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# Stealth Gets Expedited Review on NDA Resubmission
- URL: https://www.fdaweb.com/stealth-gets-expedited-review-on-nda-resubmission/
- Published: 2025-08-21T12:00:00.000Z
- Updated: 2026-09-14T15:19:47.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5159730

FDA has accepted for review a Stealth BioTherapeutics NDA resubmission for elamipretide for treating Barth syndrome. The agency is considering the submission a Class 2 response with a six-month user fee goal date of 2/15/2026, but it has told Stealth that a decision will be made by 9/26 to accommodate the company’s concerns that it may not be able to stay in business much longer if a protracted review is expected.

Stealth resubmitted its NDA on 8/15 to address a complete response letter received in May which requested additional information but did not require new clinical efficacy data, according to the company. It says the submission now includes a minor safety update, confirmation that earlier manufacturing deficiencies were resolved, and details of proposed post-marketing commitments, including a trial to further validate elamipretide’s clinical benefit. As recommended by FDA, the resubmission seeks accelerated approval of elamipretide on the basis of improvements in knee extensor muscle strength, an intermediate clinical endpoint, which improved by more than 45% in the TAZPOWER Phase 2 open-label clinical trial, the company says.

“We appreciate FDA’s recognition of the seriousness of Barth syndrome and its commitment to review our NDA resubmission as quickly as possible,” the company says in a release. “With manufacturing concerns resolved and alignment on post-marketing trial design, we believe all issues raised in the CRL have now been addressed.”

If approved, elamipretide would become the first FDA-approved therapy for Barth syndrome and the first marketed product for Stealth. The drug, a first-in-class mitochondrial-targeted therapeutic, is also being investigated for primary mitochondrial myopathy and dry age-related macular degeneration.

Barth syndrome is a rare, genetic mitochondrial disorder affecting an estimated 150 patients in the U.S., mostly males. It causes muscle weakness, severe fatigue, heart failure, and recurrent infections, with most deaths occurring in early childhood.