March 2023: Abemaciclib (Verzenio, Eli Lilly and Company) and endocrine therapy (tamoxifen or an aromatase inhibitor) have been approved by the Food and Drug Administration (FDA) for the adjuvant treatment of adult patients with early-stage, node-positive, HR-positive breast cancer who are at high risk of recurrence.
Individuals with 4 pALN (pathologic axillary lymph nodes) or 1-3 pALN and either tumour grade 3 or a tumour size of 50 mm were classified as high risk.
For the high-risk population mentioned above, abemaciclib was originally approved with the additional stipulation of having a Ki-67 score of 20% or lower. The requirement for Ki-67 testing is dropped with today’s approval.
MonarchE (NCT03155997), a randomised (1:1), open-label, two-cohort multicenter trial involving adult women and men with HR-positive, HER2-negative, node-positive, resected, early breast cancer and pathological and clinical characteristics suggestive of a high risk of recurrence, evaluated the effectiveness. Patients must have either 4 pALN or 1-3 pALN, tumour grade 3 or a tumour size 50 mm in order to be included in cohort 1. Patients required to have tumour Ki-67 score 20%, 1-3 pALN, and be ineligible for cohort 1 in order to be recruited in cohort 2. Participants were randomly assigned to receive either standard endocrine therapy alone for 2 years, or standard endocrine therapy plus the doctor’s choice of standard endocrine therapy (tamoxifen or an aromatase inhibitor).
Invasive disease-free survival was the primary efficacy outcome metric (IDFS). In the intent-to-treat (ITT) population, a statistically significant difference was seen that was predominantly attributable to the cohort 1 patients (cohort 1 N=5120 [91%]; IDFS HR 0.653 (95% CI: 0.567, 0.753)). Abemaciclib in combination with regular endocrine therapy resulted in an IDFS at 48 months of 85.5% (95% CI: 83.8, 87.0) while normal endocrine therapy alone resulted in 78.6% (95% CI: 76.7, 80.4). Overall survival data are still in their infancy, but in cohort 2, abemaciclib plus routine endocrine therapy was associated with a higher death rate (10/253 vs. 5/264). The indication was therefore limited to cohort 1.
Diarrhea, infections, neutropenia, tiredness, leukopenia, nausea, anaemia, and headache were the most frequent side effects (20%).
The starting dose of abemaciclib is 150 mg twice daily with tamoxifen or an aromatase inhibitor for 2 years or until disease recurrence or intolerable toxicity, whichever comes first.
View full prescribing information for Verzenio.
