reference for all purposes. [Background technology]

[0002] Background of the Disclosure Blood clotting involves a complex and dynamic biological pathway of interdependent biochemical reactions called the coagulation cascade. Coagulation factor VIII (FVIII) is a key component in this cascade. Factor VIII is recruited to the site of bleeding and forms a tenase complex with activated factor IX (FIXa) and factor X (FX). The tenase complex activates FX, which activates prothrombin to thrombin, which then activates other components in the coagulation cascade to generate a stable clot (reviewed in Saenko et al., Trends Cardiovasc. Med., 9:185-92 (1999) (Non-Patent Document 1); Lenting et al., Blood, 92:3983-96 (1998) (Non-Patent Document 2)).

[0003] Hemophilia A is a congenital X-linked bleeding disorder characterized by a deficiency in factor VIII activity. Decreased factor VIII activity inhibits a positive feedback loop in the coagulation cascade. This leads to defective clotting, resulting in prolonged bleeding episodes, extensive bruising, spontaneous oral and nasal bleeding, joint stiffness and chronic pain, and in severe cases, possible internal bleeding and anemia (Zhang et al., Clinic. Rev. Allerg. Immunol., 37:114-24 (2009) (Non-Patent Document 3)).

[0004] Traditionally, hemophilia A is treated with factor VIII replacement therapy, which consists of administering factor VIII protein (e.g., plasma-derived or recombinantly produced factor VIII) to patients with hemophilia A. Factor VIII is administered prophylactically to prevent or reduce the frequency of bleeding episodes, in response to acute bleeding episodes, and / or perioperatively to manage bleeding during surgery. However, factor VIII replacement therapy has several undesirable characteristics.

[0005] First, factor VIII replacement therapy is used to treat or manage hemophilia A but does not cure the underlying factor VIII deficiency. Therefore, patients with hemophilia A require factor VIII replacement therapy for the rest of their lives. Continuous treatment is expensive and patients must maintain strict compliance because missing even a few prophylactic doses can have serious consequences for patients with severe hemophilia A.

[0006] Second, because factor VIII has a relatively short half-life in vivo, conventional prophylactic factor VIII replacement therapy requires dosing every 2 or 3 days. This places a burden on patients to maintain compliance throughout their lives. Third-generation "long-acting" factor VIII drugs can reduce the frequency of dosing, but prophylactic FVIII replacement therapy with these drugs still requires monthly, weekly, or more frequent dosing for life. For example, prophylactic treatment with ELOCTATE™ [Antihemophilic Factor (Recombinant), Fc Fusion Protein] requires dosing every 3 to 5 days (ELOCTATE™ Prescribing Information, Biogen Idec Inc., (2015)). Furthermore, the long-term effects of chemically modified biologics (e.g., PEGylated polypeptides) are still not fully understood.

[0007] Third, 15% to 30% of all patients who undergo factor VIII replacement therapy develop anti-factor VIII inhibitory antibodies, rendering the therapy inefficient. Factor VIII bypass therapy (e.g., administration of plasma-derived or recombinantly produced prothrombin complex concentrates) may be used to treat hemophilia in patients who develop inhibitory antibodies. However, factor VIII bypass therapy is not as effective as factor VIII replacement therapy (Mannucci PM, J Thromb Haemost., 1(7):1349-55 (2003) (Non-Patent Document 4)) and may be associated with an increased risk of cardiovascular complications (Luu and Ewenstein, Haemophilia, 10 Suppl. 2:10-16 (2004) (Non-Patent Document 5)).

[0008] Somatic gene therapy holds great promise for the treatment of hemophilia A because it corrects the underlying low expression of functional factor VIII activity (e.g., due to missense or nonsense mutations) rather than providing patients with a single dose of factor VIII activity. This different mechanism of action compared to factor VIII replacement therapy means that a single administration of a factor VIII gene therapy vector could provide patients with factor VIII for several years, reducing the cost of treatment and eliminating the need for ongoing patient compliance.

[0009] Coagulation factor IX (FIX) gene therapy has been used to effectively treat patients with hemophilia B, a related blood clotting condition characterized by attenuated factor IX activity (Manno CS, et al., Nat Med., 12(3):342-47 (2006)). However, factor VIII gene therapy has some unique challenges. For example, the full-length, wild-type factor VIII polypeptide (2351 amino acids; UniProt accession number P00451) is five times larger than the full-length, wild-type factor IX polypeptide (461 amino acids; UniProt accession number P00740). Thus, the coding sequence for wild-type factor VIII is 7053 base pairs, too large to be packaged in conventional AAV gene therapy vectors. Moreover, previously reported recombinant expression of the B-domain deleted variant of factor VIII (BDD-FVIII) has been inefficient. Therefore, several groups have attempted to modify the codon usage of BDD-FVIII constructs with limited success. [Prior art documents] [Non-patent literature]

[0010] [Non-Patent Document 1] Saenko et al.,Trends Cardiovasc.Med.,9:185-92(1999) [Non-Patent Document 2] Lenting et al.,Blood,92:3983-96(1998) [Non-Patent Document 3] Zhang et al.,Clinic.Rev.Allerg.Immunol.,37:114-24(2009) [Non-Patent Document 4] Mannucci PM, J Thromb Haemost.,1(7):1349-55(2003) [Non-Patent Document 5] Luu and Ewenstein, Haemophilia, 10 Suppl.2:10-16(2004) [Non-Patent Document 6] Manno CS, et al., Nat Med., 12(3):342-47(2006) Summary of the Invention

[0011] Summary of the Disclosure Thus, there is a need for factor VIII variants whose coding sequences can be more efficiently packaged into and delivered by gene therapy vectors. There is also a need for synthetic codon-modified nucleic acids that more efficiently express factor VIII. There is also a need for codon-modified nucleic acids that encode factor VIII polypeptides with improved folding properties, improved secretion from expressing cells, increased activity, and / or improved in vivo circulating half-life compared to wild-type factor VIII or wild-type B-domain deleted factor VIII. Such factor VIII variants and codon-modified nucleic acids allow for improved treatment of factor VIII deficiencies (e.g., hemophilia A). The above deficiencies, as well as other problems associated with the treatment of factor VIII deficiencies (e.g., hemophilia A), are reduced or resolved by the codon-modified factor VIII variants of the present disclosure.

[0012] In one aspect, nucleic acid compositions (e.g., codon-modified polynucleotides) encoding factor VIII variants are described. In some embodiments, the nucleic acid compositions comprise a polynucleotide having high sequence identity to the sequence of CS04 (SEQ ID NO:37) or CS12 (SEQ ID NO:1) encoding a factor VIII variant as described herein. In some embodiments, the nucleic acid compositions described herein provide increased expression of factor VIII and / or increased activity of factor VIII in the blood of an animal compared to wild-type factor VIII coding sequences and / or other codon-optimized factor VIII coding sequences. In some embodiments, the nucleic acid compositions also allow for increased production of AAV-based gene therapy virions. In some embodiments, the nucleic acid compositions described herein have a reduced GC content and / or contain fewer CpG dinucleotides compared to wild-type sequences encoding factor VIII. In some embodiments, the factor VIII variants encoded by the nucleic acid compositions are secreted into the blood more effectively in vivo and / or have an extended blood circulating half-life in vivo compared to wild-type factor VIII and / or other factor VIII variants.

[0013] In some embodiments, a nucleic acid composition comprises a polynucleotide encoding a Factor VIII polypeptide having an amino acid sequence of CS12-FL-AA (SEQ ID NO:2), which has a sequence having at least 95% sequence identity (e.g., at least 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% sequence identity) to CS12-FL-NA (SEQ ID NO:1).

[0014] In some embodiments, the nucleic acid composition further comprises a promoter polynucleotide operably linked to the Factor VIII polynucleotide, wherein the promoter polynucleotide has a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to hTTR (SEQ ID NO:6). In some embodiments, the promoter is directly linked to the Factor VIII polynucleotide, e.g., as shown in FIG.

[0015] In some embodiments, the nucleic acid composition further comprises a liver-specific element operably linked to the Factor VIII polynucleotide. In some embodiments, the liver-specific element is an enhancer element having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 100%) with CRM8 (SEQ ID NO:5). In some embodiments, the nucleic acid composition comprises two such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, the nucleic acid composition comprises three such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, one or more liver-specific elements and the promoter are directly linked, for example, as shown in FIG. 11.

[0016] In some embodiments, the nucleic acid composition has a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vr (SEQ ID NO:3).

[0017] In some embodiments, the acid composition has a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vrp (SEQ ID NO: 10).

[0018] In one aspect, a mammalian gene therapy vector is described that comprises a nucleic acid encoding a factor VIII variant. In some embodiments, the nucleic acid encoding factor VIII comprises a polynucleotide having high sequence identity to the sequence of CS04 (SEQ ID NO:37) or CS12 (SEQ ID NO:1) encoding a factor VIII variant, as described herein. In some embodiments, the mammalian gene therapy vector described herein provides increased expression of factor VIII and / or increased activity of factor VIII in the blood of an animal, as compared to a gene therapy vector comprising a naturally encoded factor VIII variant polynucleotide or other codon-optimized factor VIII variant polynucleotide. In some embodiments, the mammalian gene therapy vector described herein encodes a factor VIII variant protein that is more effectively secreted into the blood in vivo and / or has an extended blood circulating half-life in vivo, as compared to wild-type factor VIII and / or other factor VIII variants.

[0019] In some embodiments, a mammalian gene therapy vector comprises a polynucleotide encoding a Factor VIII polypeptide having the amino acid sequence of CS12-FL-AA (SEQ ID NO:2), which has a sequence having at least 95% sequence identity (e.g., at least 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% sequence identity) to CS12-FL-NA (SEQ ID NO:1).

[0020] In some embodiments, the mammalian gene therapy vector further comprises a promoter polynucleotide operably linked to the Factor VIII polynucleotide, the promoter polynucleotide having a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) with hTTR (SEQ ID NO:6). In some embodiments, the promoter is directly linked to the Factor VIII polynucleotide, for example, as shown in FIG. 11.

[0021] In some embodiments, the mammalian gene therapy vector further comprises a liver-specific element operably linked to the Factor VIII polynucleotide. In some embodiments, the liver-specific element is an enhancer element having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 100%) with CRM8 (SEQ ID NO:5). In some embodiments, the nucleic acid composition comprises two such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, the nucleic acid composition comprises three such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, one or more liver-specific elements and the promoter are directly linked, for example, as shown in FIG. 11.

[0022] In some embodiments, the mammalian gene therapy vector has a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vr (SEQ ID NO:3).

[0023] In some embodiments, the mammalian gene therapy vector is contained in a plasmid having a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vrp (SEQ ID NO: 10).

[0024] In one aspect, an adeno-associated virus (AAV) particle is described that comprises a nucleic acid encoding a factor VIII variant. In some embodiments, the nucleic acid encoding factor VIII comprises a polynucleotide having high sequence identity to the sequence of CS04 (SEQ ID NO: 37) or CS12 (SEQ ID NO: 1), which encodes a factor VIII variant, as described herein. In some embodiments, the AAV particles described herein provide increased expression of factor VIII and / or increased activity of factor VIII in the blood of an animal compared to AAV particles that comprise a naturally encoded factor VIII variant polynucleotide or other codon-optimized factor VIII variant polynucleotide. In some embodiments, the AAV particles described herein encode a factor VIII variant protein that is more effectively secreted into the blood in vivo and / or has an extended blood circulating half-life in vivo compared to wild-type factor VIII and / or other factor VIII variants.

[0025] In some embodiments, the nucleic acid contained in the AAV particle includes a polynucleotide encoding a factor VIII polypeptide having the amino acid sequence of CS12-FL-AA (SEQ ID NO:2), which has a sequence having at least 95% sequence identity (e.g., at least 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% sequence identity) to CS12-FL-NA (SEQ ID NO:1).

[0026] In some embodiments, the nucleic acid contained in the AAV particle further comprises a promoter polynucleotide operably linked to the Factor VIII polynucleotide, the promoter polynucleotide having a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to hTTR (SEQ ID NO:6). In some embodiments, the promoter is directly linked to the Factor VIII polynucleotide, for example, as shown in FIG.

[0027] In some embodiments, the nucleic acid contained in the AAV particle further comprises a liver-specific element operably linked to the Factor VIII polynucleotide. In some embodiments, the liver-specific element is an enhancer element having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 100%) with CRM8 (SEQ ID NO:5). In some embodiments, the nucleic acid composition comprises two such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, the nucleic acid composition comprises three such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, one or more liver-specific elements and the promoter are directly linked, for example, as shown in FIG. 11.

[0028] In some embodiments, the nucleic acid contained in the AAV particle has a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vr (SEQ ID NO:3).

[0029] In some embodiments, the nucleic acid contained in the AAV particle is generated using a plasmid having a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vrp (SEQ ID NO: 10).

[0030] In one aspect, a method is described for treating hemophilia A by administering a nucleic acid composition encoding a factor VIII variant to a hemophilia A patient. In some embodiments, the nucleic acid composition comprises a polynucleotide having high sequence identity to the sequence of CS04 (SEQ ID NO: 37) or CS12 (SEQ ID NO: 1) encoding a factor VIII variant as described herein. In some embodiments, the method for treating hemophilia A described herein results in increased factor VIII expression and / or increased factor VIII activity in the blood of a patient that is greater than increased factor VIII expression and / or increased factor VIII activity in the blood of a patient administered a nucleic acid composition comprising a wild-type factor VIII coding sequence and / or a different codon-optimized factor VIII coding sequence. In some embodiments, the factor VIII variant encoded by the nucleic acid composition is more effectively secreted into the blood in vivo and / or has an extended circulating half-life in vivo compared to wild-type factor VIII and / or other factor VIII variants.

[0031] In some embodiments, the administered nucleic acid composition comprises a polynucleotide encoding a Factor VIII polypeptide having the amino acid sequence of CS12-FL-AA (SEQ ID NO:2), which has a sequence having at least 95% sequence identity (e.g., at least 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% sequence identity) to CS12-FL-NA (SEQ ID NO:1).

[0032] In some embodiments, the administered nucleic acid composition further comprises a promoter polynucleotide operably linked to the Factor VIII polynucleotide, the promoter polynucleotide having a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to hTTR (SEQ ID NO:6). In some embodiments, the promoter is directly linked to the Factor VIII polynucleotide, e.g., as shown in FIG.

[0033] In some embodiments, the administered nucleic acid composition further comprises a liver-specific element operably linked to the Factor VIII polynucleotide. In some embodiments, the liver-specific element is an enhancer element having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 100%) with CRM8 (SEQ ID NO:5). In some embodiments, the nucleic acid composition comprises two such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, the nucleic acid composition comprises three such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, one or more liver-specific elements and the promoter are directly linked, for example, as shown in FIG. 11.

[0034] In some embodiments, the administered nucleic acid composition has a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vr (SEQ ID NO:3).

[0035] In some embodiments, the administered nucleic acid composition has a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vrp (SEQ ID NO: 10).

[0036] In one aspect, a method is described for treating hemophilia A by administering a mammalian gene therapy vector comprising a nucleic acid encoding a factor VIII variant. In some embodiments, the nucleic acid encoding factor VIII comprises a polynucleotide having high sequence identity to the sequence of CS04 (SEQ ID NO:37) or CS12 (SEQ ID NO:1) encoding a factor VIII variant as described herein. In some embodiments, the method for treating hemophilia A described herein results in increased expression of factor VIII and / or increased activity of factor VIII in the blood of a patient that is greater than the increased expression and / or activity of factor VIII in the blood of a patient administered a mammalian gene therapy vector comprising a wild-type factor VIII coding sequence and / or a different codon-optimized factor VIII coding sequence. In some embodiments, the factor VIII variant encoded by the nucleic acid in the mammalian gene therapy vector is more effectively secreted into the blood in vivo and / or has an extended circulating half-life in the blood in vivo compared to wild-type factor VIII and / or other factor VIII variants.

[0037] In some embodiments, the administered mammalian gene therapy vector comprises a polynucleotide encoding a Factor VIII polypeptide having the amino acid sequence of CS12-FL-AA (SEQ ID NO:2), which has a sequence having at least 95% sequence identity (e.g., at least 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% sequence identity) to CS12-FL-NA (SEQ ID NO:1).

[0038] In some embodiments, the mammalian gene therapy vector administered further comprises a promoter polynucleotide operably linked to the Factor VIII polynucleotide, the promoter polynucleotide having a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) with hTTR (SEQ ID NO:6). In some embodiments, the promoter is directly linked to the Factor VIII polynucleotide, for example, as shown in FIG.

[0039] In some embodiments, the mammalian gene therapy vector administered further comprises a liver-specific element operably linked to the Factor VIII polynucleotide. In some embodiments, the liver-specific element is an enhancer element having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 100%) with CRM8 (SEQ ID NO:5). In some embodiments, the nucleic acid composition comprises two such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, the nucleic acid composition comprises three such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, one or more liver-specific elements and the promoter are directly linked, for example, as shown in FIG. 11.

[0040] In some embodiments, the administered mammalian gene therapy vector has a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vr (SEQ ID NO:3).

[0041] In some embodiments, the administered mammalian gene therapy vector is contained in a plasmid having a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vrp (SEQ ID NO: 10).

[0042] In one aspect, a method is described for treating hemophilia A by administering an adeno-associated virus (AAV) particle comprising a nucleic acid encoding a factor VIII variant. In some embodiments, the nucleic acid encoding factor VIII comprises a polynucleotide having high sequence identity to the sequence of CS04 (SEQ ID NO: 37) or CS12 (SEQ ID NO: 1), which encodes a factor VIII variant, as described herein. In some embodiments, the method for treating hemophilia A described herein results in increased expression and / or activity of factor VIII in the blood of a patient that is greater than the increased expression and / or activity of factor VIII in the blood of a patient administered an adeno-associated virus (AAV) particle comprising a wild-type factor VIII coding sequence and / or a different codon-optimized factor VIII coding sequence. In some embodiments, the factor VIII variant encoded by the nucleic acid in the adeno-associated virus (AAV) particle is more effectively secreted into the blood in vivo and / or has an extended circulating half-life in the blood compared to wild-type factor VIII and / or other factor VIII variants.

[0043] In some embodiments, the nucleic acid contained in the administered AAV particle comprises a polynucleotide encoding a factor VIII polypeptide having the amino acid sequence of CS12-FL-AA (SEQ ID NO:2), which has a sequence having at least 95% sequence identity (e.g., at least 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% sequence identity) to CS12-FL-NA (SEQ ID NO:1).

[0044] In some embodiments, the nucleic acid contained in the administered AAV particle further comprises a promoter polynucleotide operably linked to the Factor VIII polynucleotide, the promoter polynucleotide having a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to hTTR (SEQ ID NO:6). In some embodiments, the promoter is directly linked to the Factor VIII polynucleotide, for example, as shown in FIG.

