Pfizer and Sangamo dose first participant in phase III study of giroctocogene fitelparvovec for hemophilia A gene therapy treatment.

Pfizer Inc,. and Sangamo Therapeutics, Inc. a genomic medicines company, announced that the first participant has been dosed in the Phase III AFFINE study of giroctocogene fitelparvovec (SB-525), an investigational gene therapy for hemophilia A patients. AFFINE is a global Phase III, open-label, multicenter, single arm study that will evaluate the efficacy and safety of giroctocogene fitelparvovec in patients with moderately severe to severe hemophilia A. The primary endpoint is impact on annual bleed rate (ABR) through 12 months following treatment with giroctocogene fitelparvovec, compared to ABR on Factor VIII (FVIII) replacement therapy collected in the Phase III lead-in study period. Participants will be analyzed throughout the 5-year study period following the single infusion to further assess the durability and efficacy.Data from the Phase III lead-in study will provide a baseline for patients evaluated in the Phase III study. Updated Phase 1/II data announced at a Pfizer investor event on September 15, 2020 demonstrated that giroctocogene fitelparvovec was generally well tolerated. Each of the five patients in the high dose cohort sustained FVIII activity levels without bleeds or the need for prophylactic factor through up to 85 weeks. Factor VIII activity levels were sustained at a clinically meaningful level, with a geometric mean of ~71% when measured between the weeks of 9 and 52.