Neoadjuvant Sasanlimab With Radiation as an in Situ Vaccine for Cisplatin-ineligible Muscle Invasive Bladder Cancer

Patients with cT2-T4a, N0, M0 urothelial bladder carcinoma (UBC) after transurethral resection of the bladder will receive 2 doses of sasanlimab (PF-06801591) at the dose of 300mg subcutaneously, followed by 3 doses of radiation (8Gy x 3) prior to surgery (radical cystectomy). Cystectomy will be planned to be done within 6 weeks of the last dose of sasanlimab. Pathologic complete response (pT0) is the primary endpoint, in addition to a safety lead-in endpoint consisting of a composite outcome of feasibility and safety. Exploratory biomarker analysis on tissue/blood samples will include genomic and immune-system profiling in tumor and blood before and after sasanlimab/radiation therapy, and after radical cystectomy.