Cost-effectiveness and Budgetary Consequence Analysis of Durvalumab Consolidation Therapy vs No Consolidation Therapy After Chemoradiotherapy in Stage III Non-Small Cell Lung Cancer in the Context of the US Health Care System

IMPORTANCE In early 2018, durvalumab became the first immunotherapy to be approved for adjuvant treatment of patients with unresectable stage III non-small cell lung cancer (NSCLC) whose cancer has not progressed after definitive chemoradiotherapy. However, the cost-effectiveness and potential economic implications of using this high-priced therapy in this indication are unknown to date. OBJECTIVE To explore the cost-effectiveness and potential budgetary consequences of durvalumab consolidation therapy vs no consolidation therapy after chemoradiotherapy in stage III NSCLC in the context of the US health care system. DESIGN, SETTING, AND PARTICIPANTS A decision analytic microsimulation model was developed in an academic medical setting to compare the following 2 postchemoradiotherapy strategies: all patients receive no consolidation therapy until progression vs all patients receive durvalumab consolidation therapy until progression or for a maximum of 1 year. The potential budgetary consequence was calculated by applying the proportion of patients with NSCLC who were diagnosed in stage III and received chemoradiotherapy to the projected number of annual new cases for 2018 to 2022 to find total eligible patients and then multiplied by the mean difference in annual cost between the strategies over this 5-year period. Simulated conditions were matched to those of the PACIFIC phase 3 randomized clinical trial and reasonable treatment strategies for metastatic NSCLC. All simulated patients begin disease free after having received radical treatment with chemoradiotherapy and are followed up as they progress to metastatic disease first-line treatment, metastatic disease second-line treatment, end-stage progressive disease, and death. MAIN OUTCOMES AND MEASURES The main outcome of this study was the incremental cost-effectiveness ratio of durvalumab consolidation therapy vs no consolidation therapy, given as aggregate cost of treatment per quality-adjusted life-year gained. RESULTS Among 2 million simulated patients, durvalumab consolidation therapy was cost-effective compared with no consolidation therapy at a $100 000 per quality-adjusted life-year willingness-to-pay threshold, with an estimated incremental cost-effectiveness ratio of $67 421per quality-adjusted life-year, and would contribute an additional $768 million to national cancer spending in year 1. The annual budgetary consequence would then decrease to $241 million in year 5. CONCLUSIONS AND RELEVANCE Durvalumab consolidation therapy represents an indication where expensive immunotherapies can be cost-effective. Treating with immunotherapy earlier in the course of cancer progression can provide significant value, despite having a substantial budgetary consequence.