Cost–utility analysis of trastuzumab deruxtecan versus trastuzumab emtansine in HER2-positive metastatic breast cancer in Chinese setting

Purpose Trastuzumab deruxtecan (T-DXd) expressed substantial improvement in the progression-free survival and overall survival contrasted with trastuzumab emtansine (T-DM1) in patients with HER2-positive metastatic breast cancer (mBC), becoming the second-line standard of care, promisingly. We aim to estimate the cost–utility of T-DXd versus T-DM1 in HER2-positive mBC from the Chinese healthcare perspective. Methods A partitioned survival model was applied to examine the cost–utility of T-DXd versus T-DM1. Clinical patients and outcome data were sourced from the DESTINY-Breast 03 trial. Costs and utilities were sourced in Chinese setting. Total costs, quality-adjusted life months (QALMs), and an incremental cost–utility ratios (ICUR) were calculated for cost–utility analysis. The willingness-to-pay threshold was set at $3188/QALM. Univariate, scenario, and probabilistic sensitivity analyses were performed. Results T-DXd group gained ∆QALM of 7.09 months and ∆Cost of $304,503 compared with T-DM1 therapy, which caused an ICUR of $42,936/QALM. The results of sensitivity analyses confirmed the base-case findings. Furthermore, T-DXd must reduce the price to enter the Chinese mainland market. At least when the cycle cost of T-DXd is reduced to $2975, T-DXd has an 83.3% chance of becoming a better choice. Conclusions T-DXd appears to be not cost effective compared with T-DM1 for HER2-positive mBC patients previously treated with trastuzumab and a taxane.