[0045] In some embodiments, the nucleic acid contained in the administered AAV particle further comprises a liver-specific element operably linked to the Factor VIII polynucleotide. In some embodiments, the liver-specific element is an enhancer element having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 100%) with CRM8 (SEQ ID NO:5). In some embodiments, the nucleic acid composition comprises two such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, the nucleic acid composition comprises three such liver-specific elements operably linked to the Factor VIII polynucleotide. In some embodiments, one or more liver-specific elements and the promoter are directly linked, for example, as shown in FIG. 11.

[0046] In some embodiments, the nucleic acid contained in the administered AAV particle has a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vr (SEQ ID NO:3).

[0047] In some embodiments, the nucleic acid contained in the administered AAV particle is generated using a plasmid having a nucleic acid sequence having at least 90% sequence identity (e.g., at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100%) to CS12-CRM8.2-Vrp (SEQ ID NO: 10). [The present invention 1001] A nucleic acid composition comprising a factor VIII polynucleotide encoding a factor VIII protein, wherein the factor VIII polynucleotide has the nucleic acid sequence of CS12-FL-NA (sequence number 1). [The present invention 1002] 1001. The nucleic acid composition of claim 1001, further comprising a promoter polynucleotide operably linked to said Factor VIII polynucleotide, said promoter polynucleotide having the nucleic acid sequence of hTTR (SEQ ID NO:6). [The present invention 1003] The nucleic acid composition of claim 1002, wherein said promoter is directly linked to said Factor VIII polynucleotide. [The present invention 1004] The nucleic acid composition of any of claims 1001 to 1003, further comprising a liver-specific element operably linked to said Factor VIII polynucleotide, said liver-specific element having the sequence of CRM8 (sequence number 5). [The present invention 1005] The nucleic acid composition of claim 1004, wherein a second liver-specific element is operably linked to said Factor VIII polypeptide. [The present invention 1006] 1004 or 1005, wherein said liver-specific element and said promoter are directly linked. [The present invention 1007] 1001. A nucleic acid composition of the present invention having a nucleic acid sequence comprising CS12-CRM8.2-Vr (SEQ ID NO:3). [The present invention 1008] A mammalian gene therapy vector comprising any one of the nucleic acid compositions of the present invention 1001 to 1007. [The present invention 1009] The mammalian gene therapy vector of the present invention 1008 which is an adeno-associated virus (AAV) vector. [The present invention 1010] 1009. The mammalian gene therapy vector of the present invention, wherein said AAV vector is a serotype 8 adeno-associated virus (AAV-8) vector. [The present invention 1011] 1013. The mammalian gene therapy vector of any of claims 1008 to 1010, wherein said nucleic acid composition is a single-stranded polynucleotide encoding said Factor VIII protein. [The present invention 1012] An adeno-associated virus (AAV) particle comprising a capsid protein encapsulating the nucleic acid composition of any one of the present inventions 1001 to 1007. [The present invention 1013] The AAV particle of the present invention, wherein the capsid protein comprises a serotype 8 adeno-associated virus (AAV-8) capsid protein. [The present invention 1014] The AAV particle of the present invention 1012 or 1013, wherein the nucleic acid composition is a single-stranded polynucleotide encoding the factor VIII protein. [The present invention 1015] A method for treating hemophilia A, comprising administering any one of the nucleic acid compositions of the present inventions 1001 to 1007 to a patient with hemophilia A. [The present invention 1016] The nucleic acid composition of any of claims 1001 to 1007 for treating hemophilia A. [The present invention 1017] Use of any of the nucleic acid compositions of the present inventions 1001 to 1007 for the manufacture of a medicament for the treatment of hemophilia A. [The present invention 1018] A method for treating hemophilia A, comprising administering to a patient with hemophilia A any of the mammalian gene therapy vectors of the present inventions 1008 to 1011. [The present invention 1019] 13. The mammalian gene therapy vector of any of claims 1008 to 1011 for treating hemophilia A. [The present invention 1020] 20. The use of any of the mammalian gene therapy vectors of claims 1008 to 1011 for the manufacture of a medicament for the treatment of hemophilia A. [The present invention 1021] A method for treating hemophilia A, comprising administering to a patient with hemophilia A any of the adeno-associated virus (AAV) particles of the present inventions 1012 to 1014. [The present invention 1022] The adeno-associated virus (AAV) particle of any of claims 1012 to 1014 for treating hemophilia A. [The present invention 1023] Use of any of the adeno-associated virus (AAV) particles of the present invention 1012 to 1014 for the manufacture of a medicament for the treatment of hemophilia A. [The present invention 1024] A method for producing adeno-associated virus (AAV) particles, comprising introducing any one of the nucleic acid compositions of the present invention 1001 to 1007 into a eukaryotic host cell, the nucleic acid composition comprises a Factor VIII polynucleotide having the nucleic acid sequence of CS12-FL-NA (SEQ ID NO: 1) flanked by a 5' inverted terminal repeat (5'ITR) and a 3' inverted terminal repeat (3'ITR); the mammalian host cell comprises one or more polynucleotides encoding an AAVrep gene, an AAVcap gene, and a viral replication helper gene; The method. [The present invention 1025] The method of any one of claims 1 to 24, wherein the nucleic acid composition is a plasmid having the nucleic acid sequence of CS12-CRM8.2-Vrp (SEQ ID NO: 10). [The present invention 1026] The method of any one of claims 1024 to 1025, wherein the AAV cap gene is a serotype 8 adeno-associated virus (AAV-8) cap gene. [Brief description of the drawings]

[0048] [Figure 1A] 1 shows the CS12 codon-optimized nucleotide sequence (SEQ ID NO:1) encoding a Factor VIII variant according to some embodiments ("CS12-FL-NA" is the full-length coding sequence). [Figure 1B] 1 shows the CS12 codon-optimized nucleotide sequence (SEQ ID NO:1) encoding a Factor VIII variant according to some embodiments ("CS12-FL-NA" is the full-length coding sequence). [Diagram 2]1 shows a Factor VIII variant amino acid sequence (SEQ ID NO:2) encoded by the CS12 codon-modified nucleotide sequence according to some embodiments ("CS12-FL-AA" is the full-length amino acid sequence). [Figure 3A] 1 shows the nucleic acid sequence (SEQ ID NO:3) of the CS12-CRM8.2-Vr nucleotide reduced gene therapy vector encoding a Factor VIII variant, according to some embodiments. [Figure 3B] 1 shows the nucleic acid sequence (SEQ ID NO:3) of the CS12-CRM8.2-Vr nucleotide reduced gene therapy vector encoding a Factor VIII variant, according to some embodiments. [Figure 4] 1 shows the nucleic acid sequences of various genetic elements useful in gene therapy vectors encoding Factor VIII variants, including the 5'-ITR (SEQ ID NO:4), CRM8 enhancer element (SEQ ID NO:5), human TTR promoter (SEQ ID NO:6), minimal Kozak sequence (SEQ ID NO:7), and synthetic polyadenylation element (SEQ ID NO:8), and 3'-ITR (SEQ ID NO:9), according to some embodiments. [Figure 5A] 1 shows the nucleic acid sequence of the CS12-CRM8.2-Vrp plasmid (SEQ ID NO: 10) comprising a gene therapy vector encoding a Factor VIII variant, according to some embodiments. [Figure 5B] 1 shows the nucleic acid sequence of the CS12-CRM8.2-Vrp plasmid (SEQ ID NO: 10) comprising a gene therapy vector encoding a Factor VIII variant, according to some embodiments. [Figure 5C] 1 shows the nucleic acid sequence of the CS12-CRM8.2-Vrp plasmid (SEQ ID NO: 10) comprising a gene therapy vector encoding a Factor VIII variant, according to some embodiments. [Figure 6A] 1 shows the nucleic acid sequence of the CS12-CRM8.2-V gene therapy vector encoding a Factor VIII variant (SEQ ID NO:38), according to some embodiments. [Figure 6B]1 shows the nucleic acid sequence of the CS12-CRM8.2-V gene therapy vector encoding a Factor VIII variant (SEQ ID NO:38), according to some embodiments. [Figure 7A] 1 shows the CS04 codon-optimized nucleotide sequence (SEQ ID NO:37) encoding a Factor VIII variant according to some embodiments ("CS12-FL-NA" is the full-length coding sequence). [Figure 7B] 1 shows the CS04 codon-optimized nucleotide sequence (SEQ ID NO:37) encoding a Factor VIII variant according to some embodiments ("CS12-FL-NA" is the full-length coding sequence). [Figure 8A] 8A and 8B show the amino acid and nucleotide sequences of exemplary glycosylated peptides inserted into the B domain replacement linker of Factor VIII variants according to some embodiments. "NG1" or "NG1-AA" is the code for the amino acid sequence shown in the top line. "NG1-NA" is the code for the nucleic acid sequence shown in the bottom line for each set. Figures 8A and 8B disclose the amino acid sequences of SEQ ID NOs: 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, and 35, and the nucleotide sequences of SEQ ID NOs: 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, and 36, respectively, all in order of appearance. [Figure 8B] 8A and 8B show the amino acid and nucleotide sequences of exemplary glycosylated peptides inserted into the B domain replacement linker of Factor VIII variants according to some embodiments. "NG1" or "NG1-AA" is the code for the amino acid sequence shown in the top line. "NG1-NA" is the code for the nucleic acid sequence shown in the bottom line for each set. Figures 8A and 8B disclose the amino acid sequences of SEQ ID NOs: 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, and 35, and the nucleotide sequences of SEQ ID NOs: 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, and 36, respectively, all in order of appearance. [Figure 9]Western blot analysis of factor VIII variants in which a glycosylated peptide was engineered into the SQ linker (vNG4 / CS04, vNG5 / CS04, and vNG16 / CS04) and factor VIII variants in which a glycosylated peptide was not engineered into the SQ linker (vCS04 and SQ) expressed in Huh-7 cells are shown. [Figure 10] Western blot analysis of factor VIII variants with glycosylated peptides engineered into the SQ linker (vNG4 / CS04, vNG5 / CS04, and vNG16 / CS04) and factor VIII variants without glycosylated peptides engineered into the SQ linker (vCS04 and SQ) expressed in HepG2 cells after infection with AAV8 gene therapy vectors. [Figure 11] 1 shows an exemplary Factor VIII gene therapy construct encoding a Factor VIII variant, according to some embodiments. [Figure 12] 1 shows in vivo factor VIII activity levels in a "strain E" hFVIII-resistant mouse model and in vitro factor VIII activity levels using HepG2 cells following infection with an AAV8 gene therapy vector encoding a factor VIII variant protein, according to some embodiments. [Figure 13] 1 shows an agarose gel electrophoresis analysis of vCS04, vX5 / NG5 / CS120, and vX5 / NG5 / CS12 gene therapy vectors encoding Factor VIII variants, according to some embodiments. [Figure 14] 1 shows in vivo Factor VIII activity levels in a FVIII F17 ​​knock-in mouse model and in vitro Factor VIII activity levels using HepG2 cells, a human hepatocyte cell line (ATCC#HB-8065), following infection with an AAV8 gene therapy vector encoding a Factor VIII variant protein, according to some embodiments. [Figure 15]FIG. 1 shows a schematic diagram of wild-type and recombinant human Factor VIII protein constructs, as well as Factor VIII proteins encoded by CS12 polynucleotides containing X5 mutations and NG5 glycosylated peptides. [Figure 16] 1 shows the wild-type human factor VIII amino acid sequence (SEQ ID NO:39) ("FVIII-FL-AA"), according to some embodiments. [Figure 17] Exemplary coding sequences for B domain replacement linkers according to some embodiments are shown (SEQ ID NOs: 41-53, respectively, in order of appearance): BDLO04 (SEQ ID NO: 41) is a portion of the CS04 codon-modified nucleotide sequence that encodes the B domain replacement linker. [Figure 18] 1 shows an example of a plasmid backbone (SEQ ID NO:54) for incorporating a Factor VIII gene therapy genome, according to some embodiments. [Figure 19] 5 shows an example of a replicon ("pMB1 replicon" - SEQ ID NO: 55) and ampicillin resistance marker ("Bla(ApR)" - SEQ ID NO: 56) of a plasmid useful for integrating a Factor VIII gene therapy genome, according to some embodiments. [Figure 20A] 5 shows the nucleic acid sequence of the CS12-CRM8.2-Vp plasmid (SEQ ID NO:57) comprising a gene therapy vector encoding a Factor VIII variant, according to some embodiments. [Figure 20B] 5 shows the nucleic acid sequence of the CS12-CRM8.2-Vp plasmid (SEQ ID NO:57) comprising a gene therapy vector encoding a Factor VIII variant, according to some embodiments. [Figure 20C] 5 shows the nucleic acid sequence of the CS12-CRM8.2-Vp plasmid (SEQ ID NO:57) comprising a gene therapy vector encoding a Factor VIII variant, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] I. Introduction AAV-based gene therapy shows great promise for treating hemophiliacs. For hemophilia B, initial clinical data are encouraging in that FIX levels of approximately 10% can be maintained for more than a year in at least some patients. However, for hemophilia A, achieving therapeutic expression levels of 5-10% using AAV vectors remains challenging for a variety of reasons. First, the factor VIII coding sequence is too large for conventional AAV-based vectors. Second, engineered B-domain deleted or truncated factor VIII constructs suffer from poor in vivo expression even with codon optimization. Third, these B-domain deleted or truncated factor VIII variant constructs have a short half-life in vivo, exacerbating the effects of poor expression. Fourth, even when expressed, FVIII is not efficiently secreted from cells as are other clotting factors such as factor IX.

[0050] The present disclosure relates, in part, to the discovery of gene therapy vectors comprising codon-modified factor VIII variant coding sequences that solve these and other problems associated with factor VIII gene therapy. For example, in some embodiments, the factor VIII variant polynucleotides, polypeptides, and gene therapy constructs disclosed herein provide improved exogenous factor VIII expression in mammalian cells. In some embodiments, the factor VIII variant polynucleotides, polypeptides, and gene therapy constructs disclosed herein provide improved in vivo bioavailability (e.g., improved factor VIII activity in the patient's blood). In some embodiments, the factor VIII variant polynucleotides, polypeptides, and gene therapy constructs disclosed herein provide improved circulating half-life of exogenous factor VIII in the patient's blood. As described herein, one or more of these advantages are achieved by using any combination of one or more of the following improvements in gene therapy systems:

[0051] In some embodiments, one or more of these advantages are achieved by engineering an X5 mutation into a factor VIII variant polypeptide encoded by a codon-modified factor VIII polypeptide, as described herein. Advantageously, inclusion of an X5 mutation in an encoded factor VIII polypeptide, as described herein, improves the biopotency of exogenously expressed factor VIII in vivo and in vitro. For example, as described in Example 4, inclusion of five X5 mutations in the A1 domain of the heavy chain of a recombinant FVIII polypeptide increased the biopotency of exogenous factor VIII in vivo in strain E2 mice after administration of an AAV gene therapy vector encoding a recombinant factor VIII-X5 variant, compared to mice administered an identical gene therapy vector, except that it encodes a wild-type recombinant factor VIII variant (compare vX5 / CS24 with vCS04 in FIG. 12). Consistent with the in vivo results, inclusion of five X5 mutations in the A1 domain of the factor VIII heavy chain increased the in vitro biopotency of exogenous factor VIII four-fold following infection of HepG2 cells with an AAV gene therapy vector encoding the recombinant factor VIII-X5 variant compared to HepG2 cells infected with an identical gene therapy vector but encoding the wild-type recombinant factor VIII variant (compare vX5 / CS24 with vCS04 in FIG. 12).

[0052] In some embodiments, one or more of these advantages are achieved by engineering an NG5 glycosylation peptide into the B domain linker of a factor VIII variant polypeptide encoded by a codon-modified factor VIII polypeptide, as described herein. Advantageously, inclusion of the NG5 glycosylation peptide in the encoded factor VIII polypeptide improves the biopotency of exogenously expressed factor VIII in vivo, as described herein. For example, as described in Example 3, inclusion of the NG glycosylation peptide in the SQ linker of a recombinant FVIII polypeptide increased the biopotency of exogenous factor VIII in vivo in strain E2 mice after administration of an AAV gene therapy vector encoding a recombinant factor VIII-NG5 variant, compared to mice administered an identical gene therapy vector, except that it encodes a wild-type recombinant factor VIII variant (compare vNG5 / CS04 to vCS04 in FIG. 12).

[0053] In some embodiments, one or more of these advantages are achieved by engineering both the X5 mutation and the NG5 glycosylation peptide into a variant factor VIII polypeptide encoded by a codon-modified factor VIII polypeptide, as described herein. Advantageously, inclusion of the X5 mutation and the NG5 glycosylation peptide in the encoded factor VIII polypeptide, as described herein, improves the biopotency of exogenously expressed factor VIII in vivo and in vitro. For example, as described in Example 5, when a recombinant FVIII polypeptide contained five X5 mutations in the A1 domain of the heavy chain and an NG5 glycosylation peptide in the SQ linker, the in vivo biopotency of exogenous factor VIII in mice of the E2 strain following administration of an AAV gene therapy vector encoding the recombinant factor VIII-X5 / NG5 variant was increased by 4.5-fold compared to mice administered an identical gene therapy vector except encoding the wild-type recombinant factor VIII variant (compare vX5 / NG5 / CS125 with vCS04 in Figure 12). Consistent with the in vivo results, the inclusion of five X5 mutations in the A1 domain of the heavy chain of a recombinant FVIII polypeptide and an NG5 glycosylation peptide in the SQ linker increased the in vitro biopotency of exogenous factor VIII three-fold following infection of HepG2 cells with an AAV gene therapy vector encoding the recombinant factor VIII-X5 / NG5 variant compared to HepG2 cells infected with an identical gene therapy vector except encoding the wild-type recombinant factor VIII variant (compare vX5 / NG5 / CS125 with vCS04 in FIG. 12).

[0054] In some embodiments, one or more of these advantages are achieved by using the human hTTR promoter and one or more liver-specific CRM8 elements upstream of the polynucleotide sequence encoding the variant Factor VIII polypeptide. Advantageously, the use of the hTTR promoter and one or more liver-specific CRM8 elements improves the biopotency of exogenously expressed Factor VIII in human cells in vitro. For example, as described in Example 2, the use of the hTTR promoter and one or two liver-specific CRM8 elements increased the biopotency of exogenous Factor VIII in vivo in HepG2 cells by about 2-fold and 4-fold, respectively, compared to the use of the mouse TTR promoter and enhancer sequence (compare vCS115 and vCS116 with vCS04 in Figure 12).

[0055] In some embodiments, one or more of these advantages are achieved by removing exogenous nucleotides located between various elements of the AAV gene therapy vector encoding the factor VIII variant protein. Advantageously, removing exogenous nucleotides between various elements improves the biopotency of exogenously expressed factor VIII in human cells in vitro. For example, as described in Example 6, removing only 71 nucleotides from the vX5 / NG5 / CS120 AAV gene therapy vector encoding the refactor factor VIII-X5 / NG5 variant improves the in vitro biopotency of the expressed factor VIII variant by 50% (compare vX5 / NG5 / CS12 with vX5 / NG5 / CS120 in FIG. 14).

