Stealth Biotherapeutics announced top-line data from the Phase 3 MMPOWER-3 trial evaluating elamipretide for the treatment of patients with Primary Mitochondrial Myopathy (PMM). The study did not meet its primary endpoints assessing changes in the six-minute walk test and Primary Mitochondrial Myopathy Symptom Assessment (PMMSA) Total Fatigue Score. Safety results showed that treatment with elamipretide was well tolerated, with most adverse events mild to moderate in severity.
MMPOWER-3 was a randomized, double-blind, parallel-group, placebo-controlled trial to evaluate the efficacy and safety of elamipretide over 32 weeks in 218 patients with primary mitochondrial myopathy between the ages of 16 and 80. The trial was conducted at 28 clinical sites across North America, Europe, and Australia.
Elamipretide is a peptide compound that readily penetrates cell membranes and targets the inner mitochondrial membrane where it binds reversibly to cardiolipin. In preclinical or clinical studies, we have observed that elamipretide increases mitochondrial respiration, improves the electron transport chain function and ATP production, and reduces the formation of pathogenic ROS levels. This elamipretide-cardiolipin association has been shown to normalize the structure of the inner mitochondrial membrane, thereby improving mitochondrial function. Functional benefit is achieved through the improvement of ATP production and interruption, and potential reversal of damaging oxidative stress.
Primary (inherited) Mitochondrial Myopathy, or PMM, is characterized by debilitating skeletal muscle weakness and exercise intolerance. Approximately 40,000 individuals in the United States are diagnosed with this syndrome.