PTC’s candidate for the disorder failed to move the needle on the modified Friedreich Ataxia Rating Scale (mFARS), which measures disease progression. The therapy had little impact on the lower and upper limbs, which led to the failure. Despite the primary endpoint miss, PTC saw a glimmer of efficacy in the data, pointing to the upright stability subscales.
PTC is expecting to file the NDA for vatiquinone in late 2024. Klein said an open-label trial is currently ongoing, which will be used to support the package and could also provide confirmatory evidence if the FDA agrees to the accelerated review. For that type of approval, companies can get an advanced go-ahead to market a drug based on biomarker data but must later provide confirmatory evidence to show benefit.