The Montreal Clinical Research Institute (IRCM) is delighted to report that on September 19, 2025, the Food and Drug Administration (FDA) of the USA granted approval of elamipretide (SS-31), also known as Forzinity, as the first treatment option for the mitochondrial disease Barth Syndrome, co-discovered by one of its scientists, Dr. Peter W. Schiller.
This is not only of great benefit to Barth syndrome patients, but also represents a historical breakthrough, as elamipretide is the first approved mitochondria-targeted therapeutic.
Barth syndrome is an ultra-rare genetic condition characterized by mitochondrial 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 primarily in males and is estimated to affect one in 1,000,000 male births or around 150 individuals in the United States. There are no approved therapies for patients with Barth syndrome.
In Depth
Elamipretide, also known as SS-31, was co-discovered by Dr. Peter W. Schiller (IRCM) and Dr. Hazel Szeto (Cornell University College of Medicine) and is clinically developed by the company Stealth BioTherapeutics, Inc. Treatment of patients with elamipretide, in a phase 3 clinical trial and also through an Expanded Access Program, resulted in significantly improved muscle strength and remarkable amelioration of the quality of life.
The origins of elamipretide trace back to Dr. Schiller’s work at the IRCM. In collaboration with Dr. Szeto, Dr. Schiller developed mitochondria-targeting peptides based on an opioid peptide analogue he designed and synthesized in his laboratory in the year 2000. A key breakthrough occurred when Dr. Schiller created an optimal fluorescent version of this peptide for a confocal laser scanning microscopy study, allowing researchers to observe for the first time that it entered cells and concentrated specifically in mitochondria.
This led to the creation of a new class of molecules — Szeto-Schiller (SS) peptides — which localize to the inner mitochondrial membrane, the site of energy production in cells. The discovery that these peptides could act as targeted mitochondrial antioxidants and mitochondria-protecting agents opened up new therapeutic possibilities for a range of mitochondrial diseases.
A molecule without opioid activity, but with strong therapeutic potential.
Importantly, SS-31 was engineered to eliminate opioid activity while retaining mitochondrial targeting, making it suitable for mitochondrial drug development. Its therapeutic potential has since been demonstrated in hundreds of preclinical studies of mitochondrial diseases and is now being explored in advanced clinical trials by Stealth BioTherapeutics. Elamipretide is currently undergoing phase 3 clinical trials for primary mitochondrial myopathy and age-related macular degeneration.
Behind Groundbreaking Treatments, There Is Always Great Basic Science
In general, the contributions of academic research groups to drug discovery are limited to the identification of novel therapeutic targets and the subsequent drug development is carried out by the pharmaceutical industry. The fact that the two academic laboratories, involved in the discovery of elamipretide, achieved both the identification of a novel therapeutic target (the inner mitochondrial membrane) and the design and chemical synthesis of a viable drug is extraordinary.
It is also a clear reminder that basic science is at the root of great progress for human health, and that investing in top-notch research is investing in our collective well-being.
