Stealth BioTherapeutics announced that the U.S. Food and Drug Administration (FDA) has extended the Prescription Drug User Fee Act (PDUFA) action date for elamipretide, a first-in-class mitochondria-targeted therapeutic, for the treatment of Barth syndrome. The new target date is April 29, 2025.
The FDA requires additional time to fully review supplemental information provided by Stealth in response to recent agency requests. These requests followed the positive Cardiovascular and Renal Drugs Advisory Committee (CRDAC) meeting on October 10, 2024, where the panel voted 10-6 in favor of elamipretide's approval. The FDA has classified these submissions as Major Amendments to the New Drug Application (NDA), resulting in the standard three-month extension from the original action date of January 29, 2025.
Elamipretide's Regulatory Journey
This is not the first regulatory hurdle for elamipretide. The FDA previously rejected Stealth's initial NDA in 2021, citing the need for "an adequate and well-controlled trial that provides evidence of effectiveness." That application was based on the SPIBA-001 study (NCT04689360), a Phase III trial incorporating data from prior studies and historical controls. The FDA had concerns regarding potential biases in the trial design.
Continued Collaboration with the FDA
Stealth BioTherapeutics remains optimistic about the potential approval of elamipretide. "We appreciate the FDA's commitment to a thorough review of our NDA and the positive supplemental analyses submitted in response to its recent information requests, and remain confident in the robustness of this NDA package," said Reenie McCarthy, Chief Executive Officer of Stealth BioTherapeutics.
Importantly, the FDA has not identified any new safety issues and has not requested any new pre-marketing studies. The agency has also reconfirmed previously communicated post-marketing commitments, and Stealth has addressed all information requests from the agency to date.
About Barth Syndrome
Barth syndrome is an ultra-rare genetic condition primarily affecting males, with an estimated incidence of one in 1,000,000 males worldwide, or about 150 individuals in the United States. It is characterized by cardiac abnormalities, exercise intolerance, muscle weakness, debilitating fatigue, heart failure, recurrent infections, and delayed growth. The disease is associated with reduced life expectancy, with 85% of early deaths occurring by age 5. Currently, there are no FDA- or EMA-approved therapies for Barth syndrome. Elamipretide has been granted Orphan Drug, Fast Track, Priority Review, and Rare Pediatric Disease designations by the FDA, as well as Orphan Drug Designation from the EMA.
Potential Impact of Elamipretide
If approved, elamipretide would be the first marketing authorization for this mitochondria-targeted therapeutic and the first FDA-approved therapy for Barth syndrome, addressing a significant unmet medical need. The drug has shown promise in improving weight gain, strength, and overall quality of life for individuals with Barth syndrome, as highlighted during the October 2024 AdCom meeting.
