Stealth Biotherapeutics’ Barth Syndrome NDA Receives FDA Priority Review

Rare Daily Staff

The U.S. Food and Drug Administration has granted Priority Review to Stealth Biotherapeutics’ New Drug Application for elamipretide for the treatment of Barth syndrome with the user fee goal date of January 29, 2025, unchanged.

The FDA’s decision to grant Priority Review designation follows its March 29, 2024, filing decision in which the FDA assigned a standard review designation. Elamipretide has previously received Orphan Drug, Fast Track and Rare Pediatric designations for elamipretide and Orphan Drug designation from the EMA for the treatment of Barth syndrome.

“We are pleased that the FDA has recognized the serious nature of Barth syndrome, the urgency of the unmet medical need, and the potential for elamipretide, if approved, to significantly improve treatment of this devastating disease,” said Reenie McCarthy, CEO of Stealth Biotherapeutics.

FDA’s decision to accept Stealth’s NDA followed a protracted fight over several years between the agency and company and patient advocates over whether Stealth had studied the drug in an adequate number of patients for it to review its application, let alone approve it. The principal investigator of the Stealth study had already screened every patient in North America that fit the clinical trial inclusion criteria. Previously, the agency notified the company it would not consider its application.

Barth syndrome is an ultra-rare genetic condition characterized by cardiac abnormalities often leading to heart failure and reduced life expectancy, recurrent infections, muscle weakness, and delayed growth. Barth syndrome occurs almost exclusively in males and is estimated to affect one in 200,000 to 400,000 individuals worldwide. There are currently no U.S. Food and Drug Administration or European Medicines Agency-approved therapies for patients with Barth syndrome.

Elamipretide is a peptide that targets the inner mitochondrial membrane where it binds to cardiolipin, which plays an essential role in energy conversion within cells. If approved, this would be the first marketing authorization for elamipretide, a first-in-class mitochondrial targeted therapeutic. Elamipretide is also in development for primary mitochondrial myopathy, with pivotal data from a fully-enrolled phase 3 trial expected in late 2024.

The FDA grants Priority Review to applications for therapies that have the potential to provide significant improvements in the treatment, diagnosis, or prevention of serious conditions.

Photo: Reenie McCarthy, CEO of Stealth Biotherapeutics