The KHENEREXT Study

This is an open-label, multi-centre study in subjects with a genetically confirmed mitochondrial deoxyribonucleic acid (DNA) transfer ribonucleic acid (tRNA)Leu(UUR) m.3243A\>G mutation who completed study KH176-202. In the KH176-203 study subjects will be receiving KH176 100 mg BID or KH176 50 mg bid in die (BID) (as determined by the investigator based on safety / tolerability considerations) for a year, thereby ensuring continued treatment with KH176 after study KH176-202. A final follow-up visit is scheduled 4 weeks after the intake of the last dose of study medication for patients not rolling over into the compassionate use program. Primary safety data and secondary efficacy (endpoint) data will be monitored and reviewed every three months by an independent Data Safety Monitoring Board (DSMB) to evaluate potential risks and benefits.