This study is testing a treatment for a type of bladder cancer called **Non-Muscle Invasive Bladder Cancer (NMIBC)**, specifically for those who didn’t respond well to a common treatment called **Bacillus Calmette-Guérin (BCG)**. The focus is on using a special drug called **nadofaragene firadenovec**, which might be used alone or with other treatments like chemotherapy or immunotherapy.

**Eligibility:** To join, you must be 18 or older and have high-grade NMIBC that didn’t improve after at least two courses of BCG. You can't have cancer that has spread to muscles or other parts of the body. Also, your life expectancy should be more than two years, and you should be available for the entire study duration.

**Key Points:**

• The study might last several months, including multiple visits for evaluations.
• Participants will receive the experimental drug and maybe additional therapies.
• There are risks involved, such as possible side effects from the treatments.