Pembrolizumab (MK3475), Gemcitabine, and Concurrent Hypofractionated Radiation Therapy for Muscle-Invasive Urothelial Cancer of the Bladder

The investigators hypothesize that the addition of immune checkpoint inhibition with pembrolizumab, an anti-PD-1 inhibitor, to chemo-radiation therapy to the bladder may work to both increase eradication of local tumor as well as distant micrometastases through heightened immune surveillance. Due to the lack of a previous phase I trial establishing the safety of this combination (pembrolizumab, gemcitabine, and radiation therapy (RT)), an initial safety lead-in cohort of 3 to 6 patients is enrolled for assessing dose-limiting toxicities. Similar to the Phase I 3+3 design, if there is no or only one patient in that cohort experiencing a dose-limiting toxicity, the trial continues to the Phase II part to enroll additional 48 patients for efficacy evaluation.