Priority Review Granted for Stealth BioTherapeutics' Barth Syndrome NDA

Barth Syndrome, an ultra-rare, progressive, life-shortening cardioskeletal disease, impacts roughly 150 individuals in the United States. If elamipretide is approved, it would become the first therapy sanctioned for Barth Syndrome.

On May 7, 2024, Stealth BioTherapeutics, a biotechnology firm dedicated to creating therapies for diseases caused by mitochondrial dysfunction, revealed that the U.S. Food and Drug Administration (FDA) has granted its New Drug Application (NDA) for elamipretide a Priority Review designation. This status underscores the potential of elamipretide to offer significant advancements in treating Barth Syndrome. Despite this new designation, the user fee goal date remains January 29, 2025.

Priority Review is accorded to medications that could notably enhance treatment, diagnosis, or prevention of severe health conditions. Barth Syndrome is a particularly rare and severe disease that leads to frequent pediatric fatalities and places a heavy burden on those affected. Currently, there are no approved treatments or ongoing clinical developments for this condition.

The FDA's Priority Review decision follows its earlier standard review designation on March 29, 2024. Elamipretide had already been designated as an Orphan Drug, Fast Track, and Rare Pediatric Drug for Barth Syndrome by the FDA.

Reenie McCarthy, the CEO of Stealth BioTherapeutics, expressed satisfaction at the FDA's recognition of the severe nature of Barth Syndrome and the urgent need for effective treatments. McCarthy emphasized the potential of elamipretide to significantly improve patient outcomes if approved. She also mentioned the company's ongoing constructive dialogue with the FDA as they finalize the review process and prepare for a possible advisory committee meeting later in the year.

Approval of elamipretide would mark its first marketing authorization as a pioneering treatment targeting mitochondria. Besides Barth Syndrome, elamipretide is also being tested for primary mitochondrial myopathy, with crucial data from the fully enrolled Phase 3 NuPOWER trial anticipated in late 2024. Additionally, pivotal Phase 3 clinical trials for dry age-related macular degeneration are set to begin this quarter.

Barth Syndrome is a genetic disorder marked by cardiac dysfunction, leading to exercise intolerance, muscle weakness, severe fatigue, heart failure, recurrent infections, and stunted growth. The disease drastically reduces life expectancy, with 85% of early deaths occurring by the age of five. It predominantly affects males, with an estimated global prevalence of one in a million males, translating to about 150 individuals in the United States. Currently, there are no FDA or EMA-approved treatments for Barth Syndrome. However, elamipretide has received Orphan Drug, Fast Track, and Rare Pediatric Designations from the FDA and Orphan Drug Designation from the EMA for its treatment.

Stealth BioTherapeutics, based in Needham, Massachusetts, is a biotechnology company in the clinical stage. It focuses on discovering, developing, and commercializing new therapies for diseases linked to mitochondrial dysfunction. Mitochondria are essential for energy production in almost every cell and are crucial for normal organ function. Dysfunctional mitochondria are characteristic of several rare genetic and common age-related diseases, especially those affecting organs with high energy needs like the heart, eye, and brain. Stealth BioTherapeutics believes that elamipretide could treat both rare diseases such as Barth Syndrome and primary mitochondrial myopathy, as well as common age-related conditions like dry age-related macular degeneration. The company is also exploring a topical ophthalmic version of its second-generation candidate, SBT-272, for dry age-related macular degeneration. They have an extensive pipeline of novel compounds under investigation for rare neurological and cardiac diseases based on encouraging preclinical data.