PD-1 and PD-L1 inhibitors after platinum-based chemotherapy or in first-line therapy in cisplatin-ineligible patients: Dramatic improvement of prognosis and overall survival after decades of hopelessness in patients with metastatic urothelial cancer.

Until recently, there were no true innovations in the management of locally advanced (aUC) and metastatic urothelial cancer (mUC) in the last three decades. Vinflunine has been approved by the EMA (European Medicines Agency) with only limited improvement compared to best supportive care in second line treatment. In addition, gemcitabine/cisplatin has been established as an alternative to methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC). The advent of checkpoint inhibitors (CPI) revolutionized the care of these patients, transforming a unanimously deadly disease into one with hope through sustained disease control. Five immune CPI have recently been approved for aUC/mUC by the US Food and Drug Administration (FDA) including atezolizumab, nivolumab, pembrolizumab, durvalumab and avelumab. All five CPI are FDA-approved as second-line therapy with atezolizumab and pembrolizumab also being approved for first-line therapy in cisplatin-ineligible patients. The rapid acceptance in the treatment algorithm of UC is based on the impressive clinical efficacy of these agents in some patients, combined with their excellent safety profile. These new agents are indeed the most important advancement in UC care. However, the challenge in the age of precision medicine is to identify the patients who are most likely to benefit from CPIs, as the majority of patients do not respond to CPI. Toward this goal, validation of clinical, molecular and imaging biomarkers that serve for prediction and monitoring of treatment response are of central necessity.