Efficacy and cost-effectiveness of HER2+ early breast cancer therapies.

Abstract

e18380 Background: Human Epidermal Growth Factor Receptor 2 (HER2) overexpression occurs in up to 25% of breast cancer (BC) cases. Patients with HER2+ tumors have a poor prognosis even when the disease is detected at an early stage with a recurrence rate of 15-19%. The aim of this study is to assess the best approach (pertuzumab plus trastuzumab [T+P], trastuzumab for 12 months [T12], trastuzumab for 6 months [T6], or T-DM1) in terms of evidence-based medicine and cost-effectiveness. Methods: The authors extracted individual patient data and estimated Invasive Disease-Free Survival (IDFS) and Overall Survival (OS) over a 30-years lifetime horizon. We considered only direct costs from adjuvant treatment as well as recurrence treatment from a Brazilian payer perspective. Heart events were considered for utility and cost analysis. After the base case, the authors assessed cost-effectiveness among N+ patients. In the meta-analysis, we included individual patient data for the intention-to-treat (ITT) population and Bayesian comparisons for subgroup analysis (HR+/HR- and N+/N). Results: We included individual patient data from 12,753 patients. The 4-year IDFS rate was 92.9% for T+P, 89.8% for T12 (HR 1.37, 95%CI 1.16-1.63) and 87.1% for T6 (HR 1.73, 95%CI 1.45-2.06). The 4-year OS rate was 96.7% for T+P, 95% for T12 (HR 1.37, 95%CI 1.07-1.75) and 93% for T6 (HR 1.82, 95%CI 1.42-2.34). T+P, T12 and T6 had similar efficacy among patients with HR+ tumors. T+P and T12 were superior to T6 among HR- patients. T+P was superior to T12 and T6 among N+ patients. T+P, T12 and T6 had similar efficacy among N- patients. In the base case, T+P had an ICER of $332,903 compared to T12. T12 had an ICER of $42,774 compared to T6. Among N+ patients, T+P had an ICER of $308,019 compared to T12. Among patients without complete response after neoadjuvant treatment, T-DM1 had an ICER of $3,233 compared to trastuzumab. Conclusions: T+P had a modest benefit in terms of 4-years IDFS and OS, although it was not cost-effective due to its high cost. T12 remained above the cost-effectiveness threshold compared to T6, but further studies are needed in order to define patients for T6. T-DM1 was cost-effective compared to trastuzumabe for patients who did not achieve complete response after neoadjuvant treatment.