Purpose

This phase III trial compares survival in urothelial cancer patients who stop immune checkpoint inhibitor treatment after being treated for about a year to those patients who continue treatment with immune checkpoint inhibitors. Immunotherapy with monoclonal antibodies, such as avelumab, durvalumab, pembrolizumab, atezolizumab, and nivolumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Stopping immune checkpoint inhibitors early may still make the tumor shrink and patients may have similar survival rates as the patients who continue treatment. Stopping treatment early may also lead to fewer treatment-related side effects, an improvement in mental health, and a lower cost burden to patients.