[0056] In some embodiments, one or more of these advantages are achieved by engineering both the X5 mutation and the NG5 glycosylation peptide into the factor VIII variant polypeptide encoded by the codon-modified factor VIII polypeptide, and using the human hTTR promoter and one or more liver-specific CRM8 elements upstream of the polynucleotide sequence encoding the factor VIII variant polypeptide. Advantageously, the use of this combination of improvements improves the biopotency of exogenously expressed factor VIII in vivo and in vitro. For example, as described in Example 6, the use of this combination of improvements in an AAV gene therapy vector increased the in vivo biopotency by 14.5-fold compared to the use of an AAV gene therapy vector comprising a polynucleotide with the same codon modifications of the encoded wild-type recombinant factor VIII using mouse TTR promoter and enhancer sequences (compare vX5 / NG5 / CS120 to vSC04 in Figure 14). Consistent with the in vivo results, the use of these combinations of improvements in AAV gene therapy vectors increased in vitro biopotency by 17-fold compared to the use of AAV gene therapy vectors containing polynucleotides with the same codon modifications of the encoded wild-type recombinant factor VIII using mouse TTR promoter and enhancer sequences (compare vX5 / NG5 / CS120 to vSC04 in FIG. 14). As reported in Table 4 of WO2017 / 083762 (the contents of which are incorporated herein by reference), the vCS04 vector provides more than 70-fold higher in vivo FVIII biopotency compared to an equivalent gene therapy vector encoding a recombinant factor VIII polynucleotide using a wild-type coding sequence. Thus, the vX5 / NG5 / CS120 gene therapy vector is expected to provide a 1000- to 1250-fold increase in FVIII biopotency compared to the use of a wild-type recombinant coding sequence.

[0057] In some embodiments, one or more of these advantages are achieved by engineering both the X5 mutation and the NG5 glycosylation peptide into the factor VIII variant polypeptide encoded by the codon-modified factor VIII polypeptide, using the human hTTR promoter and one or more liver-specific CRM8 elements upstream of the polynucleotide sequence encoding the factor VIII variant polypeptide, and removing the exogenous nucleotides located between the various elements of the AAV gene therapy vector. Advantageously, the use of this combination of improvements improves the biopotency of exogenously expressed factor VIII in vivo and in vitro. For example, as described in Example 6, the use of this combination of improvements in an AAV gene therapy vector increased the in vivo biopotency by 14-fold compared to the use of an AAV gene therapy vector comprising a polynucleotide with the same codon modifications of the encoded wild-type refactor factor VIII using the mouse TTR promoter and enhancer sequence (compare vX5 / NG5 / CS12 to vSC04 in Figure 14). Consistent with the in vivo results, the use of this combination of improvements in AAV gene therapy vectors increased in vitro biopotency by 24-fold compared to the use of AAV gene therapy vectors containing polynucleotides with the same codon modifications of the encoded wild-type recombinant factor VIII using mouse TTR promoter and enhancer sequences (compare vX5 / NG5 / CS12 to vSC04 in FIG. 14). As reported in Table 4 of WO2017 / 083762 (the contents of which are incorporated herein by reference), the vCS04 vector provides more than 70-fold higher in vivo FVIII biopotency compared to an equivalent gene therapy vector encoding a recombinant factor VIII polynucleotide using a wild-type coding sequence. Thus, the vX5 / NG5 / CS120 gene therapy vector is expected to provide a 1000- to 1750-fold increase in FVIII biopotency compared to the use of a wild-type recombinant coding sequence.

[0058] II. Definition As used herein, the following terms have the meanings ascribed to them unless specified otherwise.

[0059] As used herein, the terms "Factor VIII" and "FVIII" are used interchangeably and refer to any protein having factor VIII activity (e.g., active FVIII, often referred to as FVIIIa) or a protein precursor (e.g., proprotein or preproprotein) of a protein that has factor IXa cofactor activity under certain conditions, as measured, for example, using the two-step chromogenic factor X activation assay described in chapter 2.7.4 of the European Pharmacopoeia 9.0. In exemplary embodiments, a factor VIII polypeptide refers to a polypeptide having a sequence with high sequence identity (e.g., at least 70%, 75%, 80%, 85%, 90%, 95%, 99%, or more) to the heavy and light chains of a wild-type factor VIII polypeptide. In some embodiments, the B domain of the factor VIII polypeptide is deleted, truncated, or replaced with a linker polypeptide to reduce the size of the polynucleotide encoding the factor VIII polypeptide.

[0060] Non-limiting examples of wild-type factor VIII polypeptides include human preprofactor VIII (e.g., GenBank Accession Nos. AAA52485, CAA25619, AAA58466, AAA52484, AAA52420, AAV85964, BAF82636, BAG36452, CAI41660, CAI41666, CAI41672, CAI43241, CAO03404, EAW72645, AAH22513, AAH64380, AAH98389, AAI11968, AAI11970, or AAB61261), the corresponding profactor VIII, and naturally occurring variants thereof; porcine preprofactor VIII (e.g., Un iProt Accession Nos. F1RZ36 or K7GSZ5), the corresponding pro-factor VIII, and naturally occurring variants thereof; mouse prepro-factor VIII (e.g., GenBank Accession Nos. AAA37385, CAM15581, CAM26492, or EDL29229), the corresponding pro-factor VIII, and naturally occurring variants thereof; rat prepro-factor VIII (e.g., GenBank Accession No. AAQ21580), the corresponding pro-factor VIII, and naturally occurring variants thereof; rat prepro-factor VIII; and other mammalian factor VIII homologs (e.g., monkey, ape, hamster, guinea pig, etc.).

[0061] As used herein, Factor VIII polypeptides include naturally occurring variants and artificial constructs that have Factor IX cofactor activity. As used in this disclosure, Factor VIII encompasses any naturally occurring variant, alternative sequence, isoform, or mutant protein that retains some basal Factor IX cofactor activity (e.g., at least 5%, 10%, 25%, 50%, 75% or more of the corresponding wild-type activity).

[0062] The definition of "Factor VIII" specifically includes Factor VIII variants, which may also be referred to as "variant FVIII." Variant FVIII proteins have at least one amino acid modification compared to human wild-type FVIII. Examples of amino acid changes of Factor VIII (relative to FVIII-FL-AA (SEQ ID NO: 19)) found in the human population include, but are not limited to: Including TIFF0007610338000001.tif92164TIFF0007610338000002.tif180165. Factor VIII proteins also include polypeptides that contain post-translational modifications.

[0063] Generally, a polynucleotide encoding factor VIII encodes an inactive single-chain polypeptide (e.g., a preproprotein) that is post-translationally processed to form an active factor VIII protein (e.g., FVIIIa). For example, with reference to FIG. 15, a wild-type human factor VIII preproprotein is first cleaved to release an encoded signal peptide (not shown) and form a first single-chain proprotein (designated as "human wild-type FVIII"). The proprotein is then cleaved between the B and A3 domains to form a first polypeptide comprising a factor VIII heavy chain (e.g., A1 and A2 domains) and a B domain, and a second polypeptide comprising a factor VIII light chain (e.g., A3, C1, and C3 domains). The first polypeptide is further cleaved to remove the B domain and separate the A1 and A2 domains, which remain associated with the factor VIII light chain of the mature factor VIIIa protein. For a review of the maturation process of Factor VIII, see Graw et al., Nat Rev Genet., 6(6):488-501 (2005), the contents of which are incorporated herein by reference in their entirety and for all purposes.

[0064] As used herein, the term "Factor VIII heavy chain," or simply "heavy chain," refers to an aggregate of the A1 and A2 domains of a Factor VIII polypeptide. In an exemplary embodiment, amino acids 20 to 759 of hFVIII-FL-AA (SEQ ID NO: 39) constitute the Factor VIII heavy chain.

[0065] As used herein, the term "Factor VIII light chain," or simply "light chain," refers to an aggregate of the A3, C1, and C2 domains of a Factor VIII polypeptide. In an exemplary embodiment, amino acids 1668-2351 of hFVIII-FL-AA (SEQ ID NO:39) constitute the Factor VIII light chain. In some embodiments, the Factor VIII light chain excludes the acidic a3 peptide, which is released during maturation in vivo.

[0066] Generally, the factor VIII heavy and light chains are expressed as a single polypeptide chain, e.g., together with an optional B domain or B domain replacement linker. However, in some embodiments, the factor VIII heavy and factor VIII light chains are expressed (e.g., co-expressed) as separate polypeptide chains and reconstituted (e.g., in vivo or in vitro) to form the factor VIII protein.

[0067] As used herein, the terms "B domain replacement linker" and "Factor VIII linker" are used interchangeably and refer to a truncated wild-type Factor VIII B domain (e.g., amino acids 760-1667 of hFVIII-FL-AA (SEQ ID NO: 39)) or a peptide engineered to replace the B domain of a Factor VIII polypeptide. As used herein, a Factor VIII linker is positioned in a Factor VIII variant polypeptide according to some embodiments between the C-terminus of the Factor VIII heavy chain and the N-terminus of the Factor VIII light chain. Non-limiting examples of B domain replacement linkers are described in U.S. Pat. Nos. 4,868,112, 5,112,950, 5,171,844, 5,543,502, 5,595,886, 5,610,278, 5,789,203, 5,972,885, 6,048,720, 6,060,447, 6,114,148, 6,228,620, 6,316,226, and 6,346,513. , 6,458,563, 6,924,365, 7,041,635, and 7,943,374, U.S. Patent Application Publication Nos. 2013 / 024960, 2015 / 0071883, and 2015 / 0158930, and PCT Publication Nos. WO2014 / 064277 and WO2014 / 127215, the disclosures of which are incorporated by reference in their entireties for all purposes.

[0068] Unless otherwise stated herein, the numbering of factor VIII amino acids refers to the corresponding amino acid in the full-length, wild-type human factor VIII sequence (hFVIII-FL-AA) presented as SEQ ID NO: 39 in Figure 16. Thus, when referring to amino acid substitutions in the factor VIII variant proteins disclosed herein, the recited amino acid number refers to the similar (e.g., structurally or functionally equivalent) and / or homologous (e.g., evolutionarily conserved in the primary amino acid sequence) amino acid in the full-length, wild-type factor VIII sequence. For example, the T2105N amino acid substitution refers to a T to N substitution at position 2105 of the full-length, wild-type human factor VIII sequence (hFVIII-FL-AA; SEQ ID NO: 39), a T to N substitution at position 1218 of the factor VIII variant protein encoded by CS12 (CS12-FL-AA; SEQ ID NO: 2).

[0069] As described herein, the numbering system for Factor VIII amino acids depends on whether a Factor VIII signal peptide (e.g., amino acids 1-19 of the full-length, wild-type human Factor VIII sequence) is included. If the signal peptide is included, the numbering is referred to as "signal peptide inclusive" or "SPI." If the signal peptide is not included, the numbering is referred to as "signal peptide exclusive" or "SPE." For example, F328S is the SPI numbering of the same amino acid as F309S in the SPE numbering. Unless otherwise indicated, all amino acid numbering refers to the corresponding amino acid in the full-length, wild-type human Factor VIII sequence (hFVIII-FL-AA) presented in FIG. 16 as SEQ ID NO: 39.

[0070] As described herein, the codon-modified polynucleotide results in increased expression of transgenic factor VIII in vivo (e.g., when administered as part of a gene therapy vector) compared to the expression level of factor VIII provided by a naturally encoded factor VIII construct (e.g., a polynucleotide encoding the same factor VIII construct using wild-type human codons). As used herein, the term "increased expression" refers to an increase in the activity level of transgenic factor VIII in the blood of an animal administered the codon-modified polynucleotide encoding factor VIII compared to the activity level of transgenic factor VIII in the blood of an animal administered the naturally encoded factor VIII construct. The activity level can be measured using any factor VIII activity known in the art, for example, the two-step chromogenic factor X activation assay described in chapter 2.7.4 of the European Pharmacopoeia 9.0. An exemplary assay for determining factor VIII activity is the Technochrome FVIII assay (Technoclone, Vienna, Austria).

[0071] In some embodiments, increased bioavailability means that the level of transgenic Factor VIII polypeptide in the blood of an animal administered a codon-modified Factor VIII polynucleotide is at least 25% greater than the level of transgenic Factor VIII polypeptide in the blood of an animal administered a naturally encoded Factor VIII polynucleotide. In some embodiments, increased bioavailability means that the level of transgenic Factor VIII polypeptide in the blood of an animal administered an improved gene therapy vector comprising a codon-modified Factor VIII polynucleotide is at least 25% greater than the level of transgenic Factor VIII polypeptide in the blood of an animal administered a different gene therapy vector comprising the same or a different codon-modified Factor VIII polynucleotide. In some embodiments, increased expression means at least 50% higher, at least 75% higher, at least 100% higher, at least 3 fold higher, at least 4 fold higher, at least 5 fold higher, at least 6 fold higher, at least 7 fold higher, at least 8 fold higher, at least 9 fold higher, at least 10 fold higher, at least 15 fold higher, at least 20 fold higher, at least 25 fold higher, at least 30 fold higher, at least 40 fold higher, at least 50 fold higher, at least 60 fold higher, at least 70 fold higher, at least 80 fold higher, at least 90 fold higher, at least 100 fold higher, at least 125 fold higher, at least 150 fold higher, at least 175 fold higher, at least 200 fold higher, at least 225 fold higher, or at least 250 fold higher transgenic Factor VIII activity in the blood of an animal administered the codon modified Factor VIII polynucleotide.

[0072] "Factor VIII activity" herein refers to the ability to promote the cleavage of a factor X polypeptide by factor IXa, e.g., factor IXa cofactor activity, by hydrolyzing the Arg194-Ile195 peptide bond in wild-type factor IX and activating factor X to factor Xa. Activity levels can be measured using any factor VIII activity assay known in the art. Suitable assays are outlined herein. An exemplary assay for determining factor VIII activity is the two-step chromogenic factor X activation assay described in chapter 2.7.4 of the European Pharmacopoeia 9.0.

[0073] As used herein, the term "biopotency" refers to the amount of activity of factor VIII in a subject's blood in vivo or in cell culture supernatant in vitro. In some embodiments, biopotency refers to the amount of activity per unit volume, e.g., units of factor XIa cofactor activity per mL of blood in vivo or per mL of cell culture supernatant in vitro. In some embodiments, biopotency is expressed as a fold increase over a first level, e.g., naturally encoded factor VIII protein or codon-optimized native factor VIII (e.g., "wild-type" recombinant FVIII protein). In some embodiments, as used herein, exogenously expressed factor VIII biopotency refers to the amount of factor VIII activity provided by recombinant factor VIII protein expressed from a gene therapy vector. That is, the amount of factor VIII activity in blood or cell culture supernatant after taking into account the baseline amount of any native factor VIII activity. Thus, increased biopotency can be achieved by either or both increasing the expression level of the exogenous Factor VIII protein and / or increasing the specific activity of the exogenous Factor VIII protein, including, for example, amino acid substitutions (e.g., X5 mutations) that result in higher specific activity.

[0074] In some embodiments, the therapeutic potential of a Factor VIII polynucleotide composition is assessed, for example, instead of or in addition to increasing Factor VIII expression and / or bioavailability, by increasing Factor VIII activity in the blood of an animal administered the Factor VIII polynucleotide. In some embodiments, as used herein, increasing Factor VIII activity means that the increase in Factor VIII activity in the blood of an animal administered the codon-modified Factor VIII polynucleotide, relative to the baseline Factor VIII activity in the blood of the animal prior to administration of the codon-modified Factor VIII polynucleotide, is greater than the increase in Factor VIII activity in the blood of an animal administered the naturally encoded Factor VIII polynucleotide, relative to the baseline Factor VIII activity in the blood of the animal prior to administration of the naturally encoded Factor VIII polynucleotide. In some embodiments, increased factor VIII activity means that the increase in factor VIII activity in the blood of an animal administered a codon modified factor VIII polynucleotide relative to the baseline level of factor VIII activity in the animal's blood prior to administration of the codon modified factor VIII polynucleotide is at least 25% greater than the increase in factor VIII activity level in the blood of an animal administered a naturally encoded factor VIII polynucleotide relative to the baseline level of factor VIII activity in the animal prior to administration of the naturally encoded factor VIII polynucleotide. In some embodiments, increased factor VIII activity means that the increase in factor VIII activity in the blood of an animal administered an improved gene therapy vector relative to the baseline level of factor VIII activity in the animal's blood prior to administration of the improved gene therapy vector comprising a codon modified factor VIII polynucleotide is at least 25% greater than the increase in factor VIII activity level in the blood of an animal administered a different gene therapy vector relative to the baseline level of factor VIII activity in the animal prior to administration of a different gene therapy vector comprising the same or a different codon modified factor VIII polynucleotide.In some embodiments, increased factor VIII activity refers to an increase in factor VIII activity in the blood of an animal administered a codon modified factor VIII polynucleotide relative to a baseline level of factor VIII activity in the blood of the animal prior to administration of the codon modified factor VIII polynucleotide, compared to an increase in the level of factor VIII activity in the blood of an animal administered a naturally encoded factor VIII polynucleotide or a different gene therapy vector comprising the same or a different codon modified factor VIII polynucleotide, relative to a baseline level of factor VIII activity in the animal prior to administration of the naturally encoded factor VIII polynucleotide or a different gene therapy vector comprising the same or a different codon modified factor VIII polynucleotide. By "activity" is meant at least 50% greater, at least 75% greater, at least 100% greater, at least 3 times greater, at least 4 times greater, at least 5 times greater, at least 6 times greater, at least 7 times greater, at least 8 times greater, at least 9 times greater, at least 10 times greater, at least 15 times greater, at least 20 times greater, at least 25 times greater, at least 30 times greater, at least 40 times greater, at least 50 times greater, at least 60 times greater, at least 70 times greater, at least 80 times greater, at least 90 times greater, at least 100 times greater, at least 125 times greater, at least 150 times greater, at least 175 times greater, at least 200 times greater, at least 225 times greater, or at least 250 times greater. Activity is measured using a two-step chromogenic factor X activation assay as described herein in Chapter 2.7.4 of the European Pharmacopoeia 9.0.

[0075] As described herein, the codon-modified polynucleotide results in increased vector production compared to the level of vector production provided by a naturally encoded factor VIII construct (e.g., a polynucleotide encoding the same factor VIII construct using wild-type human codons). As used herein, the term "increased virus production" refers to increased vector yield (e.g., titer per liter of culture) in a cell culture seeded with a codon-modified polynucleotide encoding factor VIII compared to the vector yield in a cell culture seeded with a naturally encoded factor VIII construct. Vector yield can be measured using any vector titer assay known in the art. An exemplary assay for determining vector yield (e.g., AAV vector yield) is qPCR targeting AAV2 inverted terminal repeats (Aurnhammer, Human Gene Therapy Methods:Part B 23:18-28(2012)).

