Stealth cites endpoints in Phase III mitochondrial disease miss

Shares of Stealth BioTherapeutics sank 65% to $4.75 on Friday after the company announced a Phase III miss for its lead mitochondria-targeted therapy in primary mitochondrial myopathy, just two months after Alexion obtained an option to the candidate for $30 million up front.

The company didn’t share detailed data, but said elamipretide did not meet the primary endpoints of change in six-minute walk test and Primary Mitochondrial Myopathy Symptom Assessment (PMMSA) Total Fatigue Scores in the Phase III MMPOWER-3 trial. ...