Pfizer Inc. announced today that the U.S. Food and Drug Administration (FDA) has accepted the company's Biologics License Application (BLA) for fidanacogene elaparvovec for the treatment of adults with hemophilia B. In parallel, the European marketing authorization application (MAA) for fidanacogene elaparvovec has also been accepted and is under review by the European Medicines Agency (EMA).

Fidanacogene elaparvovec is a novel, investigational gene therapy that contains a bio-engineered adeno-associated virus (AAV) capsid (protein shell) and a high-activity variant of human coagulation Factor IX (FIX) gene. For people living with hemophilia B, the goal of this gene therapy is to enable them to produce FIX themselves via this one-time treatment rather than needing regular intravenous infusions of FIX, as is the current standard of care.

"Gene therapy marks a new era of scientific advancement, and if approved, we believe fidanacogene elaparvovec has the potential to transform the lives of people living with hemophilia B who are eligible for treatment. We look forward to continuing to work with global regulatory authorities to bring this innovative potential treatment to patients as quickly as possible," said Chris Boshoff, M.D., Ph.D., Chief Development Officer, Oncology and Rare Disease, Pfizer Global Product Development. "Patients are at the center of our legacy of innovation in hemophilia. Despite significant progress in their treatment, those living with hemophilia continue to experience disruption to daily life and need new options."

The submissions for fidanacogene elaparvovec are based on efficacy and safety data from the Phase 3 BENEGENE-2 study (NCT03861273). As previously reported, the BENEGENE-2 study met its primary endpoint of non-inferiority and superiority in the annualized bleeding rate (ABR) of total bleeds post-fidanacogene elaparvovec infusion versus prophylaxis regimen with FIX, administered as part of usual care. Fidanacogene elaparvovec was generally well-tolerated, with a safety profile consistent with Phase 1/2 results.

The FDA has set a Prescription Drug User Fee Act (PDUFA) goal date in the second quarter of 2024. Fidanacogene elaparvovec has been granted Breakthrough, Regenerative Medicines Advanced Therapy (RMAT) and orphan drug designations from the FDA.

Pfizer currently has three Phase 3 programs investigating gene therapy in populations where there is a high unmet need: hemophilia B, hemophilia A, and Duchenne muscular dystrophy. A Phase 3 trial is also ongoing investigating marstacimab, a novel, investigational anti-tissue factor pathway inhibitor (anti-TFPI) being studied for the treatment of people with hemophilia A and B with and without inhibitors.