Madhusmita Behera

Significance Therapies that harness the immune system have recently been approved for cancer treatment. Identification of biomarkers to monitor or predict patients’ responses to immunotherapies would help guide treatment decisions. Herein we analyzed changes in peripheral blood T cells from lung cancer patients receiving immunotherapy blocking the PD-1 inhibitory pathway. We detected CD8 T-cell responses following treatment in most patients. In addition, our data suggest that an increase in proliferation of PD-1+ CD8 T cells in the blood within 4 wk of treatment initiation may be associated with positive clinical outcome. Our analysis provides valuable insights into cancer patients’ responses to PD-1–targeted therapies and warrant further studies on peripheral blood biomarkers.

BACKGROUND: Monoclonal antibodies against programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) are effective therapies in patients with non-small cell lung cancer (NSCLC). Herein, the authors performed a systematic review investigating differences in the toxicities of PD-1 and PD-L1 inhibitors. METHODS: An electronic literature search was performed of public databases (MEDLINE, Excerpta Medica dataBASE [EMBASE], and Cochrane) and conference proceedings for trials using PD-1 inhibitors (nivolumab and pembrolizumab) and PD-L1 inhibitors (atezolizumab, durvalumab, and avelumab) in patients with NSCLC. A formal systematic analysis was conducted with Comprehensive Meta-Analysis software (version 2.2). Clinical and demographic characteristics, response, and toxicity data were compared between both groups. RESULTS: A total of 23 studies reported between 2013 and 2016 were eligible for analysis. The total number of patients evaluated for toxicities was 3284 patients in the PD-1 group and 2460 patients in the PD-L1 group. The baseline patient characteristics of the 2 groups were similar, although there was a trend toward increased squamous histology in the group treated with PD-L1 (32% vs 25%; P = .6). There was no difference in response rate noted between PD-1 (19%) and PD-L1 (18.6%) inhibitors (P = .17). The incidence of overall adverse events (AEs) was comparable between the PD-1 and PD-L1 inhibitors (64% [95% confidence interval (95% CI), 63%-66%] vs 66% [95% CI, 65%-69%]; P = .8). Fatigue was the most frequently reported AE with both classes of drugs. Patients treated with PD-1 inhibitors were found to have a slightly increased rate of immune-related AEs (16% [95% CI, 14%-17%] vs 11% [95% CI, 10%-13%]; P = .07) and pneumonitis (4% [95% CI, 3%-5%] vs 2% [95% CI, 1%-3%]; P = .01) compared with patients who received PD-L1 inhibitors. CONCLUSIONS: In this systematic review involving 5744 patients with NSCLC, the toxicity and efficacy profiles of PD-1 and PD-L1 inhibitors appear to be similar. Cancer 2018;124:271-7. © 2017 American Cancer Society.