By Chris Wack

 

Stealth BioTherapeutics Corp. shares were down 12% to $1.22 after the company said it has received a refusal to file letter from the U.S. Food and Drug Administration regarding its new drug application for elamipretide, a mitochondria-targeted therapy for the treatment of Barth syndrome.

The biotechnology company said the FDA determined, upon its preliminary review, that the NDA wasn't sufficiently complete to permit a substantive review.

Volume for the stock was 768,000 shares at 12:35 p.m. ET, compared with its 65-day average volume of 295,000 shares. The stock hit its 52-week low of $1.06 on April 21.

In the letter, the FDA stated that the NDA doesn't contain an adequate and well-controlled trial that provides evidence of effectiveness, noting that the SPIBA-201 Phase 2 clinical trial of elamipretide for the treatment of Barth syndrome was negative during the randomized, double-blind portion of the study and that the FDA doesn't consider the open label extension of the SPIBA-201 trial to be adequate and well-controlled.

The FDA said it was committed to work with Stealth on a pathway by which a beneficial effect of elamipretide might be demonstrated within the small patient population.

The letter didn't explain why the company's positive Phase 3 trial comparing SPIBA-201 results with a retrospective natural history control and the primary basis for the NDA submission wouldn't be considered an adequate and well-controlled trial.

Stealth is evaluating the appropriate next steps and anticipates providing an update in early November.

Elamipretide was previously granted rare pediatric designation, fast-track designation and orphan drug designation by the FDA, as well as orphan drug designation by the European Medicines Agency, for the treatment of Barth syndrome.

 

Write to Chris Wack at chris.wack@wsj.com

 

(END) Dow Jones Newswires

October 20, 2021 12:56 ET (16:56 GMT)

Copyright (c) 2021 Dow Jones & Company, Inc.
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