Patients with inherited mitochondrial diseases associated with nuclear or mitochondrial deoxyribonucleic acid (DNA) mutations that impair the respiratory chain. These include, but are not limited to the following clinical syndromes: Leber's hereditary optic neuropathy; myoclonic epilepsy and ragged-red fibers (MERFF); mitochondrial encephalomyopathy, lactic acidosis, and stroke-like syndrome (MELAS); Kearn-Sayre syndrome; subacute necrotizing encephalopathy (Leigh Syndrome); polymerase gamma (POLG)-related disorders (Alpers-Huttenlocher Syndrome, Autosomal Dominant Progressive External Ophthalmoplegia, Autosomal Recessive Progressive External Ophthalmoplegia, Childhood Myocerebrohepatopathy Spectrum Disorders, Myoclonic Epilepsy Myopathy Sensory Ataxia, POLG-Related Ataxia Neuropathy Spectrum Disorders); Mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE), also called myoneurogastrointestinal encephalopathy syndrome or polyneuropathy-ophthalmoplegia-leukoencephalopathy- Intestinal pseudoobstruction (POLIP) syndrome; others, e.g., mitochondrial cardiomyopathies and other syndromes due to multiple mitochondrial DNA deletions.~Patients completing study RP103-MITO-001 (NCT02023866) are eligible for enrollment into the extension study RP103-MITO-002 if all inclusion and exclusion criteria are fulfilled. Subjects continue on the last total daily dose of cysteamine bitartrate delayed-release capsules taken during RP103-MITO-001. Dose-adjustments are permitted.
A long-term extension study to assess the safety, tolerability and efficacy of cysteamine bitartrate delayed-release capsules (RP103) in children with inherited mitochondrial diseases who previously enrolled into study RP103-MITO-001 (NCT02023866).