PTC Therapeutics has been selected as the winning bidder to acquire ST-920, a BLA-stage gene therapy for Fabry disease, from Sangamo Therapeutics in a competitive bankruptcy auction.
The planned transaction includes $111 million upfront and up to $100 million in contingent milestone payments tied to certain regulatory approvals. PTC said the acquisition expands its rare-disease portfolio while leveraging its existing global regulatory, commercial and customer-facing infrastructure.
ST-920 is a one-time administered adeno-associated virus, or AAV, gene therapy designed to enable long-term production of alpha-galactosidase A, the enzyme deficient in people with Fabry disease. The inherited lysosomal storage disorder is caused by mutations in the GLA gene and can result in serious symptoms requiring lifelong treatment.
PTC said the U.S. prevalence of Fabry disease is estimated at 11,000 people, with similar prevalence in markets where it could potentially commercialize the therapy.
A rolling BLA seeking accelerated approval of ST-920 is expected to be completed in the fourth quarter of 2026. The nonclinical and clinical modules have already been submitted, while the chemistry, manufacturing and controls package is expected in the fourth quarter. A potential commercial launch could follow in 2027.
The application is based on Phase 1/2 STAAR study data showing a positive mean annualized estimated glomerular filtration rate, or eGFR, slope at 52 weeks after treatment. PTC said the data also showed favorable effects on cardiac function and quality of life, along with an encouraging safety and tolerability profile.
All participants receiving enzyme replacement therapy when they entered the study were withdrawn from that treatment. PTC said enzyme activity has remained elevated for as long as 4.5 years in the earliest treated participant, with evidence of sustained kidney-function improvements across the study population.
ST-920 has received FDA Regenerative Medicine Advanced Therapy, Orphan Drug and Fast Track designations. The company said 104-week STAAR data are intended to provide confirmatory evidence for traditional approval.
Chief Executive Officer Matthew Klein said the program could drive revenue growth without requiring a new development or commercial build-out, while maintaining PTC’s aim of reaching cash-flow breakeven in 2026.
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