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

The purpose of this study is to assess the antitumor activity of avelumab in combination with tuvusertib in terms of objective response in participants with advanced urothelial carcinoma. Study details include: Condition/Disease: Participants with urothelial carcinoma (locally advanced and unresectable, or metastatic) that has progressed on prior anti-PD-(L)1 therapy Treatment Duration: Participants will be treated until progressive disease, death, or discontinuation due to e.g. withdrawal of consent or lost to follow-up Visit Frequency: While receiving study intervention, participants will visit the site twice per every 21-day study intervention period. 1 week after end of study intervention, participants will visit the site for an End of Study Intervention Visit, followed by 2 Safety Follow-Up visits at 1 and 3 months after last dose, and thereafter have remote Long-Term Follow-up every 3 months. Study Duration: The overall study is planned to close after the last participant has been followed up for at least 12 months.