Cost-effectiveness of Trastuzumab Deruxtecan for HER2-low Advanced Breast Cancer in the United States

Purpose Trastuzumab deruxtecan has been shown to be effective for advanced breast cancer with low levels of human epidermal growth factor receptor 2. To optimize the allocation of limited health care resources, this study evaluated the cost-effectiveness of trastuzumab deruxtecan from the US payer perspective. Methods A partitioned survival model was developed to project the disease course of advanced breast cancer. Clinical efficacy, treatment utilization, safety, and cost data were gathered from the DESTINY-Breast04 (Trastuzumab Deruxtecan in Previously Treated HER2-Low Advanced Breast Cancer) trial and the Centers for Medicare & Medicaid Services. Transition probabilities were obtained from the reported survival probabilities per DESTINY-Breast04 group. The incremental cost-effectiveness ratio (ICER), the incremental monetary benefit, and the incremental net health benefit were measured. One-way sensitivity analysis, probabilistic sensitivity analysis, and subgroup analysis were performed to explore the uncertainty of the model. Findings Trastuzumab deruxtecan had an ICER of $307,751 per quality-adjusted life-year (QALY) gained, with an incremental net health benefit of −0.317 QALY and an incremental monetary benefit of −$63,313 compared with the physician's choice of alternative chemotherapy agents. Subgroup analysis indicated that trastuzumab deruxtecan had an ICER of $383,776 per QALY gained for the hormone receptor–positive subgroup and an ICER of $194,424 per QALY for the hormone receptor–negative subgroup. One-way sensitivity analysis showed that the cost of trastuzumab deruxtecan had the most impact on model outcomes. The cost-effectiveness acceptability curve projected that the probability of trastuzumab deruxtecan being cost-effective was 5% in the overall population, 2% in the hormone receptor–positive subgroup, and 56% in the hormone receptor–negative subgroup at the willingness-to-pay threshold of $200,000 per QALY. Implications Trastuzumab deruxtecan may be a cost-effective option for hormone receptor–negative patients with advanced breast cancer with low levels of human epidermal growth factor receptor 2.