Abemaciclib Plus Endocrine Therapy Improves Survival in Patients With HR+/HER2– Breast Cancer

Abemaciclib (Verzenio; Eli Lilly) plus endocrine therapy (ET) led to clinically meaningful improvements in overall survival (OS) within 2 years of treatment compared with ET alone in patients with hormone receptor-positive (HR+), HER2-negative (HR+/HER2–), node-positive, high-risk early breast cancer. The results are from the phase 3 monarchE trial (NCT03155997).¹

Breast cancer cells | Image Credit: © sknab - stock.adobe.com

"Preventing disease relapse and helping patients live longer is the ultimate goal and a high bar in the adjuvant setting. Achieving a statistically significant OS benefit with just 2 years of [abemaciclib] therapy reinforces its differentiated profile in high-risk HR+, HER2- early breast cancer," Jacob Van Naarden, executive vice president and president of Lilly Oncology, said in a news release. "These data validate [abemaciclib] as the standard-of-care for patients with node-positive, high-risk disease and increase the urgency to ensure all eligible patients are treated."²

Abemaciclib is a CDK4/6 inhibitor with various approvals in combination with other agents such as ET or an aromatase inhibitor. It received initial approval by the FDA in 2017 as a monotherapy for adult patients who have HR+, HER2– advanced or metastatic breast cancer that has progressed after taking therapy that alters a patient’s hormones. Following this, the FDA expanded its indication to include^3-7:

• 2018: Approved in combination with an aromatase inhibitor as initial endocrine-based therapy for the treatment of postmenopausal women with HR+, HER2– advanced or metastatic breast cancer.
• 2021: Approved in combination with ET (tamoxifen or an aromatase inhibitor) for the adjuvant treatment of adult patients with HR+, HER2–, node-positive, early breast cancer at high risk of recurrence.
• 2023: Expanded indication in combination with ET for the adjuvant treatment of adult patients with HR+, HER2–, node-positive, early breast cancer at a high risk of recurrence

Abemaciclib continues to demonstrate favorable efficacy, supporting prior FDA approvals and its place in the treatment landscape for HR+, HER2– breast cancer. The 7-year landmark analysis of the global, randomized, open-label, 2-cohort, multicenter, phase 3 monarchE trial showed abemaciclib’s sustained benefits in OS, as well as invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS). The trial enrolled a total of 5637 adult patients with HR+, HER2-, node-positive early breast cancer at high risk of recurrence across over 600 sites in 38 countries.²

The patients were randomized 1:1 to receive either 150 mg of abemaciclib twice daily plus standard-of-care adjuvant ET (cohort 1: n = 2555; cohort 2: n = 253) or standard-of-care adjuvant ET alone (cohort 1: n = 2565; cohort 2: n = 264) for 2 years. The primary end point was IDFS, as defined by the length of time before breast cancer comes back, any new cancer develops, or death. The key secondary end point was OS.²

These data reinforce abemaciclib’s role as a standard-of-care adjuvant treatment for high-risk HR+, HER2– early breast cancer, demonstrating both survival benefits and durable disease control when added to ET.

REFERENCES

1. Endocrine therapy with or without abemaciclib (LY2835219) following surgery in participants with breast cancer (monarchE). Updated April 20, 2025. Accessed August 28, 2025. https://clinicaltrials.gov/study/NCT03155997

2. Lilly's Verzenio® (abemaciclib) increases overall survival in HR+, HER2-, high-risk early breast cancer with two years of therapy. Eli Lilly. August 27, 2025. Accessed August 28, 2025. https://investor.lilly.com/news-releases/news-release-details/lillys-verzenior-abemaciclib-increases-overall-survival-hr-her2

3. Stewart J. Verzenio FDA approval history. Drugs.com. March 19, 2023. Accessed August 28, 2025. https://www.drugs.com/history/verzenio.html

4. FDA Approves Verzenio. Drugs.com. September 28, 2017. Accessed August 28, 2025. https://www.drugs.com/newdrugs/fda-approves-verzenio-abemaciclib-certain-advanced-metastatic-breast-cancers-4608.html

5. Lilly receives additional FDA approval for Verzenio (abemaciclib), as initial treatment for advanced breast cancer. Drugs.com. February 26, 2018. Accessed August 28, 2025. https://www.drugs.com/newdrugs/lilly-receives-additional-fda-approval-verzenio-abemaciclib-initial-advanced-breast-cancer-4704.html

6. FDA approves Verzenio (abemaciclib) as the first and only CDK4/6 inhibitor for certain people with HR+ HER2- high risk early breast cancer. Drugs.com. October 13, 2021. Accessed August 28, 2025. https://www.drugs.com/newdrugs/fda-approves-verzenio-abemaciclib-first-only-cdk4-6-inhibitor-certain-hr-her2-risk-early-breast-5689.html

7. FDA broadens indication for Verzenio (abemaciclib) in HR+, HER2-, node-positive, high risk early breast cancer. Drugs.com. March 3, 2023. Accessed August 28, 2025. https://www.drugs.com/newdrugs/fda-broadens-indication-verzenio-abemaciclib-hr-her2-node-positive-risk-early-breast-cancer-5981.html