Cost-effectiveness analysis of the treatment pathway after trastuzumab treatment failure in patients with HER2-positive advanced breast cancer: a chinese health system perspective

OBJECTIVES: Breast cancer stands out as a prevalent and life-threatening cancer among women, ranking as the second leading cause of cancer-related fatalities globally. Trastuzumab is a commonly employed treatment for human epidermal growth factor receptor 2 (HER2) positive advanced breast cancer. Following trastuzumab treatment failure, the Chinese Society of Clinical Oncology (CSCO) recommends lapatinib with capecitabine, pyrotinib plus capecitabine, trastuzumab emtansine (T-DM1), and trastuzumab deruxtecan (T-DXd). The study aimed to evaluate the relative cost-effectiveness of four treatment approaches for advanced breast cancer with HER2 positive status in the Chinese healthcare system. METHODS: The clinical data for this study were acquired from the following clinical trials: NCT02422199, NCT03080805, NCT00829166, and NCT03529110. Survival data were reconstructed and extrapolated using fractional polynomial (FP) models, Royston-Parmar (RP) models, and standard parametric models. A partitioned survival model with a 3-week cycle length and a 10-year time horizon was developed to estimate costs, health outcomes, and incremental cost-effectiveness ratios (ICERs). The robustness of the model was tested using one-way sensitivity analysis and probabilistic sensitivity analysis. RESULTS: The ICER values for pyrotinib plus capecitabine, T-DM1, and T-DXd were $59,278.37/QALY, $50,029.87/QALY, and $148,234.68/QALY, respectively, when compared to lapatinib plus capecitabine. The deterministic sensitivity analysis indicated that ICER variability was primarily driven by drug costs, patient body weight, hazard ratios (HRs) for progression-free survival (PFS) and overall survival (OS), and the utilities of the progression-free (PF) and progressive disease (PD) health states. A probabilistic sensitivity analysis revealed that lapatinib's advantage produced a stable result at the willing-to-pay (WTP) threshold. CONCLUSION: In the context of the Chinese health system, none of the three alternative regimens-pyrotinib plus capecitabine, T-DM1, and T-DXd-demonstrated cost-effectiveness relative to lapatinib plus capecitabine at the current WTP threshold.