Safety and Efficacy of 9MW2821 in the Treatment of High-risk Non-muscle-invasive Bladder Cancer (NMIBC)

This trial is testing a new drug called 9MW2821 in people with high-risk bladder cancer that has not yet spread into the muscle wall (called non-muscle-invasive bladder cancer, or NMIBC). The drug is given directly into the bladder and is aimed at patients whose cancer has come back or who cannot tolerate the standard treatment (BCG therapy). **You may be eligible if...** - You are 18 or older with high-risk non-muscle-invasive bladder cancer (confirmed by biopsy) - You have already tried BCG or other bladder treatments and they did not work, or you cannot tolerate BCG - You had a TURBT surgery (to remove visible tumors) within the last 6 weeks with no residual tumor - You refuse or cannot undergo bladder removal surgery - Your cancer has not spread to lymph nodes or other parts of the body **You may NOT be eligible if...** - Your bladder cancer has invaded the muscle layer or spread elsewhere - You have had another cancer in the last 3 years - You have had an organ transplant, autoimmune disease, or active serious infection - You are positive for HIV or have active hepatitis B or C Talk to your doctor to see if this trial is right for you.