Cost-effectiveness analysis of lapatinib in HER-2-positive advanced breast cancer.

BACKGROUND: A recent clinical trial demonstrated that the addition of lapatinib to capecitabine in the treatment of HER-2-positive advanced breast cancer (ABC) significantly increases median time to progression. The objective of the current analysis was to assess the cost-effectiveness of this therapy from the US societal perspective.
METHODS: A Markov model comprising 4 health states (stable disease, respond-to-therapy, disease progression, and death) was developed to estimate the projected-lifetime clinical and economic implications of this therapy. The model used Monte Carlo simulation to imitate the clinical course of a typical patient with ABC and updated with response rates and major adverse effects. Transition probabilities were estimated based on the results from the EGF100151 and EGF20002 clinical trials of lapatinib. Health state utilities, direct and indirect costs of the therapy, major adverse events, laboratory tests, and costs of disease progression were obtained from published sources. The model used a 3% discount rate and reported in 2007 US dollars.
RESULTS: Over a lifetime, the addition of lapatinib to capecitabine as combination therapy was estimated to cost an additional $19,630, with an expected gain of 0.12 quality-adjusted life years (QALY) or an incremental cost-effectiveness ratio (ICER) of $166,113 per QALY gained. The 95% confidence limits of the ICER ranged from $158,000 to $215,000/QALY. A cost-effectiveness acceptability curve indicated less than 1% probability that the ICER would be lower than $100,000/QALY.
CONCLUSIONS: Compared with commonly accepted willingness-to-pay thresholds in oncology treatment, the addition of lapatinib to capecitabine is not clearly cost-effective; and most likely to result in an ICER somewhat higher than the societal willingness-to-pay threshold limits. (c) 2008 American Cancer Society.