This study is for people with high-risk non-muscle-invasive bladder cancer (HR-NMIBC). The goal is to see if TAR-210 works better than standard intravesical chemotherapy (a treatment where medicine is put directly into the bladder) in preventing cancer from coming back. Participants will be treated with either TAR-210, a new device, or the usual chemotherapy.

Eligibility: To join, you need a confirmed diagnosis of HR-NMIBC. The cancer should not have spread to muscles or other body parts. You must have a certain genetic change called an FGFR mutation and have had some specific past treatments. You should not have other active cancers or bladder conditions that could interfere with the study.

• Participation involves medical evaluations and treatment over time.
• Risks may include side effects from treatments or the device.
• Check your eligibility, especially if you have had bladder surgery or treatments before.