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NCT Number: NCT07531251

Clinical Trial in Patients With Barth Syndrome- 4TAZPower

Phase 3b/4, randomized, double-blind, parallel-group, placebo-controlled clinical trial to evaluate the efficacy, safety, and pharmacokinetics of a once daily SC injection of elamipretide in subjects with genetically confirmed BTHS for 72 weeks. The primary trial objective is to confirm the efficacy of elamipretide which is approved in the United States(FORZINITY™) under the accelerated approval based on an improvement in knee extensor muscle strength, an intermediate clinical endpoint.

Recruiting

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Key information

Age range

5 year–55 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 4

Primary location

Metabolics and Genetics in Canada (MAGIC), Calgary, Alberta, Canada

Loading trial locations.

About this study

The SPIBA-401 trial is a post marketing Phase 3b/4, randomized, double-blind, parallel-group, placebo-controlled clinical trial to evaluate the efficacy, safety, and pharmacokinetics of a once daily subcutaneous (SC) injection of elamipretide in subjects with genetically confirmed Barth syndrome (BTHS) for 72 weeks. The primary trial objective is to confirm the efficacy of elamipretide which is approved in the United States under the name FORZINITY™ as a mitochondrial cardiolipin binder indicated to improve muscle strength in adult and pediatric patients with Barth syndrome weighing at least 30 kg. This indication is approved in the United States under accelerated approval based on an improvement in knee extensor muscle strength, an intermediate clinical endpoint.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Inclusion Criteria:

  • Willing and able to provide signed informed consent form (ICF) prior to participation in any trial-related procedures. If applicable, informed consent in writing from parent(s) or legally-acceptable representative(s) and, informed assent from subject (if age appropriate according to local requirements) should be provided.
  • Agrees to adhere to the trial requirements for the length of the trial.
  • Must have genetically confirmed Barth Syndrome (pathogenic variant in the TAZ gene)
  • Male aged ≥ 5 years at time of the Screening Visit
  • Left Ventricular Ejection fraction of ≥ 50% by 3-D Echocardiogram at the Screening Visit.
  • For subjects with a medical history of cardiomyopathy, must be on a stable regimen (unchanged and constant) of background heart failure medications for at least 3 months prior to the Screening Visit.
  • Able to administer Investigational Medicinal Product (IMP) or have an appropriate designee who can administer the IMP (i.e., a capable family member or a caregiver).
  • Subjects with female partners of childbearing potential must be willing to use a highly effective method of contraception (e.g., abstinence, dual method of contraception) from the date they sign the ICF until 28 days after the last dose of IMP.

Key Exclusion Criteria:

  • Unable to perform the required functional tests or undergo echocardiography.
  • History of solid organ transplant, except successful cardiac transplantation > 12 months prior to screening, if, in the opinion of the Investigator, there is no evidence of organ rejection and post-transplant pharmacotherapy, is stable, and does not pose additional safety risk to participant.
  • Patients with an implantable cardioverter defibrillator (ICD) and with a known occurrence of ICD discharge in the 3 months prior to the Screening Visit.
  • Current placement on the waiting list for heart transplantation.
  • Hospitalization for heart failure within 6 months prior to the Screening Visit.
  • Any disease or medical condition that in the opinion of the Investigator would prevent the subject from successfully participating in the trial and reliably completing the assessments or might confound trial results.
  • Has a history of a systemic eosinophilic illness
  • Estimated Glomerular Filtration Rate (eGFR) of < 30 mL/min at the Screening Visit (using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2021 formula for subjects >16 years of age and the Schwartz 2009 formula for subjects 5-16 years of age).
  • Active malignancy or any other cancer from which the subject has been cancer-free for < 2 years. Localized squamous or non-invasive basal cell skin carcinomas are allowed, if appropriately treated prior to Screening.
  • Participation in other investigational drug or device clinical trials within 30 days or 5 half-lives (whichever is longer) of Screening; or is currently enrolled in a non-interventional clinical trial that, in the opinion of the Investigator, may be potentially confounding to the results of the current trial.
  • History of allergic reaction to the IMP or any of its components.
  • Prior participation in any elamipretide trial or expanded access programs.

Treatment and study plan

elamipretide

Drug

sub cutaneous injection

Other names: elamipretide hydrochloride

Placebo

Drug

sub cutaneous injection

Primary outcomes

  1. Primary Efficacy End Point

    Time frame: 72 weeks

    -change in the composite normalized score of the three functional tests: Six-minute walk test (6MWT), the triple-timed up and go test (3TUG), and the Five times sit-to-stand test (5XSST) from baseline to 72 weeks of treatment

Secondary outcomes

  1. Secondary Efficacy End Point 1

    Time frame: 72 weeks

    • Change in 6Minute Walk Test from Baseline to Week 72
  2. Secondary Efficacy End Point 2

    Time frame: 72 weeks

    -Change in 3Timed Up and Go Test from Baseline to Week 72

  3. Secondary Efficacy End Point 3

    Time frame: 72 weeks

    -Change in 5XSit to Stand Test from Baseline to Week 72

  4. Secondary Efficacy End Point 4

    Time frame: 72 weeks

    -Change in Patient Global Impression of Severity Scale (PGI-S) score from Baseline to Week 72

  5. Secondary Efficacy End Point 5

    Time frame: 72 weeks

    Change in Clinician Global Impression of Severity Scale (CGI-S) score from Baseline to Week 72

  6. Secondary Efficacy End Point

    Time frame: 72 weeks

    Change in knee extensor muscle strength as measured by handheld dynamometry (HHD)from Baseline to Week 72

  7. Secondary Efficacy End Point 6

    Time frame: 72 weeks

    -Change in hip flexor muscle strength as measured by HHD from Baseline to Week 72

Other outcomes

  1. Safety End Point Adverse Event Reporting

    Time frame: 72weeks

    -Report the # of subjects with adverse events and incidence and severity of such adverse events (AEs)

Study contacts

Contact information is provided by the study sponsor or research team.

Lani Glennon

CONTACT

[email protected]

Rekha Sathyanarayana

CONTACT

[email protected]

617-762-2579

Sponsors and collaborators

Lead sponsor

Stealth BioTherapeutics Inc.

Industry

Registry information

Official study title

Phase 3b/4, Randomized, Double-Blind, Parallel-Group, Placebo-Controlled, Trial to Evaluate the Efficacy and Safety of Daily Subcutaneous Injections of Elamipretide in Patients With Genetically Confirmed Barth Syndrome

Acronym: 4TAZPower

Important dates

Study start
2026
Primary completion
2029
Study completion
2029
First posted
Apr 15, 2026
Registry last updated
Jul 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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