Preclinical development of TAK-754, a high-performance AAV8-based vector expressing coagulation factor VIII

Area of Science:

• Gene Therapy
• Hemophilia A Research
• Vectorology

Background:

• Hemophilia A is a genetic bleeding disorder caused by Factor VIII (FVIII) deficiency.
• Current treatments involve FVIII replacement therapy, which can be burdensome.
• Gene therapy offers a potential alternative for long-term FVIII expression.

Purpose of the Study:

• To evaluate the preclinical safety and efficacy of TAK-754, an AAV8-based gene therapy vector for hemophilia A.
• To assess FVIII expression, hemostatic efficacy, and toxicology of TAK-754 in animal models.

Main Methods:

• Development of an AAV8 vector (TAK-754) encoding a codon-optimized, CpG-depleted FVIII transgene.
• Administration of TAK-754 to FVIII knockout mice and transgenic human FVIII mice.
• Assessment of plasma FVIII activity, blood loss in hemostatic assays, and long-term FVIII expression.
• Toxicology and biodistribution studies in C57BL/6J mice following single TAK-754 administration.

Main Results:

• Dose-dependent increases in plasma FVIII activity and corresponding decreases in blood loss were observed in FVIII knockout mice.
• TAK-754 mediated stable, long-term FVIII expression in human FVIII mice.
• Toxicology studies revealed no adverse clinical signs at the highest dose tested (5.0 × 10^13 CP/kg).
• Biodistribution showed predominant liver targeting with minimal vector DNA in other tissues.
• Integration site analysis indicated minimal vector integration without evidence of clonal outgrowth or oncogene activation.

Conclusions:

• TAK-754 demonstrates promising preclinical safety and efficacy for hemophilia A gene therapy.
• The vector effectively delivers the FVIII transgene to the liver, leading to therapeutic FVIII levels.
• Further development of TAK-754 for hemophilia A patients is warranted based on these findings.