Efficacy and safety of idebenone in the treatment of Friedreich ataxia: a review of early results and future prospects

Abstract

Friedreich ataxia (FRDA) is an autosomal-recessive neurodegenerative disorder characterized by difficulty walking, dysarthria and absent reflexes. At present, no treatment or cure exists, but the pathophysiology of FRDA suggests that antioxidants and related compounds may be efficacious. Research in the field has focused on idebenone, a lipid-soluble synthetic short-chain analogue of the quinone coenzyme Q10. Idebenone protects mitochondrial membranes from oxidative damage in vitro and may facilitate electron transport within the mitochondrial electron transport chain. In FRDA, idebenone decreases cardiac hypertrophy, but the clinical significance of this finding remains unknown. Recent Phase II trials using higher doses of idebenone have suggested a dose-dependent improvement in neurologic symptoms. To confirm these results, a Phase III trial has begun in the USA with the goal of assessing the efficacy of idebenone for the treatment of neurologic dysfunction in FRDA.