for people ages 16-80 (full criteria)
at La Jolla, California and other locations
study started
estimated completion



This is a multicenter phase 3 randomized, double-blind, parallel-group, placebo-controlled trial to evaluate the safety and efficacy of daily subcutaneous injections of elamipretide in subjects with primary mitochondrial myopathy. This will be followed by an open-label treatment extension.

Official Title

A Phase 3 Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Trial to Evaluate the Efficacy and Safety of Daily Subcutaneous Injections of Elamipretide in Subjects With Primary Mitochondrial Myopathy Followed by an Open-Label Treatment Extension


Primary Mitochondrial Myopathy Myopathy PMD Primary Mitochondrial Disease MTP-131 elamipretide Muscular Diseases Mitochondrial Myopathies elamipretide open label treatment


For people ages 16-80


Inclusion Criteria:

  • Willing and able to provide a signed informed consent form prior to participation in any trial-related procedures
  • Agrees to adhere to the trial requirements for the length of the trial, including the use of the elamipretide delivery system
  • Subject is ≥ 16 and ≤ 80 years of age
  • Diagnosed with PMM in the opinion of the investigator and confirmed by an Adjudication Committee
  • Woman of childbearing potential must agree to use a highly effective method of birth control

Exclusion Criteria:

  • Subject has myopathic signs and or/symptoms due to a neuropathic process or gait problem that would interfere with the 6MWT, in the opinion of the Investigator
  • Female who are pregnant, planning to become pregnant, or breastfeeding/lactating
  • At Screening, the estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m2

  • Subject has undergone an in-patient hospitalization within the 30 days prior to the Baseline Visit or has a planned hospitalization or a surgical procedure during the trial.
  • Subject has clinically significant cardiac disease or prior interventional procedure and/or respiratory disease (medical history or current clinical findings) within 3 months of the Baseline Visit, in the opinion of the Investigator.
  • Subject has QTc elongation (using the correction factor utilized at the clinical site) defined as a QTc >450 msec in male subjects and >480 msec in female subjects.
  • ECG evidence of acute ischemia, atrial fibrillation, or active conduction system abnormalities with the exception of any of the following:
  • First degree AV-block
  • Second degree AV-block Type 1 (Mobitz Type 1 / Wenckebach type)
  • Right bundle branch block
  • Subject has severe vision impairment that, in the opinion of the Investigator, may interfere with their ability to complete all trial requirements
  • Subject has a seizure disorder that, in the opinion of the Investigator, may interfere with their ability to complete all trial requirements.
  • Active malignancy or any other cancer from which the subject has been disease-free for < 2 years.
  • Subject has a solid organ transplant and/or is currently receiving treatment with therapy for immunosuppression, in the opinion of the Investigator.
  • Subject has been previously diagnosed with human immunodeficiency virus (HIV), hepatitis B, or hepatitis C infection.
  • Subject has a history of a systemic eosinophilic illness and/or an eosinophil count >1,000 cells x106/L at the Screening Visit.

  • Subject is currently participating or has participated in an interventional clinical trial (i.e.,investigational product or device, stem cell therapy, gene therapy) within 30 days of the Baseline Visit; or is currently enrolled in a non-interventional clinical trial (except for SPIMM-300) at the Baseline Visit which, in the opinion of the Investigator, may be potentially confounding with results of the current trial (e.g., exercise therapy trial).
  • Subject has previously received elamipretide (MTP-131), for any reason.
  • Subject has a history of active substance abuse during the year before the Baseline Visit, in the opinion of the Investigator.
  • Subject has any prior or current medical condition that, in the judgment of the Investigator, would prevent the subject from safely participating in and/or completing all trial requirements.


Continuation Criteria:

  • Subjects must continue to be able and willing to adhere to the trial requirements.
  • Subject is appropriate to continue in Part 2 (i.e. subject was compliant in Part 1), in the opinion of the Investigator.
  • Subject has not had a serious adverse event (SAE)/serious adverse device effect (SADE) attributed to the elamipretide delivery system.
  • Subject has not permanently discontinued the elamipretide delivery system.


  • University of California San Diego
    La Jolla California 92093 United States
  • Stanford University
    Palo Alto California 94304 United States


in progress, not accepting new patients
Start Date
Completion Date
Stealth BioTherapeutics Inc.
Phase 3
Study Type
Last Updated