First-line fulvestrant plus anastrozole for hormone-receptor-positive metastatic breast cancer in postmenopausal women: a cost-effectiveness analysis.

Objective: In a recent randomized, open-label trial (S0226), the addition of fulvestrant to anastrozole therapy decreased the risk of progression and death in patients with hormone-receptor-positive metastatic breast cancer. However, the cost-effectiveness of incorporating fulvestrant into the first-line setting is unknown.

Methods: We developed a Markov model to assess the costs and clinical outcomes of fulvestrant plus anastrozole compared with anastrozole as a first-line therapy in a cohort of patients with advanced hormone-receptor-positive breast cancer. The transition probabilities were estimated from the fitted survival curves in the S0226 trial. Health care costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) were calculated for fulvestrant plus anastrozole compared with anastrozole from US payer's perspective.

Results: Fulvestrant plus anastrozole led to an improvement of 0.11 QALYs compared with treatment with anastrozole alone. However, incorporating fulvestrant into the first-line therapy produced significantly higher health care costs ($72,496 vs. $38,959 for all eligible patients, and $73,728 vs. $37,239 for patients with no previous hormonal adjuvant therapy), resulting in ICERs of $300,564 and $194,450/QALY, respectively. Two-way sensitivity analysis showed that when the cost of fulvestrant decreased to $1.5/mg for all eligible patients or $3.5/mg for patients with no previous hormonal adjuvant therapy, at the perfect health in progression-free status, the ICER became $141,320 and $145,543 per QALY.

Conclusions: Substituting fulvestrant as a first-line therapy for hormone-receptor-positive metastatic breast cancer is not cost-effective compared with anastrozole based on the willing-to-pay threshold of $150,000 per QALY.