A Study to Evaluate Effects of Atezolizumab (anti-PD-L1 antibody) as an Adjuvant Therapy in Patients with High-Risk Muscle-invasive Bladder Cancer who are circulating tumor DNA (ctDNA) positive following cystectomy

Prior treatment

• Known PD-L1 IHC result for adjuvant therapy. The decision for the adjuvant therapy should not be based on the PD-L1 IHC result. If a cap is in effect limiting enrollment of PD-L1 negative patients, this exclusion criterion will not apply.
• Patients with active hepatitis B virus (HBV) or hepatitis C -Patients with past HBV infection or resolved HBV infection are eligible. A negative HBV DNA test must be obtained in these patients prior to enrollment
• Active tuberculosis confirmed by a test performed within 3 months prior to treatment initiation

Other illness

• Patients positive for hepatitis C virus (HCV) antibody are eligible only if polymerase chain reaction is negative for HCV RNA
• History of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins

Lab values

• Positive test for HIV, with the following exception: -Patients with a positive HIV test at screening are eligible provided they are stable on antiretroviral therapy, have a CD4 count >= 200/μL, and have an undetectable viral load

• Histologically confirmed muscle-invasive urothelial carcinoma (MIUC) (also termed transitional cell carcinoma [TCC]) of the bladder. Patients with carcinomas showing mixed histologys are required to have a dominant transitional cell pattern
• TNM classification (based on American Joint Committee on Cancer [AJCC] Cancer Staging Manual, 8th Edition) at pathological examination of surgical resection. – Patients who received, or did not receive, platinum-based NAC with tumor stage of (y)pT2-4aN0M0 or (y)pT0-4aN+ M0. Patients who have received at least three cycles of a platinum containing regimen will be considered as having received prior NAC Patients who have not received platinum-based NAC must be ineligible ("unfit") for cisplatin-based adjuvant chemotherapy, have refused it, or will not receive it based on the treating physician’s decision. Cisplatin ineligibility is defined by any one of the following criteria: – Impaired renal function (glomerular filtration rate [GFR] < 60 mL/min); GFR should be assessed by direct measurement (i.e., creatinine clearance or ethyldediaminetetra-acetate) or, if not available, by calculation from serum/plasma creatinine (Cockcroft‑Gault formula) – A hearing loss (measured by audiometry) of 25 dB at two contiguous frequencies – Grade 2 or greater peripheral neuropathy (i.e., sensory alteration or paresthesia including tingling) – ECOG Performance Status of 2
• Surgical resection of MIUC of the bladder
• Availability of a surgical tumor specimen that is suitable (adequate quality and quantity) for use in determining PD L1 expression, WES evaluable (ctDNA assay designability) report, and for exploratory biomarker research assessed by central laboratory testing.
• Submission of a post-surgery matched blood sample for the identification of somatic mutations in tumor tissue
• Submission of blood sample for plasma ctDNA testing, collected at least 6 weeks post-surgery