Abemaciclib was previously approved for this group of high-risk patients with the requirement that they have a Ki-67 score of at least 20%. The new expansion removes the Ki-67 testing requirement, meaning more patients are now eligible to receive this drug. High-risk patients eligible for the CDK4/6 inhibitor can now be identified solely on the basis of nodal status, tumor size, and tumor grade.
The FDA’s decision to expand the approval was based on 4-year data from the phase 3 monarchE trial of adjuvant abemaciclib, which showed benefit in invasive disease-free survival beyond the 2-year treatment course.
At 4 years, 85.5% of patients remained recurrence free with abemaciclib plus endocrine therapy, compared with 78.6% who received endocrine therapy alone, an absolute difference in invasive disease-free survival of 6.9%.
“The initial Verzenio FDA approval in early breast cancer was practice changing and now, through this indication expansion, we have the potential to reduce the risk of breast cancer recurrence for many more patients, relying solely on commonly utilized clinicopathologic features to identify them,” Erika P. Hamilton, MD, an investigator on the monarchE clinical trial, said in a press release.
A version of this article first appeared on Medscape.com.