Updated September 26th, 2023

Are You A Metastatic Breast Cancer Patient Curious About The Drug Enhertu? Here’s What You Need To Know

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Enhertu for Breast Cancer Patients

Enhertu has made a lot of headlines over the last year. And oncologists are even calling the findings from one Enhertu study "groundbreaking." But what do these results mean for patients? And what should patients be asking their doctor?
You should ask your doctor if your disease is actually considered HER2-low. If it's unknown, ask if you need another biopsy to determine the true nature of your breast cancer.
Then ask if Enhertu is a drug you're eligible to receive, based on the results of this new study.

Enhertu has been the center of some impressive study results. But what should people with breast cancer know about this drug?

The results of an Enhertu breast cancer study published earlier this year grabbed many a national headline, and oncologists even called the findings "groundbreaking." But what did these results mean for breast cancer patients?

Here at SurvivorNet, we've consulted with our medical experts to find out what patients should be asking their doctors when it comes to Enhertu and this study’s results. However, before we get to that, let's break down what this study was able to find out.

Research Breakdown & Findings

The study, which was published in The New England Journal of Medicine in March, found that the experimental drug trastuzumab deruxtecan (brand name: Enhertu), "resulted in significantly longer progression-free and overall survival than the physician's choice of chemotherapy" for patients with metastatic breast cancer. (Metastatic disease is when the cancer has spread to other parts of the body than where it originated.)

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"The reason why it (the study) got so much attention is because of the improvement in overall survival," Dr. Elizabeth Comen, a breast oncologist at Memorial Sloan Kettering Cancer Center (MSK) in New York City and SurvivorNet medical advisor, told us about this research, "which is hard to do in metastatic breast cancer patients."

More specifically, the trial reported on the use of Enhertu in women with metastatic hormone receptor-positive or negative, HER2-"low" breast cancer, who had received multiple prior lines of treatment.

It's worth noting that Enhertu is designed to target HER2, a protein that promotes the growth of cancer cells. Trial researchers analyzed more than 500 patients with metastatic disease who were categorized as HER2-low (having few HER2 cells).

Enhertu had previously shown success in women with HER2-positive breast cancer, but validation in the newly defined HER2-"low" cohort hadn't been established in a large study. What this means is that in patients who had HER2-positive tumors, the drug Enhertu had shown success, but it was unknown what would happen in patients with only minor HER2 expression that being, the HER2-"low" group.

Right now, Enhertu is approved by the U.S. Food and Drug Administration to treat metastatic HER2-positive breast cancer, HER2-positive advanced stomach cancer, HER2-Low Metastatic Breast Cancer, and HER2-Mutant Metastatic Lung Cancer.

Dr. Comen, during an on-air interview with NewsNation, gave us all a "two-minute biology lesson" to explain why the results of this study are considered especially remarkable.

"On the outside of our cancer cells, we have something called the HER2 receptor. Some breast cancer patients have it and some don't. Historically, we classified breast cancer patients as either HER2-positive, so they have a lot of it, or HER2-negative," she explained.

"What we've since learned is that some of these … patients that we thought were HER2-negative were actually HER2-low," Dr. Comen continued. "So, they had a little bit of this HER2 receptor, which means that in this trial, that they actually responded to targeted medications a specific medication called (trastuzumab deruxtecan), or Enhertu that targets the HER2 receptor, goes into the cancer cell and kills it. … In turn, as we see, improves outcomes for breast cancer patients helping them live longer, and hopefully better."

What Breast Cancer Patients Should Ask Their Doctors

Now that you’re armed with a solid understanding of this study, here’s what else you need to know.

This study is especially important for women who are actively receiving treatment, and according to Dr. Comen, there are some important questions you should be asking your doctor during your next visit.

First, it's so important that patients have their pathology report and understand, to the best of their ability, what it means, what kind of breast cancer they have and what stage their disease has reached.

Here's what you should be asking your doctor:

Ask if your disease is actually considered HER2-low.
If it's unknown, ask if you need another biopsy to determine the true nature of your breast cancer.
Then, “Is Enhertu a drug I'm eligible to receive?”

Contributing: Dr. James Taylor

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