(Reuters) – Stealth BioTherapeutics Corp’s shares crashed on Friday after its lead neuromuscular disorder drug candidate failed to help patients walk better and reduce fatigue, a major setback to the company’s wide mitochondrial diseases pipeline.

The drug, Elamipretide, co-developed with Alexion Pharmaceuticals, was being tested to treat primary mitochondrial myopathy (PMM). (https//bit.ly/35FGzTW)

There are currently no approved treatments for PMM, which affects about 1 in 5,000 people in the United States.

“This was an unanticipated and discouraging result following our early and mid stage trials in this indication,” said the company. (https://reut.rs/3918ob9)

Shares of the company fell 61% to $4.61 in early trade, touching a record low since listing in February, while shares of Alexion were down 2.13%.

Mitochondrial myopathy is a group of neuromuscular diseases caused by damage to the mitochondria, which are energy-producing structures in cells that serve as power plants.

Elamipretide is also being tested by Stealth Bio for other mitochondrial diseases including Barth syndrome, Leber’s Hereditary Optic Neuropathy and age-related macular degeneration.

The company plans to review its operational resources to further its pipeline program. It had $37.2 million cash as of Sept. 20.

(Reporting by Trisha Roy in Bengaluru; Editing by Shounak Dasgupta, Vinay Dwivedi and Shinjini Ganguli)