Stealth Initiates Extension Trial of Elamipretide for Primary Mitochondrial Disease

Stealth BioTherapeutics has initiated an extension trial of its Phase 2 study evaluating elamipretide in patients with primary mitochondrial disease. The study, MMPOWER-2, will evaluate patients who completed the initial clinical trial.

“Patients with rare primary mitochondrial diseases have no FDA-approved treatment options to address their needs,” Stealth CEO Reenie McCarthy said in a press release. “We’re committed to helping fill these significant gaps in care through our study of elamipretide.

“Following the promising results from our Phase 2 MMPOWER study, we’re happy to announce the initiation of MMPOWER-2, which will help us better understand the effects of longer treatment with elamipretide for these patients, who often face severe challenges completing even simple daily activities.”

MMPOWER Phase 2 trial is a randomized, placebo-controlled clinical trial evaluating the effectiveness, safety, and tolerability of elamipretide for the treatment of primary mitochondrial myopathy (muscle weakness) in patients with genetically confirmed mitochondrial disease. The trial evaluated elamipretide in 36 patients ages 16 to 65 in three dose cohorts. Primary endpoints were improvement in distance walked in six minutes, safety, and tolerability.

Trial results announced in June showed a statistically significant improvement with elamipretide in the distance walked in six minutes, an accepted measurement of functional exercise capacity.

“We look forward to the results of this follow-on study and hope to use these results, along with the positive data from MMPOWER, to engage in discussions with regulators to develop the design for a Phase 3 trial in primary mitochondrial disease,” Stealth Chief Medical Officer Doug Weaver said.

Mitochondrial disease is an inherited chronic illness that can be present at birth or developed later in life. It causes debilitating physical, developmental, and cognitive disabilities with symptoms including poor growth; loss of muscle coordination; muscle weakness and pain; seizures; vision or hearing loss; gastrointestinal issues; learning disabilities; and organ failure.

Elamipretide is an investigational drug with the potential to modify the disease by preserving energetics and restoring normal energy production in mitochondria while decreasing oxidative stress. The U.S. Food and Drug Administration (FDA) granted elamipretide fast track designation in January 2016 for the treatment of primary mitochondrial myopathy in patients with genetic mitochondrial diseases for which there are no FDA-approved treatments.