OBJECTIVES: Adding pembrolizumab to standard chemotherapy has been shown to have survival benefits in patients with non-small-cell lung cancer (NSCLC) regardless of PD-L1 tumor proportion score, compared with chemotherapy alone. This analysis aims to assess the cost-effectiveness of pembrolizumab in this patient population from a UK health care perspective.

METHODS: A three-health-state Markov model was developed to compare the cost and effectiveness of pembrolizumab and chemotherapy. The model used a 3-week cycle length and was run until 99% patients have died. Transition probabilities were calculated based on the hazard ratio for death, median overall survival, and median progression-free survival reported in the Phase III trial, KEYNOTE-189. Utility values were sourced from published literature and stratified by treatment as well as health state. Cost of drug acquisition, disease management, adverse event and terminal care were considered in the model. Both costs and health outcomes were discounted at an annual rate of 3.5%. Patients were assumed to receive docetaxel and pembrolizumab as second-line treatment for pembrolizumab and chemotherapy group, respectively. Incremental cost-effectiveness ratio (ICER) was calculated as cost per quality-adjusted life-years (QALYs). Deterministic sensitivity analyses were performed to assess the robustness of the model.

RESULTS: In the base case, pembrolizumab was projected to increase patient’s life expectancy by 0.97 years and 0.62 QALYs compared to platinum-based chemotherapy (1.87 vs. 1.19 life-years; 1.19 vs. 0.57 QALYs). Patients receiving pembrolizumab also incurred higher costs over lifetime compared to chemotherapy patients (£77,355 vs. £21,405). The mean ICER was estimated at £89,997 per QALY. Deterministic sensitivity analyses showed that results were very sensitive to drug acquisition cost of pembrolizumab and hazard ratio for death.

CONCLUSIONS: There is still huge uncertainty lies in the in the overall survival projection of pembrolizumab in this patient population. Long-term survival data from the trial are needed to better estimate the cost-effectiveness of pembrolizumab.