Cost-Effectiveness of Zoledronic Acid Plus Endocrine Therapy in Premenopausal Women With Hormone-Responsive Early Breast Cancer

Purpose: The aim of this study was to estimate the cost-effectiveness of adding zoledronic acid 4 mg intravenously every 6 months to endocrine therapy in premenopausal women with hormone receptor-positive early breast cancer from a US health care system perspective. Materials and Methods: A Markov model was developed to predict disease progression, mortality, and costs of breast cancer care for premenopausal women with hormone receptor-positive early breast cancer receiving up to 3 years of (1) endocrine therapy (goserelin plus tamoxifen or anastrozole); or (2) endocrine therapy plus zoledronic acid. Model parameters were obtained from ABCSG-12 (Austrian Breast and Colorectal Cancer Study Group Trial-12) and the literature. The incremental cost per quality-adjusted life year (QALY) gained with zoledronic acid was calculated under 2 scenarios: (1) benefits of zoledronic acid persist to maximum (7 years) follow-up in ABCSG-12 ("trial benefits") or (2) benefits persist until death ("lifetime benefits"). Results: Adding zoledronic acid to endocrine therapy was projected to yield a gain of 0.41 life years (LYs) and 0.43 QALYs assuming trial benefits and 1.34 LYs and 1.41 QALYs assuming lifetime benefits. Assuming trial benefits, the incremental cost per QALY gained with zoledronic acid was $9300. Assuming lifetime benefits, zoledronic acid was estimated to increase QALYs and reduce costs. Cost per QALY gained was <=$56,000 in all deterministic sensitivity analyses and was <=$50,000 in 94% and 97% of probabilistic sensitivity analyses for trial and lifetime benefits scenarios, respectively. Conclusion: Adding zoledronic acid to endocrine therapy in premenopausal women with hormone receptor-positive early breast cancer is cost-effective from a US health care system perspective.