Cost-effectiveness analysis of capivasertib plus fulvestrant in the -altered subgroup with HR+/HER2- advanced breast cancer: a United States payer perspective.

[AIMS] Capivasertib plus fulvestrant has emerged as a promising targeted therapy for HR+/HER2- advanced breast cancer (ABC). This study evaluated the cost-effectiveness of capivasertib plus fulvestrant vs. fulvestrant monotherapy in pathway-altered patients with HR+/HER2- ABC from a U.S. payer's perspective.

[MATERIALS AND METHODS] A partitioned survival model with three health states (progression-free, progressive disease, and death) was developed over a 5-year time horizon. Progression-free survival (PFS) and overall survival (OS) data were derived from the CAPItello-291 trial (NCT04305496). Utility, disutility, and direct medical costs were obtained from published literature and the Centers for Medicare and Medicaid Services. Capivasertib cost was based on wholesale acquisition cost. Costs were presented in 2025 U.S. dollars. Both costs and outcomes were discounted by 3%. Incremental cost-effectiveness ratios (ICERs) based on quality-adjusted life-year (QALY) gained and equal value of life years gained (evLYG) were compared using a willingness-to-pay (WTP) threshold of $150,000. Sensitivity analyses, scenario analyses (10-year horizon and phase II trial data) and threshold analysis were conducted.

[RESULTS] Capivasertib plus fulvestrant yielded more QALYs (1.89 vs. 1.29) and life years (3.31 vs. 2.49) but higher costs ($539,625 vs. $158,679) than fulvestrant alone, resulting in ICERs of $636,455/QALY gained and $459,358/evLYG over a 5-year time horizon. The cost of capivasertib ($28,332/4 weeks) had the greatest impact and would need to be reduced to $5,598/4 weeks to achieve cost-effectiveness.

[LIMITATIONS] Extrapolation of survival data reflects limited long-term trial data and increases uncertainty surrounding model parameters. Efficacy based on clinical trials may differ from real-world effectiveness.

[CONCLUSIONS] Despite clinical benefits, capivasertib plus fulvestrant was not cost effective at current price from a U.S. payer's perspective. The cost of capivasertib per 4 weeks would be required to decrease by ∼80% from $28,332 to $5,598 (about $87 per 200 mg) to meet the WTP threshold of $150,000.