The following is an excerpt from a press release from Pfizer. Read the press release in its entirety here.
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. These data are being presented as a late-breaking oral abstract at the World Federation of Hemophilia 2020 World Congress, which is being held virtually from June 14 to June 19, 2020.
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. Among the five patients in the 3e13 vg/kg dose cohort, four received corticosteroids for liver enzyme (alanine aminotransferase, ALT) elevations. Three patients had subsequent ALT elevations that responded to corticosteroids. All episodes of ALT elevations fully resolved with oral corticosteroids.
“We are excited that these data affirm previous findings from this Phase 1/2 study, and that all five patients have sustained levels of factor VIII activity with no bleeding events or use of factor replacement therapy. We are encouraged by the potential of giroctocogene fitelparvovec to demonstrate longer-term durability, an important element for patients living with severe hemophilia A,” said 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.”
The additional follow-up builds on data presented at the 61st Annual Meeting of the American Society of Hematology (ASH) in December 2019, which demonstrated that giroctocogene fitelparvovec was generally well tolerated and resulted in sustained FVIII levels up to 44 weeks, the extent of follow-up for the longest-treated patient in the 3e13 vg/kg dose cohort at that time. The previously presented data included 11 patients treated across four ascending dose cohorts: 9e11 vg/kg (2 patients), 2e12 vg/kg (2 patients), 1e13 vg/kg (2 patients) and 3e13 vg/kg (5 patients). Pfizer and Sangamo plan to present further follow-up data from the Alta study when all five patients in the 3e13 vg/kg dose cohort have been followed for at least one year.
Read the press release in its entirety here.