Recently updated three-year survival data from the PACIFIC trial showed that durvalumab consolidation therapy improved OS rates versus placebo for patients with unresectable stage III non-small cell lung cancer (NSCLC) after chemoradiotherapy. Considering the impact of the high cost of durvalumab, its cost-effectiveness should be updated to see if its cost-effectiveness has changed from the US payers' perspective. A comprehensive Markov model was used to evaluate mean lifetime costs and effectiveness of first-line durvalumab consolidation therapy versus placebo for patients with unresectable stage III NSCLC imputing updated survival and quality-of-life data from the PACIFIC trial. The main endpoints include total costs, life years (LYs), quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). One-way, two-way, and probabilistic sensitivity analyses were conducted to access the uncertainty in the variables. We also considered durvalumab cost-effectiveness in the subgroups. Durvalumab consolidation therapy resulted in additional 1.34 LYs and 1.01 QALYs, resulting in an ICER of $138,920 per QALY versus the placebo treatment. One-way sensitivity analysis revealed that the utility values of two treatments, body weight, and unit cost of durvalumab have the greatest influence on the result. Subgroup analyses demonstrated that durvalumab was more cost effective for patients with non-squamous-cell lung cancer, followed by 25% or greater PD-L1 expression. Probabilistic sensitivity analysis showed that the probability of durvalumab being cost-effective versus the placebo is 62.6% at a willingness-to-pay (WTP) of $150,000 per QALY CONCLUSION: Our analyses demonstrated that receiving durvalumab consolidation therapy was more cost-effective than placebo at a WTP threshold of $150,000. These results can be of use to US practitioners in the application of durvalumab and for durvalumab prescription and reimbursement policies. Copyright © 2020 Elsevier B.V. All rights reserved.