Forzinity (elamipretide)
An approved treatment for Barth Syndrome.
Drug facts
The same compound appears under different names depending on the context. Here is how to identify Elamipretide wherever you encounter it, plus the key facts at a glance.
- Generic name
- Elamipretide
- Brand name
- Forzinity
- Development codes
- MTP-131, Bendavia, SS-31
- Drug class
- Cardiolipin-stabilizing tetrapeptide
- Manufacturer
- Mighty Therapeutics (formerly Stealth BioTherapeutics)
- How it's taken
- Forzinity is administered as a once-daily subcutaneous injection.
The first FDA-approved therapy for Barth syndrome, which its maker describes as the first FDA-approved mitochondria-targeted therapeutic.
- Forzinity is a small peptide that binds cardiolipin in the inner mitochondrial membrane, stabilizing the membrane structure that Barth patients cannot maintain because of their TAFAZZIN gene defect.
- Approved on September 19, 2025 via accelerated approval to improve muscle strength in adult and pediatric patients with Barth syndrome weighing at least 30 kilograms (about 66 pounds).
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Where Elamipretide fits
First and only FDA-approved therapy specifically for Barth syndrome (accelerated approval September 19, 2025, and still the only one as of September 2026) and the first mitochondria-targeted therapeutic ever approved.
- The on-label indication is for patients weighing at least 30kg, which excludes many young pediatric patients; expanded access is available for under-weight patients.
- Standard supportive care for Barth (heart failure medications, G-CSF for neutropenia, prophylactic antibiotics, nutritional support, physical therapy) continues alongside Forzinity.
How Elamipretide works
In Barth syndrome, a defective tafazzin enzyme cannot properly remodel cardiolipin, a phospholipid that mitochondria need to make energy. Without mature cardiolipin, mitochondrial membranes become unstable and the electron transport chain cannot produce normal amounts of ATP, which leaves the heart, skeletal muscle, and white blood cells underpowered.
Forzinity is a small four-amino-acid peptide that selectively concentrates in the inner mitochondrial membrane and binds cardiolipin directly. By stabilizing cardiolipin even when tafazzin is missing, Forzinity helps preserve the structure of the membrane and the function of the energy-producing complexes embedded in it. The drug does not correct the underlying genetic defect, so it must be taken long-term.
Side effects and safety
The most common side effects are injection site reactions such as redness, pain, hardening, itching, bruising, and hives. Serious allergic reactions needing emergency care have been reported, with rash, skin lesions, or cough, and can happen minutes to months after starting. Forzinity contains benzyl alcohol and is not approved for newborns.
In the 12-week placebo-controlled study, all 12 patients had injection site redness on Forzinity, against 3 of 12 on placebo. Eosinophil counts, a type of white blood cell, often rose in the first months and returned to baseline within 6 to 12 months, without symptoms. The full safety profile in Barth patients continues to be characterized through expanded access and post-marketing studies.
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Elamipretide
Forzinity is administered as a once-daily subcutaneous injection. Patients and caregivers are trained to self-inject at home, with rotating injection sites. The dose is 40mg once daily for patients weighing at least 30 kilograms, reduced to 20mg once daily in adults with severe kidney impairment.
Availability and cost
Only available as the brand-name product.
Targeted therapy for an ultra-rare disease (~150 U.S. patients). Coverage typically requires biochemical or genetic confirmation of Barth syndrome. Stealth maintains expanded access for under-weight pediatric patients while pursuing label expansion.
Help paying for Forzinity
With private insurance, the drugmaker's copay card can lower what you pay for Forzinity. Drugmaker copay cards can't be used with Medicare, Medicaid or TRICARE, but charity funds often can. None of the 2 charity funds for Barth Syndrome were open on October 26, 2026. Pick your insurance below to see which offers fit you.
- Copay help
Commercially insured patients may pay as little as $0; annual maximum applies. Medicare, Medicaid, TRICARE, VA and other government plans are not eligible.
For: private insurance · source - Free medicine program
Insurance Specialists check eligibility for patient assistance. Criteria not stated on official pages.
