NOVATO, Calif., Dec. 10, 2013 (GLOBE NEWSWIRE) -- Raptor Pharmaceutical Corp. (Nasdaq:RPTP) today announced that it has submitted an investigational new drug application (IND) to the U.S. Food and Drug Administration (FDA) for the clinical development of RP103 as a potential treatment for Leigh syndrome and other mitochondrial disorders. RP103 is currently marketed in the U.S. as PROCYSBI ® (cysteamine bitartrate) delayed-release capsules for the management of nephropathic cystinosis in adults and children 6 years and older. "Leigh syndrome is one of the most devastating of mitochondrial disorders and the RP103-MITO-001 trial will explore a new mechanism of action against this deadly illness," said the trial's lead investigator, Bruce H. Cohen, M.D., Professor of Pediatrics and Director of Neurology at Akron Children's Hospital. "RP103 may stimulate steady and continuous depletion of reactive oxygen species which are toxic to cellular function and structure. These reactive oxygen species are abnormally high in patients with Leigh syndrome." The RP103-MITO-001 trial is designed to evaluate the safety, tolerability and efficacy of RP103 in patients with genetically confirmed Leigh syndrome and other mitochondrial disorders. The clinical plan includes an open label, 24 week, Phase 2b study in 32 patients (up to a maximum of 64 patients). Patients with Leigh syndrome are expected to comprise two-thirds of the enrolled population in the study. Initiation of the clinical trial is planned for the first quarter of 2014 at four clinical sites in the U.S. Based on an adaptive design statistical plan, Raptor will conduct two interim analyses, after 12 patients and then 24 patients have completed the study to determine final sample size. The primary endpoint of the study will be the change from baseline in the Newcastle Pediatric Mitochondrial Disease Scale (NPMDS) at 24 weeks. Secondary endpoints will include observations of myopathy, dystonia, seizures, motor development, dyskinesia, quality of life, and activities of daily living. Interim results from the initial 24 patients are expected by the end of 2014.