Adding the targeted therapy Kisqali (chemical name: ribociclib) to the hormonal therapy Femara (chemical name: letrozole) as a first treatment for advanced-stage hormone-receptor-positive HER2-negative breast cancer in postmenopausal women improved overall survival by more than 1 year, according to the latest results from the MONALEESA-2 study.
The research was presented on Sept. 19, 2021, at the European Society for Medical Oncology (ESMO) Congress 2021. Read the abstract of “Overall survival (OS) results from the phase III MONALEESA-2 (ML-2) trial of postmenopausal patients (pts) with hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) advanced breast cancer (ABC) treated with endocrine therapy (ET) ± ribociclib (RIB).”
Gabriel Hortobagyi, M.D., of the University of Texas MD Anderson Cancer Center, recently joined the Breastcancer.org Podcast to discuss the MONALEESA-2 study.
Overall survival is how long people live, whether or not the cancer grows.
Advanced-stage breast cancer is either locally advanced or metastatic. 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.
About Kisqali and Femara
Kisqali 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. Kisqali — a pill taken by mouth — works by stopping cancer cells from dividing and growing.
Kisqali is used in combination with an aromatase inhibitor, a type of hormonal therapy, to treat advanced-stage or metastatic hormone-receptor-positive HER2-negative breast cancer that hasn’t been treated with hormonal therapy yet in premenopausal, perimenopausal, and postmenopausal women.
Premenopausal and perimenopausal women who take Kisqali also should be treated with a medicine to suppress ovarian function.
Besides Femara, two other aromatase inhibitors are used to treat breast cancer:
- Arimidex (chemical name: anastrozole)
- Aromasin (chemical name: exemestane)
Aromatase inhibitors stop the production of estrogen in postmenopausal women. Aromatase inhibitors work by blocking the enzyme aromatase, which turns the hormone androgen into small amounts of estrogen in the body. This means that less estrogen is available to stimulate the growth of hormone-receptor-positive breast cancer cells.
Kisqali also is used in combination with the hormonal therapy Faslodex (chemical name: fulvestrant) to treat advanced-stage or metastatic hormone-receptor-positive HER2-negative breast cancer that hasn’t been treated with hormonal therapy yet or has grown while being treated with a different hormonal therapy in postmenopausal women.
Femara — also a pill taken by mouth — is used to treat all stages of breast cancer in postmenopausal women.
About the MONALEESA-2 study
The MONALEESA-2 study included 668 postmenopausal women diagnosed with advanced-stage hormone-receptor-positive HER2-negative breast cancer. None of the women had received treatment for the advanced-stage disease.
The researchers randomly assigned the women to one of two treatment groups:
- 334 women received Kisqali and Femara
- 334 women received Femara and a placebo, a pill that looked just like Kisqali but contained no medicine
Earlier results from the MONALEESA-2 study found that the combination of Kisqali and Femara improved progression-free survival more than Femara alone.
Progression-free survival is how long people live without the cancer growing.
To analyze overall survival, the researchers looked at data collected through June 10, 2021. Half the women were followed for less than 79.7 months and half were followed for a longer period of time.
Overall survival was:
- 63.9 months for women who received Kisqali and Femara
- 51.4 months for women who received Femara alone
This difference of 12.5 months was statistically significant, which means that it was likely because of the difference in treatment and not just due to chance.
“This is the longest median survival reported to date in any advanced breast cancer phase III clinical trial,” Dr. Hortobagyi said during his presentation. “Ribociclib and letrozole should be considered the preferred treatment option for [hormone-receptor-positive HER2-negative] advanced breast cancer.”
He also pointed out that other MONALEESA studies looking at Kisqali in combination with other hormonal therapy medicines to treat advanced-stage hormone-receptor-positive HER2-negative breast cancer in pre- and postmenopausal women also showed better overall survival for people receiving Kisqali than hormonal therapy alone.
“Taken together, the MONALEESA trials with ribociclib demonstrate a consistent overall survival benefit regardless of endocrine therapy partner, line of therapy, or menopausal status,” Dr. Hortobagyi said.
What this means for you
If you’re a postmenopausal woman who’s been diagnosed with advanced-stage hormone-receptor-positive HER2-negative breast cancer that hasn’t been treated yet, these results are very good news.
As you and your doctor discuss first treatment options, you may want to bring up this study and ask if treatment with Kisqali and hormonal therapy is a good option for your unique situation.
Read more about Kisqali.
To discuss treatment options with others who have been diagnosed with advanced-stage disease, join the Breastcancer.org Discussion Board forum Stage IV/Metastatic Breast Cancer ONLY.
Written by: Jamie DePolo, senior editor
Reviewed by: Brian Wojciechowski, MD, medical adviser
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