Stealth’s Elamipretide Granted FDA Orphan Drug Status for Primary Mitochondrial Myopathy

Stealth BioTherapeutics‘ investigational medicine elamipretide, formerly known as Bendavia, has been granted orphan drug status by the U.S. Food and Drug Administration’s (FDA) for the treatment of primary mitochondrial myopathy (PMM).

Stealth specializes in the development of drug candidates for mitochondrial disease treatment.

The FDA’s Office of Orphan Products Development aims to advance the development of products that show potential for the diagnosis or treatment of rare diseases, defined as those affecting fewer than 200,000 people in the U.S., or that are not expected to make a profit.

After the investigative therapy meets FDA criteria and is designated an orphan drug, the drug’s sponsor is then qualified for certain development incentives, including tax credits for clinical testing and years of marketing exclusivity after FDA approval.

Elamipretide is a peptide that specifically targets mitochondria. It reduces the number of free radicals and penetrates the cellular and outer mitochondrial membranes, targeting cardiolipin, which is found exclusively in the inner mitochondrial membrane. This may help protect cardiolipin from the degradative effects of free radicals on mitochondrial function.

In June, Stealth announced the results from its MMPOWER-2 study (NCT02805790), a Phase 2 continuation trial evaluating the safety, tolerability, and effectiveness of elamipretide in people with PMM who participated in the previous MMPOWER study.

Results showed that use of elamipretide was beneficial and supported a Phase 3 trial in people with primary mitochondrial myopathy.

Stealth BioTherapeutics is now recruiting about 300 patients with primary mitochondrial disease for its RePOWER observational study (NCT03048617). The study will take place at 33 sites in the U.S., Canada, Australia, and several European countries.

Researchers intend to assess the relationship of genotype to phenotype and compare local and regional differences in standard of care and management of patients with primary mitochondrial disease.

“We are thrilled to achieve this key regulatory milestone for the treatment of PMM, a debilitating condition characterized by muscle weakness and fatigue with no FDA-approved treatments,” Reenie McCarthy, Stealth’s CEO, said in a press release. “We will continue to work closely with the FDA as we advance into our Phase 3 trial of elamipretide in patients with PMM.”