Ueno M, et al. - In Japanese patients with biliary tract cancer, researchers evaluated the tolerability and safety of the immune checkpoint inhibitor nivolumab, as monotherapy or combined with chemotherapy. For this multicentre, open-label, phase 1 trial, nivolumab monotherapy (240 mg every 2 weeks [monotherapy cohort]) was given to patients with unresectable or recurrent biliary tract cancer that was refractory or intolerant to gemcitabine-based treatment regimens. Nivolumab (240 mg every 2 weeks) and cisplatin (25 mg/m²) plus gemcitabine (1000 mg/m²) chemotherapy (combined therapy cohort) were administered to chemotherapy-naive patients with unresectable or recurrent biliary tract cancer. From January 13, 2016, to April 19, 2017, 30 patients were recruited in each cohort. In patients with unresectable or recurrent biliary tract cancer, nivolumab had a manageable safety profile and signs of clinical activity. This initial nivolumab assessment for the treatment of advanced cancer of the biliary tract provides supporting evidence for future larger randomized nivolumab studies in this difficult cancer treatment. The most frequently reported treatment-related adverse events were decreased appetite, malaise, and pruritus in the monotherapy cohort and neutrophil count decrease and platelet count decrease in the combined therapy cohort.