[0076] In some embodiments, increased virus production means that the yield of the codon-modified vector is at least 25% higher than that of the naturally encoded factor VIII construct under the same type of culture. In some embodiments, increased virus production means that the yield of the improved vector comprising the codon-modified factor VIII polynucleotide is at least 25% higher than that of a different vector comprising the same or different codon-modified factor VIII polynucleotide. In some embodiments, increased vector production means that the yield of the codon-modified vector is at least 50% higher, at least 75% higher, at least 100% higher, at least 3-fold higher, at least 4-fold higher, at least 5-fold higher, at least 6-fold higher, at least 7-fold higher, at least 8-fold higher, at least 9-fold higher, at least 10-fold higher, at least 15-fold higher, or at least 20-fold higher.

[0077] As used herein, the term "hemophilia" refers to a group of conditions characterized largely by reduced clotting or blood coagulation. Hemophilia can refer to hemophilia A, B, or C, or a combination of all three disease types. Hemophilia A (hemophilia A) is caused by reduced or lost factor VIII (FVIII) activity and is the most prominent of the hemophilia subtypes. Hemophilia B (hemophilia B) is due to a loss or reduced factor IX (FIX) clotting function. Hemophilia C (hemophilia C) is the result of a loss or reduced factor XI (FXI) clotting activity. Hemophilia A and B are X-linked disorders, while hemophilia C is autosomal. Conventional treatments for hemophilia include prophylactic and on-demand administration of clotting factors such as FVIII, FIX (including Bebulin®-VH), and FXI, as well as FEIBA-VH, desmopressin, and plasma infusions.

[0078] As used herein, the term "FVIII gene therapy" includes any therapeutic approach that provides a patient with a nucleic acid encoding factor VIII to alleviate, reduce, or prevent recurrence of one or more symptoms (e.g., clinical factors) associated with hemophilia. The term encompasses providing any compound, drug, procedure, or regimen that includes a nucleic acid encoding a factor VIII molecule (e.g., a factor VIII variant), including any modified form of factor VIII, to maintain or improve the health of a patient with hemophilia. One of skill in the art will appreciate that any course of FVIII therapy or dose of FVIII therapeutic agent may be modified based on, for example, the results obtained in accordance with the present disclosure.

[0079] As used herein, the term "factor VIII gene therapy" or "FVIII gene therapy" includes any therapeutic approach that provides a patient with a nucleic acid encoding a factor VIII polypeptide to alleviate, reduce, or prevent the recurrence of one or more symptoms (e.g., clinical factors) associated with factor VIII deficiency (e.g., hemophilia A). The term encompasses providing any compound, drug, procedure, or regimen that includes a nucleic acid encoding a factor VIII molecule, including any modified form of factor VIII (e.g., factor VIII variants having X5 mutations, B-domain deletions, and / or glycosylated peptides inserted into the B-domain linker polypeptide), to maintain or improve the health of a patient with factor VIII deficiency (e.g., hemophilia A). One of skill in the art will appreciate that any course of FVIII gene therapy or dosage of a therapeutic agent for FVIII gene therapy may be modified based on, for example, the results obtained in accordance with the present disclosure.

[0080] As used herein, the term "bypass therapy" includes any therapeutic approach that provides a patient with a non-factor VIII hemostatic agent, compound, or clotting factor to alleviate, reduce, or prevent recurrence of one or more symptoms (e.g., clinical factors) associated with hemophilia. Non-factor VIII compounds and clotting factors include, but are not limited to, factor VIII inhibitor bypass activity (FEIBA), recombinant activated factor VII (FVIIa), prothrombin complex concentrate, and activated prothrombin complex concentrate. These non-factor VIII compounds and clotting factors may be recombinant or plasma-derived. One of skill in the art will appreciate that any course of bypass therapy or dose of bypass therapy may be modified based on, for example, the results obtained in accordance with the present disclosure.

[0081] As used herein, "combination therapy," including administration of a nucleic acid encoding a factor VIII molecule and a conventional hemophilia A therapeutic, includes any therapeutic approach that provides a patient with both a nucleic acid encoding a factor VIII molecule and a factor VIII molecule and / or a non-factor VIII hemostatic agent (e.g., a bypassing therapy) to alleviate, reduce, or prevent the recurrence of one or more symptoms (e.g., clinical factors) associated with hemophilia. The term encompasses providing any compound, drug, procedure, or regimen that is useful for maintaining or improving the health of a hemophilia patient, including a nucleic acid encoding a factor VIII molecule, including any modified form of factor VIII, including any of the therapeutic agents described herein.

[0082] The term "therapeutically effective amount or dose" or "therapeutically sufficient amount or dose" or "effective or sufficient amount or dose" refers to a dose that provides a therapeutic effect to the subject to which it is administered. For example, a therapeutically effective amount of a drug useful for treating hemophilia can be an amount that is capable of preventing or alleviating one or more symptoms associated with hemophilia.

[0083] In some embodiments, a therapeutically effective treatment results in a reduction in the frequency and / or severity of bleeding events in a subject.

[0084] In some embodiments, a therapeutically effective treatment results in an increase in the activity of Factor VIII in the patient's bloodstream compared to the activity before treatment.

[0085] As used herein, the term "gene" refers to a segment of a DNA molecule that encodes a polypeptide chain (e.g., a coding region). In some embodiments, a gene is positioned by regions immediately preceding, immediately following, and / or intervening regions (e.g., control elements such as promoters, enhancers, polyadenylation sequences, 5' untranslated regions, 3' untranslated regions, or introns) that are involved in producing the polypeptide chain.

[0086] As used herein, the term "control elements" means nucleotide sequences such as promoters, enhancers, terminators, polyadenylation sequences, introns, and the like that provide for the expression of a coding sequence in a cell.

[0087] As used herein, the term "promoter element" refers to a nucleotide sequence that helps control the expression of a coding sequence. Generally, promoter elements are located 5' of the translation start site of a gene. However, in certain embodiments, promoter elements may be located within an intron sequence or 3' of a coding sequence. In some embodiments, promoters useful in gene therapy vectors are derived from the native gene of the target protein (e.g., the factor VIII promoter). In some embodiments, promoters useful in gene therapy vectors are specific for expression in a particular cell or tissue of the target organism (e.g., a liver-specific promoter). In still other embodiments, one of several well-characterized promoter elements is used in the gene therapy vectors described herein. Non-limiting examples of well-characterized promoter elements include the CMV early promoter, the β-actin promoter, and the methyl-CpG binding protein 2 (MeCP2) promoter. In some embodiments, the promoter is a constitutive promoter that drives substantially constant expression of the target protein. In other embodiments, the promoter is an inducible promoter that drives expression of the target protein in response to a particular stimulus (e.g., exposure to a particular treatment or agent). For a review of promoter design for AAV-mediated gene therapy, see Gray et al. (Human Gene Therapy 22:1143-53 (2011)), the contents of which are incorporated by reference in their entirety and for all purposes.

[0088] As used herein, "CRM8" element refers to a cis-acting regulatory module derived from the SERPINA1 gene (NCBI accession number NM_000295.4) that enhances the expression of a liver-specific, functionally linked gene, such as a sequence encoding a factor VIII polypeptide, that has high sequence identity with SEQ ID NO:5. In some embodiments, the CRM8 element is identical to SEQ ID NO:5. As used herein, CRM8 element refers to a single copy of a regulatory element, which in some embodiments is contained in one or more copies, such as 1, 2, 3, or more copies, in a factor VIII polynucleotide. For more information regarding CRM elements such as CRM8, see Chuah MK et al., Mol Ther., 22(9):1605-13 (2014), which is incorporated herein by reference.

[0089] As used herein, the term "operably linked" refers to the relationship between a first reference nucleotide sequence (e.g., a gene) and a second nucleotide sequence (e.g., a regulatory control element) that allows the second nucleotide sequence to affect one or more properties (e.g., transcription rate) associated with the first reference nucleotide sequence. In the present disclosure, a regulatory control element is operably linked to a Factor VIII transgene when the regulatory element is positioned within a gene therapy vector such that it affects transcription of the Factor VIII transgene (e.g., has a stimulatory or tissue-selective effect).

[0090] As used herein, the term "vector" refers to any vehicle used to transfer a nucleic acid (e.g., encoding a Factor VIII gene therapy construct) into a host cell. In some embodiments, a vector includes a replicon that functions to replicate the vehicle along with the target nucleic acid. Non-limiting examples of vectors useful for gene therapy include plasmids, phages, cosmids, artificial chromosomes, and viruses that function as autonomous replication units in vivo. In some embodiments, a vector is a viral vehicle for introducing a target nucleic acid (e.g., a codon-modified polynucleotide encoding a Factor VIII variant). Many modified eukaryotic viruses are known in the art that are useful for gene therapy. For example, adeno-associated viruses (AAV) are particularly suitable for use in human gene therapy because humans are the natural host of this virus, the natural virus is not known to contribute to any disease, and these viruses induce a mild immune response.

[0091] As used herein, the term "Factor VIII viral vector" refers to a recombinant virus comprising a Factor VIII polynucleotide encoding a Factor VIII polypeptide sufficient for expression of the Factor VIII polypeptide when introduced into a suitable animal host (e.g., human). The definition of Factor VIII viral vector specifically includes recombinant viruses in which a codon-modified Factor VIII polynucleotide encoding a Factor VIII polypeptide has been inserted into the genome of the virus. The definition of Factor VIII viral vector also specifically includes recombinant viruses in which the native genome of the virus has been replaced with a Factor VIII polynucleotide encoding a Factor VIII polypeptide. The definition of Factor VIII viral vector includes recombinant viruses comprising a Factor VIII polynucleotide encoding a variant of Factor VIII having an X5 mutation, a B-domain deletion, and / or a glycosylated peptide inserted into the B-domain linker polypeptide.

[0092] As used herein, the term "Factor VIII virion" refers to a virion encapsulating a Factor VIII polynucleotide encoding a Factor VIII polypeptide that is specific for expression of the Factor VIII polypeptide when introduced into a suitable animal host (e.g., human). The definition of Factor VIII virion specifically includes recombinant virions encapsulating a genome into which a codon-modified Factor VIII polynucleotide encoding a Factor VIII polypeptide has been inserted. The definition of Factor VIII virions also specifically includes recombinant virions encapsulating a Factor VIII polynucleotide encoding a Factor VIII polypeptide that replaces the native genome of the virus. The definition of Factor VIII virions includes recombinant virions encapsulating a Factor VIII polynucleotide encoding a Factor VIII polypeptide that has an X5 mutation, a B-domain deletion, and / or a glycosylated peptide inserted into the B-domain linker polypeptide.

[0093] As used herein, "AAV" or "adeno-associated virus" refers to Dependoparvovirus, which belongs to the Parvoviridae family of viruses. As used herein, AAV can refer to a virus derived from a naturally occurring "wild-type" AAV genome into which a Factor VIII polynucleotide has been inserted, a recombinant virus derived from a recombinant Factor VIII polynucleotide packaged into a capsid using capsid proteins encoded by a naturally occurring AAV cap gene, or a recombinant virus derived from a recombinant Factor VIII polynucleotide packaged into a capsid using capsid proteins encoded by a non-native capsid cap gene. The definition of AAV includes AAV type 1 (AAV1), AAV type 2 (AAV2), AAV type 3 (AAV3), AAV type 4 (AAV4), AAV type 5 (AAV5), AAV type 6 (AAV6), AAV type 7 (AAV7), AAV type 8 (AAV8), and AAV type 9 (AAV9) viruses that encapsulate a Factor VIII polynucleotide, as well as viruses formed by one or more variant AAV capsid proteins that encapsulate a Factor VIII polynucleotide.

[0094] By "AAV8," "AAV-8," or "AAV serotype 8" herein is meant a virus formed by the AAV8 capsid viral proteins that encapsulates a Factor VIII polynucleotide.

[0095] As used herein, the term "CpG" refers to a cytosine-guanine dinucleotide along a single strand of DNA, where the "p" represents a phosphate bond between the two.

[0096] As used herein, the term "CpG island" refers to a region of a polynucleotide that has a statistically high density of CpG dinucleotides. As used herein, a region of a polynucleotide (e.g., a polynucleotide encoding a codon-modified Factor VIII protein) is one that, over a window of 200 base pairs, (i) has a GC content of greater than 50% and (ii) satisfies the following relationship: A CpG island is one in which the ratio of observed CpG dinucleotides per expected CpG dinucleotide is at least 0.6, as defined by TIFF0007610338000003.tif8128. For further information on how to identify a CpG island, see Gardiner-Garden M. et al., J Mol Biol., 196(2):261-82 (1987). The contents of which are expressly incorporated herein by reference in their entirety and for all purposes.

[0097] As used herein, the term "nucleic acid" refers to deoxyribonucleotides or ribonucleotides and their polymers in either single-stranded or double-stranded form, as well as their complements. The term includes nucleic acids of synthetic, natural, and non-natural origin that contain known nucleotide analogs or modified backbone residues or linkages, have similar binding properties as the reference nucleic acid, and are metabolized in a manner similar to the reference nucleotide. Examples of such analogs include, but are not limited to, phosphorothioates, phosphoramidates, methyl phosphonates, chiral-methyl phosphonates, 2-O-methyl ribonucleotides, and peptide-nucleic acids (PNAs).

[0098] The term "amino acid" refers to naturally occurring amino acids, including those encoded by the genetic code, as well as those amino acids that are later modified, e.g., hydroxyproline, y-carboxyglutamate, and O-phosphoserine. Naturally occurring amino acids can include, for example, D- and L-amino acids. Amino acids may be referred to herein by either their commonly known three letter symbols or the one-letter symbols recommended by the IUPAC-IUB Biochemical Nomenclature Commission. Nucleotides may also be referred to by their commonly accepted one-letter abbreviations.

[0099] "Modification" herein refers to amino acid substitutions, insertions, and / or deletions in a polypeptide sequence, or modifications to moieties chemically bound to a protein. For example, a modification may be an altered carbohydrate or PEG structure attached to a protein. "Amino acid modification" herein refers to amino acid substitutions, insertions, and / or deletions in a polypeptide sequence. For clarity, unless otherwise indicated, the amino acid modification is always to a DNA-encoded amino acid, e.g., the 20 amino acids for which DNA and RNA have codons.

[0100] "Amino acid substitution" or "substitution" herein refers to replacing an amino acid at a particular position of a parent polypeptide sequence with a different amino acid. In particular, in some embodiments, the substitution is for a non-naturally occurring amino acid at a particular position, either in an organism or in any organism. For example, the substitution G151K refers to a variant polypeptide in which glycine at position 151 is replaced with lysine. For clarity, a protein engineered to change the nucleic acid coding sequence but not the starting amino acid (e.g., replacing CGG (which codes for arginine) with CGA (which also codes for arginine) to increase expression levels in a host organism) is not an "amino acid substitution"; that is, if a new gene is created that codes for the same protein, but the protein has the same amino acid at the starting position, it is not an amino acid substitution. Thus, each variation of the nucleic acid that codes for the same polypeptide is implied in each sequence described, not in terms of the actual gene therapy construct, but in terms of the expression product.

[0101] "Amino acid insertion" or "insertion" as used herein means the addition of an amino acid sequence at a particular position in a parent polypeptide sequence. For example, -233E or 233E indicates the insertion of glutamic acid after position 233 and before position 234. Furthermore, -233ADE or A233ADE indicates the insertion of AlaAspGlu after position 233 and before position 234.

[0102] "Amino acid deletion" or "deletion" as used herein means removing an amino acid sequence at a particular position in a parent polypeptide sequence. For example, E233- or E233#, E233() or E233del indicate a deletion of glutamic acid at position 233. Additionally, EDA233- or EDA233# indicates a deletion of the sequence GluAspAla starting at position 233. The terms "identical" or percent "identity" in the context of two or more nucleic acid or peptide sequences, refer to two or more sequences or subsequences that are the same or have a specified percentage of amino acid residues or nucleotides that are the same (i.e., about 60% identity over a given region, preferably 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher identity when compared and aligned for maximum identity over a comparison window or designated region), as measured using the BLAST or BLAST 2.0 sequence comparison algorithm with the default parameters described below, or by manual alignment and visual inspection.

[0103] As is known in the art, a number of different programs can be used to identify whether a protein (or nucleic acid, as discussed further below) has sequence identity or similarity to a known sequence. Sequence identity and / or similarity may be determined using, but is not limited to, the local sequence identity algorithm of Smith & Waterman, Adv. Appl. Math., 2:482 (1981), the sequence identity alignment algorithm of Needleman & Wunsch, J. Mol. Biol., 48:443 (1970), the similarity search method of Pearson & Lipman, Proc. Natl. Acad. Sci. USA, 85:2444 (1988), computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group, 575 Science Drive, Madison, WI), the Best Fit algorithm as described by Devereux et al., Nucl. Acid Res., 12:387-395 (1984), and the sequence identity alignment algorithm of Needleman & Wunsch, J. Mol. Biol., 48:443 (1970). The percent identity is determined using standard techniques known in the art, including by the Fit sequence program, preferably using default settings, or by inspection. Preferably, the percent identity is calculated by FastDB, based on the following parameters: mismatch penalty of 1; gap penalty of 1; gap size penalty of 0.33; and joining penalty of 30. "Current Methods in Sequence Comparison and Analysis," Macromolecule Sequencing and Synthesis, Selected Methods and Applications, pp 127-149 (1988), Alan R. Liss, Inc. (all of which are incorporated by reference).

[0104] One example of a useful algorithm is PILEUP. PILEUP creates a multiple sequence alignment from a group of related sequences using progressive pairwise alignments. It can also plot a tree showing the clustering relationships used to create the alignment. PILEUP uses a simplification of the progressive alignment method of Feng & Doolittle, J. Mol. Evol. 35:351-360 (1987). The method is similar to that described in Higgins & Sharp CABIOS 5:151-153 (1989), both of which are incorporated by reference. Useful PILEUP parameters include a default gap weight of 3.00, a default gap length weight of 0.10, and weighted end gaps.

[0105] Another example of a useful algorithm is the BLAST algorithm described in Altschul et al., J. Mol. Biol. 215, 403-410, (1990); Altschul et al., Nucleic Acids Res. 25:3389-3402 (1997); and Karlin et al., Proc. Natl. Acad. Sci. USA 90:5873-5787 (1993), all of which are incorporated by reference. A particularly useful BLAST program is the WU-BLAST-2 program, obtained from Altschul et al., Methods in Enzymology, 266:460-480 (1996); http: / / blast.wustl / edu / blast / README.html. WU-BLAST-2 uses several search parameters, most of which are set to the default values. The adjustable parameters are set to the following values: overlap span=1, overlap fraction=0.125, word threshold (T)=11. The HSP S and HSP S2 parameters are dynamic values ​​and are established by the program itself depending on the composition of the particular sequence and the particular database in which the sequence of interest is searched. However, these values ​​may be adjusted to increase sensitivity.

