PTC to Acquire Sangamo’s Fabry Disease Gene Therapy

Editor’s Take: Sangamo Therapeutics filed for Chapter 11 bankruptcy in June due to financial distress, mounting cash pressure and the loss of key revenue-generating partnerships, such as its gene therapy program with Pfizer.

PTC Therapeutics Inc. has made a winning bid to acquire ST-920, a BLA-stage one-time administered AAV gene therapy for Fabry disease, from Sangamo Therapeutics in a competitive bankruptcy auction.

Fabry disease is a rare, inherited lysosomal storage disorder caused by mutations in the GLA gene, resulting in deficiency of the alpha-galactosidase A (α-Gal A) enzyme and causing a range of serious signs and symptoms that require lifelong treatments. ST-920 is designed as a one-time administered AAV gene therapy that enables long-term production of the deficient α-Gal A enzyme and significant reduction in globotriaosylceramide (Gb3) levels with demonstrated durable clinical benefit and reduction of the burden associated with chronic Enzyme Replacement Therapy (ERT).

Terms of the Deal

The terms include $111 million upfront and up to $100 million in contingent milestone payments based on certain regulatory approvals. A rolling BLA submission to FDA for accelerated approval of ST-920 is expected to be completed in Q4 2026 based on evidence of meaningful favorable clinical effect on renal function and safety and tolerability profile over 52 weeks in the Phase 1/2 STAAR study.

“This transaction advances our strategy of leveraging our accomplished existing rare disease global commercial infrastructure to accelerate short- and intermediate-term revenue growth,” said Matthew B. Klein, M.D., CEO, PTC Therapeutics. “The ST-920 gene therapy program puts another innovative and valuable product in the demonstrated capable hands of our customer-facing teams. This was a unique opportunity with the potential for significant return on investment without the need for any development or commercial build and without impacting our objective of reaching cashflow break even in 2026. We look forward to working to bring ST-920 to all individuals who may benefit from this therapy as quickly as possible.”

The BLA submission for accelerated approval is based on the intermediate clinical endpoint of annualized eGFR at Week 52 as aligned with FDA, with 104-week results from the STAAR study planned to provide confirmatory evidence to support traditional approval. The nonclinical and clinical BLA modules have already been submitted as part of a rolling submission, with the CMC package expected to be submitted in Q4 2026. PTC will also pursue regulatory approval outside of the United States, again leveraging existing regulatory and commercial rare disease infrastructure.

The acquisition remains subject to customary closing conditions. It is expected to close in late Q3 or early Q4 2026.

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