ST-920 (isaralgagene civaparvovec) for Fabry disease
The FDA is expected to decide on ST-920 for Fabry disease in an undisclosed window, under a BLA (rolling) from PTC Therapeutics.
What is being decided
PTC Therapeutics has a BLA (rolling) under FDA review for ST-920 (isaralgagene civaparvovec) in Fabry disease. One-time AAV gene therapy with RMAT designation; rolling BLA underway with the final module expected in Q4 2026. PTC is acquiring the program from Sangamo. A PDUFA date follows once the FDA accepts the completed application.
Who this decision matters to
Fabry disease is a rare inherited lysosomal storage disorder where a missing enzyme causes fatty substances called globotriaosylceramide to accumulate in cells throughout the body. This buildup damages blood vessels, organs, and tissues, leading to progressive kidney, heart, and neurological problems. Enzyme replacement therapy and substrate reduction therapies can help manage the condition.
Prevalence: 1 in 40,000 to 60,000 males; higher in females when accounting for carrier status. See our full Fabry Disease page for current treatments, recruiting trials, and community resources.
What each outcome would mean
An approval starts a second race rather than ending the first one: specialty pharmacy setup, insurance review, and patient assistance typically take weeks even when everything goes right. Our guide to the 90 days after a rare disease approval explains the timeline and the moves families can make on day 1.
A complete response letter would mean the FDA declined to approve in the application's current form. CRLs are often about manufacturing or data presentation rather than efficacy, and resubmission is common. Either way, this page updates with the outcome and what it means.
Where Fabry Disease treatment stands today
Active research is expanding treatment options for Fabry disease across both classical and atypical presentations. Next-generation enzyme replacement therapies promise improved efficacy and convenience, while novel substrate reduction inhibitors offer additional pathways to slow disease progression. The Fabry Support and Information Group and National Fabry Disease Foundation maintain registries linking patients with trials. Cascade screening of family members, particularly female relatives, can identify others who might benefit from early intervention. Your metabolic specialist or cardiologist can discuss which newer therapies align with your specific disease pattern and help determine trial eligibility, as treatment approaches continue to expand.
Meanwhile, 43 Fabry Disease trials are recruiting
Whatever the FDA decides here, research on Fabry Disease does not stop. A few currently enrolling studies, US sites first:
Other drugs Trial Friend tracks for Fabry Disease
Get notified when new fabry-disease trials open or existing trials change status, add sites, or update eligibility.
Our coverage
Frequently asked questions
When will the FDA decide on ST-920?
PTC Therapeutics has disclosed a decision window of later this cycle for ST-920 in Fabry disease, without an exact date.
What is ST-920 being reviewed for?
PTC Therapeutics submitted a BLA (rolling) for ST-920 in Fabry disease. One-time AAV gene therapy with RMAT designation; rolling BLA underway with the final module expected in Q4 2026. PTC is acquiring the program from Sangamo. A PDUFA date follows once the FDA accepts the completed application.
What happens after the ST-920 decision?
If approved, availability is not immediate: specialty pharmacy setup, insurance review, and patient assistance typically take weeks even when everything goes right. If the FDA issues a complete response letter, the application was not approved in its current form; CRLs are often about manufacturing or data presentation rather than efficacy, and sponsors frequently resubmit. This page updates with the outcome either way.
Where this date comes from
The FDA does not publish PDUFA dates; companies disclose them. This one comes from PTC Therapeutics SEC filing. Dates can move, and the FDA can act early or late. This page rechecks against our calendar, which is re-verified weekly.