Sangamo and Pfizer’s gene therapy increases FVIII activity in severe haemophilia A in early study
Sangamo Therapeutics and Pfizer have unveiled new Phase 1/2 data for their jointly developed investigational gene therapy SB-525, demonstrating that the treatment “was generally well-tolerated and demonstrated a dose-dependent increase in Factor VIII (FVIII) levels” across four dosages in severe haemophilia A.
The study evaluated the efficacy of four different dosages (9e11 vg/kg, 2e12 vg/kg, 1e13 vg/kg and 3e13 vg/kg) in eight participants, with two in each group. Clinically relevant increases in FVIII activity were observed in the three higher dosage groups, with normal levels of 50-150% seen in the 3e13 vg/kg group.
Additionally, patients in the highest dose group did not need FVIII replacement therapy after receiving an initial dose of prophylactic factor, and they did not experience any bleeds.
While the therapy was generally well-tolerated, one participant experienced a related serious adverse event of hypertension and fever following vector infusion, but this was resolved within 24 hours.
“The interim data from the first eight patients with haemophilia A treated with SB-525 gene therapy in the Alta study are encouraging and demonstrate a dose-dependent relationship, evidence of sustained factor levels, and low variability, both within each patient and within each cohort,” commented Dr Edward Conner, Chief Medical Officer of Sangamo. “These interim results suggest that SB-525 may be well-tolerated and may prove to have the predictability and sustained treatment effect that can bring clinical benefit in patients with haemophilia A. We need to continue observing how the data mature and how additional patients in the expansion cohort respond to SB-525. We look forward to working with Pfizer to potentially advance SB-525 into a registrational study.”
Seng Cheng, SVP and Chief Scientific Officer of Pfizer’s Rare Diseases Research Unit, spoke for the US giant: “We are encouraged by the early clinical data suggesting tolerability of the recombinant AAV6 vector and potential for normalisation of Factor VIII levels. We look forward to the opportunity to expand the cohort administered a 3e13 vg/kg dose and subsequent planning for the pivotal study. As the development and commercial partner for SB-525, we are encouraged by the possibility that SB-525 may one day transform the treatment landscape for patients with haemophilia A.”
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