Pemetrexed and Avelumab in Treating Patients With MTAP-Deficient Metastatic Urothelial Cancer

This phase II trial studies how well pemetrexed and avelumab work in treating patients with MTAP-deficient urothelial cancer that has spread to other places in the body. Pemetrexed may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Immunotherapy with monoclonal antibodies, such as avelumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Giving pemetrexed and avelumab may work better in treating patients with MTAP-deficient urothelial cancer.