Key clinical point: Adjuvant abemaciclib plus endocrine therapy (ET) showed a manageable and acceptable safety profile in patients with hormone receptor-positive (HR+), human epidermal growth factor 2-negative (HER2-), high-risk, early breast cancer breast cancer.
Major finding: Grade ≥3 adverse events (AE) were more frequent in the abemaciclib+ET vs. ET alone arm ( 49.7% vs. 16.3% ); however, neutropenia, the most frequent grade ≥3 AE, was manageable with dose modification. The discontinuation of abemaciclib and abemaciclib+ET due to AE occurred in 18.5% and 6.5% of patients, respectively, with 66.8% discontinuing abemaciclib because of grade 1/2 AE and < 1% because of neutropenia, increased transaminase, interstitial lung disease, or venous thromboembolism.
Study details: Findings are from a safety analysis of the phase 3 monarchE study including 5591 patients with HR+/HER2-, node-positive, high-risk, early breast cancer who received ≥1 dose of abemaciclib+ET or ET alone in the adjuvant setting.
Disclosures: This study was supported by Eli Lilly and Company. Six authors declared being employees or shareholders of Eli Lilly and other authors reported ties with various sources, including Eli Lilly .
Source: Rugo HS et al. Adjuvant abemaciclib combined with endocrine therapy for high risk early breast cancer: Safety and patient-reported outcomes from the monarchE study. Ann Oncol. 2022 (Mar 22). Doi: 10.1016/j.annonc.2022.03.006