The PD-1 inhibitor pembrolizumab has demonstrated promise in patients with non-small cell lung cancer (NSCLC), explains Alice T. Shaw, MD, PhD. Results presented at ASCO 2014 demonstrated an overall response rate by RECIST of 26%. The disease control rate, defined as complete response, partial response, and stable disease, was 64%.

The PD-1 inhibitors have demonstrated a great deal of promise in melanoma, with approvals gained for both the pembrolizumab and nivolumab. Both drugs are being explored in phase III studies, with promising results already announced. In addition to the efficacy seen with these agents, their side effects seem to be tolerable, notes Corey J. Langer, MD.

In addition to PD-1 inhibitors, PD-L1 blocking agents are also showing promise. The PD-L1 inhibitor MPDL3280A demonstrated a 21% response rate in a phase I study of patients with multiple solid tumors, notes D. Ross Camidge, MD, PhD.

Patients treated with these agents are commonly tested for PD-L1 positivity. However, responses are indicated, whether positive or negative; with a higher response seen in positive patients. If a patient is positive, a PD-1/PD-L1 agent could be used in the frontline setting, Camidge notes. However, if negative, a PD-1 inhibitor can be utilized in a later setting.