The median duration of treatment with sonidegib was 6 weeks (range, 3–58 weeks). Five patients experienced progressive disease with sonidegib... SMO mutations with in vitro data suggesting resistance to Hh pathway inhibition were identified in 5 patients, and none of these patients experienced responses while on sonidegib....Patients with advanced BCCs that were previously resistant to treatment with vismodegib similarly demonstrated treatment resistance with sonidegib....Clinical characteristics and outcomes of 9 patients with vismodegib-resistant advanced BCCs treated with sonidegib...Four patients with an SMO mutation demonstrated progressive disease on sonidegib, and 1 patient with an SMO mutation demonstrated stable disease for 58 weeks before eventual disease progression.