Rare disease · Phase 3
MMPOWER-3: mitochondrial myopathy
What was tested?
Elamipretide versus placebo in people with primary mitochondrial myopathy. ↗
Registered primary question: Change in six-minute walking distance and symptom-assessment total fatigue score at week 24. ↗
What the reviewed report found
Journal year 2023 · Article summary reviewed 2026-09-15
Neither walking distance nor fatigue met the primary efficacy endpoint. Most reported adverse events were mild or moderate.↗
Keep in context: Neither primary endpoint was met. Findings in primary mitochondrial myopathy should not be substituted for evidence in Barth syndrome. ↗↗
What a closer reading adds
Selected full-text sections checked 2026-09-20. These notes add context to the earlier article summary; they are not a complete risk-of-bias assessment.
Overall result versus exploratory subgroup
The full text reports neither primary endpoint was met in the overall population. Its genetic subgroup analyses are exploratory, and the nuclear-DNA subgroup result is identified as post hoc; it cannot replace the overall primary result. Full text ↗ · Indexed abstract ↗
Sections: Subgroup Analyses by PMM Genotype; Primary Endpoints of Overall ITT; Analyses by Genetic Subgroup: mtDNA vs nDNA; Discussion.
An abstract and full-text discrepancy
The indexed abstract and the full-text primary-results section give different confidence intervals and p values for the fatigue comparison. Both describe a nonsignificant result. We retain that shared conclusion without selecting one conflicting numerical estimate as definitive. Full text ↗ · Indexed abstract ↗
Sections: Primary Endpoints of Overall ITT.
Participants, design, limitations and sources
Registry snapshot
- Registry enrollment
- 218 · reported actual
- Registry status
- Terminated
- Allocation and masking
- Randomized · Quadruple
- Design
- Parallel
- Eligible ages
- 16 Years to 80 Years
- Registry results
- Posted in this snapshot
Registry source ↗ · Updated 2022-01-24; retrieved 2026-09-20. Registry enrollment is not necessarily the analyzed sample in a publication. Posted registry results and published article results are separate.
MMPOWER-3: primary mitochondrial myopathy
- Design in the report
- A randomized, blinded, placebo-controlled phase 3 trial assessed 24-week outcomes.↗
- Participants in the report
- The study randomized 218 participants with genetically confirmed primary mitochondrial myopathy.↗
- Limitations
- This is a different disease population from Barth syndrome. Overall null results cannot be replaced by favorable exploratory subgroup findings.↗
This reading covers the article abstract and record metadata. Read its preserved Human Evidence Review →
How the study identity and sources were checked
Study context checked 2026-09-20. Existing article summaries keep their original review dates. This is a selected study reading, not a complete literature or full-text appraisal.
Registry
A Trial to Evaluate Safety and Efficacy of Elamipretide Primary Mitochondrial Myopathy Followed by Open-Label Extension ↗
Protocol identifier: SPIMM-301. Sponsor: Stealth BioTherapeutics Inc..
Retrieved 2026-09-20; SHA-256 be49db47416dd4a43e15baa432c72141e12dbecf3114000bf16680f2f85967f4.
PMID 37268435
Exact trial identity is declared in PubMed’s ClinicalTrials.gov databank field. The registry independently labels this reference DERIVED. These source labels do not establish that every result in a paper applies to this trial.
Identity metadata retrieved 2026-09-20. EFetch batch XML; locate MedlineCitation/PMID 37268435. SHA-256 f2177628b98083064df17512c3dd229b760887c00cc64c4cfa4fc4e49523b12a.
Scientific summary uses the original 2026-09-15 source snapshot: SHA-256 ed6e6945e4e878261ab8d7868ae3118cae1354effbbf604ee9aeddfdce7df940.
Selected full text: PMC10382259
Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy ↗
Retrieved 2026-09-20; SHA-256 35fbf3139ae775f5ff4d3a011ce2461ea5cf7dc8eef296f1f8abf47cc56f1342. Section identifiers and hashes are included in the cited study data.