The role of switch maintenance therapy in urothelial cancers.

Maintenance therapy with immune checkpoint inhibitors (ICIs) has changed the treatment paradigm of metastatic urothelial carcinoma (mUC). The JAVELIN Bladder 100 trial established avelumab, one of several ICIs in use today, as a life-prolonging maintenance therapy for patients with advanced urothelial carcinoma. Platinum-based chemotherapy is most often used in the first-line treatment of mUC, and while response rates approach about 50%, disease control is usually short-lived upon completion of the standard three to six cycles of chemotherapy. Much progress has been made in recent years in the second-line space and beyond with the use of ICIs, antibody-drug conjugates (ADCs), and tyrosine kinase inhibitors (TKIs) in eligible patients at the time of disease progression post-platinum-based chemotherapy. However, many patients with progressive mUC after first-line chemotherapy suffer from rapid progression of disease, treatment toxicity with subsequent lines of therapy, and a limited life expectancy. Until the results of the JAVELIN Bladder 100 trial were presented in 2020, there were no maintenance strategies proven to be beneficial over best supportive care after disease control is achieved with first-line platinum-based chemotherapy. To date, standard of care frontline treatment of metastatic urothelial cancer remains to be four to six cycles of platinum-based chemotherapy followed by maintenance avelumab. This review summarizes the current evidence available on maintenance therapies in mUC, as well as several highly anticipated clinical trials that we hope will result in further progress in the management of this aggressive cancer and improve patient outcomes.