Programmed death-1 inhibition in renal cell carcinoma: clinical insights and future directions.

The treatment of metastatic renal cell carcinoma (mRCC) has evolved markedly over the past decade, broaden- ing beyond immune-based strategies (eg, interleukin-2 and interferon-α) to include targeted agents (eg, sunitinib [Sutent, Pfizer] and sorafenib [Nexavar, Bayer]). Recently, there has been a renewed interest in immune-based strategies, with clinical trials underway to assess vaccines and other immunomodulatory agents. Of particular interest are agents that inhibit the interaction between the programmed death-1 (PD-1) receptor and its ligand (PD-L1) at the T-cell/antigen-presenting cell interface. This interaction produces T-cell anergy and therefore stifles the antitumor immune response. Monoclonal antibodies to PD-1 (eg, nivolumab, lambrolizumab, and pidilizumab) and PD-L1 (MPDL3280A and BMS-936559) are in various stages of clinical development. The clinical trajectory of these agents is discussed herein, with specific attention to the potential placement of PD-1/ PD-L1 inhibition in the crowded therapeutic landscape of mRCC.