Abstract
BACKGROUND: Abemaciclib was recently approved by the European Medicines Agency in combination with adjuvant endocrine therapy (ET) for adult patients with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-), node-positive early breast cancer (EBC) at high risk of recurrence. OBJECTIVE: To evaluate the cost-effectiveness of abemaciclib plus ET vs. ET alone in patients with HR+, HER2-, node-positive EBC at high risk of disease recurrence, from the Italian healthcare system perspective. METHODS: A cohort state transition model was developed with five states: invasive disease-free survival (IDFS), nonmetastatic recurrence, remission, metastatic recurrence, and death. The analysis had a time horizon of 30 years. Individual patient-level data from the monarchE trial (NCT03155997) were used to generate IDFS estimates. Resource use included drug acquisition/administration, best supportive care, terminal care, adverse events, hospitalization, post-progression therapy, and associated resource use in the metastatic disease health state. Health state utilities were derived from monarchE patient-level data and other sources, applying Italian tariffs where feasible. RESULTS: The estimated total discounted costs (€39,249 vs. €16,806; difference: €22,443) and quality-adjusted life years (QALYs) (11.49 vs. 10.50; difference: 0.99) were higher for abemaciclib plus ET compared with ET alone. The incremental cost-effectiveness ratio was €22,651 per QALY gained. The likelihood of abemaciclib plus ET being cost-effective vs. ET alone was 99% at a willingness-to-pay threshold of €30,000 per QALY gained. CONCLUSION: Abemaciclib plus ET is a cost-effective treatment option vs. ET alone for those with HR+, HER2- node-positive EBC at high risk of recurrence in Italy.