BOSTON — The Barth Syndrome Foundation (BSF) has expressed deep frustration following the U.S. Food and Drug Administration’s (FDA) latest update on elamipretide, a potential treatment for Barth syndrome, an ultra-rare and life-threatening genetic disorder. Despite a favorable advisory committee vote last year, the agency has declined to approve the drug’s current application, prompting outrage from families and advocates.
The FDA recently informed Stealth BioTherapeutics, the drug’s developer, that it would not approve the existing application for elamipretide. However, for the first time, the agency provided a written outline of a potential path to accelerated approval, citing data that shows a more than 45 percent improvement in muscle strength among patients and its correlation with increased physical function.
Emily Milligan, executive director of the Barth Syndrome Foundation, called the delay unacceptable. “It’s unconscionable that it now will take even longer for the FDA to rule on this drug for our very small population with no other specific therapies,” she said. “We need FDA leadership to take strong, decisive action and put an end to the hemming and hawing. This literally translates into life, death and better lives for our children.”
Barth syndrome, which primarily affects males, currently has no FDA-approved treatments and no other therapies in late-stage development. Clinical studies have shown elamipretide’s potential to improve mitochondrial and heart function significantly. Many patients in the initial clinical trial have continued treatment for more than eight years with ongoing benefits, and numerous others, including critically ill infants, have received the drug under emergency access provisions approved by the FDA.
Despite a 10-6 positive vote by the FDA’s Cardiovascular and Renal Drugs Advisory Committee in October 2023 and a strong safety record, the agency has not moved forward with approval. Approximately 20 percent of U.S. patients with Barth syndrome are currently receiving elamipretide through an expanded access program.
The FDA’s proposed regulatory path, however, excludes infants and the sickest patients—many of whom are currently receiving the drug. Over half of all deaths from Barth syndrome occur in the first few years of life, and Milligan criticized the FDA’s decision to leave these patients out of the approval plan, citing feasibility concerns around pre-approval studies.
“No safety concerns have been raised, and the agency acknowledged the difficulty of conducting traditional trials in a disease this rare,” said Milligan. “Still, families are left in limbo, waiting on a treatment that medical experts, patient experiences and common sense overwhelmingly support.”
The push for FDA approval has garnered widespread support. More than 50 medical professionals and nearly 20,000 individuals worldwide have signed letters and petitions urging immediate approval of elamipretide. Advocates argue that with no alternatives available, the prolonged inaction is costing lives.
“With no approved therapies and limited access to treatment, every day of inaction carries a devastating cost,” said Milligan. “The FDA made a promise to our community—to conduct a fair, thorough and equitable review of elamipretide through the advisory committee process. That promise remains unfulfilled.”
