Cost-Effectiveness of Anastrozole Versus Tamoxifen as First-Line Therapy for Postmenopausal Women with Advanced Breast Cancer

Background: In a recent trial of first-line therapy in 353 postmenopausal women with predominantly hormone receptor-positive advanced breast cancer (the North American trial), anastrozole 1 mg QD produced a significantly longer time to disease progression (TTP) than tamoxifen 20 mg QD (11.1 months vs 5.6 months; P = 0.005). Both treatments were well tolerated, but there were fewer thromboembolic events and a reduced incidence of vaginal bleeding with anastrozole. Objective: The aim of this study was to conduct an economic analysis of anas-trozole versus tamoxifen based on data from the North American trial. Methods: Quality-adjusted TTP (QATTP) was determined by combining TTP values with uniform or graded weights for adverse events using the Quality-adjusted Time Without Symptoms and Toxicity method. Direct health care costs before and after disease progression were determined from the perspective of 4 types of health care insurers in the United States: health maintenance organizations (HMOs), indemnity plans, preferred provider organizations (PPOs), and point-of-service (POS) plans. Results: Median QATTP with graded weights was 9.7 months for anastrozole, compared with 4.6 months for tamoxifen (P = 0.003). A resultant reduction in health care resource utilization was observed, particularly the requirements for hospitalization, outpatient visits, and chemotherapy, but the statistical significance of this observation was not assessed. Incremental cost savings per patient before and after disease progression were observed with anastrozole compared with tamoxifen ($9064 for HMO, $9678 for indemnity plan, $14,273 for PPO, and $12,715 for POS; all P < 0.01). Conclusions: In the US managed care setting, anastrozole produced a higher QATTP and incurred lower treatment costs than tamoxifen in a population of postmenopausal women with predominantly hormone receptor-positive advanced breast cancer. Therefore, anastrozole was more cost-effective than tamoxifen as first-line endocrine therapy in the population studied.