Economic Evaluation of Trastuzumab Deruxtecan in Previously Treated HER2-Low Advanced Breast Cancer in the United States

Yitian Lang,1 Bin Wu,2 Xiaoyan Liu1 1Department of Pharmacy, Huangpu Branch, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China; 2Medical Decision and Economic Group, Department of Pharmacy, Ren Ji Hospital, South Campus, School of Medicine, Shanghai Jiaotong University, Shanghai, People’s Republic of ChinaCorrespondence: Xiaoyan Liu, Department of Pharmacy, Huangpu Branch, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, No. 58 Puyu East Roa, Huangpu Districtd, Shanghai, 200011, People’s Republic of China, Email liuxiaoyanrj@sjtu.edu.cnPurpose: Recently, the DESTINY-Breast04 trial revealed that significant benefits in both overall survival (OS) and progression-free survival (PFS) in patients with HER2-low advanced or metastatic breast cancer treated with trastuzumab deruxtecan (T-DXd) compared with chemotherapy. The current study assessed the cost-effectiveness of T-DXd from the perspective of the United States payer.Methods: We developed a partitioned survival model to project the disease course of breast cancer. The OS and PFS data were derived from the DESTINY-Breast04 trial. We extrapolate the survival data beyond the follow-up time to assess the long-term survival prognosis. Direct medical costs and utility data were collected. The incremental cost-utility ratio (ICUR) was the primary outcome that evaluated the cost-effectiveness of a therapy regimen. One-way sensitivity and probabilistic sensitivity analysis were implemented to explore the uncertainty of outputs.Results: In the base-case, the ICUR of T-DXd versus chemotherapy is $346,571.8/QALY and $337,789.4/QALY for all patients group and hormone-receptor-positive (HR+) subgroup, respectively. One-way sensitivity analyses revealed that the hazard ratio of OS, the unit cost of T-DXd, and body weight had a relatively large impact on the base-case result. Probabilistic sensitivity analyses showed that the likelihood that T-DXd was cost-effective is 14.5% and 12.6% for all patients group and HR+ subgroup, respectively.Conclusion: The cost-effectiveness analysis suggested that, at current price, trastuzumab deruxtecan is unlikely to be a preferred option for patients with HER2-low breast cancer at a threshold of $150,000/QALY from a US payer perspective.Keywords: cost-effectiveness, HER2-low breast cancer, trastuzumab deruxtecan, partitioned survival approach