The official page does not say who qualifies. Ask the program. · source - Insurance and case manager help
Care Managers, Insurance Specialists and visiting nurses for injection education; run with specialty pharmacy AnovoRx.
The official page does not say who qualifies. Ask the program. · source
Good to know: Patient assistance program is mentioned but who qualifies is not stated. Copay program is for commercial insurance only.
Charity funds for Barth Syndrome
- From a charity · NORD RareCareBarth Syndrome Emergency Relief fundWaitlist
Pays for: Emergency relief.
The foundation says: “Temporarily Waitlisting”
Clinical trial results
FDA accelerated approval was based on the open-label extension of the Phase 2/3 TAZPOWER trial in people 12 and older with Barth syndrome. In the 12-week placebo-controlled part, Forzinity did not beat placebo on its main goals (6-minute walk distance and fatigue score), but knee extensor muscle strength improved from baseline during the open-label extension.
Because this is an accelerated approval, continued FDA approval may be contingent on verification of clinical benefit in a confirmatory trial. That trial, 4TAZPower (NCT07531251), is a 72-week placebo-controlled study in people aged 5 to 55 that began recruiting in July 2026. At approval, the company said it planned to expand the indication to children under 30kg.
Development history
Elamipretide was originally developed as a broader mitochondrial-protective candidate (under codes MTP-131, Bendavia, SS-31) and studied in conditions ranging from acute myocardial infarction to primary mitochondrial myopathy. Stealth BioTherapeutics refocused development on Barth syndrome after recognizing the strong mechanistic match with cardiolipin-stabilization and the high unmet need in the Barth community.
After a complex regulatory path that included an initial Complete Response Letter, the FDA granted accelerated approval on September 19, 2025, making elamipretide the first targeted therapy for Barth syndrome and the first mitochondria-targeted drug ever approved. In June 2026, Stealth BioTherapeutics changed its name to Mighty Therapeutics, the company that now markets Forzinity.
Explore Barth Syndrome trials
Common questions about Elamipretide
▸What is Elamipretide (Forzinity)?
The first FDA-approved therapy for Barth syndrome, which its maker describes as the first FDA-approved mitochondria-targeted therapeutic. Forzinity is a small peptide that binds cardiolipin in the inner mitochondrial membrane, stabilizing the membrane structure that Barth patients cannot maintain because of their TAFAZZIN gene defect. Approved on September 19, 2025 via accelerated approval to improve muscle strength in adult and pediatric patients with Barth syndrome weighing at least 30 kilograms (about 66 pounds).
▸How does Elamipretide work?
In Barth syndrome, a defective tafazzin enzyme cannot properly remodel cardiolipin, a phospholipid that mitochondria need to make energy. Without mature cardiolipin, mitochondrial membranes become unstable and the electron transport chain cannot produce normal amounts of ATP, which leaves the heart, skeletal muscle, and white blood cells underpowered.
Forzinity is a small four-amino-acid peptide that selectively concentrates in the inner mitochondrial membrane and binds cardiolipin directly. By stabilizing cardiolipin even when tafazzin is missing, Forzinity helps preserve the structure of the membrane and the function of the energy-producing complexes embedded in it. The drug does not correct the underlying genetic defect, so it must be taken long-term.
▸What are the side effects of Elamipretide?
The most common side effects are injection site reactions such as redness, pain, hardening, itching, bruising, and hives. Serious allergic reactions needing emergency care have been reported, with rash, skin lesions, or cough, and can happen minutes to months after starting. Forzinity contains benzyl alcohol and is not approved for newborns. In the 12-week placebo-controlled study, all 12 patients had injection site redness on Forzinity, against 3 of 12 on placebo. Eosinophil counts, a type of white blood cell, often rose in the first months and returned to baseline within 6 to 12 months, without symptoms. The full safety profile in Barth patients continues to be characterized through expanded access and post-marketing studies.
▸How is Elamipretide taken?
Forzinity is administered as a once-daily subcutaneous injection. Patients and caregivers are trained to self-inject at home, with rotating injection sites. The dose is 40mg once daily for patients weighing at least 30 kilograms, reduced to 20mg once daily in adults with severe kidney impairment.
