Triple-Negative Breast Cancer: New Treatment Combos Show Promise

Triple-negative breast cancer doesn’t respond to many standard breast cancer treatments, but clinical trials of combination therapies are showing promise.

Although breast cancer survival rates are improving on the whole, those for women diagnosed with the triple-negative form remain significantly lower. In large part, that’s because triple-negative breast cancer (TNBC) doesn’t respond to many of the more modern, targeted treatments.

But results of trials of combination therapies, which attack different aspects of the disease, are showing promise. At Celgene, we are committed to  helping improve the lives of patients with TNBC.

About 10 percent of breast cancer cases are triple-negative. While 93 percent of women with other types of breast cancer survive five years after diagnosis, only 77 percent of those TNBC can say the same, according to a 2007 study of 50,000 women with breast cancer.

“With all the progress that’s been made in treating certain types of breast cancer, triple-negative metastatic breast cancer unfortunately remains especially challenging,” Denise Yardley, senior investigator at Sarah Cannon Research Institute Breast Cancer Research Program, said. “That’s due in part to the genetics of the tumors, in part to where the metastases tend to occur, and in part because the disease is so aggressive.”

Indeed, TNBC is one of the most aggressive types of cancer. Women diagnosed with TNBC are four times more likely to have that cancer spread, or metastasize, to other organs within five years than patients with other types of cancer. Most often, TNBC tends to spread to vital organs such as the brain and lungs.

In a study published in Clinical Cancer Research in 2007, researchers found that the median time to metastatic recurrences in TNBC patients was just 2.6 years, while the median time for patients with other breast cancers was 5.0 years. In addition, the survival time from diagnosis of distance metastatic TNBC was just 9 months compared with 22 months for other cancers.

Some of the most effective breast cancer treatments today target proteins on the surface of breast cancer cells, such as human epidermal growth factor receptor 2 (HER2), estrogen receptors and progesterone receptors. Because the growth of TNBC cells isn’t supported by the presence of too many HER2 receptors, or by progesterone or estrogen hormones, these therapies are less effective.

Clearly, different approaches to treating this particularly aggressive form of breast cancer are required. One strategy that has received significant attention lately is a combination of therapies.

At the 2013 San Antonio Breast Cancer Symposium, researchers from Northwestern University presented promising data from a clinical trial of a combination of chemotherapies that showed improved outcomes for women with TNBC. After being treated with the combination therapy, 43 percent of women in the study were tumor-free. Historically, only 30 percent of women with TNBC are tumor-free after treatment.

“Triple-negative breast cancer tends to be very aggressive, and because it is aggressive it metastasizes very fast,” said Virginia Kaklamani, director of translational breast cancer research at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University and lead researcher of the study, said in a statement. “We don’t have many good treatments for it, which is why the results of our study is such good news.”

The results of combination therapy trials for TNBC are promising, although more effective treatments are still needed. Trials of different combination therapies are ongoing, so patients with TNBC should consider enrolling in trials and should always discuss all their treatment options with their doctors.