PRV Watch

@PRVWatch

19 Sep 2025

PRV Watch

@PRVWatch

22 Aug 2025

The FDA has accepted the now third NDA submission from Stealth BioTherapeutics, for elamipretide in Barth Syndrome (rare, genetic disorder). I have put together a timeline below of the very tortuous history between Stealth and the FDA.

• Dec ’16 - Stealth submits a protocol to mipretide in patients with Barth syndrome.
• Nov ’17 - FDA grants Fast Track designation.
• Mar ’18 - FDA grants Orphan Drug designation.
• Jan ’19 - Stealth meets with the FDA, indicating its intent to submit an NDA.
• Mar ’20 - FDA grants Rare Pediatric Disease designation.
• Jan ’19 to May ’21 - Several meetings with the FDA. FDA states existing data is unlikely to support filing and recommends a new phase 3 trial.
• Aug ’21 - Stealth submits an NDA for Barth syndrome despite prior FDA feedback.
• Oct ’21 - FDA issues refuse-to-file letter
• Nov ’21 - Stealth and the FDA discuss the refuse-to-file letter. FDA continue to recommend a new phase 3 trial. Stealth informs the FDA of their intent to resubmit the NDA without conducting a new trial.
• Aug ’22 - Stealth takes company private.
• Dec ’23 - The Barth Syndrome Foundation submits a petition to the FDA advocating for a fair, equitable and appropriate review.
• Jan ’24 - Stealth resubmits the NDA.
• Mar ’24 - FDA accepts the NDA (Standard Review) to conduct a more detailed review of the data and plans to convene an advisory committee for external input.
• Apr ’24 - FDA upgrades the review to Priority Review.
• Oct ’24 - The Cardiovascular and Renal Drugs Advisory Committee votes 10–6 that elamipretide is effective for treating patients with Barth syndrome.
• Jan ’25 - Following the AdCom, the FDA requests additional data constituting a major amendment. The PDUFA date is extended by three months.
• Apr ’25 - FDA misses the PDUFA date.
• May ’25 - FDA issues a Complete Response Letter. Stealth cuts its workforce by ~30%.
• May ’25 - FDA responds to Dec ’23 petition.
• 18 Aug ’25 - Stealth resubmits the NDA following feedback from the FDA, seeking accelerated approval based on an intermediate clinical endpoint, using data already included in prior submissions.
• 21 Aug ’25 - FDA accepts the resubmission with goal date of 26 September 2025.