Pfizer and Sangamo Announce Updated Results in Hemophilia A Gene Therapy

The following is an excerpt from a press release from Pfizer. Read the full press release here.

Pfizer Inc. and Sangamo Therapeutics Inc., a genomic medicines company, 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. These data are being presented today at the 62nd American Society for Hematology Annual meeting taking place virtually from December 5th – 8th. The oral presentation slides, which include follow-up data up to 85 weeks for the longest treated patient, are available on Sangamo’s website in the Investors and Media section under Events and Presentations.
All five patients in the high dose 3 x 1013 vg/kg cohort have had at least one year of follow-up and showed sustained factor VIII (FVIII) activity levels, with a group median FVIII activity of 56.9% and a group geometric mean FVIII activity of 70.4% via chromogenic assay from week 9 to 52. Steady-state FVIII activity was achieved for all patients in the 3 x 1013 vg/kg cohort within 9 weeks of treatment with giroctocogene fitelparvovec, with no bleeding events and no FVIII infusions (beyond 3 weeks post-infusion) within the first year. As of the cutoff date of August 31, 2020, one patient had one target joint bleed requiring FVIII therapy, occurring after week 52.
“It is promising to see how quickly all five patients in the 3 x 1013 vg/kg cohort achieved steady-state FVIII activity levels, with no bleeding events and no factor usage within the first year and only one target joint bleed after 52 weeks,” said Andrew D. Leavitt, MD, Professor of Medicine, University of California, San Francisco, CA, and investigator of the Alta and AFFINE studies. “Our focus now is to confirm these exciting findings in the Phase 3 study, and to gather long-term data by following these patients and others in the Phase 3 study over a longer period of time.”
Read the full press release here.