Cost-Effectiveness of PDL1 Based Test-And-Treat Strategy with Pembrolizumab as the 1st Line Treatment for NSCLC in Hong Kong

Abstract

Background: Pembrolizumab, a monoclonal antibody against PD-1, is approved by several regulatory agencies for first line treatment in metastatic NSCLC with a PD-L1 tumour proportion score (TPS) ≥50%. An economic model was developed to evaluate the cost-effectiveness of employing a biomarker (PD-L1) test-and-treat strategy (BTS), in which patients with TPS ≥50% are treated with pembrolizumab, and other patients receive standard-of-care (SoC) cytotoxic chemotherapies versus a non-BTS strategy with all patients receiving SoC. Patients with activating EGFR mutations and ALK translocations were excluded from the analysis. Methods: The model was built with partitioned survival approach to estimate the incremental cost effectiveness ratio (ICER) expressed as cost per quality-adjusted life-year (QALY) gained. The clinical efficacy, utility and safety data used in this model were derived from the KN024 trial. The base case comparator in the model included five different platinum-based chemotherapy regimens used as SoC for advanced NSCLC in Hong Kong. The base-case time horizon for the model was 10 years with costs and health outcomes discounted at a rate of 3% per year. Utilities for the base case were based on utility data collected in KN024. Costs and disutility associated with grade 3-5 adverse effects of incidence rate 5%, including anaemia, neutropenia, pneumonia, thrombocytopenia and pneumonitis were considered in the model. Treatment was continued until disease progression or maximum 2 years for pembrolizumab. Local drug acquisition costs, PD-L1 testing costs, drug administration costs, disease management costs were applied. A series of sensitivity analyses were conducted to evaluate the uncertainty of cost-effectiveness results. Results: The BTS approach was projected to increase QALY by 0.29 with an additional total cost of HK$ 249,077 (USD 31,933) compared to non-BTS approach resulting in an incremental cost-effectiveness ratio (ICER) of HK$ 865,189 (USD 110,922) per QALY gained. This is lower than the World Health Organization (WHO) cost-effectiveness threshold of 3 times 2016 GDP per capita of Hong Kong, HK$ 1,017,819 (USD 130,490). Probabilistic sensitivity analysis showed 94.6% probability that the ICERs would be below this threshold. In a scenario analysis, a lower ICER of HK$ 859,284 (USD 110,165) was shown in comparison of pembrolizumab versus SoC among patients with TPS ≥50%. Conclusion: A BTS to identify a subset of NSCLC patients with PD-L1 TPS ≥50% to be treated with pembrolizumab in the first line setting can be considered cost-effective in Hong Kong.