Nancy Chan, MD, Director of Breast Cancer Clinical Research at NYU Langone’s Perlmutter Cancer Center, New York, commented on the monarchE analysis for The ASCO Post. She noted that the study investigated the addition of adjuvant abemaciclib (an oral CDK4/6 inhibitor) to endocrine therapy in a population of patients with hormone receptor–positive, HER2-negative breast cancer deemed at high clinical or biologic risk.

“The latest update tells clinicians that the invasive disease–free survival benefits are not only seen in the first 2 years when abemaciclib was taken by patients, but they are maintained thereafter. At 4 years, an improvement from 79.4% to 85.8% was observed. There is a continued separation of the curves associated with an absolute benefit in invasive disease–free survival compared with years 2 and 3. These data are very encouraging for patients—they will continue to benefit from having taken adjuvant abemaciclib, even after the 2-year course is completed,” Dr. Chan said.

In addition, she said, a Ki67 index of more than 20% continues to be an indicator for a worse prognosis. However, a similar benefit was derived from abemaciclib regardless of Ki67 index.

Nancy Chan, MD

The overall survival data remain immature, but numerically there is a trend favoring abemaciclib. More definitive findings will require further follow-up. 

As diarrhea continues to be a concern with this agent, Dr. Chan recommended monitoring and early intervention. “We ensure that patients have the proper antidiarrheal medications at hand and remind/encourage them not to wait,” Dr. Chan said. “Maintaining communication with their clinical team is crucial, so we can help them adjust the dose and prevent progression to more serious diarrhea, which may lead to volume depletion and in some cases colitis.” 

DISCLOSURE: Dr. Chan has served as an advisor to Novartis.