A Study of Atezolizumab Versus Observation as Adjuvant Therapy in Participants With High-Risk Muscle-Invasive Urothelial Carcinoma (UC) After Surgical Resection

Inclusion Criteria

• •Histologically confirmed muscle-invasive UC (also termed transitional cell carcinoma) of the bladder or upper urinary tract (i.e., renal pelvis or ureters)
• •For participants treated with prior neoadjuvant chemotherapy: tumor stage of ypT2-4a or ypN+ (ypT2-4 or ypN+ for participants with upper urinary tract UC) and M0
• •For participants who have not received prior neoadjuvant chemotherapy: tumor stage of pT3-4a or pN+ (pT3-4 or pN+ for participants with upper urinary tract UC) and M0
• •Representative formalin-fixed paraffin-embedded tumor specimens from surgical resection (i.e., radical cystectomy, nephroureterectomy, or lymph node dissection) in paraffin blocks (blocks preferred) or at least 15 unstained slides, with an associated pathology report, for central testing and determined to be evaluable for tumor programmed death-ligand 1 (PD-L1) expression prior to study enrollment
• •Absence of residual disease and absence of metastasis, as confirmed by a negative baseline computed tomography (CT) or magnetic resonance imaging scan of the pelvis, abdomen, and chest no more than 4 weeks prior to randomization
• •Full recovery from cystectomy or nephroureterectomy within 14 weeks following surgery
• •Eastern Cooperative Oncology Group performance status of less than or equal to (\</=) 2
• •Life expectancy greater than or equal to (\>/=) 12 weeks
• •Adequate hematologic and end-organ function
• •For women who are not postmenopausal or surgically sterile: agreement to remain abstinent or use contraceptive methods that result in a failure rate of less than (\<) 1 percent (%) per year during the treatment period and for at least 5 months after the last dose of atezolizumab