This study is testing a new treatment, UGN-103, for patients with a type of bladder cancer called low-grade non-muscle invasive bladder cancer (LG-NMIBC). Participants will receive the treatment once a week for 6 weeks. Doctors will check how well the treatment works by looking at the bladder with a special camera called a cystoscope and by testing urine samples. If the cancer is gone after 3 months, patients will have regular check-ups for up to 15 months. If the cancer is still there, doctors will decide on other treatments. To join, you need to have specific medical conditions and agree to follow the study rules. Women and men must agree to use birth control during and after the study. You can't join if you've had certain treatments or conditions recently.

• Study lasts about 15 months with visits every 3 months.
• Participants receive 6 weekly treatments in the bladder.
• Regular check-ups will monitor effectiveness and safety.