[0106] A further useful algorithm is Gapped BLAST, reported by Altschul et al., Nucl. Acids Res., 25:3389-3402, which is incorporated by reference. Gapped BLAST uses the BLOSUM-62 substitution score, the threshold T parameter is set to 9, triggers ungapped extensions with a 2-hit strategy, imposes a cost of 10+k on a gap length of k, Xu is set to 16, and Xg is set to 40 in the database search phase and 67 in the output phase of the algorithm. Gapped alignments are triggered by scores corresponding to approximately 22 bits.

[0107] Percent amino acid sequence identity is determined by dividing the number of matching identical residues in the aligned region by the total number of residues in the "longer" sequence. The "longer" sequence is the one that has the most actual residues in the aligned region (gaps introduced by WU-Blast-2 to maximize the alignment score are ignored). Similarly, "percent (%) nucleic acid sequence identity" with respect to the coding sequence of the identified polypeptide is defined as the percentage of nucleotide residues in the candidate sequence that are identical to the nucleotide residues in the coding sequence of the cell cycle protein. A preferred method utilizes the BLASTN module of WU-BLAST-2 set to default parameters, with overlap span and overlap fraction set to 1 and 0.125, respectively.

[0108] Alignment may include introducing gaps into the sequences to be aligned. Furthermore, for sequences that contain more or fewer amino acids than the protein encoded by the sequence of FIG. 1 (SEQ ID NO:1), it is understood that in one embodiment, the percentage of sequence identity is determined based on the number of identical amino acids or nucleotides relative to the total number of amino acids or nucleotides. Thus, for example, as explained in more detail below, the sequence identity of a sequence shorter than the sequence shown in FIG. 1 (SEQ ID NO:1) is determined in one embodiment using the number of nucleotides in the shorter sequence. In calculating the percent identity, no relative weight is assigned to the occurrence of various sequence changes, such as insertions, deletions, substitutions, etc.

[0109] In one embodiment, only identities are given a positive score (+1) and any form of sequence variation, including gaps, is assigned a value of "0", thus eliminating the need for the weighting scale or parameters described below when calculating sequence similarity. Percent sequence identity can be calculated, for example, by dividing the number of matching identical residues in the aligned region by the total number of residues in the "shorter" sequence and multiplying by 100. The "longer" sequence is the one that has the most actual residues in the aligned region.

[0110] The term "allelic variant" refers to polymorphisms of a gene at a particular locus, as well as cDNA derived from the mRNA transcript of the gene and the polypeptides encoded thereby. The term "preferred mammalian codons" refers to a subset of codons most frequently used in proteins expressed in mammalian cells from the set of codons encoding amino acids selected from the following list: Gly (GGC, GGG); Glu (GAG); Asp (GAC); Val (GTG, GTC); Ala (GCC, GCT); Ser (AGC, TCC); Lys (AAG); Asn (AAC); Met (ATG); Ile (ATC); Thr (ACC); Trp (TGG); Cys (TGC); Tyr (TAT, TAC); Leu (CTG); Phe (TTC); Arg (CGC, AGG, AGA); Gln (CAG); His (CAC); and Pro (CCC).

[0111] As used herein, the term codon modification means that in a polynucleotide sequence encoding a polypeptide (e.g., a variant Factor VIII protein), at least one codon of a native polynucleotide encoding the polypeptide has been altered to improve a property of the polynucleotide sequence. In some embodiments, the improved property promotes increased transcription of the mRNA encoding the polypeptide, increased stability of the mRNA (e.g., improved mRNA half-life), increased translation of the polypeptide, and / or increased packaging of the polynucleotide in a vector. Non-limiting examples of modifications that can be used to achieve improved properties include altering the codon usage and / or distribution for particular amino acids, adjusting global and / or local GC content, removing AT-rich sequences, removing repetitive sequence elements, adjusting global and / or local CpG dinucleotide content, removing potential regulatory elements (e.g., TATA box and CCAAT box elements), removing intron / exon splice sites, improving regulatory sequences (e.g., introduction of Kozak consensus sequences), and removing sequence elements that can form secondary structures (e.g., stem-loops) in the transcribed mRNA.

[0112] As detailed herein, there are various nomenclatures that refer to components of the disclosure herein. "CS number" (e.g., "CS12", "CS04", etc.) refers to a codon-modified polynucleotide encoding a FVIII polypeptide and / or the encoded polypeptide, including variants. For example, CS12-FL refers to the full-length codon-modified CS12 polynucleotide sequence or the amino acid sequence encoded by the CS12 polynucleotide sequence (sometimes referred to herein as "CS12-FL-AA" for the amino acid sequence and "CS12-FL-NA" for the nucleic acid sequence). Similarly, "CS12-LC" refers to either the codon-modified nucleic acid sequence encoding the light chain of the FVIII polypeptide (sometimes referred to herein as "CS12-LC-NA") or the amino acid sequence of the FVIII light chain encoded by the CS12 polynucleotide sequence (sometimes referred to herein as "CS12-LC-AA"). Similarly, CS12-HC, CS12-HC-AA, and CS12-HC-NA are the same for the FVIII heavy chain. As will be appreciated by those of skill in the art, for constructs such as CS04 that are only codon modified (e.g., do not contain additional amino acid substitutions compared to the recombinant), the amino acid sequence will be identical since the amino acid sequence is not modified by codon optimization. Thus, sequence constructs of the present disclosure include, but are not limited to, CS12-FL-NA, CS12-FL-AA, CS12-LC-NA, CS12-LC-AA, CS12-HC-AA, and CS12-HC-NA.

[0113] This nomenclature also applies to the glycosylated peptides shown in FIG. 8, where "NG1-AA" refers to the amino acid sequence and "NG1-NA" refers to the nucleic acid sequence.

[0114] The present disclosure also includes additional new Factor VIII variants, as described below using the appropriate nomenclature.

[0115] As used herein, the term "liver-specific expression" refers to the in vivo expression of a particular gene (e.g., a codon-modified transgenic Factor VIII gene) that is preferential or predominant in liver tissue compared to other tissues. In some embodiments, liver-specific expression refers to at least 50% of the total expression of a particular gene occurring in the liver tissue of a subject. In other embodiments, liver-specific expression refers to at least 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100% of the total expression of a particular gene occurring in the liver tissue of a subject. Thus, a liver-specific control element is a control element that drives the liver-specific expression of a gene in liver tissue.

[0116] As used herein, the terms "less than" X and "less than" X% refer to a range from 0 to X (excluding the value X), for example, 0% to X% (excluding X%). As used herein, these terms are used synonymously with a range starting at 0 or 0% but not including X or X%.

[0117] As used herein, the terms "less than or equal to" X or "less than or equal to" X% refer to a range from 0 to X (inclusive of the value X), for example, 0% to X% (inclusive of X%). As used herein, these terms are used synonymously with a range starting with 0 or 0% and including X or X%.

[0118] As used herein, the terms "greater than" X or "greater than" X% refer to a range from X to an upper limit (excluding the value X), e.g., X% to 100% (excluding X%). As used herein, these terms are used synonymously with a range starting at X or X% but not including X or X%, up to an upper limit which, in the case of a percentage, is 100%.

[0119] As used herein, the terms "at least" X or "at least" X% refer to a range from X to an upper limit (including the value X), for example, X% to 100% (including X%). As used herein, these terms are used synonymously with a range starting from and including X or X%, up to an upper limit that is 100% in the case of a percentage.

[0120] As used herein, the terms "'X' to 'Y'", "'X'% to 'Y'%", "'X' to 'Y'", and "'X'% to 'Y'%" refer to a range from X to Y (inclusive of values ​​X and Y), e.g., X% to Y% (inclusive of X% and Y%). As used herein, these terms are used synonymously with a range starting at X or X% and including Y or Y%.

[0121] III. Codon-modified Factor VIII Polynucleotides In some embodiments, the present disclosure provides codon-modified polynucleotides that encode factor VIII variants. These codon-modified polynucleotides, when administered in AAV-based gene therapy constructs, result in significantly improved factor VIII biopotency (e.g., activity). The codon-modified polynucleotides also show improved AAV-virion packaging compared to conventional codon-optimized constructs.

[0122] Wild-type factor VIII is encoded by a 19 amino acid signal peptide (amino acids 1-19 of SEQ ID NO: 39), which is cleaved from the encoded polypeptide prior to activation of factor VIII. As will be appreciated by those of skill in the art, the factor VIII signal peptide can be mutated, replaced with signal peptides from other genes or factor VIII genes of other organisms, or removed entirely, without affecting the sequence of the mature polypeptide that remains after the signal peptide is removed by cellular processing.

[0123] Thus, in some embodiments, the codon modified polynucleotides (e.g., nucleic acid compositions) provided herein comprise heavy and light chains of factor VIII and a short 14 amino acid B domain replacement linker (e.g., the in 1, which further comprises one or more of the five "X5 mutations" (e.g., one, two, three, four, or all five of the I105V / A127S / G151K / M166T / L171P mutations (SPI numbering; (SPE numbering is I86V / A108S / G132K / M147T / L152P, respectively) relative to the full-length human wild-type factor VIII sequence), and / or a short glycosylated peptide (e.g., NG5; SEQ ID NO: 15) inserted into the B domain replacement linker (e.g., the SQ linker).

[0124] Specifically, the X5 mutation set is based on the fact that substitution of porcine amino acids 82-176 for the corresponding human amino acids in a B-domain deleted gene therapy construct increased the activity of factor VIII expressed in HEK293 cells (W. Xiao, Short Communication). Backmutation of single porcine amino acids into a human BDD-FVIII construct identified five amino acids in the A1 domain that contribute to this phenomenon: I105V, A127S, G151K, M166T, and L171P (SPI). Introduction of combinations of these mutations into the human construct reproduced the improved activity of the larger porcine substitutions (W. Xiao, Short Communication). Thus, in some embodiments, the encoded factor VIII polypeptide comprises one or more amino acid substitutions selected from I105V, A127S, G151K, M166T, and L171P, with the entire five amino acid set being particularly useful in many embodiments.

[0125] CS12 codon-modified polynucleotide In some embodiments, the nucleic acid compositions provided herein include a codon-modified Factor VIII polynucleotide having a nucleotide sequence with high sequence identity to CS12-FL-NA (SEQ ID NO: 1) and encoding a Factor VIII polypeptide having a human Factor VIII heavy and light chains and a short 14 amino acid B domain replacement linker ("SQ" linker) containing a furin cleavage site that facilitates in vivo maturation of active FVIIIa protein, wherein the heavy chain of the Factor VIII polypeptide contains five X5 mutations (I105V, A127S, G151K, M166T, and L171P (SPI) relative to the full-length human wild-type Factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker.

[0126] In some embodiments, the Factor VIII polynucleotide has a nucleotide sequence that has at least 95% identity to CS12-FL-NA (SEQ ID NO:1). In some embodiments, the nucleotide sequence has at least 96% identity to CS12-FL-NA (SEQ ID NO:1). In some embodiments, the nucleotide sequence has at least 97% identity to CS12-FL-NA (SEQ ID NO:1). In some embodiments, the nucleotide sequence has at least 98% identity to CS12-FL-NA (SEQ ID NO:1). In some embodiments, the nucleotide sequence has at least 99% identity to CS12-FL-NA (SEQ ID NO:1). In some embodiments, the nucleotide sequence has at least 99.5% identity to CS12-FL-NA (SEQ ID NO:1). In some embodiments, the nucleotide sequence has at least 99.9% identity to CS12-FL-NA (SEQ ID NO:1). In some embodiments, the nucleotide sequence is identical to CS12-FL-NA (SEQ ID NO:1).

[0127] In some embodiments, the Factor VIII variant encoded by the codon modified polynucleotide has an amino acid sequence with high sequence identity to CS12-FL-AA (SEQ ID NO: 2), including five X5 mutations (I105V / A127S / G151K / M166T / L171P (SPI) relative to the full-length human wild-type Factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker.

[0128] In some embodiments, the amino acid sequence of the encoded factor VIII variant has at least 97% identity to CS12-FL-AA (SEQ ID NO: 2), including five X5 mutations (I105V / A127S / G151K / M166T / L171P (SPI) relative to the full-length human wild-type factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker.

[0129] In some embodiments, the amino acid sequence of the encoded factor VIII variant has at least 98% identity with CS12-FL-AA (SEQ ID NO: 2), including five X5 mutations (I105V / A127S / G151K / M166T / L171P (SPI) relative to the full-length human wild-type factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker.

[0130] In some embodiments, the amino acid sequence of the encoded factor VIII variant has at least 99% identity to CS12-FL-AA (SEQ ID NO: 2), including five X5 mutations (I105V / A127S / G151K / M166T / L171P (SPI) relative to the full-length human wild-type factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker.

[0131] In some embodiments, the amino acid sequence of the encoded factor VIII variant has at least 99.5% identity with CS12-FL-AA (SEQ ID NO: 2), including five X5 mutations (I105V / A127S / G151K / M166T / L171P (SPI) relative to the full-length human wild-type factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker.

[0132] In some embodiments, the amino acid sequence of the encoded factor VIII variant has at least 99.9% identity with CS12-FL-AA (SEQ ID NO: 2), including five X5 mutations (I105V / A127S / G151K / M166T / L171P (SPI) relative to the full-length human wild-type factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker.

[0133] In some embodiments, the amino acid sequence of the encoded Factor VIII variant is relative to CS12-FL-AA (SEQ ID NO:2).

[0134] Factor VIII B domain replacement linker As mentioned above, the junction between the heavy and light chains of FVIII (e.g., the B domain of wild-type factor VIII) is modified in the factor VIII variants described herein. Removal of the B domain from wild-type factor VIII constructs does not appear to affect the activity of the activated enzyme (e.g., FVIIIa), likely because the B domain is removed during activation. Due to the size limitations of AAV packaging capacity, B domain deletion, truncation, and / or linker replacement variants should improve the efficacy of FVIII gene therapy constructs. The most used B domain replacement linker to date is the SQ FVIII, which retains only 14 amino acids of the B domain as a linker sequence. Another variant of porcine VIII ("OBI-1" described in U.S. Pat. No. 6,458,563) is well expressed in CHO cells and has a slightly longer linker of 24 amino acids. In some embodiments, the factor VIII constructs encoded by the codon-modified polynucleotides described herein comprise an SQ B domain linker sequence. In other embodiments, the Factor VIII construct encoded by the codon modified polynucleotides described herein comprises an OBI-1 type B domain linker sequence.

[0135] Although the factor VIII B domain is not essential for activity, the B domain contains several residues that are post-translationally modified, for example, by N-linked or O-linked glycosylation. In silico analysis of wild-type factor VIII B domain (Prediction of N-glycosylation sites in human proteins, R. Gupta, E. Jung and S. Brunak, in preparation (2004)) predicts that at least four of these sites are glycosylated in vivo. These modifications in the B domain are believed to contribute to the post-translational regulation and / or half-life of factor VIII in vivo. Thus, in some embodiments, the polypeptide linker of the encoded factor VIII constructs described herein comprises one or more glycosylation sequences to allow for in vivo glycosylation. In some embodiments, the polypeptide linker comprises at least one consensus glycosylation sequence (e.g., an N-linked or O-linked glycosylation consensus sequence). In some embodiments, the polypeptide linker comprises at least two consensus glycosylation sequences. In some embodiments, the polypeptide linker comprises at least three consensus glycosylation sequences. In some embodiments, the polypeptide linker comprises at least four consensus glycosylation sequences. In some embodiments, the polypeptide linker comprises at least five consensus glycosylation sequences. In some embodiments, the polypeptide linker comprises at least six, seven, eight, nine, ten, or more consensus glycosylation sequences.

[0136] In some embodiments, the polypeptide linker comprises at least one N-linked glycosylation sequence NXS / T, where X is any amino acid other than P, S, or T. In some embodiments, the polypeptide linker comprises at least two N-linked glycosylation sequences NXS / T, where X is any amino acid other than P, S, or T. In some embodiments, the polypeptide linker comprises at least three N-linked glycosylation sequences NXS / T, where X is any amino acid other than P, S, or T. In some embodiments, the polypeptide linker comprises at least four N-linked glycosylation sequences NXS / T, where X is any amino acid other than P, S, or T. In some embodiments, the polypeptide linker comprises at least five N-linked glycosylation sequences NXS / T, where X is any amino acid other than P, S, or T. In some embodiments, the polypeptide linker comprises at least 6, 7, 8, 9, 10, or more N-linked glycosylation sequences NXS / T, where X is any amino acid other than P, S, or T.

[0137] In some embodiments, the encoded factor VIII polypeptide described herein comprises an SQ-type B-domain linker that comprises amino acids 760-762 / 1657-1667 of the wild-type human factor VIII B-domain (FVIII-FL-AA; SEQ ID NO:39) (Sandberg et al. Thromb. Haemost. 85:93 (2001), the contents of which are incorporated herein by reference). In some embodiments, the SQ-type B-domain linker has one amino acid substitution relative to the corresponding wild-type sequence. In some embodiments, the SQ-type B-domain linker has two amino acid substitutions relative to the corresponding wild-type sequence.

[0138] In some embodiments, the glycosylated peptide is inserted into the SQ-type B domain linker. In some embodiments, the glycosylated peptide is selected from those shown in FIG. 8 (SEQ ID NOs: 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, and 35, respectively, in order of appearance). In some embodiments, the glycosylated peptide is encoded by each of the polynucleotides shown in FIG. 8 (SEQ ID NOs: 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, and 36, respectively, in order of appearance). In a particular embodiment, the NG5 glycosylated peptide (SEQ ID NO: 15) is inserted into the SQ-type B domain linker of the Factor VIII polypeptide described herein. In a particular embodiment, the NG5 glycosylated peptide is encoded by a polynucleotide having the nucleic acid sequence of SEQ ID NO: 16.

[0139] In some embodiments, the SQ-type B domain linker comprises a glycosylated peptide encoded by each of the polynucleotides shown in Figure 17 (SEQ ID NOs: 40 to 53, respectively, in the order of appearance). In certain embodiments, the SQ-type B domain linker comprises a glycosylated peptide encoded by a polynucleotide having the nucleic acid sequence of SEQ ID NO: 43.

