Abstract: OBJECTIVE To evaluate the anti-PD-1 immunotherapy drug-pembrolizumab compared to platinum-doublet chemotherapy as first-line therapy for advanced nonsmall cell lung cancer(NSCLC). METHODS Retrieved survival, progression, and safety data comparing first-line pembrolizumab to platinum-doublets for advanced NSCLC patients with PD-L1 expression ≥ 50%, non-mutated EGFR, and non-translocated ALK, from KEYNOTE-024. The analysis was based on a Bayesian Markov model of disease with full lifetime horizon. Estimated costs in USD and summarized effectiveness as quality-adjusted life-years(QALYs). RESULTS Patients treated with pembrolizumab accumulated 1.80 QALYs(95% CrI 1.56-1.89), compared to 1.06 QALYs(0.94-1.13) with chemotherapy. The ICER was 52 000 per end-of-life(EoL) adjusted QALY gained, above the 30 780 threshold. CONCLUSION Compared with platinum-doublets, pembrolizumab is not cost-effective in the first-line setting for patients with NSCLC, unless the individual has a higher willingness to pay.