Immunotherapy revolutionises non-small-cell lung cancer therapy: Results, perspectives and new challenges

Immune checkpoint inhibitors (ICIs) are antibodies that target key signalling pathways such as programmed death 1 (PD1)/programmed death-ligands 1 and 2 (PDL1 and PDL2) to improve anti-tumour immune responses. Until recently, nivolumab was the only ICI validated for advanced non-small-cell lung cancer (NSCLC) in a second-line treatment setting. Results from recent phase II and phase III randomised trials testing other ICIs have been presented. In Keynote-024, pembrolizumab, an anti-PD1 antibody, was reported to have great efficacy in the first-line treatment of PDL1 ≥ 50% tumours (30% of screened tumours), with a progression-free survival (PFS, median) of 10.4 months versus 6.0 months with chemotherapy (CT; hazard ratio [HR] = 0.50; 95% confidence interval [95% CI] 0.37-0.68, P < 0.001), overall response rate (ORR) of 45% versus 28% with CT (P = 0.0011), and a 1-year overall survival (OS) of around 70%. In contrast, Checkmate-026 reported that nivolumab failed to show any benefit compared with standard platinum-based CT, with a PFS (median) in the PDL1 ≥ 5% NSCLC group of 4.2 months (nivolumab) versus 5.9 months (CT; HR = 1.15: 95% CI 0.91-1.45, P = 0.25). No benefit was observed in the PDL1 ≥ 50% subgroup. An encouraging report of the efficacy of pembrolizumab in addition to CT in first-line treatment in unselected NSCLC was also presented (Keynote-021) with an ORR of 55% versus 29% with CT alone (P = 0.0016). Atezolizumab, an anti-PDL1 antibody, showed efficacy for second-line treatment compared with docetaxel (OAK phase III study) with an OS (median) of 13.8 months versus 9.6 months with docetaxel. These results suggest a new paradigm for the treatment of advanced NSCLC using pembrolizumab for the first-line treatment of PDL1 ≥ 50% tumours.