After attempting to sneak in the back door and getting it slammed in its face, Stealth BioTherapeutics has been given a chance at a good old-fashioned business meeting to shore up an FDA application for a Barth syndrome drug.
The U.S. regulator has granted the troubled biotech a Type B meeting, which are typically used to discuss therapies before a new drug application is filed or in the event of a rejection. Stealth will meet with the agency’s Division of Cardiology and Nephrology to discuss new data that have come to light for the drug, called elamipretide.
That therapy hit a major roadblock in October 2021 when the biotech received a refusal to file letter from the FDA based on a request for another phase 3 trial. Stealth had tried to file the application without that late-stage study, hoping for a miracle, but the agency saw through the attempt and shut down the application without review.
Now, Stealth thinks new clinical data from an open-label extension of the phase 2 TAZPOWER study will do the trick to get elamipretide approved for Barth syndrome, a rare disorder that causes heart muscle weakness, growth issues and other health problems.
The original application for elamipretide was tied to a phase 3 study that showed it met the main goal, but the data were compared to an open-label portion of a different phase 2/3 study and natural history controls—a strategy the FDA did not like. Stealth pushed back, saying that there was no way to design a feasible trial given the ultra-rare nature of Barth syndrome.
Stealth will present the new clinical data at an upcoming medical conference and is keen to do the same with the FDA at the upcoming meeting, slated for the third quarter.
News that the FDA would not review elamipretide in the fall sent shares sliding 15% to $1.17, and that decline has continued to 28 cents apiece as of market close Monday. The FDA meeting news sent shares up a mere 2 cents, or a little over 7%.
The FDA stumble is not the only challenge Stealth has faced recently, leading to the share decline. Elamipretide also failed a phase 2 clinical trial in geographic atrophy, which is an advanced form of dry age-related macular degeneration, in May. That facilitated a 30% share decline to the range of a quarter apiece.
Elamipretide is also being tested in primary mitochondrial myopathy, for which it recently received an orphan-drug designation from the European Medicines Agency.
Stealth ended 2021 with $47.1 million in the bank. The company has not held a public earnings call since the third quarter of 2021. In April, Stealth sold a group of shares to raise $8.5 million to a single healthcare-focused institutional investor. In a prospectus filed in conjunction with the financing, the company said its cash on hand should extend to the fourth quarter of 2022. But more money was needed to advance its candidates through the clinic and commercialize any potentially approved medicines.