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Stealth Bio to cut jobs after FDA rejects therapy for rare disorder
By Sriparna Roy - 5/29/2025
By Sriparna Roy
(Reuters) -Privately held Stealth BioTherapeutics said on Thursday the U.S. Food and Drug Administration had declined to approve its therapy for an ultra-rare condition called Barth Syndrome, prompting it to cut 30% of its workforce.
Barth syndrome, which is estimated to affect around 150 people in the United States, has no approved treatments. It typically affects boys and causes heart and muscle weakness, as well as delayed growth.
The FDA has asked the company to resubmit its application, which Stealth said would require more capital and prompted the job cuts.
The FDA did not respond to a Reuters request for comment
The therapy, elamipretide, has faced several setbacks, including the FDA's refusal to accept its marketing application in 2021. The company subsequently went private in 2022.
The latest setback comes after a 16.5-month review, during which the FDA extended its review from January to April to assess additional data. Last month, the regulator missed the extended deadline.
The company said the rejection came "out of the blue".
"We don't understand why it wasn't an approval, because there isn't really a request that we resubmit new data," said CEO Reenie McCarthy.
"I think our frustration is: why didn't this come sooner?" McCarthy said.
In October, a panel of advisers to the FDA voted 10-6 in favor of the therapy.
Stealth had submitted data from a mid-stage trial that showed improvement in knee muscle strength by over 45%, which correlated with improvements on the six-minute walk test.
FDA raised the possibility of an accelerated approval based on the findings, but is hesitant to extend the pathway to critically ill newborns, who make up nearly two-thirds of the therapy's expanded access program participants.
The company said it will meet with the FDA next month.
(Reporting by Sriparna Roy in Bengaluru; Editing by Tasim Zahid and Vijay Kishore)