Elamipretide
Mitochondria-targeted cardiolipin-binding tetrapeptide
Status
Approved
Granted FDA accelerated approval on 19 September 2025 as Forzinity, to improve muscle strength in adults and children with Barth syndrome weighing at least 30 kg; it is the first approved therapy for Barth syndrome and the first approved mitochondria-targeted drug. Continued approval depends on a confirmatory trial, the phase 4 4TAZPower study, which dosed its first patient in July 2026. It holds EU orphan designation for Barth syndrome but is not approved by the EMA.
Evidence
Preliminary
Approval rests on 12 patients: the randomised crossover trial missed both primary endpoints, and the muscle strength gains that supported approval appeared only in the open-label extension.
A four-amino-acid drug that concentrates in mitochondria and binds cardiolipin, a lipid of the inner mitochondrial membrane. It is approved in the US to improve muscle strength in Barth syndrome, a rare inherited disease.
Structure
4 residuesPoint at a bead, or focus the chain and use the arrow keys, to name it. Pick a chemistry to highlight it.
D-form (mirror image), shown in lower case
Sequence as text
H-D-Arg-Dmt-K-F-NH2
What it is used for
- Barth syndrome, to improve muscle strength in patients weighing at least 30 kg (approved)
- Primary mitochondrial myopathy, where the phase 3 MMPOWER-3 trial missed its endpoints (studied)
- Mitochondrial myopathy caused by POLG mutations (studied)
How it works
Cardiolipin is a lipid that holds the folded inner membrane of mitochondria in shape and keeps the respiratory chain packed together. In Barth syndrome the TAFAZZIN gene fails to remodel cardiolipin, so that structure breaks down. Elamipretide carries a positive charge and an aromatic residue pattern that drives it into the inner membrane, where it binds cardiolipin reversibly and improves mitochondrial shape and function, as the label describes. It does not correct the underlying gene defect.
How strong the evidence is
Preliminary
TAZPOWER randomised 12 men and boys with genetically confirmed Barth syndrome to 12 weeks of elamipretide then placebo, or the reverse. It failed both primary endpoints, the six-minute walk distance and total fatigue score. Knee extensor strength, a secondary endpoint, did not improve during the randomised phase but rose during the open-label extension, with a median gain of 63 newtons at week 168 in the eight patients still enrolled. FDA accepted that intermediate endpoint under accelerated approval. In a different disease, the 218-patient MMPOWER-3 trial in primary mitochondrial myopathy did not meet its endpoints.
Risks and side effects
- Injection site reactions are near universal: every patient in the trial had redness, and pain, induration, itching, bruising or hives were common
- Hypersensitivity reactions including serious allergic reactions have occurred, sometimes months after starting
- The product contains benzyl alcohol and is not for use in neonates, in whom benzyl alcohol has caused fatal gasping syndrome
- Blood eosinophil counts rise with exposure beyond 30 days, peaking around 90 days, without clinical consequences seen so far
- The dose must be reduced in adults with severe kidney impairment, and there is no dosing information for people on dialysis
- Benefit is not yet confirmed: approval is conditional on the phase 4 trial and could be withdrawn
Label dosing
Label: 40 mg subcutaneously once daily in patients weighing at least 30 kg, reduced to 20 mg once daily in adults with severe renal impairment who are not on dialysis.
Regulatory status
| Region | Year | Approved for |
|---|---|---|
| USFDA | 2025 | To improve muscle strength in adult and paediatric patients with Barth syndrome weighing at least 30 kg (accelerated approval) |
Status by country
| Jurisdiction | Status | Source |
|---|---|---|
| USUnited States | Authorised medicine | Source 1 |
| EUEuropean Union | No authorised medicine | Source 8 |
| UKUnited Kingdom | No authorised medicine | Source 9 |
| AUAustralia | No authorised medicine | Source 10 |
| CACanada | No authorised medicine | Source 11 |
Trials of Elamipretide to watch
ReNEW(opens the source in a new tab)
ReNEW:Phase 3 Study of Efficacy, Safety & Pharmacokinetics of Subcutaneous Injections of Elamipretide in Subjects With Dry Age-Related Macular Degeneration (Dry AMD)
Timeline
2027
2026
2025
- ApprovalFDA grants accelerated approval to elamipretide (Forzinity) for Barth syndrome
- Approved, US (FDA)To improve muscle strength in adult and paediatric patients with Barth syndrome weighing at least 30 kg (accelerated approval)
Articles about Elamipretide
Sources
- 01FORZINITY (elamipretide) injection, for subcutaneous use: US prescribing information(opens the source in a new tab)
- 02Drug Trials Snapshots: Forzinity(opens the source in a new tab)
- 03Stealth BioTherapeutics Announces FDA Accelerated Approval of FORZINITY (elamipretide HCl)(opens the source in a new tab)
- 04Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER(opens the source in a new tab)
- 05Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial(opens the source in a new tab)
- 06A Clinical Trial in Patients With Barth Syndrome (4TAZPower), NCT07531251(opens the source in a new tab)
- 07Elamipretide: First Approval(opens the source in a new tab)
- 08Find medicine: centrally authorised medicines(opens the source in a new tab)
- 09MHRA Products: active substances beginning with E(opens the source in a new tab)
- 10Australian Register of Therapeutic Goods (ARTG)(opens the source in a new tab)
- 11Think twice before injecting peptides bought online: unauthorized products can seriously harm you(opens the source in a new tab)
Educational information, not medical advice. Talk to a licensed clinician before starting, stopping or changing any medicine.