The KEYNOTE 042 trial showed a benefit of treating patients with non-oncogene addicted advanced NSCLC with PD L1 tumour proportion score over 50% with Pembrolizumab as monotherapy over platinum doublet chemotherapy. To contextualize these results, we undertake a detailed emulation of the inclusion criteria in Keynote 042 using Norwegian health registry data, and discuss both the clinical context, as well as the general utility of such registry data for pharmacoepidemiologic research in oncology. Within the population of patients with PD L1 tumour proportion score over 50%, an observational analogue of an intention to treat analysis showed similar results to those of the Keynote 042 study.

NordicRWE, a real-world evidence research company, conducted this study in collaboration with the University of Oslo. The research study was carried out independently, without any involvement from the pharmaceutical industry. Jonasson and Thoresen are co-founders, owners and employees of NordicRWE. Brant is an employee of NordicRWE. Boro is a PhD-candidate at the University of Oslo and an employee of Merck. Helland reports advisory/consultancy/meeting presentation roles for AbbVie, AstraZeneca, BMS, Pfizer, Roche, Janssen, MSD, Sanofi, Bayer, Medicover, and Takeda with honoraria directed to own institution, and receiving research grants from Roche, BMS, Ultimovacs, AstraZeneca, Novartis, InCyte, Eli Lilly, Illumina, Merck, Nanopore, GlaxoSmithKline. No other potential conflicts of interest relevant to this article were reported.

The study was supported by a research grant from the Research Council of Norway (grant no. 327887).

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Patient-level data were de-identified to guarantee the protection of individual patient integrity, and ethical approval was obtained from the Regional Committee for Medical and Health Research Ethics, South-East D (ID number 108024), which waived the requirement of informed consent.

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Data access is available upon separate request and approval by the Norwegian Regional Committees for Medical and Health Research Ethics and the data permit authority at the Norwegian Institute of Public Health.