The FDA issued a complete response letter denying approval for PTC Therapeutics’ vatiquinone for Friedreich’s ataxia, citing insufficient evidence of efficacy. The regulatory agency requested an additional well-controlled study to support resubmission. Vatiquinone missed its primary endpoint in a Phase 3 trial, although some secondary endpoints showed benefit. The company expressed disappointment but plans to engage with the FDA to discuss next steps. This setback maintains Biogen’s Skyclarys as the only approved treatment for Friedreich’s ataxia pending new data.