Sangamo Therapeutics Achieves Key Milestones for Fabry Disease Gene Therapy, Paving Way for Potential BLA Submission

RICHMOND, Calif. – May 6, 2025 – Sangamo Therapeutics, Inc. (Nasdaq: SGMO), a genomic medicine company, today announced significant progress in the regulatory pathway for isaralgagene civaparvovec (ST-920), its wholly owned gene therapy candidate for Fabry disease, marking important steps toward a planned Biologics License Application (BLA) submission.

A crucial milestone has been reached in the Phase 1/2 STAAR study, with all treated patients now having completed at least 52 weeks of follow-up. This duration of data is a key requirement by the FDA for an Accelerated Approval regulatory pathway for ST-920. Preliminary analysis of clinical data collected up to this 52-week mark (data cutoff: September 12, 2024) across all 32 dosed patients indicates that the mean estimated glomerular filtration rate (eGFR) slope continued its positive trend, consistent with the previous clinical update at WORLDSymposium in February 2025. The gene therapy candidate continues to demonstrate good tolerability. Pivotal data from the study is anticipated by the end of the second quarter of 2025.

Furthermore, Sangamo held a productive Type B meeting with the FDA in April 2025, which provided the company with a clear Chemistry, Manufacturing, and Controls (CMC) pathway for a planned BLA submission in the first quarter of 2026. This clarity includes plans for process validation, the path to commercial specifications, and the designated commercial launch manufacturing site. This BLA submission timeline positions Sangamo for a potential approval and commercial launch as early as the second half of 2026.

“Following our alignment with the FDA last year on an Accelerated Approval regulatory pathway for ST-920, we are excited to have now gathered the one-year mean eGFR slope data, which will serve as the primary efficacy endpoint for our planned BLA submission,” said Nathalie Dubois-Stringfellow, Ph. D., Chief Development Officer at Sangamo. “Coupled with our recent productive FDA Type B meeting, we have a clear regulatory pathway to a potential approval decision for ST-920, and we are actively advancing our BLA preparation activities.”

Discussions with the European Medicines Agency (EMA) regarding the proposed pathway to potential approval for isaralgagene civaparvovec in Europe are ongoing. Additionally, Sangamo continues to engage in business development negotiations for a potential commercialization agreement for Fabry disease.

About the STAAR Study:

The Phase 1/2 STAAR study is a global, open-label, single-dose, dose-ranging, multicenter clinical trial designed to assess the safety and tolerability of isaralgagene civaparvovec (ST-920), a gene therapy candidate for Fabry disease. Isaralgagene civaparvovec is administered as a single intravenous infusion without the need for preconditioning. The STAAR study enrolled both male and female patients with Fabry disease who were either on enzyme replacement therapy (ERT), ERT pseudo-naïve (off ERT for six or more months), or ERT-naïve. The FDA has granted Orphan Drug, Fast Track, and RMAT designations to isaralgagene civaparvovec, which has also received Orphan Medicinal Product designation and PRIME eligibility from the EMA and Innovative Licensing and Access Pathway from the U.K. Medicines and Healthcare products Regulatory Agency.

About Fabry Disease:

Fabry disease is a lysosomal storage disorder resulting from mutations in the galactosidase alpha gene (GLA), leading to a deficiency in the alpha-galactosidase A (α-Gal A) enzyme. This enzyme is crucial for the metabolism of globotriaosylceramide (Gb3). The accumulation of Gb3 within cells can cause significant damage to vital organs, including the kidneys, heart, nerves, eyes, gastrointestinal system, and skin. Symptoms of Fabry disease can include reduced or absent sweat production, heat intolerance, angiokeratoma (skin lesions), vision problems, kidney disease, heart failure, gastrointestinal issues, mood disorders, neuropathic pain, and tingling in the extremities.