Sarfaty M, Ostrovnaya I, Teo MY, et al. - Researchers tested durvalumab and tremelimumab for activity and safety in patients with metastatic non-transitional cell carcinoma of the urothelial tract (non-TCC) in this single-arm, phase II study. The cases eligible for inclusion were those with unresectable/metastatic non-TCC with ECOG PS 0-1 irrespective of previous therapy (except for patients with small cell carcinoma who must have progressed post-chemotherapy). The treatment regimen used was: durvalumab 1500 mg and tremelimumab 75 mg IV Q4W for up to 4 cycles, then durvalumab 1500 mg IV Q4W for a total treatment duration of 12 months. The overall response rate by RECIST 1.1 was assessed as the primary endpoint. Overall 13 patients received the treatment, including 7 (54%) with small cell carcinoma, 3 (23%) with squamous cell carcinoma, and 3 (23%) with adenocarcinoma. A median follow-up of 6.8 months revealed a median PFS of 1.8 months and median OS of 6.43 months. The occurrence of grade 3-4 treatment-related adverse events was seen in 31% of patients. Findings revealed no responses to treatment with durvalumab and tremelimumab in this poor prognosis cohort of patients with non-TCC. There is an urgent requirement for new therapeutic strategies for patients with metastatic non-TCC.