Immune checkpoint inhibitors for metastatic bladder cancer
For more than twenty years, chemotherapy has represented the only active therapy for advanced urothelial carcinoma (UC). Nonetheless, prognosis for patients with metastatic disease remains poor. In recent years, the improved understanding of the interaction between immune system and tumour cells has led to the development of a new class of drugs acting on immune checkpoints which are revolutionizing the treatment of many solid tumors, including UC. As a matter of fact, immune checkpoint inhibitors have shown promising clinical activity with safety profile in patients with urothelial cancer, evolving a twentyyear treatment paradigm. After the approval of the first immune checkpoint inhibitor, atezolizumab, several other immune agents have been tested or are currently under investigation alone or in combination with other therapies in different settings. In this review, we focus on the recent results of clinical trials assessing the efficacy of programmed death ligand 1 (PD-L1), programmed death receptor 1 (PD-1) and cytotoxic-T lymphocyte antigen 4 (CTLA 4) inhibitors in UC. We also describe the main ongoing trials and future strategies that will probably change our clinical practice in next years.