Dr Kruse on Long-Term Data for Adjuvant Abemaciclib Plus Endocrine Therapy in HR+/ HER2– Early Breast Cancer

"It's really encouraging to see that [there] appears to be a durable benefit when patients are treated with adjuvant abemaciclib; hopefully, we are truly curing more patients with the inclusion of the adjuvant CDK4/6 inhibitor."

Megan Kruse, MD, a medical oncologist at Cleveland Clinic Taussig Cancer Institute, discussed updated long-term outcomes from the phase 3 monarchE trial (NCT03155997), which evaluated adjuvant abemaciclib (Verzenio) in combination with endocrine therapy in patients with hormone receptor–positive, HER2-negative, node-positive, high-risk early breast cancer.

At a median follow-up of 54 months, the abemaciclib regimen maintained benefits vs endocrine therapy alone in terms of invasive disease-free survival (IDFS; HR, 0.680; 95% CI, 0.599-0.772) and distant relapse-free survival (DRFS; HR, 0.675; 95% CI, 0.588-0.774). According to Kruse, updated monarchE results reinforce the distinct profile of abemaciclib in the adjuvant setting. The observed IDFS benefit not only persisted but appeared to deepen over time, supporting the hypothesis that abemaciclib may exert a durable antitumor effect in patients with residual disease following standard local and systemic therapies.

Kruse noted that these results are particularly significant for medical oncologists managing high-risk early breast cancer, as they provide reassurance that adding abemaciclib to endocrine therapy contributes to sustained disease control. Although long-term overall survival data remain immature, the consistency and depth of IDFS improvement with extended follow-up bolster confidence in abemaciclib’s use in clinical practice. Kruse emphasized that these findings may signal a meaningful shift toward curative outcomes for a subset of patients traditionally considered at high risk for recurrence.