This study investigates the effectiveness of an investigational medication for patients with non-muscle invasive bladder cancer that has returned and not responded to previous treatment. Non-muscle invasive bladder cancer is a type of cancer that affects the inner lining of the bladder but does not penetrate the bladder muscle. The study aims to measure the complete response of patients at 25 weeks after enrollment and evaluate event-free survival at 18 months.

Participants in this study will receive the investigational medication and will be monitored for their response to the treatment. Event-free survival means the length of time after treatment during which the patient remains free from certain complications or events that the study is measuring. The study does not involve payment for participation.

• Who can participate: Adults with recurrent, non-muscle invasive bladder cancer that is stage T1 high-grade, stage CIS, or stage Ta high-grade may be eligible. Patients must have a diagnosis within 60 days prior to enrollment. Those with mixed urothelial carcinoma and glandular or squamous components are eligible, but not those with pure adenocarcinoma or pure squamous cell carcinoma.
• Study details: Participants will receive an investigational medication. The study aims to assess how well the medication works in preventing cancer recurrence and improving survival without events.