Pembrolizumab and EV With Radiation Therapy for MIBC Patients (PEVRAD)

During the induction phase, MK-3475 200 mg will be administered as four cycles of 3-weeks regimen, with ASG-22CE 1.25 mg/kg administered on Day 1 and Day 8 of each cycle. The treatment and maintenance phases will consist of 9 cycles of one course per 6 weeks, with MK-3475 400 mg administered on Day 1 of each course at Q6W.

During the induction phase, four cycles of 3-weeks regimen are administered, with ASG-22CE 1.25 mg/kg administered on Day 1 and Day 8 of each cycle.

All participants who were not determined to have PD on imaging during the induction phase should have had a maximal TURBT performed at 13 (± 1week) weeks after the first dose of trial drug.

Radiotherapy will be initiated no later than 8 weeks after maximal TUR-BT. In this trial, a total dose of 56 Gy will be delivered using 2 Gy per dose. 40 Gy/20 fr (2 Gy/fr) to the small pelvis followed by 16 Gy /8 fr (2 Gy/fr) to the whole bladder 5 times a week for 5 consecutive days using Three-Dimensional Conformal Radiation Therapy (3D-CRT).