In Triple Negative Breast Cancer, New Drug Trodelvy Extends Life

"New treatments that meaningfully change outcomes for triple-negative breast cancer patients are always incredibly important and something we get excited about," Elizabeth Comen, MD, a medical oncologist who treats breast cancer at Memorial Sloan Kettering Hospital in New York, tells SurvivorNet.

The FDA approved Trodelvy for treatment of metastatic triple negative breast cancer in women who had already received two previous types of treatment. The new data released last week, based on 468 patients, show that women who take Trodelvy survive a median 12.1 months compared to those who survive a median 6.7 months on chemotherapy. The drug halted disease progression for a median 5.6 months, compared to 1.7 months on chemotherapy.

"Obviously, we want cures, but a six-month improvement in overall survival compared to chemotherapy is meaningful for patients," Comen says. "It means more time with their families, fewer untoward issues related to disease progression."

Why Triple-Negative Breast Cancer Is Harder to Treat

Some of the most effective drugs for breast cancer target common characteristics that help many breast tumors grow. Those characteristics are tumors that have the HER2 gene, estrogen receptors or progesterone receptors. Triple-negative breast cancers have none of these. Targeted drugs are available to treat HER2+ breast cancers as well as estrogen-receptor- and progesterone-receptor-positive breast cancer.

Dr. Elizabeth Comen discusses treatment for triple negative breast cancer.

"Triple-negative breast cancer has historically been the hardest and most aggressive cancer to treat because we don't have the same targeted therapies like we use for HER2+ positive disease or hormone-receptor positive disease," Comen says.

Trodelvy Finds and Kills Cancer Cells

Trodelvy is a type of drug called an antibody drug conjugate. That means it's an antibody and drug combined. The way it works is that the anti-cancer drug is attached to an antibody that recognizes cancer cells. When the drug enters the blood stream, by IV infusion, the antibodies deliver the anti-cancer drug directly to the cancer cells. Because the drug goes straight to cancer cells, it has minimal effects on healthy cells. Traditional chemotherapy, on the other hand, doesn't target cancer cells as strictly. It can damage healthy cells, too. That's what causes the side effects for which chemo is well known.

That doesn't mean that Trodelvy is without side effects. About one in ten people who take the drug have severe diarrhea. About half hit very low levels of the type of white blood cell (neutrophils) that help fight bacterial infections.

Related: Vegas Showgirl Dances Her Way Through Treatment for Triple Negative Breast Cancer

Trodelvy is approved for people who have not responded to or have stopped responding to two prior chemotherapy treatments. They receive the drug by IV on the first and eighth days of a 21-day cycle. They repeat this cycle for as long as the drug continues to work.

"This new data means that we should be considering this as the standard of care for patients who've had two prior lines of treatment for metastatic triple negative breast cancer," Comen says.

Is My Cancer Really Triple-Negative?

Dr. Heather McArthur, Clinical Director of the Breast Cancer Program at Simmons Cancer Center at UT Southwestern Medical Center, has spoken with SurvivorNet on this relevant topic.

You might be told you have triple-negative breast cancer, that means that your cancer is not being fueled by any of the three main types of receptors: estrogen, progesterone nor the HER2 protein. But now you could be categorized as HER2 low instead of HER2 negative.

Breast cancer cells with higher-than-normal levels of HER2 are called HER2-positive, those with low levels of HER2 are (or were) called HER2 negative. Recently, however, researchers have looked to further expand this definition to include patients that have a minimal amount of HER2 expression but do not meet the classic definition for HER2-positive tumors. This group has been called HER2 "low" and is very important as it represents almost 50% of all patients with breast cancer.

This excitement stems from the fact that HER2-low breast cancers are targetable with a recently new FDA-approved Enhertu (Fam-trastuzumab deruxtecan-nxki). It appears that Enhertu is extremely effective for appropriate patients and can greatly improve their quality of life and help them live longer.

Therefore, it is exceedingly important to discuss with your physician about your HER2 status.

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