Targeted Drug May Lower Odds for Breast Cancer's Return in Some Patients

TUESDAY, June 6, 2023 (HealthDay News) -- Here's some good news for women with the most common type of breast cancer: Adding a targeted breast cancer drug to hormonal therapy reduced the risk of cancer returning by 25% for women with early-stage disease, a new clinical trial shows.

Hormone-receptor (HR) positive/HER2 negative breast cancer accounts for about 70% of breast cancer cases in the United States.

“The results from the clinical trial have immediate implications for patients,” said Dr. Dennis Slamon, director of clinical and translational research at the University of California, Los Angeles (UCLA) Comprehensive Cancer Center.

“The findings show this combination is a treatment of choice for patients with stage 2 or stage 3 HR positive/HER2 negative breast cancer,” he added in a university news release.

Patients with HR positive/HER2 negative breast cancer who took the combination therapy -- the drug ribociclib (Kisqali) and standard hormone therapy -- had substantially longer invasive disease-free survival compared to those who were treated with hormone therapy alone. That was true whether or not the cancer had spread to the lymph nodes, the researchers said.

Slamon shared the results on Friday at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago. Such research is considered preliminary until published in a peer-reviewed journal.

Ribociclib is already FDA-approved to treat metastatic breast cancer, meaning cancer that's advanced. It is one of three cyclin-dependent kinase inhibitors (CDK4/6 inhibitors) approved for combination treatment with standard hormone therapies.

However, it is priced up to $15,000 a month, according to drug maker Novartis, which funded the new trial. And CNN reported that a recent analysis suggested it is not a cost-effective treatment, even in its use in people with advanced cancer.

In the new clinical trial, more than 5,100 patients with stage 2 or stage 3 early HR positive/HER2 negative breast cancer were randomized into two groups. More than 2,500 were given the combination treatment and more than 2,500 others received only the hormone therapy.

Researchers followed with study participants for roughly 34 months. About 20% of the participants were treated with ribociclib for three years and 57% for two years.

The invasive disease-free survival rates at three years were about 90%, compared to just over 87% for women who were treated with only hormone therapy.

“Overall, the combination therapy showed more favorable outcomes, significantly reducing the risk of the cancer returning,” Slamon said. “These results should change how we evaluate and treat patients.”

More information

The American Cancer Society has more on breast cancer.

SOURCE: University of California, Los Angeles, news release, June 2, 2023