[0140] In some embodiments, the polypeptide linker (e.g., an SQ-type B domain linker) comprises a glycosylated peptide having high sequence identity to any one of SEQ ID NOs: 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, and 35, in the order of appearance shown in Figures 8A-8B, respectively. In some embodiments, the glycosylated peptide has no more than two amino acid substitutions to any one of SEQ ID NOs: 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, and 35, in the order of appearance shown in Figures 8A-8B, respectively. In some embodiments, the glycosylated peptide has no more than one amino acid substitution to any one of SEQ ID NOs: 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, and 35, in the order of appearance shown in Figures 8A-8B, respectively. In some embodiments, the glycosylated peptide has an amino acid sequence selected from any of SEQ ID NOs: 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, and 35, in the order depicted in Figures 8A-8B, respectively. In some embodiments, the glycosylated peptide is encoded by a polynucleotide sequence having a high degree of sequence identity to a corresponding nucleotide sequence selected from SEQ ID NOs: 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, and 36, in the order depicted in Figures 8A-8B, respectively.

[0141] In some embodiments, the glycosylated peptide has no more than two amino acid substitutions with respect to SEQ ID NO: 15 and is encoded by a polynucleotide sequence having at least 90% identity to SEQ ID NO: 16. In some embodiments, the glycosylated peptide has no more than two amino acid substitutions with respect to SEQ ID NO: 15 and is encoded by a polynucleotide sequence having at least 95% identity to SEQ ID NO: 16. In some embodiments, the glycosylated peptide has no more than two amino acid substitutions with respect to SEQ ID NO: 15 and is encoded by a polynucleotide sequence having at least 98% identity to SEQ ID NO: 16.

[0142] In some embodiments, the glycosylated peptide has no more than one amino acid substitution with SEQ ID NO: 15 and is encoded by a polynucleotide sequence having at least 90% identity to SEQ ID NO: 16. In some embodiments, the glycosylated peptide has no more than one amino acid substitution with SEQ ID NO: 15 and is encoded by a polynucleotide sequence having at least 95% identity to SEQ ID NO: 16. In some embodiments, the glycosylated peptide has no more than one amino acid substitution with SEQ ID NO: 15 and is encoded by a polynucleotide sequence having at least 98% identity to SEQ ID NO: 16.

[0143] In some embodiments, the glycosylated peptide has the amino acid sequence of SEQ ID NO: 15 and is encoded by a polynucleotide sequence having at least 90% identity to SEQ ID NO: 16. In some embodiments, the glycosylated peptide has the amino acid sequence of SEQ ID NO: 15 and is encoded by a polynucleotide sequence having at least 95% identity to SEQ ID NO: 16. In some embodiments, the glycosylated peptide has the amino acid sequence of SEQ ID NO: 15 and is encoded by a polynucleotide sequence having at least 98% identity to SEQ ID NO: 16.

[0144] Cis-regulatory elements In some embodiments, the nucleic acid compositions encoding the factor VIII variants provided herein also include one or more cis-acting control elements, such as promoters and / or enhancer elements, that drive expression in vivo and are operably linked to the polynucleotide encoding the factor VIII variant. In this context, "cis-acting" means that the control elements are present on the same DNA molecule as the gene they control. As will be understood by those of skill in the art and as will be explained in more detail below, control elements suitable for use in the present invention include, but are not limited to, promoters, enhancer elements, polyadenylation signal elements, and / or inverted terminal repeat elements.

[0145] promoter Promoters useful in the present invention are operably linked to the coding region, and are generally directly linked (e.g., no additional nucleotides between the promoter and the coding region), although in some embodiments indirect linkage may be used, for example, by use of a non-functional linker, or where additional control elements that function "downstream" of the promoter but "upstream" of the coding region may be used. However, due to the size limitations of the vectors of the present invention, this is generally not preferred.

[0146] Enhancer elements In some embodiments, one or more enhancer elements are used in the factor VIII variant construct.As known in the art, enhancer elements generally drive expression in a tissue-dependent manner, e.g., primarily in a specific tissue.In general, enhancer elements are generally located "upstream" of promoter elements, as described below.Since factor VIII is primarily synthesized in the liver, in some embodiments, the nucleic acid compositions described herein comprise liver-specific control elements that substantially restrict the expression of encoded factor VIII variant to hepatocytes.

[0147] In general, the liver-specific regulatory element can be derived from any gene known to be expressed only in the liver. WO2009 / 130208 identifies several genes that are specifically expressed in the liver, including serpin peptidase inhibitor clade A member 1, also known as alpha-antitrypsin (SERPINA1; gene ID 5265), apolipoprotein CI (APOC1; gene ID 341), apolipoprotein C-IV (APOC4; gene ID 346), apolipoprotein H (APOH; gene ID 350); transthyretin (TTR; gene ID 7276), albumin (ALB; gene ID 213), aldolase B (ALDOB; gene ID 229), cytochrome P450, family 2, subfamily E, polypeptide 1 (CYP2E1; gene ID 1571), fibrinogen alpha chain (FGA; gene ID 2243), transferrin (TF; gene ID 7018), and haptoglobin-related protein (HPR; gene ID 3250). In some embodiments, the nucleic acid compositions described herein comprise liver-specific regulatory elements derived from one or more genomic loci of these proteins.Some examples of such elements are described in WO2009 / 130208, the contents of which are expressly incorporated herein by reference in their entirety for all purposes.

[0148] One example of a liver-specific control element is from the transthyretin (TTR) gene, commonly referred to as "TTRe" or "TTREnh". Hsieh JL, et al., Cancer Sci., 100(3):537-45 (2009), the contents of which are expressly incorporated herein by reference in their entirety and for all purposes. In some embodiments, the nucleic acid compositions encoding factor VIII variants described herein comprise a human TTR promoter element. In one embodiment, the human TTR promoter has a nucleic acid sequence that has high sequence identity with the hTTR promoter (SEQ ID NO: 6) shown in FIG. 4. In some embodiments, the human TTR promoter has a nucleic acid sequence that is at least 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 6.

[0149] Another example of a liver-specific regulatory element is one derived from the SERPINA1 gene, as described in PCT Publication No. WO2016 / 146757, the contents of which are expressly incorporated herein by reference in their entirety and for all purposes. One example of such an element is the CRM8 regulatory control element (SEQ ID NO:5) shown in Figure 4. In some embodiments, the SERPINA1-derived regulatory control element has a nucleic acid sequence that is at least 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical to CRM8 (SEQ ID NO:5).

[0150] In some embodiments, nucleic acid compositions encoding factor VIII variants provided herein comprise one or more SERPINA1-derived regulatory control elements, as exemplified by the construct depicted in FIG. 11. In one embodiment, the factor VIII polynucleotide comprises one SERPINA1-derived regulatory control element (e.g., CRM8). In another embodiment, the factor VIII polynucleotide comprises two SERPINA1-derived regulatory control elements (e.g., CRM8). In yet other embodiments, the factor VIII polynucleotide comprises three, four, five, six, or more SERPINA1-derived regulatory control elements (e.g., CRM8).

[0151] In one embodiment, the nucleic acid compositions encoding the Factor VIII variants provided herein comprise one or more SERPINA1-derived regulatory control elements (e.g., CRM8) and a human TTR promoter element, as illustrated in Figure 11. In one embodiment, the nucleic acid compositions encoding the Factor VIII variants provided herein comprise two CRM8 elements and a human TTR promoter element operably linked to a polynucleotide encoding the Factor VIII variant.

[0152] In some embodiments, the nucleic acid composition encoding factor VIII variant provided herein comprises one or more CRM8 elements located upstream of human TTR promoter.For example, one or more CRM8 elements are located 5' of the TTR promoter of double-stranded constructs with respect to the transcriptional direction of the molecule.This means that in (+) single-stranded constructs (e.g., when single-stranded encodes factor VIII variant), one or more CRM8 elements are located 5' of the TTR promoter.

[0153] As reported in Example 6, due to the large size of the factor VIII variant constructs described herein, a small reduction in the number of nucleotides in the factor VIII polynucleotide that is part of the AAV gene therapy vector can significantly increase the factor VIII bioactivity of the vector. Thus, in some embodiments, one or more CRM8 elements are directly linked to the 5' end of the TTR promoter, e.g., there are no exogenous nucleotides located between the CRM8 element and the TTR promoter. Similarly, in some embodiments, the TTR promoter is directly linked to the 5' end of the coding sequence of the factor VIII variant polypeptide or to the translation initiation sequence (e.g., Kozak sequence), e.g., there are no exogenous nucleotides located between the TTR promoter and the factor VIII variant gene.

[0154] Polyadenylation Signal In some embodiments, the control element of the constructs described herein (e.g., nucleic acid compositions encoding a Factor VIII variant) is a polyadenylation signal, e.g., as shown in the exemplary construct in FIG. 11. The polyadenylation signal directs the synthesis of a polyA tail at the 3' end of the mRNA transcript generated from the Factor VIII polynucleotide. Thus, the polyadenylation signal is located 3' to the Factor VIII variant coding sequence. Non-limiting examples of polyadenylation signals that can be used in the Factor IX gene therapy constructs described herein include synthetic polyadenylation signals, polyadenylation signals derived from the simian virus 40 (SV40) late gene, bovine growth hormone (BGH) polyadenylation signal, and minimal rabbit β-globin (mRBG) gene polyadenylation signal.

[0155] In some embodiments, nucleic acid compositions encoding Factor VIII variants provided herein comprise a synthetic polyadenylation signal, as exemplified by the construct shown in Figure 11. In one embodiment, the synthetic polyadenylation signal has a nucleic acid sequence that is at least 90%, 95%, 97%, or 100% identical to the synthetic polyA signal (SEQ ID NO:8) shown in Figure 4.

[0156] As reported in Example 6, due to the large size of the factor VIII variant constructs described herein, a small reduction in the number of nucleotides in the factor VIII polynucleotide that is part of the AAV gene therapy vector can significantly increase the factor VIII bioactivity of the vector.Thus, in some embodiments, the polyadenylation signal is directly linked to the 3' end of the coding sequence of the factor VIII variant polypeptide, including one or more stop codons located at the end of the coding sequence.For example, there is no exogenous nucleotide located between the factor VIII variant gene and the polyadenylation sequence.

[0157] Inverted terminal repeats In some embodiments, the nucleic acid compositions encoding the factor VIII variants provided herein also contain adeno-associated virus (AAV) internal terminal repeats (ITRs) adjacent to the factor VIII variant coding sequence and associated control elements (e.g., promoters, enhancers, polyadenylation signals, etc.). Each inverted terminal repeat forms a hairpin, which promotes self-priming for primase-independent synthesis of the second DNA strand. The ITRs also help promote packaging of the AAV genome into the AAV virion and integration into the host cell genome.

[0158] In some embodiments, the nucleic acid compositions encoding Factor VIII variants provided herein comprise a 5'ITR that has high sequence identity (e.g., at least 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical) to the AAV2 5'ITR (SEQ ID NO:4) shown in Figure 4. In some embodiments, the nucleic acid compositions encoding Factor VIII variants provided herein comprise a 3'ITR that has high sequence identity (e.g., at least 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical) to the AAV2 3'ITR (SEQ ID NO:9) shown in Figure 4.

[0159] As reported in Example 6, due to the large size of the factor VIII variant constructs described herein, a small reduction in the number of nucleotides in the factor VIII polynucleotide that is part of the AAV gene therapy vector can significantly increase the factor VIII bioactivity of the vector. Thus, in some embodiments, the 5'ITR is directly linked to the 5' end of the liver-specific element (e.g., one or more CRM8 elements) such that there are no exogenous nucleotides located between the 5'ITR sequence and the liver-specific element. Similarly, in some embodiments, the 3'ITR is directly linked to the 3' end of the polyadenylation signal such that there are no exogenous nucleotides located between the polyadenylation signal and the 3'ITR sequence.

[0160] IV. Factor VIII Expression Vector In some embodiments, the codon modified polynucleotides described herein are incorporated into expression vectors.Non-limiting examples of expression vectors include viral vectors (e.g., vectors suitable for gene therapy), plasmid vectors, bacteriophage vectors, cosmids, phagemids, artificial chromosomes, etc.In general, there are two basic types of expression vectors that are useful in the present invention: those that are used in cell culture to produce factor VIII polypeptides, and those that are used as gene therapy vectors to administer to patients to increase the endogenous level of factor VIII (either protein or activity).

[0161] Non-limiting examples of viral vectors include retroviruses, such as Moloney murine leukemia virus (MMLV), Harvey murine sarcoma virus, mouse mammary tumor virus, and Rous sarcoma virus; adenoviruses, adeno-associated viruses; SV40 viruses; polyoma viruses; Epstein-Barr virus; papilloma viruses; herpes viruses; vaccinia viruses; and polio viruses.

[0162] In many embodiments, the codon-optimized polynucleotides of the invention are used in gene therapy applications such that, upon administration to a patient, Factor VIII is produced as generally described herein. In general, the gene therapy viral vector is preferably replication-deficient such that introduction of the gene therapy vector into a patient does not result in viral spread.

[0163] Thus, in some embodiments, the codon-modified polynucleotides described herein are incorporated into gene therapy vectors. In some embodiments, the gene therapy vector is a retrovirus, particularly a replication-defective retrovirus. In some embodiments, the codon-modified polynucleotides described herein are incorporated into retroviral expression vectors. These systems have been previously reported and are generally well known in the art (Mann et al., Cell, 33:153-159, 1983; Nicolas and Rubinstein, In: Vectors: A survey of molecular cloning vectors and their uses, Rodriguez and Denhardt, eds., Stoneham: Butterworth, pp.494-513, 1988; Temin, In: Gene Transfer, Kucherlapati (ed.), New York: Plenum Press, pp.149-188, 1986). In certain embodiments, the retroviral vector is a lentiviral vector (see, e.g., Naldini et al., Science, 272(5259):263-267, 1996; Zufferey et al., Nat Biotechnol, 15(9):871-875, 1997; Blomer et al., J Virol., 71(9):6641-6649, 1997; U.S. Patent Nos. 6,013,516 and 5,994,136). Protocols for the generation of replication-defective retroviruses are known in the art. For reviews, see Kriegler, M., Gene Transfer and Expression, A Laboratory Manual, W.H. Freeman Co., New York (1990) and Murry, E.J., Methods in Molecular Biology, Vol. 7, Humana Press, Inc., Cliffton, NJ (1991).

[0164] A wide variety of vectors can be used to express Factor VIII polypeptides from codon-modified polypeptides in cell culture, including eukaryotic and prokaryotic expression vectors. In certain embodiments, plasmid vectors are envisioned for use in expressing Factor VIII polypeptides in cell culture. Generally, plasmid vectors containing replicon and control sequences derived from a species compatible with the host cell are used in connection with these hosts. The vector may carry a replication site, as well as marking sequences that allow phenotypic selection in transformed cells. The plasmid contains a codon-modified polynucleotide encoding a Factor VIII polypeptide operably linked to one or more control sequences, such as a promoter.

[0165] Non-limiting examples of vectors for expression in prokaryotes include plasmids such as pRSET, pET, pBAD, and the like, and promoters used in prokaryotic expression vectors include lac, trc, trp, recA, araBAD, and the like. Examples of vectors for expression in eukaryotes include: (i) for expression in yeast, vectors such as pAO, pPIC, pYES, pMET, which use promoters such as AOX1, GAP, GAL1, AUG1, etc.; (ii) for expression in insect cells, vectors such as pMT, pAc5, pIB, pMIB, pBAC, etc., which use promoters such as PH, p10, MT, Ac5, OpIE2, gp64, polh, etc., and (iii) for expression in mammalian cells, vectors such as pSVL, pCMV, pRc / RSV, pcDNA3, pBPV, etc., and vectors derived from viral systems such as vaccinia virus, adeno-associated virus, herpes virus, retrovirus, etc., which use promoters such as CMV, SV40, EF-1, UbC, RSV, ADV, BPV, and β-actin.

[0166] Adeno-associated virus (AAV) vectors In one embodiment, the codon-modified polynucleotides described herein are incorporated into adeno-associated virus (AAV)-based gene therapy vectors. The AAV system has been previously described and is generally well known in the art (Kelleher and Vos, Biotechniques, 17(6):1110-17(1994); Cotten et al., Proc Natl Acad Sci USA, 89(13):6094-98(1992); Curiel, Nat Immun, 13(2-3):141-64(1994); Muzyczka, Curr Top Microbiol Immunol, 158:97-129(1992); and Asokan A, et al., Mol. Ther., 20(4):699-708(2012), each of which is incorporated herein by reference in its entirety and for all purposes). Details regarding the generation and use of rAAV vectors are described, for example, in U.S. Pat. Nos. 5,139,941 and 4,797,368, each of which is incorporated by reference herein in its entirety for all purposes.

[0167] Thus, in some embodiments, an AAV gene therapy vector is provided, which includes a codon-modified polynucleotide (e.g., a nucleic acid composition) comprising a nucleotide sequence having high sequence identity to a portion of CS12-FL-NA (SEQ ID NO: 1) encoding the heavy and light chains of factor VIII and a short 14 amino acid B domain replacement linker (e.g., an "SQ" linker containing a furin cleavage site that facilitates in vivo maturation of active FVIIIa protein), as described herein, and further comprising one or more of the five X5 mutations (e.g., one, two, three, four, or all five of the I105V, A127S, G151K, M166T, L171P mutations (SPI) relative to the full-length human wild-type factor VIII sequence), and / or a short glycosylated peptide (e.g., NG5; SEQ ID NO: 15) inserted into the B domain replacement linker (e.g., the SQ linker).

[0168] In some embodiments, the AAV gene therapy vector includes a codon-modified factor VIII polynucleotide having a nucleotide sequence with high sequence identity to CS12-FL-NA (SEQ ID NO: 1) and encoding a factor VIII polypeptide having human factor VIII heavy and light chains and a short 14 amino acid B domain replacement linker ("SQ" linker) containing a furin cleavage site that facilitates in vivo maturation of active FVIIIa protein, wherein the heavy chain of the factor VIII polypeptide contains five X5 mutations (I105V, A127S, G151K, M166T, and L171P (SPI) relative to the full-length human wild-type factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker. In some embodiments, the Factor VIII polynucleotide has a nucleotide sequence having at least 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% identity to CS12-FL-NA (SEQ ID NO:1).

[0169] In some embodiments, the Factor VIII variant encoded by the codon-modified polynucleotide of the AAV gene therapy vector has an amino acid sequence with high sequence identity to CS12-FL-AA (SEQ ID NO: 2), including five X5 mutations (I105V / A127S / G151K / M166T / L171P (SPI) relative to the full-length human wild-type Factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker. In some embodiments, the amino acid sequence of the encoded factor VIII variant has at least 97%, 98%, 99%, 99.5%, 99.9%, or 100% identity to CS12-FL-AA (SEQ ID NO: 2), including five X5 mutations (I105V / A127S / G151K / M166T / L171P (SPI) relative to the full-length human wild-type factor VIII sequence) and an NG5 glycosylated peptide (SEQ ID NO: 15) inserted into the SQ linker.

[0170] In some embodiments, the polynucleotide encoding the Factor VIII variant in the AAV gene therapy vector is operably linked to a promoter element having a nucleic acid sequence with high sequence identity to the hTTR promoter (SEQ ID NO:6) shown in Figure 4. In some embodiments, the promoter element has a nucleic acid sequence that is at least 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO:6.

