This study is for people with a type of bladder cancer called **NMIBC CIS** (Non-Muscle Invasive Bladder Cancer with Carcinoma In Situ). It focuses on those who didn't respond to a bladder cancer treatment called **nadofaragene firadenovec** after their first dose. Researchers want to see if a second dose helps. To join, you should have had this cancer treatment less than 5 months ago and should not show signs of cancer spreading to muscles or other parts of the body. You need to have had **BCG therapy** before, which is another treatment for bladder cancer. People with signs of cancer spreading, other serious medical problems, or recent treatments not included in this study cannot join.

• The study is in **Phase 4**, meaning it focuses on safety and efficacy after the drug is available.
• Participants must not have other types of cancer that have been treated in the last 5 years, except certain skin cancers.
• There are no new drugs involved; the focus is on re-administering nadofaragene firadenovec.