PTC Completes ST-920 Fabry Gene Therapy Purchase
The rare-disease company closed a competitive bankruptcy auction for a BLA-stage AAV program it plans to file in the fourth quarter.
PTC Therapeutics, Inc. (PTCT) 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.
The rare-disease company described the asset as a one-time infusion that targets the enzyme deficient in Fabry disease, a rare inherited lysosomal storage disorder. Chief Executive Officer Matthew B. Klein, M.D., said the team looks forward to completing the ST-920 BLA submission and potentially bringing a one-time-administered, safe, effective, and durable disease treatment that addresses the limitations of chronic enzyme replacement therapy to the Fabry community.
PTC was selected as the winning bidder in a competitive bankruptcy auction. Terms include $111 million upfront and up to $100 million in contingent milestone payments based on certain regulatory approvals. A rolling BLA submission to the FDA for accelerated approval of ST-920 is expected to be completed in the fourth quarter of 2026, with potential for commercial launch in 2027.
The BLA is based on evidence of a meaningful favorable clinical effect on renal function and a safety and tolerability profile over 52 weeks in the Phase 1/2 STAAR study. Isaralgagene civaparvovec requires a one-time infusion without preconditioning. The FDA has granted Orphan Drug, Fast Track, and RMAT designations.
Klein said the transaction advances a strategy of leveraging existing rare-disease global commercial infrastructure to accelerate short- and intermediate-term revenue growth and that the program puts another product in the hands of customer-facing teams. He said it was a unique opportunity with the potential for significant return on investment without the need for any development or commercial build and without impacting the objective of reaching cash-flow break-even in 2026.
The acquisition remains subject to definitive documentation, bankruptcy court approval, antitrust review, and other customary closing conditions. It is expected to close in late third quarter or early fourth quarter of 2026.