Middleton G, Brock K, Savage J, et al. - In patients with non-small-cell lung cancer (NSCLC) of performance status (PS) 2, researchers evaluated the safety and effectiveness of pembrolizumab in this multicentre, single-arm, open-label, phase 2 trial (PePS2) performed in ten hospitals in the UK. Pembrolizumab 200 mg was administered every 3 weeks in patients with NSCLC and a of PS2. In first-line patients (n=24) and in subsequent-line patients (n=36), durable clinical benefit (DCB) incidence was estimated to be 38% and 36%, respectively. In patients with a tumour proportion score (TPS) less than 1% (n=27), a TPS of 1–49% (n=15), and in patients with a TPS of 50% or greater (n=15), the DCB was found to be 22%, 47%, and 53%, respectively. Based on the findings of this trial, experts concluded that it is safe to use pembrolizumab to treat these patients; there was also no increase in the risk of immune-related or other toxicities. Compared to patients with PS0–1, the observed efficacy outcomes were at least as good. For patients suffering from NSCLC of PS2, these results allow clinicians to be confident in including pembrolizumab into the treatment pathway.