What’s the Breast Cancer Vaccine Landscape Like Today

The landscape of breast cancer research is undergoing a significant shift, moving toward complex, combination strategies designed to overcome the body’s own immune suppression.

Keith Knutson, a cancer vaccine researcher at the Mayo Clinic, recently discussed these developments as part of the CURE “Speaking Out” video series on behalf of the Cancer Vaccine Coalition. According to Knutson, while the concept of breast cancer vaccines dates back decades, the strategy for making them effective has had to evolve to match a deeper understanding of tumor biology.

Research into the immune response to cancer began gaining traction in the early to mid 1990s, Knutson noted. The initial goal was straightforward: utilize vaccines to treat metastases, shrink tumors and ultimately cure the individual. However, early clinical trials had disappointing results.

The primary hurdle, researchers discovered, was the tumor microenvironment itself. Tumors are protect themselves by suppressing the immune system, making those early vaccines ineffective.

“We started to realize, like in other cancers, that there’s a lot of immune suppression in the tumor microenvironment,” Knutson explained. “So we had to think about ways that we could subvert that immune suppression and get the cancer vaccines to work.”

This has led to the current era of combination-type approaches. The modern strategy involves a two-pronged attack, using agents to reduce the tumor’s immune-suppressive burden while using vaccines to stimulate the immune system to attack.

Knutson highlighted Keytruda (pembrolizumab) as an example of this evolution. Keytruda is known to reverse specific forms of immune suppression within the cancer microenvironment.

“Whereas many, many years ago, when we started to think about vaccines and using vaccines, we use those … as a solo treatment, now we're thinking about, ‘How can we combine vaccines with an agent like [Keytruda] that can reverse that immune suppression?’” Knutson said.

Beyond the delivery method, the science of identifying what the vaccines should target has also advanced. A major element of current development is the identification of new antigens, the proteins that the immune system detects and targets. Trials utilizing these new combination strategies are currently underway.

Editor’s note: Content was generated with AI, reviewed by a human editor, but not independently verified by a medical professional.

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