PTC Therapeutics closes acquisition of Sangamo's ST-920 Fabry gene therapy

PTC Therapeutics announced on September 21, 2026 that it had 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.¹

The company said a rolling BLA submission to FDA for accelerated approval of ST-920 is expected to be completed in the fourth quarter of 2026.¹ According to the filing, the regulatory package rests 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 of ST-920.¹ PTC also said it plans to pursue approval for ST-920 in markets outside the United States.

ST-920, also known as isaralgagene civaparvovec, is described as a single-dose AAV gene therapy candidate for Fabry disease. In earlier clinical work, PTC said the therapy supported sustained production of the alpha-galactosidase A enzyme that Fabry patients lack, along with a marked drop in globotriaosylceramide (Gb3) accumulation, which the company linked to lasting clinical benefit and less reliance on standard enzyme replacement therapy.

The therapy has already picked up several regulatory designations: Orphan Drug, Fast Track, and Regenerative Medicine Advanced Therapy (RMAT) status from the FDA, plus Orphan Medicinal Product designation and PRIME eligibility from the European Medicines Agency, and inclusion in the U.K.'s Innovative Licensing and Access Pathway, according to the release.

Fabry disease itself stems from mutations in the GLA gene that leave patients short of the alpha-galactosidase A enzyme needed to break down Gb3, a buildup that can cause serious damage to vital organs, including the kidney, heart, nerves, eyes, gut and skin.¹ The filing was signed by PTC's Chief Financial Officer, Pierre Gravier.