Cost-Effectiveness of Lapatinib plus Letrozole in her2-Positive, Hormone Receptor–Positive Metastatic Breast Cancer in Canada

Abstract

Background: The cost-effectiveness of first-line treatment with lapatinib plus letrozole for postmenopausal women with hormone receptor–positive (HR+), human epidermal growth factor receptor 2–positive (HER2+) metastatic breast cancer (mBC) has not been assessed from the Canadian health care system and societal perspectives. Methods: A partitioned survival analysis model with 3 health states (alive, pre-progression; alive, post-progression; dead) was developed to estimate direct and indirect costs and quality-adjusted life years (QALYS) with lapatinib–letrozole, letrozole, anastrozole, or trastuzumab–anastrozole as first-line treatment. Clinical inputs for lapatinib–letrozole and letrozole were taken from the EGF30008 trial (NCT00073528). Clinical inputs for anastrozole and trastuzumab–anastrozole were taken from a network meta-analysis of published studies. Drug costs were obtained from the manufacturer’s price list, the Quebec list of medications, and imsBrogan. Other costs were taken from the Ontario Health Insurance Plan’s Schedule of Benefits and Fees and published studies. A 10-year time horizon was used. Costs and QALYS were discounted at 5% annually. Deterministic and probabilistic sensitivity analyses were performed to assess the effects of changes in model parameters. Results: Quality-adjusted life years gained with lapatinib–letrozole were 0.236 compared with trastuzumab–anastrozole, 0.440 compared with letrozole, and 0.568 compared with anastrozole. Assuming a health care system perspective, incremental costs were $5,805, $67,029, and $67,472 respectively. Given a cost per QALY threshold of $100,000, the probability that lapatinib–letrozole is preferred was 21% compared with letrozole, 36% compared with anastrozole, and 68% compared with trastuzumab–anastrozole. Results from the societal perspective were similar. Conclusions: In postmenopausal women with HR+/HRR2+ mbc receiving first-line treatment, lapatinib–letrozole may not be cost-effective compared with letrozole or anastrozole, but may be cost-effective compared with trastuzumab–anastrozole.