[0171] In some embodiments, the polynucleotide encoding the factor VIII variant in the AAV gene therapy vector is operably linked to one or more liver-specific control elements having a nucleic acid sequence with high sequence identity to the CRM8 element (SEQ ID NO:5) shown in Figure 4. In some embodiments, the liver-specific control element has a nucleic acid sequence that is at least 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO:5. In some embodiments, the polynucleotide comprises one CRM8 element, as shown in Figure 11. In some embodiments, the polynucleotide comprises two CRM elements, as shown in Figure 11.

[0172] In some embodiments, a polynucleotide encoding a factor VIII variant in an AAV gene therapy vector is operably linked to one CRM8 element and a human TTR promoter element, as illustrated in Figure 11. In some embodiments, a polynucleotide encoding a factor VIII variant in an AAV gene therapy vector is operably linked to two CRM8 elements and a human TTR promoter element, as illustrated in Figure 11. As described in Example 2, the use of the hTTR promoter and one or two liver-specific CRM8 elements increased the biopotency of exogenous factor VIII in vivo in HepG2 cells by approximately 2-fold and 4-fold, respectively, compared to the use of the mouse TTR promoter and enhancer sequence (compare vCS115 and vCS116 to vCS04 in Figure 12).

[0173] As reported in Example 6, due to the large size of the factor VIII variant constructs described herein, a small reduction in the number of nucleotides in the factor VIII polynucleotide that is part of the AAV gene therapy vector can significantly increase the factor VIII bioactivity of the vector. Thus, in some embodiments, one or more CRM8 elements are directly linked to the 5' end of the TTR promoter, e.g., there are no exogenous nucleotides located between the CRM8 element and the TTR promoter. Similarly, in some embodiments, the TTR promoter is directly linked to the 5' end of the coding sequence of the factor VIII variant polypeptide or to the translation initiation sequence (e.g., Kozak sequence), e.g., there are no exogenous nucleotides located between the TTR promoter and the factor VIII variant gene.

[0174] In some embodiments, the polynucleotide encoding the Factor VIII variant in the AAV gene therapy vector is operably linked to a polyadenylation signal, for example, as shown in the exemplary construct in Figure 11. In one embodiment, the synthetic polyadenylation signal has a nucleic acid sequence that is at least 90%, 95%, 97%, or 100% identical to the synthetic polyA signal (SEQ ID NO:8) shown in Figure 4.

[0175] As reported in Example 6, due to the large size of the factor VIII variant constructs described herein, a small reduction in the number of nucleotides in the factor VIII polynucleotide that is part of the AAV gene therapy vector can significantly increase the factor VIII bioactivity of the vector.Thus, in some embodiments, the polyadenylation signal is directly linked to the 3' end of the coding sequence of the factor VIII variant polypeptide, including one or more stop codons located at the end of the coding sequence.For example, there is no exogenous nucleotide located between the factor VIII variant gene and the polyadenylation sequence.

[0176] Internal terminal repeats are necessary cis-regulatory elements for AAV-based recombinant vectors. Thus, the polynucleotides encoding factor VIII variants used in the AAV gene therapy vectors described herein comprise 5' and 3' ITR sequences. In some embodiments, the 5' ITR has high sequence identity (e.g., at least 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical) with the AAV2 5' ITR (SEQ ID NO: 4) shown in Figure 4. In some embodiments, the 3' ITR has high sequence identity (e.g., at least 90%, 95%, 96%, 97%, 98%, 99%, or 100% identical) with the AAV2 3' ITR (SEQ ID NO: 9) shown in Figure 4.

[0177] As reported in Example 6, due to the large size of the factor VIII variant constructs described herein, a small reduction in the number of nucleotides in the factor VIII polynucleotide that is part of the AAV gene therapy vector can significantly increase the factor VIII bioactivity of the vector. Thus, in some embodiments, the 5'ITR is directly linked to the 5' end of the liver-specific element (e.g., one or more CRM8 elements) such that there are no exogenous nucleotides located between the 5'ITR sequence and the liver-specific element. Similarly, in some embodiments, the 3'ITR is directly linked to the 3' end of the polyadenylation signal such that there are no exogenous nucleotides located between the polyadenylation signal and the 3'ITR sequence.

[0178] In certain embodiments, as illustrated in Figure 11, a polynucleotide contained in an AAV gene therapy vector provided herein includes, from the 5' to 3' direction, a 5' ITR sequence (e.g., having high sequence identity to SEQ ID NO: 4), one or two CRM elements having high sequence identity to SEQ ID NO: 5, an hTTR promoter element having high sequence identity to SEQ ID NO: 6, a minimal Kozak consensus sequence having high sequence identity to SEQ ID NO: 7, a Factor VIII variant polynucleotide having high sequence identity to SEQ ID NO: 1, a polyadenylation sequence (e.g., having high sequence identity to SEQ ID NO: 8), and a 3' AAV ITR sequence (e.g., having high sequence identity to SEQ ID NO: 9). In some embodiments, the described polynucleotides have high sequence identity (e.g., at least 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% identity) to the CS12-CRM8.2-Vr vector (SEQ ID NO: 3) shown in Figure 3.

[0179] The AAV gene therapy vectors described herein are used with AAV capsid proteins that encapsulate a polynucleotide encoding a variant Factor VIII polypeptide, as described herein, i.e., delivery of the viral vector that produces Factor VIII is accomplished using a viral particle that includes a capsid protein "shell" that encapsulates the viral vector.

[0180] The serotype of an AAV vector is usually defined by the capsid protein used. Several AAV serotypes have been characterized, including AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, and AAV9. Generally, any AAV serotype can be used in the factor VIII gene therapy constructs described herein. However, serotypes have different tropisms, e.g., preferentially infect different tissues. In one embodiment, since factor VIII is primarily produced in the liver, the AAV serotype of the gene therapy construct of the present disclosure is selected based on the liver tropism found in at least serotypes AAV7, AAV8, and AAV9. Thus, in one embodiment, the factor VIII gene therapy construct is an AAV7 serotype vector. In another embodiment, the factor VIII gene therapy construct is an AAV8 serotype vector. In yet another embodiment, the factor VIII gene therapy construct is an AAV9 serotype vector.

[0181] In some embodiments, a plasmid polynucleotide incorporating a codon-modified Factor VIII gene therapy genome is also provided. The plasmid is useful for generating final AAV particles (e.g., AAV virions carrying a polynucleotide encoding a variant Factor VIII polypeptide) when introduced, for example, into a mammalian cell competent for recombinant AAV production (e.g., a cell harboring nucleic acid encoding the AAV rep and cap genes, as well as helper genes for AAV production (e.g., adenovirus genes). In some embodiments, the plasmid comprises control elements that allow for replication of the plasmid (e.g., scale-up of the plasmid) in a host cell (e.g., a prokaryotic host cell such as bacteria, or a eukaryotic host cell such as yeast).

[0182] For example, the sequence of an exemplary plasmid carrying a codon modified Factor VIII gene therapy genome according to one embodiment of the present disclosure is shown in Figure 5 (CS12-CRM8.2-Vrp; SEQ ID NO: 10). The CS12-CRM8.2-Vrp plasmid comprises the CS12-CRM8.2-Vr Factor VIII gene therapy genome (shown in Figure 3 as SEQ ID NO: 3) and the plasmid backbone (shown in Figure 18 as SEQ ID NO: 54). As mentioned above, the genetic elements of the CS12-CRM8.2-Vr Factor VIII gene therapy genome are shown in Figure 4. The plasmid backbone of the CS12-CRM8.2-Vrp plasmid contains the pMB1 replicon (shown in FIG. 19 as SEQ ID NO:55; Bolivar F., Life Sci., 25(10):807-17(1979)), which facilitates replication of the plasmid in bacterial host cells, and the Bla (ApR) ampicillin resistance gene (shown in FIG. 19 as SEQ ID NO:56; Sutcliffe, PNASUSA, 75(8):3737-41(1978)), which facilitates selection of bacterial host cells transformed by the plasmid. The location of each element in the CS12-CRM8.2-Vrp plasmid is shown in Table 1 below.

[0183] Table 1. Elements present in the CS12-CRM8.2-Vrp plasmid TIFF0007610338000004.tif89168

[0184] In one embodiment, the plasmid incorporating the Factor VIII variant gene therapy genome has high sequence identity to the CS12-CRM8.2-Vrp plasmid (SEQ ID NO: 10) shown in Figure 5. In some embodiments, the described polynucleotides have high sequence identity (e.g., at least 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% identity) to the CS12-CRM8.2-Vrp plasmid (SEQ ID NO: 10) shown in Figure 5. In some embodiments, the described polypeptides include sequences having at least 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% identity to a Factor VIII-BDD coding sequence, e.g., a Factor VIII-BDD coding sequence disclosed herein, and high sequence identity to the remainder of the CS12-CRM8.2-Vrp plasmid shown in FIG. 5, e.g., at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100% identity to nucleotides 1-528 and 4924-7794 of SEQ ID NO: 10. In some embodiments, the described polynucleotides are plasmids that include some or all of the elements shown in Table 1. In some embodiments, one or more of the elements shown in Table 1 are replaced by a comparable element.

[0185] Generation of AAV vectors The codon-modified Factor VIII polynucleotides and viral vectors described herein are produced according to conventional methods of nucleic acid amplification and vector production. Several platforms have been developed for the large-scale production of recombinant AAV vectors. The first platform is based on introducing a plasmid containing the sequence of the desired viral genome into a mammalian cell that contains a polynucleotide encoding the AAV rep and cap genes, as well as viral replication helper genes. For reviews, see Kotin RM, Hum. Mol. Genet., 20(R1):R2-6(2011); Penaud-Budloo, M. et al., Mol Ther Methods Clin Dev., 8(8):166-80(2018); and Aponte-Ubillus JJ et al., Appl Microbiol Biotechnol., 102(3):1045-54(2018). The contents of which are expressly incorporated herein by reference in their entirety and for all purposes. The second platform is based on the construction of a stable mammalian cell line in which the desired viral genome is integrated into the mammalian cell genome, for example by co-infecting the mammalian cells with a wild-type adenovirus and a recombinant adenovirus carrying the sequence of the desired viral genome. For a review, see Penaud-Budloo, M. et al., Mol Ther Methods Clin Dev., 8(8):166-80 (2018), the contents of which are expressly incorporated herein by reference in their entirety and for all purposes. The third platform is based on co-infecting mammalian cells with a first recombinant HSV carrying the sequence of the desired viral genome and a second recombinant HSV encoding the AAVrep and cap genes. For reviews, see Penaud-Budloo, M. et al., Mol Ther Methods Clin Dev., 8(8):166-80(2018), and Aponte-Ubillus JJ et al., Appl Microbiol Biotechnol., 102(3):1045-54(2018).The contents of which are expressly incorporated herein by reference in their entirety and for all purposes. The fourth platform is based on co-infecting insect cells with a first recombinant baculovirus carrying the sequence of the desired viral genome and a second recombinant baculovirus encoding AAVrep and cap genes. For reviews, see Penaud-Budloo, M. et al., Mol Ther Methods Clin Dev., 8(8):166-80 (2018), and Aponte-Ubillus JJ et al., Appl Microbiol Biotechnol., 102(3):1045-54 (2018), the contents of which are expressly incorporated herein by reference in their entirety and for all purposes. The fifth platform is based on introducing a plasmid containing the sequence of the desired viral genome into a yeast cell that contains a polynucleotide encoding the AAVrep and cap genes, as well as viral replication helper genes. For a review, see Aponte-Ubillus JJ et al., Appl Microbiol Biotechnol., 102(3):1045-54 (2018), the contents of which are expressly incorporated by reference herein in their entirety and for all purposes.

[0186] V. Methods of Treating Hemophilia A In some embodiments, the nucleic acid compositions (e.g., codon modified polynucleotides encoding factor VIII variants) and gene therapy vectors (e.g., AAV particles comprising codon modified polynucleotides encoding factor VIII variants) described herein are administered to a hemophilia A patient for the treatment of hemophilia A according to known administration methods. Methods of administering gene therapy vectors are well known in the art. These include, but are not limited to, intravenous administration, intramuscular injection, intratissue injection, and intrahepatic administration (e.g., into the hepatic artery or into the hepatic vein). For reviews, see, e.g., Chuah MK et al., Hum Gene Ther., 23(6):557-65(2012), Chuah MK et al., J Thromb Haemost., 10(8):1566-69(2012), Chuah MK et al., J Thromb Haemost.11 Suppl 1:99-110(2013), VandenDriessche et al., Hum Gene Ther.23(1):4-6(2012), High KA, Blood, 120(23):4482-87(2012), Matrai et al., Mol Ther., 18(3):477-90(2010), and Matrai et al., Curr Opin Hematol., 17(5):387-92(2010). the contents of each of which are incorporated herein by reference.

[0187] Thus, the present disclosure provides methods of treating factor VIII deficiency (e.g., hemophilia A). In some embodiments, the methods include administering a nucleic acid composition (e.g., a codon-modified factor VIII polynucleotide construct and / or a recombinant AAV vector) described herein to a patient in need thereof. In some embodiments, the nucleic acid composition includes a codon-modified polynucleotide encoding a factor VIII variant polypeptide, e.g., having high nucleic acid sequence identity (e.g., at least 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, or 100%) to CS12-FL-NA (SEQ ID NO:1). As described herein, in some embodiments, the codon-modified polynucleotide encoding the factor VIII variant polypeptide is operably linked to a promoter (e.g., a human TTR promoter as described herein) and one or more liver-specific control elements (e.g., one or two CRM8 elements as described herein).

[0188] In some embodiments, the nucleic acid composition is part of a mammalian gene therapy vector. In certain embodiments, the mammalian gene therapy vector is a viral vector, such as a lentivirus, retrovirus, adenovirus, or adeno-associated virus vector.

[0189] In one embodiment, the gene therapy vector is an adeno-associated virus (AAV) particle that has a viral vector that encodes a codon-modified factor VIII variant coding sequence. Generally, the viral vector includes an inverted terminal repeat (ITR) at each end, one or more expression control elements (e.g., a promoter (e.g., the human TTR promoter as described herein) and one or more liver-specific control elements (e.g., one or two CRM8 elements as described herein)), a codon-modified factor VIII coding sequence, and a polyA signal sequence.

[0190] Assessment of treatment efficacy The therapeutic efficacy of hemophilia A treatment can be evaluated, for example, by measuring the factor VIII-dependent clotting potential of the blood of the subject being treated. Criteria for evaluating clotting potential include, but are not limited to, in vitro activated partial thromboplastin time assay (APPT), factor IX chromogenic activity assay, clotting time, and factor VIII antigen levels (e.g., using a factor VIII-specific ELISA). It should be noted that a therapeutic dose need not result in wild-type levels of factor VIII in the patient; rather, expression sufficient to reduce symptoms in a meaningful or measurable way is considered therapeutic for purposes of this disclosure.

[0191] According to the National Hemophilia Foundation, a subject is classified as having mild hemophilia A when the subject's plasma contains 6% to 49% of the factor VIII activity of normal human plasma. Subjects with mild hemophilia A usually bleed only after a significant injury, trauma, or surgery. In many cases, mild hemophilia is only diagnosed when an injury, surgery, or tooth extraction results in prolonged bleeding. The first episode may not occur until adulthood. Women with mild hemophilia often experience menorrhagia, or heavy menstrual periods, and may bleed heavily after giving birth.

[0192] According to the National Hemophilia Foundation, a subject is classified as having moderate hemophilia A when the subject's plasma contains 1% to 5% of the factor VIII activity of normal human plasma. Subjects with moderate hemophilia A are prone to bleeding episodes after injury. Bleeding that occurs without an obvious cause is called a spontaneous bleeding episode.

[0193] According to the National Hemophilia Foundation, when a subject's plasma contains less than 1% of the factor VIII activity of normal human plasma, the subject is classified as having severe hemophilia A. Subjects with severe hemophilia A may experience frequent spontaneous bleeding episodes that bleed after injury, often into the joints and muscles.

[0194] In some embodiments, normal human plasma is defined as containing 1 IU of factor VIII activity per mL. Thus, in some embodiments, the plasma of a subject classified as having mild hemophilia A contains 0.06-0.49 IU of factor VIII activity per mL. In some embodiments, the plasma of a subject classified as having moderate hemophilia A contains 0.01-0.05 IU of factor VIII activity per mL. In some embodiments, the plasma of a subject classified as having severe hemophilia A contains 0.01-0.05 IU of factor VIII activity per mL.

[0195] In some embodiments, a therapy is therapeutically effective when it reduces the severity of symptoms of hemophilia A, for example, by increasing the average level of factor VIII activity in the blood of a subject. Thus, in some embodiments, a hemophilia A therapy is therapeutically effective when it increases the average level of factor VIII activity in the blood / plasma of a subject. In some embodiments, a therapeutically effective therapy increases the average level of factor VIII activity in the blood / plasma of a subject by at least 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or more.

[0196] In some embodiments, a therapeutically effective treatment increases the average level of factor VIII activity in the subject's blood such that the subject is classified as having a less severe form of hemophilia A. For example, in one embodiment, a subject initially classified as having severe hemophilia A is reclassified as having moderate hemophilia A or mild hemophilia A after receiving therapeutically effective treatment. In another embodiment, a subject initially classified as having moderate hemophilia A is reclassified as having mild hemophilia A after receiving therapeutically effective treatment. In another embodiment, a subject initially classified as having mild hemophilia A is reclassified as not having hemophilia A after receiving therapeutically effective treatment.

[0197] Prescription Provided herein is a composition for use in the treatment of hemophilia A. Such a composition comprises a therapeutically effective amount of a nucleic acid composition, e.g., an AAV gene therapy vector comprising a codon-modified polynucleotide encoding factor VIII, as described herein. A therapeutically effective amount of a codon-modified factor VIII polynucleotide (e.g., an AAV gene therapy vector comprising a codon-modified factor VIII coding sequence) is mixed with a suitable pharmaceutical carrier or vehicle, e.g., for systemic administration. The final formulation of the codon-modified factor VIII polynucleotide disclosed herein is within the capabilities of one of ordinary skill in the art.

