This clinical trial is focused on studying a type of bladder cancer known as High-Risk Non-Muscle-Invasive Bladder Cancer (HR-NMIBC). The study will evaluate the effectiveness and safety of a treatment called TAR-200 compared to other chemotherapy options chosen by the doctors involved in the study. Participants in this trial have previously received a treatment called Bacillus Calmette-Guérin (BCG) and have experienced a recurrence of their cancer. They are either not eligible for or have chosen not to undergo a surgical procedure called radical cystectomy, which involves removing the bladder.

The purpose of the study is to compare how long participants remain free from the disease after receiving the treatments. The study will involve the use of gemcitabine hydrochloride, which is a chemical substance used in chemotherapy, and mitomycin, another chemotherapy drug. These medications will be administered directly into the bladder, a method known as intravesical use. The study will also involve the use of a device called a urinary placement catheter, which helps deliver the treatment directly to the bladder.

Participants will be randomly assigned to receive either the TAR-200 treatment or the chemotherapy chosen by their doctor. The study will monitor the participants over a period to observe the recurrence of cancer, any progression of the disease, or any other significant health events. The trial aims to provide valuable information on the effectiveness of these treatments in managing HR-NMIBC and improving the quality of life for those affected by this condition.