Sangamo and Pfizer Announce Updated Phase 1/2 Results Showing Sustained Increased Factor VIII Activity Through 44 Weeks Following SB-525 Gene Therapy Treatment
Sangamo Therapeutics, Inc. (Nasdaq: SGMO), a genomic medicine company, and Pfizer, Inc. (NYSE: PFE), today announced updated follow-up results from the Phase 1/2 Alta study evaluating investigational SB-525 gene therapy in patients with severe hemophilia A. The data showed that SB-525 was generally well tolerated and demonstrated sustained increased Factor VIII (FVIII) levels following treatment with SB-525 through to 44 weeks, the extent of follow-up for the longest treated patient in the 3e13 vg/kg dose cohort. Data from 11 patients treated with SB-525 will be featured in a poster presentation today, December 7, 2019, at the 61st Annual Meeting of the American Society of Hematology (ASH) in Orlando, FL. The SB-525 ASH poster, which includes the full set of data, is available on Sangamo’s website in the Investors and Media section under Events and Presentations.
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“I am pleased that all five patients in the high dose (3e13 vg/kg) cohort rapidly achieved normal levels of Factor VIII, and that Factor VIII levels have been stable and durable in the normal range for the first two patients up to 44 and 37 weeks following treatment respectively, with no bleeding events or factor usage up to a follow up of 44 weeks in the longest treated patient,” said Barbara Konkle, M.D., Bloodworks Northwest, Professor of Medicine at University of Washington and a Principal Investigator of the Alta study. “It is important to continue to follow these patients to determine whether these results are sustained in the longer term as the combination of a favorable safety profile coupled with sustained expression at a level that prevents bleeding and allows normal activity will be the hallmark of a successful gene therapy for hemophilia A.”
Alta study data presented at ASH 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). The data cutoff date was October 17, 2019.
An analysis of plasma FVIII antigen was assessed by ELISA and demonstrated antigen concentrations consistent with the FVIII activity measured by the chromogenic assay. Dose dependent increases in FVIII activity over baseline were observed across the dose cohorts. The lower-dose cohorts indicate durable FVIII activity with up to 52 weeks of follow-up.