PTC Completes Acquisition of ST-920 Fabry Disease Gene Therapy (Form 8-K)

PTC Completes Acquisition of ST-920 Fabry Disease Gene Therapy

- Completion of BLA submission expected in Q4 2026 -

WARREN, N.J., Sept. 21, 2026 - PTC Therapeutics, Inc., (NASDAQ: PTCT) today announced that it completed the previously announced agreement with Sangamo Therapeutics, Inc. to acquire ST-920 - a BLA-stage, one-time administered AAV gene therapy for Fabry disease. A rolling BLA submission to FDA for accelerated approval of ST-920 is expected to be completed in Q4 2026.

"Our team looks forward to completing the ST-920 BLA submission and potentially bringing a one-time administered, safe and effective durable disease treatment that addresses the limitations of chronic enzyme replacement therapy to the Fabry community," said Matthew B. Klein, M.D., Chief Executive Officer.

About ST-920

ST-920 or isaralgagene civaparvovec is a one-time administered AAV gene therapy product candidate for the treatment of Fabry disease. In clinical studies, isaralgagene civaparvovec enabled long-term production of the deficient alpha-galactosidase A (α-Gal A) enzyme and significant reduction in globotriaosylceramide (Gb3) levels with durable clinical benefit and reduction of the burden associated with chronic Enzyme Replacement Therapy (ERT). 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 European Medicines Agency 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 caused by mutations in the galactosidase alpha gene (GLA), which leads to deficient alpha-galactosidase A (α-Gal A) enzyme activity, which is necessary for metabolizing globotriaosylceramide (Gb3). The buildup of Gb3 in the cells can cause serious damage to vital organs, including the kidney, heart, nerves, eyes, gut and skin. Symptoms of Fabry disease can include decreased or absent sweat production, heat intolerance, angiokeratoma (skin blemishes), vision problems, kidney disease, heart failure, gastrointestinal disturbance, mood disorders, neuropathic pain and tingling in the extremities.

About PTC Therapeutics, Inc.

PTC is a global biopharmaceutical company dedicated to the discovery, development and commercialization of clinically differentiated medicines for children and adults living with rare disorders. PTC is advancing a robust and diversified pipeline of transformative medicines as part of its mission to provide access to best-in-class treatments for patients with unmet medical needs. The company's strategy is to leverage its scientific expertise and global commercial infrastructure to optimize value for patients and other stakeholders.

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