Pembrolizumab monotherapy in advanced NSCLC patients with low PD-L1 expression: is there real evidence?

In the immunotherapy possibilities, pembrolizumab appeared as a leader, along with nivolumab and atezolizumab, in the second-line setting (1). In the last years, the results of phase III KEYNOTE trials (2-6) confirmed the Pembrolizumab as ahead of other checkpoint inhibitors in the first-line setting. Firstly, KEYNOTE-10 (7) showed that the PD-1 inhibitor represented a standard second-line treatment option in NSCLC as it significantly improved OS in comparison with docetaxel following prior platinum-based chemotherapy.