Verzenio Plus Aromatase Inhibitor Improves Survival in Advanced-Stage, Hormone Receptor-Positive, HER2-Negative Breast Cancer
Adding the targeted therapy Verzenio (chemical name: abemaciclib) to an aromatase inhibitor as a first treatment for advanced-stage, hormone receptor-positive, HER2-negative breast cancer improved overall survival versus using an aromatase inhibitor alone, according to the latest results from the MONARCH 3 study.
The research, “MONARCH 3: Interim overall survival (OS) results of abemaciclib plus a nonsteroidal aromatase inhibitor (NSAI) in patients (pts) with HR+, HER2- advanced breast cancer (ABC),” was presented at the European Society for Medical Oncology (ESMO) Congress 2022 on Sept. 9, 2022.
Overall survival is how long people live, whether or not the breast cancer grows.
Advanced-stage breast cancer is either locally advanced breast cancer or metastatic breast cancer. Locally advanced breast cancer is breast cancer that has spread to tissue near the breast, but not to parts of the body away from the breast. Metastatic breast cancer is breast cancer that has spread to parts of the body away from the breast, such as the bones or liver.
Matthew Goetz, MD, professor of oncology and pharmacology at the Mayo Clinic, who presented the research, recently joined The Breastcancer.org Podcast to discuss results from the MONARCH 3 trial.
About Verzenio
Verzenio is a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor. A kinase is a type of protein in the body that helps control cell division. Verzenio works by stopping cancer cells from dividing and growing. Verzenio is a pill taken by mouth.
There are two other CDK4/6 inhibitors used to treat breast cancer:
Ibrance (chemical name: palbociclib)
Kisqali (chemical name: ribociclib)
About the MONARCH 3 study
The ongoing MONARCH 3 study includes 493 post-menopausal women diagnosed with advanced-stage, hormone receptor-positive, HER2-negative breast cancer. None of the women had received hormonal therapy for advanced-stage disease.
The researchers randomly split the women into two treatment groups:
328 women took Verzenio plus one of two aromatase inhibitors: Arimidex (chemical name: anastrozole) or Femara (chemical name: letrozole)
165 women took either Arimidex or Femara plus a placebo pill, a pill that contained no medicine but looked just like Verzenio
Results from MONARCH 3 published in 2019 showed that Verzenio plus an aromatase inhibitor improved progression-free survival by about 14 months. Progression-free survival was:
28.18 months for women taking Verzenio plus an aromatase inhibitor
14.76 months for women taking only an aromatase inhibitor
This difference was statistically significant, which means that it was likely due to the difference in treatment and not just because of chance.
Progression-free survival is how long a person lives without the cancer growing.
Better progression-free survival is a good outcome, but the researchers wanted to know if adding Verzenio to an aromatase inhibitor would improve overall survival.
In this latest analysis — after about 5.8 years of follow-up — overall survival was:
67.1 months for women taking Verzenio and an aromatase inhibitor
54.5 months for women taking an aromatase inhibitor alone
This difference of 12.6 months wasn’t statistically significant, but Dr. Goetz explained that the results were trending toward statistical significance and that longer follow-up time would likely show significance.
“We will continue to follow patients until we get the final overall survival results,” Dr. Goetz told Breastcancer.org. “These data are maturing quite favorably. We’re seeing a difference in median overall survival by over 12 months.”
When the researchers looked specifically at women diagnosed with visceral disease — meaning the breast cancer had spread to the soft internal organs such as the liver or lungs — Verzenio improved overall survival by 16.3 months.
Overall survival among women with visceral disease was:
65.1 months for women who took Verzenio and an aromatase inhibitor
48.8 months for women who took an aromatase inhibitor alone
“Again, this didn’t cross the boundary to what we would refer to as statistical significance because it’s at an early time,” Dr. Goetz said. “And I would say that in my estimation, seeing a greater than 16-month improvement in overall survival in this group of patients with aggressive disease is really quite impressive.”
What this means for you
If you’ve been diagnosed with advanced-stage, hormone receptor-positive, HER2-negative breast cancer, the results of this study are very encouraging.
Still, other CDK4/6 inhibitors are used to treat advanced-stage, hormone receptor-positive, HER2-negative breast cancer. So how do you and your doctor decide which medicine is right for you?
“In my conversations with patients,” Dr. Goetz added, “I’m going to choose a drug with a proven survival advantage and probably individualized based on the patient’s preferences, potential toxicity profiles, their past medical history, knowing that if they run into problems, we can switch to another one.”
Learn more about Verzenio.
— Last updated on November 16, 2022 at 7:26 PM