Presenting Author: Andrea LeVoir, PharmD, Eli Lilly and Company, Indianapolis, IN
Co-Authors: Laura Spring, MD, Massachusetts General Hospital, Boston, MA; Wambui Gathirua-Mwangi, PhD, Sangmi Kim, PhD, Zhanglin Lin Cui, PhD, Samuel Whipple, MPH, Astra M. Liepa, PharmD, Erich Brechtelsbauer, PharmD, MS, Raisa Volodarsky, PharmD, and Sarah Rybowski, MBBS, Eli Lilly and Company, Indianapolis, IN; Madeline Richey, MPH, and Jingru Wang, BS, Flatiron Health, New York City, NY; Hatem Soliman, MD, Moffitt Cancer Center and Research Institute, Tampa, FL
BACKGROUND: Abemaciclib in combination with endocrine therapy is approved for adjuvant treatment of adult patients with hormone receptor (HR)-positive/HER2-negative, node-positive early breast cancer at high risk of recurrence. Anecdotal insights indicate providers may initiate abemaciclib at a lower dose than the approved 150 mg twice daily to aid tolerability with the aim to increase to the approved dose. This real-world study describes demographic and clinical characteristics, dosing patterns, and incidence of prespecified adverse events (AEs) in patients with early breast cancer who were started on abemaciclib at a lower dose.
METHODS: This study used the nationwide Flatiron Health electronic health records–derived deidentified database. Patients started on abemaciclib October 2021 to November 2022 were included. All results were summarized descriptively. Additional analyses were conducted to compare characteristics of patients starting <150 mg twice daily versus 150 mg twice daily.
RESULTS: Among 453 patients, 65 started abemaciclib at <150 mg twice daily (median follow-up time, 7.1 months). Median age was 56 years, 33.8% had stage III disease, 49.2% had ECOG Performance Scale score of 0 and median Charlson Comorbidity Index score was 0. Abemaciclib was frequently combined with aromatase inhibitors (92.3%), and most patients (56.9%) had a dose modification. The most common starting doses were 100 mg twice daily (56.9%) and 150 mg daily (24.6%); the time to first dose increase was 71 and 15 days, respectively. At first dose modification, 32.3% of patients increased the dose to 150 mg twice daily. Common real-world AEs were diarrhea (58.5%), fatigue (52.3%), and nausea/vomiting (40.0%). In comparison to patients started on 150 mg twice daily (n=388), patients started on a lower dose were more likely to be aged ≥75 years (4.9% vs 13.8%; P=.022).
CONCLUSIONS: In the real world, patients with HR-positive/HER2-negative early breast cancer started on abemaciclib at <150 mg twice daily were started on different doses and titration intervals. One-third of patients received the dose increase to 150 mg twice daily. Real-world AEs were generally consistent with clinical trial results.
This abstract was previously presented at the 2024 European Society for Medical Oncology Breast Cancer Annual Meeting.