Sangamo Therapeutics Announces Updated Phase 1/2 STAAR Study Data in Fabry Disease Showing Sustained Benefit and Differentiated Safety Profile

Sangamo Therapeutics, Inc. (Nasdaq: SGMO), a genomic medicine company, today announced updated preliminary data from the Phase 1/2 STAAR clinical study evaluating isaralgagene civaparvovec, or ST-920, a wholly owned gene therapy product candidate for the treatment of Fabry disease. In the largest known clinical gene therapy program in Fabry disease to date, data from 24 patients continued to show durable safety and preliminary efficacy data as of the data cutoff date, which continue to underscore the potential of isaralgagene civaparvovec as a single-dose treatment option for Fabry disease.

These data will be shared at the 20^th Annual WORLDSymposium^TM in San Diego, CA on Wednesday, February 7, 2024, via an oral presentation in the Clinical Applications session from 8:00-9:00 a.m. P.T. and a poster presentation from 3:00-5:00 p.m. P.T. (Poster Ref: 145). These data will also be available on Sangamo’s website on the Presentations page.

“Despite the availability of ERT and chaperone therapies, Fabry disease treatment is burdensome, with some patients still developing disease progression. To date, ST-920 has been well-tolerated, and the preliminary data showing sustained supraphysiologic α-Gal A activity and the ability to discontinue and remain off ERT are promising,” said Dr. Robert Hopkin, M.D., Cincinnati Children’s Hospital Medical Center, and investigator of the Phase 1/2 STAAR study. “The early improvements reported in disease severity, quality of life and gastrointestinal symptoms, together with evidence of reduced immunogenicity, illustrate the potential of ST-920 as a treatment option for adults with Fabry disease.”

“We remain encouraged by the emerging safety and efficacy data supporting the potential durable benefit that ST-920 could offer patients with Fabry disease as a convenient single-dose treatment option,” said Lisa Rojkjaer, M.D., Chief Medical Officer of Sangamo. “We expect to complete dosing of the remaining patients in the first half of this year as we continue to explore potential partnerships and other financing options to support the initiation of a registrational trial.”

Updated Phase 1/2 STAAR Study Results

• As of the September 19, 2023 data cutoff date, 24 patients had been dosed; as of the treatment date, 13 (54%) were on ERT and 10 (42%) had mild to moderate renal dysfunction at baseline.

Safety:

• Isaralgagene civaparvovec continued to be generally well-tolerated. The most common adverse events were pyrexia, headache, COVID-19, fatigue and nasopharyngitis (majority Grade 1/2, with one Grade 3 pyrexia).
• No LFT elevations post-dosing requiring steroids occurred. No prophylactic steroids or other immunomodulatory agents were administered, as per protocol.

Efficacy (all dosed patients):