In 2021, the U.S. Food and Drug Administration notified Stealth Biotherapeutics it would not consider its application seeking approval for elamipretide as a treatment for the ultra-rare mitochondrial disease Barth syndrome. The agency wants the company to produce evidence of the drug’s efficacy in a larger population of Barth syndrome patients than it studied, but the company believes it has exhausted the population in the United States of patients who fit the clinical trial criteria. Patients have lobbied the agency to give the drug a hearing, but there is growing concern that if the FDA fails to act, elamipretide will become unavailable to patients, who say the drug has given them the ability to lead a normal life. In an effort to move the FDA, Shelley Bowen, co-founder and director of family services for the Barth Syndrome Foundation, launched a Change.org petition calling on the agency to give a full and fair hearing to the drug. We spoke to Bowen about Barth syndrome, the fight over approval for the first drug to treat the condition, and why it points to a systemic problem with the lack of consistent use of the flexibility Congress granted the FDA to get treatments to patients with ultra-rare diseases.