OBJECTIVES: To estimate utility weights in patients with metastatic triple negative breast cancer (mTNBC) and disutility due to treatment-related adverse events (AEs) from the perspective of Japanese general population to inform future cost-effectiveness analyses.

METHODS: Literature review and interviews with clinical experts led to the development of health states that characterize the impact of mTNBC symptoms and AEs on health-related quality of life (HRQL). Three basic health states were developed to describe a typical patient with mTNBC: diagnosed with mTNBC and currently receiving chemotherapy (basic state 1), exacerbated by primary chemotherapy and receiving new drug (sacituzumab govitecan (SG)) (basic state 2), and exacerbated by SG and receiving tertiary therapy (basic state 3). Six additional health conditions described treatment-related adverse events. The utilities of three basic states and six health states with AE were estimated based on lead time trade-off (L-TTO) method for 56 Japanese participants, by using generalized estimating equation model.

RESULTS: Mean L-TTO scores for Base state 1-3 were 0.791 (95% CI: 0.733~0.850), 0.728 (95% CI: 0.671~0.785) and 0.619 (95% CI: 0.528~0.710), respectively. Disutility due to treatment-related adverse events showed that nausea/vomiting had the greatest impact on HRQL (-0.801) and neutropenia had the least burden (-0.007).

CONCLUSIONS: This study quantified utility weights in patients with mTNBC and magnitude of impact of AEs. These findings emphasized the importance of considering reduction in HRQL when evaluating the cost-effectiveness of treatments for mTNBC. The data obtained in this study can be used in future cost-evaluation analyses of drugs for mTNBC, considering the preferences of the Japanese population.