Updated February 22nd, 2023

Hopeful News for Breast Cancer: A New Drug Combination to Extend Survival Time

A combination of three drugs increased the amount of time that women with metastatic HER2-positive breast cancer could live without their cancer getting worse.

Caroline Hopkins SurvivorNet

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There may be a new treatment option for women with an advanced stage of a certain type of breast cancer called HER2-positive breast cancer
The new treatment, a combination of three drugs, could significantly extend survival time
The benefit also applied to women whose cancer had spread to their brain, especially encouraging as brain metastases are notoriously difficult to treat

There’s promising new news for women with metastatic HER2-positive breast cancer, a particularly aggressive form of the disease. A new combination of drugs could both steady the cancer’s progression for some two-and-a-half months, and increase overall survival time another 4.5 months. This may not seem like a long time to some, but for women with metastatic breast cancer, it can be meaningful, allowing more time to spend with loved ones.

“This study gives us a new promising option for all patients upon disease progression after [previous treatment], including those with untreated and treated brain metastases who have typically been excluded from trials,” Dr. Natalie Berger, a hematologist and oncologist who treats women with breast cancer at Mount Sinai in New York City, tells SurvivorNet.

The study, published in the New England Journal of Medicine and presented at the recently held San Antonio Breast Cancer Symposium, looked at women whose cancer has spread beyond the breast to other parts of the body, including to the brain. The combination of drugs are:

Tacutinib, a new, investigational drug
Trastuzumab (known by its brand name, Herceptin) which is a targeted drug already used to treat HER2-positive breast cancer
Capecitabine (known by its brand name, Xeloda), which is a type of chemotherapy used to treat women with breast cancer

There may be a new treatment option for women with an advanced stage of a certain type of breast cancer called HER2-positive breast cancer
The new treatment, a combination of three drugs, could significantly extend survival time
The benefit also applied to women whose cancer had spread to their brain, especially encouraging as brain metastases are notoriously difficult to treat

Importantly, the women who took part in this trial had already been treated with a number of different drugs for their cancer (including Herceptin by itself, as well as another drug called pertuzumab). The group of women who experienced survival benefit from the new drug combination, in other words, had already tried a number of treatments, but their cancer still had progressed.

Improved Survival for Women with Brain Metastases

What was especially encouraging, experts say, is that this benefit was also seen among women with brain metastases. When breast cancer spreads to the brain — which happens for about 10% to 15% of women with metastatic breast cancer — the prognosis can be especially difficult, in part because the brain can’t always be treated in the same way ass other areas of the body without causing damage to brain function.

“The treatment of breast cancer brain metastases is a very difficult clinical space, because we don’t have a lot of drugs that actually penetrate well into the brain,” Dr. Heather McArthur, medical director of Breast Oncology at the Cedars-Sinai Medical Center, told SurvivorNet in a previous conversation, one held before this new study. “And so we really rely on local strategies like surgery and radiation to treat brain metastases when they occur.”

“So to identify a drug that actually potentially crosses the blood-brain barrier and could potentially enable us to treat brain metastases with drug treatment would be an incredible innovation,” Dr. McArthur continued.

“Historically, HER2 therapies often work very well but do not effectively cross the brain barrier, meaning that the brain may be more susceptible to developing metastasis there,” added Dr. Elizabeth Comen, a breast cancer oncologist at the Memorial Sloan Kettering Cancer Center and a medical advisor to SurvivorNet.

Brian metastases are most common in women with aggressive subtypes of metastatic breast cancer, including HER2-positive breast cancer.

“This trial offers an exciting new treatment,” Dr. Hannah Irie, Associate Professor of Medicine, Hematology and Medical Oncology at Mount Sinai added. “What is particularly promising is the effectiveness of this novel therapy against brain metastases, which is particularly challenging and difficult to treat.”

Does the New Drug Combination Have Side Effects?

According to the new study, adding tucatinib to the combination of Herceptin and chemo did increase the frequency of diarrhea — which is an uncomfortable, but common side effect. There will need to be more research to fully evaluate all the potential side effects of the drug, however.

Dr. George Sledge, a pioneer of breast cancer treatment at Stanford University, shared his insight about the study and its side effects in a tweet from the San Antonio Breast Cancer Conference:

My take on tucatinib: always happy to see an increase in OS. Relatively well tolerated with some increase in diarrhea. Should receive FDA approval.
George W Sledge MD (@GeorgeSledge51) December 11, 2019

As Dr. Sledge pointed out, tucatinib has not yet been approved by the U.S. Food and Drug Administration (FDA). But experts art hopeful. “Based on all the data, including this trial, we expect Seattle Genetics [the company that makes tucatinib] will likely receive FDA approval for the drug,” said Dr. Virginia Borges, director of the Breast Cancer Research Program and Young Women’s Breast Cancer Translational Program at CU Cancer Center and one of the authors on the study. “I’m just incredibly happy to see this drug getting to where we expect it will soon be made available to more patients who can benefit.”

Dr. Elizabeth Comen of Memorial Sloan Kettering spoke with SurvivorNet about stage 4 breast cancer and its treatment.

What Does It Mean to Have HER2-Positive Breast Cancer?

HER2-positive breast cancer is a breast cancer that tests positive for a protein called human epidermal growth factor receptor 2, or “HER2” for short. The receptor sits on the outside of the cell and promotes the growth of cancer cells. But according to Dr. Comen, “There are ways that we can actually block the ability of that HER2 receptor to stimulate the cell from growing.” These include drugs like Herceptin — and now tucatinib.

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Caroline Hopkins is a writer for SurvivorNet. Read More