The U.S. Food and Drug Administration said on Friday it had approved Stealth Biotherapeutics’ once-daily injection for a rare, genetic disease that primarily affects males, making it the first treatment to be greenlit for the condition.
Stealth’s Forzinity was granted accelerated approval for treating Barth syndrome, in patients weighing at least 30 kg. Barth syndrome is a rare, serious and life-threatening disease of the mitochondria, the energy-producing parts of cells.
It typically starts with severe heart failure in infancy, and causes premature death. Patients who survive into adolescence and adulthood often have fatigue, poor stamina and exercise intolerance, according to the FDA.
According to a study on the National Institutes of Health’s website, as of 2020, an estimated 230 to 250 males were identified with Barth syndrome worldwide.
The under-the-skin or subcutaneous injection works by binding to the inner part of the mitochondria, improving its structure and function.
The accelerated approval is based on improved strength of the muscle used to straighten the leg at the knee. The FDA said it considers this improvement reasonably likely to predict patient benefit, such as an ability to stand more easily or walk farther.
Under the FDA’s accelerated approval pathway that allows earlier approval of medications that treat serious conditions and fill an unmet medical need, it mandates additional post-market trials that verify the drug’s benefits.
Privately held Stealth will conduct a trial to confirm the changes seen on knee muscle strength translate into patient benefit.
If data from the trial do not show the drug’s effectiveness, the regulator can ask the company to withdraw it from the market.