LBA1 - Baseline characteristics of patients from Asia enrolled in monarchE, evaluating abemaciclib in high risk early breast cancer

Background

Approximately 90% of patients with breast cancer are diagnosed at an early stage. While the risk of recurrence for many patients with HR+, HER2- early breast cancer (EBC) is relatively low, certain clinical and/or pathological features such as number of lymph nodes involved, tumor size, histologic grade, and proliferation index may increase the risk of recurrence. Thus, patients with high risk features may benefit from additional adjuvant treatment. monarchE, an open-label, phase 3 trial, randomized (1:1) patients with EBC at high risk of recurrence to receive standard of care endocrine therapy (ET) with or without abemaciclib (150mg BID for up to 2 years). Patients with breast cancer from Asian countries are known to have different clinical characteristics compared to Western countries. We report baseline characteristics of patients from Asia enrolled in monarchE to characterize the demographics and disease characteristics of this population.

Methods

Eligible women and men had ≥4 positive nodes, or 1-3 nodes and either tumor size ≥5 cm, histologic grade 3, or central Ki-67 ≥20%. Patients with HR+, HER2-, node-positive, high risk, EBC were randomized by an interactive web response system and stratified by prior treatment, menopausal status and region (North America/Europe vs Asia vs Other).

Results

Between July 2017 and August 2019, 1155 patients were enrolled from Asia: Japan (n=377), China (n=357), Korea (n=245), Taiwan (n=124), Singapore (n=32), and Hong Kong (n=20). Patients from Asia were younger, more commonly premenopausal and had a higher incidence of ≥4 positive nodes.

Conclusions

To our knowledge, these are the first reported baseline characteristics in patients from Asia with high risk EBC in a CDK4 & 6 inhibitor adjuvant study. These characteristics suggest that patients from Asia may have a higher risk of recurrence than patients from non-Asia and would benefit from additional adjuvant treatment.

Clinical trial identification

NCT03155997

Editorial acknowledgement

Writing and editorial support was provided by Sarah C. Nabinger (Eli Lilly and Company)