A Study of TAR-200 in Combination With Cetrelimab and Cetrelimab Alone in Participants With Muscle-Invasive Urothelial Carcinoma of the Bladder

Open to people ages 18 years and up

• Histologically proven, cT2-T4a N0, M0 infiltrating urothelial carcinoma of the bladder. Initial diagnosis must have been within 90 days of randomization date. Participants with variant histologic subtypes (example squamous differentiation) are allowed if urothelial (transitional cell) differentiation is predominant (example, less than [<]20 percent [%] variant histologic subtype). However, the presence of any neuroendocrine, micropapillary, signet ring cell, plasmacytoid, or sarcomatoid features will make a participant ineligible
• Participants with an individual intravesical tumor size of less than or equal to <=3 centimeter (cm) following transurethral resection of bladder tumor (TURBT) are eligible. Participants with persistent multifocal tumors at screening must undergo a second debulking, re-staging TURBT to reduce the tumor burden. Participants will be ineligible if any individual tumor is greater than (>)3 cm
• Deemed eligible for and willing to undergo RC by the operating urologist
• Eastern Cooperative Oncology Group (ECOG) performance status Grade 0 or 1
• Thyroid function tests within normal range or stable on hormone supplementation per investigator assessment
• All adverse events associated with any prior surgery must have resolved to common terminology criteria for adverse events (CTCAE) version 5.0 Grade less than (<) 2 prior to randomization

• Must not have received prior systemic chemotherapy, targeted small molecule therapy, or radiation therapy within 2 years prior to starting study treatment
• Participants must not have evidence of cT4b, or N1-3, or M1 disease based on local radiology staging (chest, abdomen, and pelvis must be performed using computed tomography [CT] or magnetic resonance imaging [MRI]) within 42 days prior to randomization
• Presence of any bladder or urethral anatomic feature that, in the opinion of the Investigator, may prevent the safe placement, indwelling use, or removal of TAR-200
• Prior systemic chemotherapy for urothelial cell carcinoma of the bladder at any time
• Currently participating or has participated in a study of an investigational agent and received study therapy or investigational device within 4 weeks prior to enrollment
• Participants with evidence of bladder perforation during diagnostic cystoscopy. Participant is eligible if perforation has resolved prior to dosing