Cost-Effectiveness Analysis of Trastuzumab Deruxtecan versus Trastuzumab Emtansine in Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer in the USA

IntroductionBased on data from the DESTINY-Breast03 trial, we performed a cost-effectiveness analysis of trastuzumab deruxtecan (T-DXd) in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer who had been previously treated with trastuzumab and a taxane from the US payer perspective.MethodsWe conducted a Markov model to assess the cost-effectiveness of T-DXd versus trastuzumab emtansine (T-DM1). The simulation time horizon for this model was the lifetime of patients. Transition probabilities were based on data from the DESTINY-Breast03 trial. Health utility data were derived from published studies. Outcome measures were costs (in 2022 US$), quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio (ICER). One-way and probabilistic sensitivity analyses assessed the uncertainty of key model parameters and their joint impact on the base-case results.ResultsThe base-case results found that T-DXd provided an improvement of 3.90 QALYs compared with T-DM1, and the ICER was $220,533 per QALY. The one-way sensitivity analysis demonstrated that the utility value of progression-free survival, hazard ratios of T-Dxd versus T-DM1, and cost of T-Dxd contributed substantial uncertainty to the model. Probabilistic sensitivity analysis predicted T-DXd being cost-effective compared to T-DM1 was 0, 1, 16, and 46% at willingness-to-pay of $50,000, $100,000, $150,000, and 200,000 per QALY, respectively.ConclusionT-DXd was unlikely to offer a reasonable value for the money spent compared to T-DM1 in a US payer setting.