1 more study may be enough for Fabry gene therapy approval: FDA
Sangamo 'thankful' for agency alignment on regulatory pathway for ST-920
The U.S. Food and Drug Administration (FDA) has advised Sangamo Therapeutics that positive results from a single well-controlled clinical trial, in addition to existing evidence, may be sufficient to form the basis for approving its Fabry disease gene therapy candidate.
For Sangamo, that means that one more study may be enough for a positive regulatory decision in the U.S. on its ST-920 (isaralgagene civaparvovec) gene therapy — which “would significantly reduce anticipated complexity, cost and time to potential approval,” the company said in a press release.
In a meeting with the developer, the FDA agreed that the proposed trial would include up to 25 male and female participants with Fabry disease. The agency also agreed that the trial would not require a control arm or a head-to-head comparison with a standard enzyme replacement therapy (ERT), which is expected to allow the study to be done faster and more cheaply.
“We are thankful for the FDA’s support and alignment on a regulatory pathway that could potentially deliver a new treatment option for Fabry disease patients on an expedited, cost-effective timeline,” said Nathalie Dubois Stringfellow, PhD, chief development officer at Sangamo.
Fabry gene therapy candidate granted orphan drug status in US and EU
On the other side of the Atlantic, the European Medicines Agency (EMA) has granted ST-920 priority medicines (PRIME) eligibility, a designation given to therapies with the potential to fill unmet medical needs that aims to get much-needed treatments to market faster.
“We appreciate the support from the EMA and the opportunity to advance our development plans in Europe,” Stringfellow said.
ST-920 has been designated an orphan drug by both the EMA and the FDA, providing Sangamo with incentives to speed its development, and the promise of market exclusivity if the therapy ultimately is approved. An orphan drug is one developed to treat rare diseases, defined in the U.S. as affecting fewer than 200,000 people, and in the European Union as being diagnosed in fewer than 5 in 10,000 people.
The U.S. and European regulatory support for ST-920 and the serious unmet medical need in Fabry disease signal the important role that ST-920 could play in improving the lives of Fabry patients across the globe.
The U.S. agency also has given the Fabry gene therapy candidate fast track designation, which hastens the review of potentially important therapies, as well as regenerative medicine advanced therapy (RMAT) designation. RMAT is a specific designation for gene therapies created under the
“The U.S. and European regulatory support for ST-920 and the serious unmet medical need in Fabry disease signal the important role that ST-920 could play in improving the lives of Fabry patients across the globe,” Stringfellow said.
Fabry is caused by mutations in the gene encoding the alpha-GalA enzyme, resulting in the toxic buildup of fatty molecules in organs. ST-920 is a one-time treatment designed to deliver to liver cells a healthy version of the gene, allowing production of a functional enzyme and clearance of the toxic fatty molecules.
Sangamo is sponsoring an ongoing Phase 1/2 clinical trial called STAAR (NCT04046224), which is testing the therapy in people with Fabry disease. The company earlier this month announced interim data suggesting the gene therapy reduced disease severity and stabilized kidney function in the first year after treatment. Data from STAAR also have indicated the therapy increases alpha-GalA levels as designed.
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