Cost-effectiveness analysis of pembrolizumab plus chemotherapy versus placebo plus chemotherapy for patients with previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer in China

Background: The present study aimed to evaluate the cost-effectiveness of pembrolizumab combined with chemotherapy versus placebo plus chemotherapy for patients with previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer from the perspective of the Chinese healthcare system. Methods: A Markov model was developed to track patients' transitions over 3-week cycles and evaluate the health and economic outcomes over a 10-year horizon for the two competing treatments. The survival data were gathered from the KEYNOTE-355 trial, and cost and utility values were obtained from the published studies. Total costs, life-years, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER) were the model outcomes. We conducted analysis based on patients' programmed death-ligand 1 (PD-L1) combined positive score (CPS), including subgroups with CPS≥10, CPS≥1, and the intention-to-treat population. One-way sensitivity analysis, probabilistic sensitivity analysis and scenario analysis were performed to examine the robustness of the model results. Results: In the base case analysis for patients highly expressing PD-L1 (CPS≥10), pembrolizumab plus chemotherapy yielded a marginal cost of $85,838.75 and an additional 0.47 QALYs, resulting in an ICER of $184,030.56 per additional QALY gained, which exceeded the willingness-to-pay (WTP) threshold of $38,224 per QALY in China. And the ICERs were $319,506.90/QALY for patients lowly expressing PD-L1 (CPS≥1) and $776,786.75/QALY for the intention-to-treat population. Sensitivity analyses confirmed the robustness of the model outcomes. Scenario analysis demonstrated that price reductions for pembrolizumab could enhance its likelihood of achieving cost-effectiveness. Conclusion: The findings of this cost-effectiveness analysis suggest that pembrolizumab plus chemotherapy was not a cost-effective treatment for patients with previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer in China.