Stealth BioTherapeutics is planning a Phase 2a clinical trial of elamipretide (SS-31) as a treatment for people with vision loss and/or heart disease associated with Friedreich’s ataxia (FA).
The company expects to use data from this study — planned to start later this year — in designing a pivotal clinical trial, which will confirm the candidate therapy’s safety and efficacy before seeking regulatory approval.
“We are poised to progress our planned clinical expansion into rare metabolic cardiomyopathies [diseases of the heart muscle] and neurological diseases, with multiple trial initiations expected this year,” Reenie McCarthy, CEO of Stealth, said in a press release.
Elamipretide is an antioxidant designed to protect cells and reduce organ damage by restoring the mitochondria’s ability to produce energy.
Mitochondria are cellular compartments that produce the energy needed for nearly all cellular processes. Disruptions in this mitochondrial function result in a high amount of reactive oxygen species (ROS, also known as free radicals). While healthy and useful in small quantities, too many ROS can damage and kill cells, contributing to the progression of FA.
Elamipretide reduces oxidative stress by limiting ROS production. Oxidative stress is the imbalance between the production and clearance of these toxic free radicals.
One study in cells from FA patients found that elamipretide reduced oxidative stress, increased levels of frataxin (the protein that is lost in FA), and boosted the amount of certain iron-containing compounds that are needed by the mitochondrial proteins to function properly.
As a final measure of the experimental therapy’s potential use in mitochondrial disorders, the investigators examined the mitochondria themselves and found that the shape and structure of these organelles, along with the health of their outer membrane and several other key measures, all improved upon treatment.
Other studies have reported on elamipretide’s ability to help mitochondria maintain their shape. It appears to do this through an interaction with cardiolipin, an essential fat in the mitochondrial membrane. Defects in cardiolipin underly heart involvement in several disorders, including FA and Barth syndrome.
In addition to FA, Stealth is investigating elamipretide’s therapeutic potential in heart disease associated with Duchenne muscular dystrophy, Barth syndrome, and Leber’s hereditary optic neuropathy.