Edison Pharmaceuticals, a specialty pharmaceutical company dedicated to developing treatments for children and adults with orphan mitochondrial diseases, has initiated a phase 2B/3 study entitled, "A Phase 2B/3 Open-label Study of EPI-743 in Children with Leigh Syndrome" to be conducted in conjunction with Dainippon Sumitomo Pharma Co, Ltd.

The trial is an open-label study lasting six months. To be eligible for the trial, children must have clinical and radiographic evidence of Leigh syndrome with or without genetic confirmation, and meet certain disease severity criteria. At least five subjects will be enrolled. The clinical trial primary endpoint is the Newcastle Paediatric Mitochondrial Disease Scale. Secondary endpoints include neurologic, muscular, and biomarker indices.

The study design agreed to by the Japanese Pharmaceuticals and Medical Devices Agency (PMDA) and Dainippon Sumitomo Pharma (DSP) is based upon positive phase 2A data previously reported in Molecular Genetics and Metabolism EPI-743 reverses the progression of the paediatric mitochondrial disease—Genetically defined Leigh Syndrome 107 (2012) 383-388, and on the ongoing phase 2B clinical trial of EPI-743 in Leigh syndrome patients being conducted in the United States.

Leigh syndrome is an inherited lethal, progressive, predominately paediatric, neuromuscular disorder for which there are no approved treatments. Initially described in 1951, the hallmarks of the disease include bilateral necrosis (death) of central nervous system regions responsible for the control of breathing and other neurologic functions. Leigh syndrome belongs to a large family of disorders identified as "mitochondrial disease." The disorders share as a common biochemical feature defects in cellular energy metabolism.

EPI-743 is an orally bioavailable small molecule being developed by Edison Pharmaceuticals for the treatment of Leigh syndrome and other inherited mitochondrial diseases. EPI-743 is a member of the para-benzoquinone class of drugs. Through a redox-based mechanism, EPI-743 augments endogenous glutathione biosynthesis – essential for the control of oxidative stress. EPI-743 is in phase 2 clinical development for the treatment of inherited respiratory chain disorders. Double-blind, placebo-controlled trials are ongoing for the following indications: Friedreich's ataxia, Leigh syndrome, Cobalamin C defect, and Undiagnosed Disorders of Oxidation-Reduction.

Dainippon Sumitomo Pharma Co., Ltd. (DSP) is a multi-billion dollar, top-ten listed pharmaceutical company in Japan with a diverse portfolio of pharmaceutical products.