STEALTH BIOTHERAPEUTICS' BARTH SYNDROME NDA RECEIVES PRIORITY REVIEW DESIGNATION

Barth Syndrome is an Ultra-rare, Progressive, Life-Shortening, Cardioskeletal Disease that Affects Approximately 150 Individuals in the United States

If Approved, Elamipretide Would Become the First Approved Therapy for Barth Syndrome

NEEDHAM, Mass., May 7, 2024 /PRNewswire/ -- Stealth BioTherapeutics, a clinical-stage biotechnology company focused on the discovery, development and commercialization of novel therapies for diseases involving mitochondrial dysfunction, today announced that the U.S. Food and Drug Administration ("FDA") has now determined that its New Drug Application ("NDA") for elamipretide for the treatment of Barth syndrome is entitled to a Priority Review designation. Per FDA policy, the user fee goal date of January 29, 2025 is unchanged.

The FDA grants Priority Review to applications for therapies that have the potential to provide significant improvements in the treatment, diagnosis, or prevention of serious conditions. Barth syndrome is an ultra-rare cardioskeletal disease which results in frequent pediatric deaths and imposes a significant disease burden on all affected individuals. There are no other therapies approved or known to be in clinical development for this disease.

The FDA's decision to grant Priority Review designation follows its March 29, 2024 filing decision in which the FDA assigned a standard review designation. Elamipretide has previously received Orphan Drug, Fast Track and Rare Pediatric Designations for elamipretide for the treatment of Barth syndrome.

"We are pleased that the FDA has recognized the serious nature of Barth syndrome, the urgency of the unmet medical need, and the potential for elamipretide, if approved, to significantly improve treatment of this devastating disease," said Reenie McCarthy, Chief Executive Officer. "We welcome our continued constructive engagement with the Agency as we complete the review process and plan for an anticipated advisory committee meeting later this year."

If approved, this would be the first marketing authorization for elamipretide, a first-in-class mitochondrial targeted therapeutic. Elamipretide is also in development for primary mitochondrial myopathy, with pivotal data from the fully-enrolled Phase 3 NuPOWER trial expected in late 2024, and dry age-related macular degeneration, with pivotal Phase 3 clinical trials initiating this quarter.

About Barth Syndrome

Barth syndrome is an ultra-rare genetic condition characterized by cardiac abnormalities leading to exercise intolerance, muscle weakness, debilitating fatigue, heart failure, recurrent infections, and delayed growth. The disease is associated with reduced life expectancy, with 85% of early deaths occurring by age 5. Barth syndrome occurs almost exclusively in males and is estimated to affect one in 1,000,000 males worldwide or around 150 individuals in the United States. There are currently no FDA- or EMA-approved therapies for patients with Barth syndrome. Elamipretide has Orphan Drug, Fast Track and Rare Pediatric Designation from the FDA and Orphan Drug Designation from the EMA for the treatment of Barth syndrome. 

About Stealth BioTherapeutics

Stealth BioTherapeutics is a clinical-stage biotechnology company focused on the discovery, development, and commercialization of novel therapies for diseases involving mitochondrial dysfunction. Mitochondria, found in nearly every cell in the body, are the body's main source of energy production and are critical for normal organ function. Dysfunctional mitochondria characterize a number of rare genetic diseases and are involved in many common age-related diseases, typically involving organ systems with high energy demands such as the heart, the eye, and the brain. The Company believes its lead product candidate, elamipretide, has the potential to treat rare diseases including Barth syndrome and primary mitochondrial myopathy and common age-related diseases including dry age-related macular degeneration. The Company is also evaluating a topical ophthalmic formulation of its second-generation clinical-stage candidate, SBT-272, for dry age-related macular degeneration. The Company has a deep pipeline of novel compounds under evaluation for rare neurological and cardiac disease indications following promising preclinical data.

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SOURCE Stealth BioTherapeutics Inc.