Critères d'inclusion : - Have a histologically confirmed diagnosis of muscle invasive bladder cancer (T2-T4aN0M0) with predominant (≥50%) urothelial histology (histology and presence of muscle invasion to be confirmed by BICR): Participants with mixed histology are eligible provided the urothelial component is ≥50%.
Participants whose tumors contain any neuroendocrine component are not eligible.
Urothelial carcinomas not originating from the bladder (e.g., upper tract [ureters, renal pelvis], urethra) are not eligible.
Have clinically non-metastatic bladder cancer (N0M0) determined by imaging (computed tomography (CT) chest or magnetic resonance imaging (MRI) of the abdomen/pelvis.
Be deemed eligible for RC + PLND by his/her urologist and/or oncologist and agree to undergo curative intent standard RC + PLND (including prostatectomy if applicable).
Have a transurethral resection (TUR) of a bladder tumor that is submitted and adequate to determine histology, muscle invasion, and PD-L1 status by central pathology vendor.
Have Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
Have demonstrated adequate organ function.
Critères de non-inclusion :
Has a known additional malignancy that is progressing or has required active anti-cancer treatment ≤3 years of study randomization with certain exceptions.
Has received any prior systemic anti-neoplastic treatment for MIBC.
Is cisplatin-ineligible, as defined by meeting any one of the study criteria.
Has received prior therapy with an anti-PD-1, anti-PD-L1, or anti PD-L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., CTLA-4, OX-40, CD137).
Has received therapy with hematopoietic growth factor such as granulocyte-colony stimulating factor (G-CSF) or granulocyte-monocyte-colony stimulating factor(GM-CSF) in 14 days prior to randomization.
Has received prior systemic anti-cancer therapy including investigational agents within 3 years of randomization.
Has received any prior radiotherapy to the bladder.
Has received a live vaccine within 30 days prior to the first dose of study drug.
Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks prior to the first dose of study intervention.
Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior the first dose of study drug.
Has hypersensitivity to monoclonal antibodies (mAbs, including pembrolizumab) and/or any of their excipients.
Has severe hypersensitivity (≥Grade 3) to cisplatin and/or gemcitabine and any of their excipients.
Has an active autoimmune disease that has required systemic treatment in past 2 years
Has a history of (non-infectious) pneumonitis that required steroids or has current pneumonitis.
Has an active infection requiring systemic therapy.