EPI-743 is currently in Phase IIb/III studies in patients with inherited respiratory chain diseases of the mitochondria.

Edison Pharmaceuticals reported FDA approval of an expanded access program for its EPI-743 candidate in the treatment of seriously ill patients with inherited mitochondrial respiratory chain diseases. Forty patients globally have already been treated with the clinical-stage candidate. Edison separately announced that FDA granted EPI-743 orphan drug designation for the inherited mitochondrial respiratory chain disease indication.

EPI-743 is an orally absorbed small molecule that crosses into the central nervous system and targets NADPH quinone oxidoreductase 1 (NQO1). Edison says it acts to effectively synchronize energy generation in mitochondria. The firm and its clinical investigators are currently working with FDA and the European Medicines Agency to expedite prospective Phase IIb/III clinical studies.

Edison is focused on the development of treatments for inherited mitochondrial diseases. The firm is exploiting specialist assays and know-how that facilitate the modeling of redox defects in biological systems for the discovery and optimization of redox-directed drugs. Inherited mitochondrial diseases are clinically diverse and poorly understood, but all share a common defect in how cells make and regulate energy, Edison notes.

They can be caused by defects in either nuclear or mitochondrial genes, and often lead to central nervous system manifestations. However, Edison notes, mitochondrial diseases can also result in a range of clinical disorders including diabetes, muscle weakness, liver failure, deafness, blindness, and renal insufficiency.

Estimates vary widely on the incidence of mitochondrial disease worldwide, the firm adds. Conservative estimates put the incidence at about 1–5 people in 10,000, but other estimates place the number of clinically diagnosed mitochondrial disease patients who don’t have a genetic diagnosis at 10 times the number of genetically defined cases.