Mitochondrial Disease
https://academic.oup.com/brain/article/148/3/896/7877163
This study reports on a Phase 2b clinical trial investigating sonlicromanol, a novel redox-modulating drug, in individuals with mitochondrial disease due to the m.3243A>G variant in mitochondrial DNA. This mutation is associated with a range of symptoms including encephalopathy, fatigue, cognitive impairment, mood disorders, and myopathy, due to defective energy production in cells. In the double-blind, placebo-controlled phase of the trial, patients were randomised to receive either sonlicromanol or placebo over a 28-day period, followed by a 1-year open-label extension where all participants received the drug. The primary goal was to assess safety and tolerability, while secondary outcomes evaluated the drug’s effect on cognitive performance, mood, fatigue, and neuromuscular symptoms. Results showed that the treatment was well tolerated, with no significant safety concerns reported. Encouragingly, participants receiving sonlicromanol showed improvements in mood, fatigue levels, and executive functioning, particularly during the extension phase. Some patients also experienced enhanced coordination, strength, and reduced muscle pain, suggesting potential benefits across multiple domains affected by mitochondrial dysfunction. However, changes in cognitive test scores were variable, which can be attributed to the clinical and phenotypic heterogeneity of the m.3243A>G mutation. The authors of this study emphasise the need for more targeted outcome measures in this diverse patient population. The findings of this study support the continued development of sonlicromanol as a potential disease-modifying therapy for m.3243A>G-related mitochondrial disease. A follow-up placebo-controlled Phase 2b trial in a more refined patient subgroup is ongoing to confirm these promising early results.