This study was a single-arm study of the efficacy and safety of oral sonidegib in patients with Hh-pathway activated relapsed medulloblastoma. It was initially designed as a randomized, controlled, open-label phase III study of adults and children with Hh-pathway activated MB whose disease had failed standard of care therapy, including radiation therapy (RT). The original study consisted of a randomized controlled part and a non-randomized uncontrolled part. Approximately 69 patients were to be randomized in a 2:1 ratio to receive sonidegib oral suspension or the active control, temozolomide (TMZ) capsules. Randomization was to be stratified according to age, <18 years versus ≥ 18 years. Approximately 40 patients were to receive sonidegib in the non-randomized uncontrolled part of the study. Following the enrollment of 11 patients, the study was amended to become a phase II single-arm study with only sonidegib, and the target enrollment was changed to 20 patients. Prior to the study amendment, TMZ participants whose disease progressed while on TMZ were permitted to crossover to sonidegib. After the amendment, participants receiving TMZ were crossed over to sonidegib.