Stealth BioTherapeutics Resubmits Third FDA Application for Rare Disease Drug

Stealth BioTherapeutics has resubmitted its new drug application to the FDA for elamipretide, a treatment for Barth syndrome, marking its third attempt for approval.13

The resubmission follows a May 2025 FDA rejection and contains no new clinical efficacy data, but does include safety updates, confirmation of corrected manufacturing deficiencies, and proposed post-marketing commitments as the FDA requested.13

Barth syndrome is an ultra-rare genetic disorder affecting about 150 people in the U.S., and elamipretide is designed to improve mitochondrial function in these patients.15

The FDA previously rejected the application partly due to the drug failing a key clinical trial endpoint and concerns about data quality, which remain unresolved in the latest application.13

Stealth Bio has asked the FDA for a 'Class 1' review to expedite the process, but the standard evaluation period could last six months.3

The drug remains available through an expanded access program, and the company’s future is uncertain if approval is delayed further, which has caused concern among patients, families, and physicians.25

Sources:

1. https://www.fiercebiotech.com/biotech/stealth-bio-submits-fda-application-rare-disease-candidate-third-time-0

2. https://www.statnews.com/pharmalot/2025/08/18/stealth-biotherapeutics-barth-syndrome-fda-rejection-letter/

3. https://www.biopharmadive.com/news/stealth-fda-resubmit-application-elamipretide-barth-syndrome/757885/

5. https://www.statnews.com/2025/08/18/stealth-biotherapeutics-barth-syndrome-fda-rejection-letter/