Study of Avelumab and Tuvusertib in Participants With Advanced Urothelial Cancer That Has Progressed on Prior Anti-PD-(L)1 Therapy (JAVELIN DDRiver Bladder)

Inclusion Criteria: * Histologically confirmed, locally advanced, and unresectable or metastatic urothelial carcinoma. * No more than 2 lines of therapy for advanced disease. Chemotherapy followed by avelumab (switch maintenance) counts as 1 line of therapy. Additionally, (neo)-adjuvant chemotherapy for Muscle invasive bladder cancer with recurrence or progression within 12 months of last dose, counts as a line of therapy. * Measurable disease by RECIST 1.1, as assessed by the Investigator. * Eastern Cooperative Oncology Group Performance status 0 to 1. * Adequate hematologic function as indicated by: * Platelet count more than or equal to 100,000 per microliter * Absolute neutrophil count more than or equal to 1,500 per microliter with no growth factor treatment within the last 14 days * Hemoglobin more than or equal to 9.0 gram/deciliter with no erythropoietin or red blood cell transfusion within the last 14 days * Only one line of an antibody-drug conjugate (ADC) is allowed. * Other protocol defined inclusion criteria could apply. Exclusion Criteria: * Any condition, including any uncontrolled disease state other than aUC, that in the Investigator's opinion constitutes an inappropriate risk or a contraindication for participation in the study or that could interfere with the study objectives, conduct, or evaluation. * Any known additional malignancy that is progressing and/or requires active treatment including adjuvant hormonal therapy. * Presence of brain metastases u…