Elamipretide (SS-31): FDA accelerated approval for Barth syndrome
On 19 September 2025 the FDA cleared the first treatment for this rare mitochondrial disease — with a confirmatory trial still required.
Elamipretide (SS-31) is a mitochondria-targeted tetrapeptide that binds cardiolipin on the inner mitochondrial membrane. It is often discussed online as a general “anti-aging” research peptide. The 2025 regulatory event is narrower — and more important.
What the FDA decided
On 19 September 2025, the FDA granted accelerated approval to Forzinity (elamipretide) injection for Barth syndrome in patients weighing at least 30 kg. Approval rested on improved knee-extensor strength, judged reasonably likely to predict clinical benefit. The agency required a post-approval randomized, placebo-controlled trial to confirm that strength change becomes a real-world benefit such as standing or walking farther.
What it did not decide
Accelerated approval is not a general mitochondrial-aging license. An earlier Phase 3 trial in mixed primary mitochondrial myopathy (MMPOWER-3) did not meet its primary endpoints. Common trial side effects included injection-site reactions; serious reactions have also been reported.
Bottom line
Evidence ladder: Human RCT in a rare disease, with residual uncertainty. The 2025 label is a case study in how a research peptide becomes a drug — specific population, specific product, confirmatory science still pending.
Sources
Educational content only — not medical advice. See our Medical disclaimer and Editorial policy.