Lapatinib for the treatment of HER2-overexpressing breast cancer

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of lapatinib for the treatment of advanced or metastatic HER2-overexpressing breast cancer based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The scope included women with advanced, metastatic or recurrent HER2-overexpressing breast cancer who have had previous therapy that includes trastuzumab. Outcomes were time to progression, progression-free survival, response rates, overall survival, health-related quality of life and adverse effects. The submission's evidence came from one randomised controlled trial (RCT) of reasonable methodological quality, although it was not powered to detect a statistically significant difference in mean overall survival. Median time to progression was longer in the lapatinib plus capecitabine arm than in the capecitabine monotherapy arm {27.1 [95% confidence interval (CI) 17.4 to 49.4] versus 18.6 [95% CI 9.1 to 36.9] weeks; hazard ratio 0.57 [95% CI 0.43 to 0.77; p = 0.00013]}. Median overall survival was very similar between the groups [67.7 (95% CI 58.9 to 91.6) versus 66.6 (95% CI 49.1 to 75.0) weeks; hazard ratio 0.78 (95% CI 0.55 to 1.12; p = 0.177)]. Median progression-free survival was statistically significantly longer in the lapatinib plus capecitabine group than in the capecitabine monotherapy group [27.1 (95% CI 24.1 to 36.9) versus 17.6 (95% CI 13.3 to 20.1) weeks; hazard ratio 0.55 (95% CI 0.41 to 0.74); p = 0.000033]. The manufacturer's economic model to estimate progression-free and overall survival for patients with HER2-positive advanced/metastatic breast cancer who had relapsed following treatment with an anthracycline, a taxane and trastuzumab was appropriate for the disease area. The base-case incremental cost-effectiveness ratios (ICERs) for lapatinib plus capecitabine compared with capecitabine monotherapy or vinorelbine monotherapy were higher than would conventionally be considered cost-effective. When compared with trastuzumab-containing regimes, lapatinib plus capecitabine dominated. In sensitivity analyses the ICER for lapatinib plus capecitabine compared with capecitabine monotherapy or vinorelbine monotherapy was robust to variation in assumptions. In all sensitivity analyses the ICERs remained higher than would conventionally be considered cost-effective. ICERs for trastuzumab-containing regimes were particularly sensitive to assumptions over the frequency of treatment, which had a large effect on the cost-effectiveness of lapatinib plus capecitabine. In conclusion, there was a general lack of evidence on the effectiveness of comparators included in the model and on key parameters such as dose adjustments and the model outputs need to be interpreted in the light of this uncertainty. At the time of writing, NICE were still considering the available evidence for this appraisal.