Pembrolizumab in the treatment of locally advanced or metastatic urothelial carcinoma: clinical trial evidence and experience

The treatment of advanced urothelial carcinoma (UC) has dramatically changed with the advent of immune checkpoint inhibitors that disrupt the T-cell inhibitory interaction between the programmed cell death (PD)-1 receptor and its ligand (PD-L1). Pembrolizumab, a highly specific, monoclonal antibody directed against PD-1, has demonstrated clinical efficacy as well as a favorable toxicity profile, and has emerged as a new standard of care in the treatment of advanced UC. This review will summarize clinical efficacy from recent trials that led to the approval of pembrolizumab in treating platinum-refractory advanced UC as well as treating patients who are ineligible for first-line cisplatin-containing chemotherapy. While immune checkpoint inhibition has reinvigorated the treatment landscape of advanced UC and generated a great deal of optimism, only a minority of patients benefit. Combination strategies with the goal of increasing response rates are desperately needed as are biomarkers predictive of response.