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Researchers are hoping to test a new type of treatment for triple-negative breast cancer in humans soon. Image credit: Monty Rakusen/Getty Images.
  • About 2.3 million women globally have breast cancer.
  • Between 10%–15% of all diagnosed cases are triple-negative breast cancer, which is the most aggressive form and the hardest to treat.
  • Researchers from the University of Arizona have developed a drug specifically for treating triple-negative breast cancer with little to no toxic side effects.

An estimated 2.3 million women around the world received a diagnosis of breast cancer in 2020. That same year, about 685,000 women globally died from the disease.

Triple-negative breast cancer accounts for between 10% to 15% of diagnosed breast cancers. This specific type of breast cancer is known for being aggressive and harder to treat. Those with a triple-negative breast cancer diagnosis have a 5-year survival rate of about 62%.

Now, a team of researchers from the University of Arizona has developed a drug targeted specifically for triple-negative breast cancer. Developed using epidermal growth factor receptor (EGFR) technology, the drug reportedly causes little or no toxic side effects.

In this study, researchers tested the new drug in animal models and are now working towards approval from the Food and Drug Administration (FDA) to test the drug in a phase 1 clinical trial in humans.

This study recently appeared in the journal Cancer Gene Therapy.

Triple-negative breast cancer tests negative for three receptors — proteins in or on cells that connect to specific materials in the blood — normally found in breast cancer. These are:

Studies show that Black women have a higher likelihood of developing triple-negative breast cancer compared to white women, as do women younger than 40 compared to women aged between 50–64 years. Additionally, women who have a BRCA1 mutation are also at a higher risk for developing this type of breast cancer.

Because of those missing receptors, doctors have fewer options for treating triple-negative breast cancer. For example, hormone therapies are not effective. Current treatment options for this type of breast cancer include:

Epidermal growth factor receptor (EGFR) is a protein found on certain cells. This protein can bind to something called epidermal growth factor (EGF). When the two connect, the EGF stimulates cell division and growth. This has some benefits for the body — for example, EGFR and EGF play important roles in the healing of wounds.

Reportedly, EGFR is overexpressed in over three-quarters of triple-negative breast cancer cases. Scientists have therefore been developing agents that block EGFR proteins to stop cells from growing too much

According to Dr. Joyce Schroeder, head of the Department of Molecular and Cellular Biology at the University of Arizona and senior author of this study, most triple-negative breast cancers express EGFR, making it a potential high-impact target.

The drug developed by the research team blocks EGFR from entering a part of the cell that keeps the cancer alive. The therapy is able to stop the EGFR protein in cancer cells, but not in healthy cells.

“The therapy goes inside the cell and blocks EGFR from accumulating in the nucleus,” Dr. Schroeder detailed. “Nuclear EGFR (nEGFR) is thought to drive aggressive, metastatic breast cancer, and by blocking nEGFR, we hoped to develop a therapy for metastatic triple-negative breast cancer.”

The research team also stated that because their therapy leaves healthy cells alone, there are no unwanted side effects.

“When we tested the drug in animal models, we got this fabulous result where it actually didn’t just stop the tumors from going, it caused them to regress and go away, and we’re seeing no toxic side effects,” Dr. Schroeder says. “We are so excited about this because it’s very tumor-specific.”

And Dr. Schroeder talked about the research team’s next steps for this therapy. “Test it in a metastatic model, get FDA approval for a phase 1 clinical trial, and run that trial,” she said.

Medical News Today also spoke with Dr. Bhavana Pathak, a board-certified hematologist and medical oncologist at MemorialCare Cancer Institute at Orange Coast Medical Center in Fountain Valley, CA, about this study.

As a doctor who treats patients with breast cancer, she said her first reaction to this is that it is “exciting” to see a therapeutic that seems to have a number of specificities based on preliminary studies.

“Triple-negative breast cancer, unlike other breast cancers such as hormone-positive or HER2-positive breast cancers, does not have those predictive biomarkers that tell us, ‘okay, you will respond to a specific therapy’,” she said. “They don’t have essentially good targets. They don’t have targeted treatments for triple-negative.”

“And so when we come across a drug that potentially could work, especially in this population that has a high prevalence of EGFR mutation, [that is] something we can capitalize on to treat this patient population,” Dr. Pathak added.

However, she stressed this is still in the early stages and that testing in human patients still needs to be done:

“I think the logical next step is to see how it works in humans — phase 1 trials seeing ‘is it tolerable?’ And then additionally, it would be interesting to see how we can use this drug in other ways in terms of cancer therapy. We target the growth mechanism of the cancer, stopping its growth. But another aspect is making sure we can stop its spread — the spread of it is a different mechanism. So to see if you could stop both types of issues within this presentation.”