The company’s candidate, giroctocogene fitelparvovec, met its primary and key secondary objectives of superiority compared to the standard treatment of regular Factor VIII infusions.
Pfizer announced a Phase III victory Wednesday for its investigational gene therapy to treat hemophilia A, as it looks to advance a growing franchise targeting the inherited bleeding disorder.
The pharma giant said its candidate giroctocogene fitelparvovec met the primary and secondary endpoints in a late-stage trial, proving non-inferiority and superiority to the prophylaxis treatment for patients—regular Factor VIII (FVIII) infusions. Pfizer’s gene therapy maintained greater than 5% of FVIII activity in 84% of participants at 15 months post infusion, with a majority having greater than 15% of normal FVIII levels, according to topline results.
The gene therapy was considered well tolerated with serious adverse events reported in 15 patients, or 20% of participants in the AFFINE trial, including 13 events in 10 patients that investigators related to the treatment.
“For people living with hemophilia A, the physical and emotional impact of needing to prevent and treat bleeding episodes through frequent IV infusions or injections cannot be underestimated,” AFFINE’s lead investigator Andrew Leavitt said in a statement, noting that the gene therapy provided “superior bleeding protection” compared to the current standard of care.
Pfizer had its first gene therapy win in April 2024 when the FDA approved Beqvez for the treatment of hemophilia B. The treatment has a list price of $3.5 million, which is in line with other gene therapies on the market.
Giroctocogene fitelparvovec has been granted Fast Track and Regenerative Medicine Advanced Therapy designations from the FDA, as well as Orphan Drug designations in the U.S. and the European Union. Pfizer said Wednesday that it will discuss its Phase III data from the AFFINE trial with the regulator “in the coming months.”
If successful in garnering approval for giroctocogene fitelparvovec, Pfizer will be up against BioMarin, whose hemophilia A therapy was the first gene therapy greenlit by the FDA in June 2023. However, BioMarin has had some trouble with its launch.
“Reimbursement and market access challenges continued to impact the ability of interested patients to receive Roctavian,” BioMarin stated in its first-quarter 2024 financial report. CEO Alexander Hardy said on an earnings call with analysts in April that the company may consider divesting the therapy from its portfolio if uptake doesn’t improve.
None of the FDA-approved gene therapies are curative for their respective diseases. In a paper published last summer, a group of hemophilia experts noted many patients will not choose gene therapy at this point, considering the current generation “inadequate” and “not living up to the expectations of the community for a cure.”
The paper also indicated that the declining FVIII levels following Roctavian administration as a negative influence on patient interest in receiving gene therapy. Gene therapies are delivered via a viral capsid, meaning patients can only receive it once, even if efficacy wanes, due to immunity developed after initial dosing.
