OBJECTIVES: Pembrolizumab is one of the standard treatments for non-small cell lung cancer (NSCLC) patients. However, an economic evaluation study in Thailand is required to support the decision process on whether pembrolizumab should be enlisted in the National List of Essential Medicines (NLEM). This study aims to assess the cost-effectiveness and budget impact of pembrolizumab as first-line monotherapy treatment for metastatic NSCLC, PD-L1 tumour proportion score (TPS) ≥50%, in Thailand.

METHODS: Partitioned survival analysis was used to assess incremental cost-effectiveness ratio (ICER) of pembrolizumab compared with standard chemotherapy (carboplatin + paclitaxel and carboplatin + gemcitabine). The main clinical efficacy and safety data were derived from KEYNOTE 024 trial, with July 10, 2017, cut-off date. The payer perspective was used, time horizon was 20 years. Pembrolizumab cost was based on the local price list. All other cost-related data were retrieved from publications and expert opinions. The budget impact model was constructed to calculate 5-year budget impact concerning the patient population, Treatment-related costs, and market share assumptions for each available treatment for patients.

RESULTS: Pembrolizumab increased life year expectancy by 1.14 quality-adjusted life years (QALYs) at additional costs of THB 3,326,239. ICER of pembrolizumab, compared with standard chemotherapy, was THB 2,921,493/QALY which was above the current acceptable ICER threshold of Thailand. Pembrolizumab had lower AE management costs vs chemotherapy. Listing pembrolizumab into NLEM for this indication, it would increase the 5-year annual budget by THB 1.3 billion with estimated 1,350-1,361 new patients per year.

CONCLUSIONS: Pembrolizumab showed clinical benefits in incremental QALYs vs chemotherapy as a first-line treatment for this patient group but was not cost-effective at the list price in Thailand context. Considering the clinically significant survival benefits data, collaboration between policymaker and drug company is needed to find a potential solution to improve access to pembrolizumab for Thai patients.