Granted FDA accelerated approval Sept 19, 2025 as FORZINITY (elamipretide) to improve muscle strength in Barth syndrome patients ≥30 kg — the first FDA-approved mitochondria-targeted therapeutic. Not approved for heart failure or primary mitochondrial myopathy, both of which failed their primary endpoints in Phase 2/3 trials.
SS-31 is a cell-permeable aromatic-cationic tetrapeptide that concentrates in the inner mitochondrial membrane, proposed to bind and stabilize cardiolipin, preserving cristae structure and electron tr...
SS-31 is a cell-permeable aromatic-cationic tetrapeptide that concentrates in the inner mitochondrial membrane, proposed to bind and stabilize cardiolipin, preserving cristae structure and electron transport chain organization and reducing reactive oxygen species production. Its clinical trial history is a useful, honest case study in mixed results: it improved 6-minute walk distance and fatigue in Barth syndrome (the basis for its 2025 approval), but did not significantly improve left ventricular function in a heart failure trial (PROGRESS-HF) or meet its primary endpoints in a primary mitochondrial myopathy trial (MMPOWER-3) — it was generally well tolerated across all of these, with injection-site reactions as the most frequent adverse event.
Genetics in Medicine · 2024
Sustained tolerability and significant improvements in 6-minute walk distance and fatigue — the data underpinning the 2025 FDA accelerated approval for Barth syndrome.
View Source →Neurology · 2023
Did not meet primary endpoints (6-minute walk distance, fatigue) versus placebo; a post hoc analysis suggested possible benefit in a nuclear-DNA-variant subgroup.
View Source →Journal of Cardiac Failure · 2020
Well tolerated but did not significantly improve left ventricular end-systolic volume versus placebo — a negative result, reported here for accuracy.
View Source →Circulation: Heart Failure · 2017
Phase 1/2 trial: the highest dose reduced left ventricular end-diastolic/end-systolic volumes versus placebo, with no serious adverse events.
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