Pfizer/Sangamo gene therapy: positive effect in early-stage hemophilia A study

Pfizer (PFE -0.8%) and collaborator/licensor Sangamo Therapeutics (SGMO +0.4%) announce updated data from an open-label, 11-subject Phase 1/2 clinical trial evaluating gene therapy giroctocogene fitelparvovec (SB-525, or PF-07055480) in patients with severe hemophilia A. The results were presented virtually at the World Federation of Hemophilia World Congress.

All five patients in the 3e13 vg/kg dose arm showed sustained factor VIII (FVIII) activity levels with a median of 64.2% (normal range: 50 – 150%) as measured by chromogenic assay as long as 61 weeks post-treatment. None experienced bleeding events or required FVIII infusions.

On the safety front, one participant in the 3e13 vg/kg dose arm experienced moderate fever and severe hypotension with symptoms of headache and tachycardia (rapid heartbeat) that occurred six hours after infusion that resolved within 24 hours. No other serious treatment-emergent adverse events were reported. Four of the five patients in the same dose arm received corticosteroids for elevations in a liver enzyme called ALT (biomarker for organ stress/damage). All resolved.

Enrollment is underway in a Pfizer-sponsored 63-subject, open-label, Phase 3 trial, AFFINE. The primary endpoint is annualized bleeding rate at month 12. The estimated primary completion date is August 2022.

Yesterday, competitor BioMarin Pharmaceutical (BMRN +3.6%) reported positive data on its hemophilia A gene therapy candidate valoctocogene roxaparvovec.

https://seekingalpha.com/news/3584187-pfizer-sangamo-gene-therapy-shows-positive-effect-in-early-stage-hemophilia-study