1031P - Cost-effectiveness analysis (CEA) of adjuvant trastuzumab therapy use in HER2-positive early-stage breast cancer (EBC)

Abstract

Adjuvant treatment options for HER2-positive early-stage breast cancer (EBC) have expanded in recent years. Trastuzumab has been shown in several randomized controlled trials (RCTs) to offer significant survival advantage in patients with high-risk HER2-positive EBC. This study aimed to estimate cost-effectiveness of adjuvant trastuzumab therapy compared to standard chemotherapy alone in patients with HER2-positive EBC in Ireland. A CEA was performed using a decision-tree model using estimate outcomes and costs over a 10-year period using a cohort of women with HER2-positive EBC, treated with or without 12 months of trastuzumab after adjuvant chemotherapy. These patients received ambulatory care in the Department of Medical Oncology (DoMO), University Hospital Limerick (UHL). Transition probabilities were derived from the cohort. Costs were estimated from the perspective of the Irish healthcare system. Both costs and outcomes were discounted by 5%. One-way sensitivity analysis was undertaken to assess the associated uncertainties in the expected output measures. In this study group, our model showed that adjuvant trastuzumab treatment in HER2-positive EBC, yield 8.54 quality-adjusted life-years (QALY) compared to adjuvant chemotherapy alone. Adjuvant trastuzumab treatment yielded an incremental cost-effectiveness ratio (ICER) of €42,801.62 per QALY. It has been shown that for a 10-year time horizon, adjuvant trastuzumab is a cost-effective therapy for patients with HER2-positive, high-risk EBC (i.e. less that €45,000.00 threshold set in Republic of Ireland).