▸Is Elamipretide FDA approved?
Yes, Elamipretide (Forzinity) is FDA approved (2025) for the treatment of Barth Syndrome.
▸Is Forzinity the first FDA-approved treatment for Barth syndrome?
Yes. On September 19, 2025, the FDA granted accelerated approval to Forzinity (elamipretide) to improve muscle strength in adult and pediatric Barth syndrome patients weighing at least 30 kilograms (about 66 pounds). Before this approval, Barth patients were managed with heart failure medications, G-CSF for neutropenia, prophylactic antibiotics, and supportive care, none of which addressed the underlying mitochondrial defect.
▸What does the 30 kilogram (about 66 pound) weight cutoff mean for young children with Barth syndrome?
Many young children with Barth weigh less than 30kg, the lower limit of the on-label indication. For these patients, Forzinity is not yet on-label, but Mighty Therapeutics (formerly Stealth BioTherapeutics) provides expanded access for under-weight patients who are already receiving treatment or who need emergency access. The company is also working with the FDA to generate the data needed to expand the indication to younger and lighter patients. Discuss the expanded access pathway with your cardiologist or metabolic specialist.
▸What does "accelerated approval" mean for Forzinity?
Accelerated approval allows the FDA to approve a drug for a serious condition based on a surrogate endpoint that is reasonably likely to predict clinical benefit, with the requirement that the manufacturer continue to study the drug in confirmatory trials. For Forzinity, the surrogate is improvement in muscle strength. Continued approval may be contingent on verification of broader clinical benefit in those follow-up studies.
▸How does Forzinity work?
Forzinity is a small four-amino-acid peptide that selectively concentrates in mitochondria and binds cardiolipin, the phospholipid that Barth patients cannot remodel correctly. By stabilizing cardiolipin, Forzinity supports the structure of the inner mitochondrial membrane and the function of the energy-producing complexes embedded in it. It does not correct the genetic defect, so it must be taken long-term.
▸Is Forzinity a cure?
No. Forzinity does not correct the underlying tafazzin gene mutation. It stabilizes cardiolipin to support mitochondrial function and improve muscle strength, but it must be taken long-term to maintain benefit. Research into curative approaches, including gene therapy, is ongoing.
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- U.S. Food and Drug Administration · September 2025. FORZINITY (elamipretide) injection, Prescribing Information. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/215244s000lbl.pdf
- Stealth BioTherapeutics via BioSpace · September 19, 2025. Stealth BioTherapeutics Announces FDA Accelerated Approval of FORZINITY (elamipretide HCl), the First Therapy for Progressive and Life-limiting Ultra-rare Genetic Disease Barth Syndrome. https://www.biospace.com/press-releases/stealth-biotherapeutics-announces-fda-accelerated-approval-of-forzinity-elamipretide-hcl-the-first-therapy-for-progressive-and-life-limiting-ultra-rare-genetic-disease-barth-syndrome
- ClinicalTrials.gov. TAZPOWER: A Trial Evaluating Elamipretide in Patients With Barth Syndrome. https://clinicaltrials.gov/study/NCT03098797
- Barth Syndrome Foundation · September 19, 2025. FDA Approves First Medication for Barth Syndrome. https://www.barthsyndrome.org/newsevents/newsandpressreleases.html/article/2025/09/19/fda-approves-first-medication-for-barth-syndrome
- Drugs (peer-reviewed journal). Elamipretide: First Approval. https://pubmed.ncbi.nlm.nih.gov/41335372/
- Mighty Therapeutics via BioSpace · June 16, 2026. Mighty Therapeutics, Formerly Stealth BioTherapeutics, Announces New Name Honoring the Mitochondrial Disease Community. https://www.biospace.com/press-releases/mighty-therapeutics-formerly-stealth-biotherapeutics-announces-new-name-honoring-the-mitochondrial-disease-community
- ClinicalTrials.gov. Clinical Trial in Patients With Barth Syndrome- 4TAZPower. https://clinicaltrials.gov/study/NCT07531251