Pfizer Inc. and Sangamo Therapeutics Inc. announced updated follow-up data from the Phase 1/2 Alta study of giroctocogene fitelparvovec (SB-525, or PF-07055480), an investigational gene therapy for patients with severe hemophilia A. All five patients with severe hemophilia A who received the 3e13 vg/kg dose showed sustained factor VIII (FVIII) activity levels, with a median of 64.2% via chromogenic assay (patient-level geometric means after week 9 post-infusion).
No patients experienced bleeding events or required FVIII infusions. The factor VIII activity levels reflect measurements up to 61 weeks, the extent of follow-up for the longest-treated patient in the cohort.
Giroctocogene fitelparvovec was generally well tolerated. As previously reported, one patient in the 3e13 vg/kg dose cohort had a treatment-related serious adverse event of hypotension (grade 3) and fever (grade 2), with symptoms of headache and tachycardia, which occurred six hours post-infusion with giroctocogene fitelparvovec, and which fully resolved within 24 hours. No other treatment-related serious adverse events were reported.
Seng Cheng, Senior Vice President and Chief Scientific Officer of Pfizer’s Rare Disease Research Unit
THE PHASE 3 LEAD IN STUDY IS ONGOING, AND WE LOOK FORWARD TO DOSING PATIENTS WITH THIS INVESTIGATIONAL GENE THERAPY IN THE PIVOTAL PHASE 3 TRIAL LATER THIS YEAR.
“The current standard of care for severe hemophilia A requires regular infusions to replace missing Factor VIII. Gene therapy, on the other hand, offers a new approach with the potential to provide a one-time treatment that would enable patients to produce the missing factor on their own,” said Bettina M. Cockroft, M.D., M.B.A., Chief Medical Officer of Sangamo. “These follow-up data indicate that treatment with giroctocogene fitelparvovec resulted in sustained factor levels up to 14 months following treatment and suggests the potential of this investigational gene therapy to alleviate the treatment burden of current hemophilia disease management.”
Giroctocogene fitelparvovec (SB-525 or PF-07055480), comprises a recombinant adeno-associated virus serotype 6 vector (AAV6) encoding the complementary deoxyribonucleic acid for B domain deleted human FVIII.