[0198] Dosage The nucleic acid composition of the present invention is administered to a patient in need thereof. The amount or dosage of the therapeutic gene therapy agent administered depends on factors such as the specific codon modified VIII polynucleotide construct, the delivery vector used, the severity of the disease, and the general characteristics of the subject. The exact dosage depends on the purpose of the treatment and can be ascertained by those skilled in the art using known techniques (see, for example, Lieberman, Pharmaceutical Dosage Forms (vols.1 3, 1992); Lloyd, The Art, Science and Technology of Pharmaceutical Compounding (1999); Pickar, Dosage Calculations (1999); and Remington: The Science and Practice of Pharmacy, 20th Edition, 2003, Gennaro, Ed., Lippincott, Williams & Wilkins). The determination of the specific dosage and dosing regimen for treating a particular subject is within the capabilities of a skilled physician. EXAMPLES

[0199] VI. Working Examples Example 1: Improvement of single-chain AAV8 vector constructs expressing FVIII by addition of an N-glycosylation linker sequence To investigate whether additional N-glycosylation sites in the SQ sequence of BDD-FVIII could increase FVIII protein expression, a set of short peptide sequences containing putative N-linked glycosylation sites was designed. Previously, McIntosh et al. (Blood 121(17):3335-44(2013)) showed that the concept of N-glycosylation at six potential sites (the "V3 peptide") led to improved FVIII expression levels in mouse plasma. Interestingly, in silico prediction of the "V3 peptide" confirmed that two of the six sites were potentially N-glycosylated in vivo.

[0200] Twelve different linker sequences, shown as NG1 to NG21 in Figures 8A-8B, were designed in the context of the codon-optimized BDD-FVIII "CS01" sequence (see WO2017 / 083762, the contents of which are incorporated herein by reference) by applying the program NetNGlyc-Database (Steentoft et al., H. EMBO J, 32(10):1478-88, 2013), with the aim of generating short sequences containing multiple N-glycosylation sites. The NetNGly platform combines nine neural networks that analyze the N-glycosylation patterns of human protein sequences. Based on the NetNGly database, the designed peptides were analyzed for their potential to convey N-glycosylation as a post-translational modification, as described in Steentoft et al., H. EMBO J, 32(10):1478-88, (2013), the contents of which are incorporated herein by reference. Among the 12 novel alternative peptides, four promising NG linkers predicted to be less immunogenic (as described below) were inserted into the 14 amino acid sized SQ sequence of the codon-optimized BDD-FVIII sequence "CS04" (SEQ ID NO: 10) (SFSQN-novel peptide-PPVLKRHQR).

[0201] Post-translational modification of the predicted N-glycosylation sites was experimentally confirmed for three vectors, including vNG4 / CS04, vNG5 / CS04, and vNG16 / CS04, by transfecting human liver Huh-7 cells and detecting the modified BDD-FVIII by anti-FVIII Western blot analysis (Figure 9). The large size of the heavy chain of the modified FVIII compared to the BDD-FVIII containing only the SQ sequence was detected by gel electrophoresis, indicating the presence of a novel N-glycosylation site. Furthermore, AAV8 infection of the human hepatic cell line HepG2 confirmed N-glycosylation, as illustrated for the expression vector vNG5 / CS04 and the highly secreted X5 variant vX5 / NG5 / CS125 (Figure 10; vX5 / NG5 / CS125 is described in Examples 3 and 5).

[0202] The focus of the linker sequence design was to generate short peptide sequences (7-17 amino acid residues) with low risk of immunogenicity. For this, in silico immunogenicity profiling Epibase™ (Lonza) was applied (HLA binding). The Epibase™ epitope prediction method includes structural and statistical layers for the prediction of immunogenicity. The structural part estimates binding affinity based on Pepscope technology as described in Desmet et al., Proteins. 58(1):53-69 (2005), the contents of which are incorporated herein by reference. The statistical part extracts information from peptide sequences and their experimental binding affinities. Based on the number of essential epitopes, the immunogenic risk of the proteins was estimated using risk scores for the relevant HLA class II allotypes (Krischmann et al., J Immunol. 15;155(12):5655-62 (1995); Verreck et al., Int Immunol. 8(3):397-404 (1996), the contents of which are incorporated herein by reference), and DRB1 (Laupeze et al., Hum Immunol. 60(7):591-7 (1999), the contents of which are incorporated herein by reference). Based on this scoring system, the immunogenic risk of peptide NG16 is moderate, that of NG4 and NG10 is low, and that of NG5 is even lower than the unmodified SQ sequence of BDD-FVIII (Table 2).

[0203] Table 2. In vivo FVIII activity after 2 weeks of AAV treatment TIFF0007610338000005.tif60170

[0204] Additionally, vectors vNG4 / CS04, vNG5 / CS04, vNG10 / CS04 and vNG16 / CS04 were analyzed in an exon 16 FVIII knockout mouse model generated in the laboratory of Haig Kazazian at the University of Pennsylvania (Table 2). Two weeks after AAV8 infection, FVIII expression levels were determined by chromogenic activity of mouse plasma samples. 4.0×10 12 Two weeks after AAV8 infection at a dose of 1.0 mg / mL, FVIII expression levels were 1.4-2.4 times higher than the vCS04 construct without peptide. Overall, construct vNG5 / CS04 showed the most favorable characteristics, including high FVIII expression levels (3.8 IU / mL), the lowest immunogenicity risk, and the shortest peptide size (7 amino acid residues). Construct vNG5 / CS04 was further tested in another FVIII mouse model, the "lineage E" model. The "lineage E" model shows immune tolerance to human FVIII (described in Reipert et al., Haemophilia. 16(Suppl 5):47-53 (2010) and van Helden et al., Blood 118(13):3698-707 (2011), the contents of which are expressly incorporated herein by reference). In this independent mouse model, elevated FVIII expression in vNG5 / CS04 was confirmed, estimated to be three-fold higher than that in vCS04.

[0205] In summary, an improved vector, named vNG5 / CS04, containing a short novel N-glycosylated peptide sequence has been developed that exhibits very low immunogenicity risk and enhanced levels of FVIII expression in vivo.

[0206] Example 2: Improvement of single-chain AAV8 vector constructs expressing FVIII by promoter / enhancer replacement The promoter cassette of the first FVIII-expressing AAV8-based single-stranded vector construct, named vCS04, contains the core promoter and enhancer sequences derived from the liver-specific mouse transthyretin (TTR) gene (Yan et al., EMBO J, 9:869-78 (1990), the contents of which are incorporated herein by reference). See FIG. 11. This liver-specific mTTR promoter / enhancer cassette was modified in two steps. First, the mouse core (basal) promoter sequence was completely replaced with the corresponding human sequence. Second, the mouse enhancer sequence was replaced with the recently reported liver-specific cis-regulatory module CRM8 (Nair et al., Blood, 123:3195-99 (2014) and Chuah et al., Mol Ther, 22:1605-13 (2014), the contents of which are incorporated herein by reference). One or two CRM8 elements were inserted upstream of the human TTR core (basal) promoter, resulting in vector constructs vCS115 and vCS116, respectively (Figure 11).

[0207] The strength of the novel promoter cassettes was evaluated in human liver-derived HepG2 cell line and "line E" mice at a dose of 4.0E+12vg / kg by in vitro and in vivo analysis. In vitro, constructs containing one CRM8 element (vCS115) and two CRM8 elements (vCS116) yielded 2.2-fold and 3.7-fold higher biopotency units, respectively, compared to the reference (vCS04) (Figure 12). In vivo, the CRM8 / hTTR promoter cassette showed comparable performance to the mTTR promoter / enhancer (Figure 12).

[0208] The CRM8-associated enhancing effect on FVIII expression was further evaluated in a triplet set of constructs combining the described promoter cassettes, including the mTTR promoter / enhancer, 1xCRM8 / hTTR, and 2xCRM8 / hTTR, with novel modified forms of BDD-FVIII (see Examples 3-5, below). Overall, the in vitro data reveal increased biopotency units based on the presence of one and two CRM8 elements by directly comparing (1) vNG5 / CS04 to vNG5 / CS117 (2.5-fold higher) and vNG5 / CS118 (4.0-fold higher), (2) vX5 / CS24 to vX5 / CS101 (1.8-fold higher) and vX5 / CS105 (5.3-fold higher), and (3) vX5 / NG5 / CS125 to vX5 / NG5 / CS119 (4.4-fold higher) and vX5 / NG5 / CS120 (6.2-fold higher). No CRM8-dependent effect on FVIII levels was observed in vivo. Nevertheless, the in vivo data demonstrate that both the novel 1xCRM8 / hTTR and 2xCRM8 / hTTR promoter cassettes perform equally well in mouse models compared to the mTTR promoter / enhancer.

[0209] Example 3: Improvement of single-chain AAV8 vector constructs expressing FVIII by introduction of the "NG5" variant Based on the data shown in Example 1, the N-glycosylation linker NG5 in construct vNG5 / CS04 was selected to combine with the novel human liver-specific promoters 1xCRM8 / hTTR and 2xCRM8 / hTTR to obtain constructs vNG5 / CS117 and vNG5 / CS118 (Figure 11). The vNG5 / CS04 construct contains an mTTR promoter / enhancer cassette (Figure 11). The in vivo biopotency level of vNG5 / CS04 was 1.9-fold higher than vCS04 due to a positive effect on the NG5 linker sequence (Figure 12). In vitro, increased biopotency was observed for vectors containing CRM8 element(s), vNG5 / CS117 and vNG5 / CS118. In vivo, the expression levels of vNG5 / CS117 and vNG5 / CS118 were similar to vNG5 / CS04 (Figure 12).

[0210] Example 4: Improvement of single-chain AAV8 vector constructs expressing FVIII by introduction of the "X5" variant To further improve the vector expressing FVIII, the X5 variant (described as mutation "m2" in WO2017 / 083762, the contents of which are incorporated herein by reference) was introduced into BDD-FVIII. The X5 variant contains five porcine FVIII amino acid residues in the A1 domain of the heavy chain that allow efficient secretion of human FVIII (Cao et al., 2014, ASGCT abstract #460; details of the variant were disclosed by oral description). Specifically, the X5 variant of BDD-FVIII was combined with the mTTR promoter / enhancer to result in vX5 / CS24, and with one or two CRM8 elements(s) and the hTTR promoter to result in constructs vX5 / CS101 and vX5 / CS105 (Figure 11). The three novel constructs were analyzed in vitro in the liver-derived HepG2 cell line and in vivo in "line E2" mice (a transgenic FVIII knockout mouse line that expresses trace amounts of human FVIII cDNA and confers immune tolerance to human FVIII (van Helden PM, et al., Blood 118(13):3698-707 (2011), the contents of which are incorporated herein by reference in their entirety and for all purposes)) and compared to the reference construct vCS04. In vivo, vX5 / CS24, vX5 / CS101, and vX5 / CS105 provided 2.5- to 3.1-fold increased levels of FVIII activity (FIG. 12). In vitro, the increase in biopotency ranged from 4.0 to 21.2. The in vitro test system revealed a 4.0-fold increase resulting from the X5 variant (construct vX5 / CS24), followed by a 7.3- and 21.2-fold increase with constructs containing X5 and one or two copies of the CRM8 element (constructs vX5 / CS101 and vX5 / CS105, respectively).

[0211] Example 5: Improvement of single-chain AAV8 vector constructs expressing FVIII by introducing both the "X5" and "NG5" variants In a further set of vectors, the N-glycosylated linkers NG5 (example 3) and X5 variants (example 4) were introduced in parallel into BDD-FVIII and further combined with three different promoters including mTTR promoter / enhancer, 1xCRM8 / hTTR, and 2xCRM8 / hTTR, resulting in constructs vX5 / NG5 / CS125, vX5 / NG5 / CS119, and vX5 / NG5 / CS120, respectively (Figure 11). Compared to vCS04, the in vivo and in vitro biopotencies of vX5 / NG5 / CS125, vX5 / NG5 / CS119, and vX5 / NG5 / CS120 were increased by 3.6-5.5-fold and 3.2-19.8-fold, respectively. The introduction of the two novel modifications X5 and NG5 reveals further expression increase in vivo, as shown for three series of constructs, each with a common promoter. For example, in the series with 2xCRM8 / hTTR promoters (constructs vCS116, vNG5 / CS118, vX5 / CS105, and vX5 / NG5 / CS120), the presence of NG5 alone increases FVIII expression levels from 1.9 IU / mL to 2.9 IU / mL, the presence of X5 alone increases FVIII expression from 1.9 IU / mL to 5.1 IU / mL, and the presence of both X5 and NG5 increases FVIII expression from 1.9 IU / mL to 11.4 IU / mL.

[0212] In summary, construct vX5 / NG5 / CS120, which harbors a novel 2xCRM8 / hTTR promoter cassette, a codon-optimized BDD-FVIII "CS04" nucleotide sequence, and additionally two modifications of the X5 variant and the NG5 sequence, was determined to be the construct with the highest in vitro and in vivo biological potency.

[0213] Example 6: Nucleotide reduction of single-stranded AAV8 vector constructs To reduce the vector size of the slightly oversized vector construct vX5 / NG5 / CS120, which should allow for more efficient packaging, all non-functional DNA sequences within the flanking ITRs were deleted. This resulted in a total reduction of 71 nucleotides from 5191 nucleotides, resulting in an expression cassette with a size of 5120 nucleotides. The deletions included 19 nucleotides between the 5'-ITR and CRM8 sequences, 9 nucleotides between the human TTR promoter and Kozak sequences, 27 nucleotides between the BDD-FVIII coding sequence and the synthetic polyadenylation site, and 16 nucleotides between the synthetic polyadenylation site and the 3'-ITR sequences. This size-reduced expression cassette, vX5 / NG5 / CS12, consists of a promoter containing two CRM8 elements and the core human TTR promoter sequence, a BDD-FVIII sequence containing the NG5 sequence with the X5 variant, and a synthetic polyadenylation site, flanked by two AAV2-based inverted terminal repeats. The construct vX5 / NG5 / CS12 is shown diagrammatically in FIG.

[0214] The vector genome integrity of AAV vector genome preparations vCS04, vX5 / NG5 / CS120, and vX5 / NG5 / CS12 was examined by agarose gel electrophoresis. The results shown in Figure 13 indicate that vCS04, vX5 / NG5 / CS120, and vX5 / NG5 / CS12 viral vectors have similar sized genomes, as indicated by a distinct band of approximately 5 kb. Although the calculated vector size was approximately 5.2 kb, the genome is a uniform band supporting proper packaging of the slightly oversized genome (relative to the 4.7 kb AAV wild-type genome). The shorter vX5 / NG5 / CS12 variant is preferred.

[0215] A set of AAV8-based viral vectors, including vCS04, vX5 / NG5 / CS120, and vX5 / NG5 / CS12, was injected into FVIII F17 ​​knock-in mice at 5 × 10 11 vg / kg, 1×10 12 vg / kg, and 4 × 10 12vX5 / NG5 / CS12 and vX5 / NG5 / CS120 were administered at vector doses of 1×10 12 A vector dose of 1×10 vg / kg resulted in comparable expression levels of approximately 4 IU / mL. 12 In contrast to the reference construct vCS04, which had a very low FVIII expression level of 0.3 IU / mL at a dose of 1000 ng / kg, the improved vectors vX5 / NG5 / CS12 and vX5 / NG5 / CS120 showed approximately 14-fold increased FVIII expression levels (Figure 14). 11 Even at a dose of 1.5 vg / kg, the vector vX5 / NG5 / CS12 was able to obtain an expression level of FVIII of 1.5 IU / mL. According to the in vivo data, the in vitro biopotency of vX5 / NG5 / CS120 and vX5 / NG5 / CS12 was significantly increased by approximately 17- and 24-fold, respectively, infecting HepG2 cells at equal multiplicities of infection (MOI) (Figure 14). Thus, since all vectors were administered at the same concentration (MOI), the difference in biopotency is due to the variant used and is not size-dependent.

Claims

1. A nucleic acid composition comprising a Factor VIII polynucleotide encoding a Factor VIII protein, said Factor VIII polynucleotide having the nucleic acid sequence of CS12-FL-NA (SEQ ID NO:1).

2. 2. The nucleic acid composition of claim 1, further comprising a promoter polynucleotide operably linked to the Factor VIII polynucleotide, the promoter polynucleotide having a nucleic acid sequence of hTTR (SEQ ID NO:6).

3. The nucleic acid composition of claim 2 , wherein the promoter is directly linked to the Factor VIII polynucleotide.

4. 4. The nucleic acid composition of any one of claims 1 to 3, further comprising a liver-specific element operably linked to said Factor VIII polynucleotide, said liver-specific element having the sequence of CRM8 (SEQ ID NO:5).

5. The nucleic acid composition of claim 4 , wherein a second liver-specific element is operably linked to the Factor VIII polypeptide.

6. The nucleic acid composition of claim 4 or 5, wherein the liver-specific element and the promoter are directly linked.

7. 2. The nucleic acid composition of claim 1, having a nucleic acid sequence comprising CS12-CRM8.2-Vr (SEQ ID NO:3).

8. A mammalian gene therapy vector comprising the nucleic acid composition of any one of claims 1-7.

9. 9. The mammalian gene therapy vector of claim 8 which is an adeno-associated virus (AAV) vector.

10. 10. The mammalian gene therapy vector of claim 9, wherein said AAV vector is a serotype 8 adeno-associated virus (AAV-8) vector.

11. The mammalian gene therapy vector of any one of claims 8 to 10, wherein said nucleic acid composition is a single-stranded polynucleotide encoding said Factor VIII protein.

12. An adeno-associated virus (AAV) particle comprising a capsid protein encapsulating a nucleic acid composition according to any one of claims 1 to 7.

13. The AAV particle of claim 12, wherein the capsid protein comprises a serotype 8 adeno-associated virus (AAV-8) capsid protein.

14. The AAV particle of claim 12 or 13, wherein the nucleic acid composition is a single-stranded polynucleotide encoding the Factor VIII protein.

15. The nucleic acid composition according to any one of claims 1 to 7 for treating hemophilia A.

16. Use of a nucleic acid composition according to any one of claims 1 to 7 for the manufacture of a medicament for the treatment of hemophilia A.

17. A mammalian gene therapy vector according to any one of claims 8 to 11 for treating hemophilia A.

18. Use of a mammalian gene therapy vector according to any one of claims 8 to 11 for the manufacture of a medicament for the treatment of hemophilia A.

19. The adeno-associated virus (AAV) particle of any one of claims 12 to 14 for treating hemophilia A.

20. Use of an adeno-associated virus (AAV) particle according to any one of claims 12 to 14 for the manufacture of a medicament for the treatment of hemophilia A.

21. An in vitro method for producing adeno-associated virus (AAV) particles comprising introducing into a eukaryotic host cell a nucleic acid composition according to any one of claims 1 to 7, the nucleic acid composition comprises a Factor VIII polynucleotide having the nucleic acid sequence of CS12-FL-NA (SEQ ID NO:1) flanked by a 5' inverted terminal repeat (5' ITR) and a 3' inverted terminal repeat (3' ITR); the mammalian host cell comprises one or more polynucleotides encoding an AAVrep gene, an AAVcap gene, and a viral replication helper gene; The method.

22. 22. The in vitro method of claim 21, wherein the nucleic acid composition is a plasmid having the nucleic acid sequence of CS12-CRM8.2-Vrp (SEQ ID NO: 10).

23. 23. The in vitro method of claim 21 or 22, wherein the AAV cap gene is a serotype 8 adeno-associated virus (AAV-8) cap gene.

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