Stealth BioTherapeutics originally submitted elamipretide for approval in January 2024, only to receive a rejection in May of this year. In addition to accepting the biotech’s resubmission, the FDA has promised to take action on the candidate by Sept. 26.
Stealth BioTherapeutics is taking another shot at getting its Barth syndrome therapy elamipretide approved, with the FDA accepting a resubmitted application and agreeing to a speedy September decision date just days after the new filing.
Elamipretide has been resubmitted to treat the ultra-rare genetic disorder that causes muscle weakness, fatigue and heart failure. About 85% of patients with Barth die by the age of five.
Stealth originally submitted the application in January 2024 after years of discussion with the FDA and an advisory committee meeting that ultimately supported the approval of elamipretide. But in May, after a 16.5 month review, Stealth announced that the FDA had rejected the drug.
The biotech at the time did not fully state the FDA’s concerns, noting some manufacturing issues. However, the Cardiovascular and Renal Drugs Advisory Committee in 2024 flagged the flawed nature of Stealth’s data that supported the drug and uncertainties regarding clinical efficacy.
In rejecting the drug, the FDA left the door open for a resubmitted application under the accelerated review pathway. Stealth resubmitted that application on August 15, requesting the speedy review. The FDA has granted the accelerated review, promising to take action on elamipretide by Sept. 26, instead of Feb. 15, 2026, which would be the target date under a standard review application.
The resubmission seeks approval of the drug based on improvements in knee extensor muscle strength. Stealth requested that this be the main endpoint for approval in the original application, which the FDA has agreed to. Knee extensor muscle strength is associated with improvements in a six-minute walk test.
During Stealth’s Phase II TAZPOWER trial, which underpins the application, patients saw a greater than 45% improvement in the endpoint. The company has offered to conduct a post-marketing trial to confirm clinical benefit.
Elamipretide is a mitochondria-targeted therapeutic that Stealth is also developing for primary mitochondrial myopathy and dry age-related macular degeneration.
