Can Pfizer do what BioMarin couldn’t in hemophilia A?
Pfizer announced Wednesday that its gene therapy for hemophilia A met the primary objective in a key clinical trial, and the company plans to bring the data to regulators for approval in the upcoming months. But in commercializing its hemophilia A gene therapy, Pfizer may face an uphill battle — one that BioMarin has been fighting for the past year.
BioMarin received approval last year for its hemophilia A gene therapy Roctavian, but has struggled with slow uptake and said in April it could consider divesting the gene therapy.
The Phase 3 AFFINE study showed the gene therapy, known as giroctocogene fitelparvovec, was both comparable and superior to routine factor VIII replacement therapy in reducing bleeding rates. Bleeds dropped 98.3% compared to before the gene therapy, from around four episodes yearly to nearly zero, according to Pfizer’s announcement.
One participant returned to receiving routine factor VIII replacement therapy after getting the gene therapy.
Pfizer said the hemophilia A gene therapy was “generally well tolerated,” with transiently elevated factor VIII levels seen in about half of those who received the gene therapy. Ten patients experienced serious adverse events related to treatment.
Pfizer said it plans to present the full results at a future medical meeting, and will bring data to regulators across the world for approval.
What’s Pfizer’s future in gene therapy?
Part of the commercial challenge in hemophilia A is that patients have other treatment options that work, including Roche’s antibody Hemlibra. Pfizer is hoping to challenge Roche with its own antibody injection, called marstacimab, in both hemophilia A and B. It expects an FDA decision by the end of the year.
Last year, Pfizer had three late-stage gene therapies listed in its portfolio — two for hemophilia A and B, and one for Duchenne muscular dystrophy — but all three face significant hurdles. Pfizer reported in June that the Duchenne gene therapy failed a pivotal trial.
In April, Pfizer received FDA approval for the hemophilia B gene therapy Beqvez, but likewise faces an uncertain commercial market for the treatment. CSL Behring, which received approval for its hemophilia B gene therapy Hemgenix in late 2022, went roughly half a year before dosing its first commercial patient.
Pfizer has not said whether it has dosed any patients with Beqvez.
The pharma company last year stepped away from its earlier-stage gene therapy projects, selling some of its portfolio to AstraZeneca.
The news of the hemophilia A trial success was a boon to Sangamo Therapeutics, which saw its shares $SGMO go up over 40% on Wednesday. The hemophilia A gene therapy was developed using Sangamo’s technology, and the struggling company could receive up to $220 million in regulatory and commercial milestones from Pfizer. Sangamo said in its last earnings update that it had enough cash to operate until the third quarter of 2024.
Editor’s note: This story was updated substantially throughout to include additional details about Pfizer’s gene therapy portfolio and Sangamo.