Patients were randomly assigned (1:1) via an interactive voice response system and integrated web response system to receive either pembrolizumab 200 mg every 3 weeks (35 cycles) or investigator-choice platinum-doublet chemotherapy (4-6 cycles or until documented disease progression or unacceptable toxicity). Eligible patients had measurable disease (per RECIST version 1.1) and an Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. In this multicentre, international, randomised, open-label, phase 3 trial, we recruited patients with treatment-naive, stage IV NSCLC in 102 sites in 16 countries. Here we report the prespecified exploratory endpoint of pembrolizumab versus chemotherapy on patient-reported outcomes (PROs). In the phase 3 KEYNOTE-024 trial, treatment with pembrolizumab conferred longer progression-free survival than did platinum-based therapy in patients with treatment-naive, advanced non-small-cell lung cancer (NSCLC) with a programmed cell death-ligand 1 (PD-L1) tumour proportion score of 50% or greater (PD-L1-positive). 15 Lung Clinic Grosshansdorf, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Grosshansdorf, Germany.13 Okayama University Hospital, Okayama, Japan.12 MedStar Franklin Square Hospital, Baltimore, MD, USA.11 The Royal Marsden Hospital, Sutton, Surrey, UK.James's Hospital and Cancer Trials Ireland (formerly ICORG - All Ireland Cooperative Oncology Research Group), Dublin, Ireland.

9 Southern Medical Day Care Centre, Wollongong, NSW, Australia.8 Davidoff Cancer Center, Tel Aviv University, Petah Tikva, Israel.7 Meir Medical Center, Kfar-Saba, Israel.6 Országos Korányi TBC és Pulmonológiai Intézet, Budapest, Hungary.5 Jász-Nagykun-Szolnok County Hospital, Szolnok, Hungary.4 Westmead Hospital and the University of Sydney, Sydney, NSW, Australia.3 Cancer Centre of Southeastern Ontario at Kingston General Hospital, Kingston, ON, Canada.Electronic address: 2 Hospital Universitario Insular de Gran Canaria, Las Palmas, Spain. 1 Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA.

Keynote 024 trial