The purpose of this research is to study benefit of the combination of lurbinectedin chemotherapy with maintenance avelumab immunotherapy in patients with advanced cancer of the urinary tract who have completed platinum-based chemotherapy. Avelumab alone is the usual approach and is already approved by the US FDA for the treatments of patients with this type of cancer. Lurbinectedin is approved for a type of lung cancer, but is not approved for urinary tract cancer.
A nonrandomized phase II trial is proposed combining avelumab (PD-L1 inhibitor immunotherapy) + lurbinectedin as switch maintenance therapy for mUC following stable or responding disease on 4-6 cycles of first line platinum-based chemotherapy