An Experimental Breast Cancer Vaccine Might Already Be Saving Lives

A novel treatment should train the immune system to target breast cancer. It's shown major promise in a 10-year-long clinical trial.

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A shot given to an arm. A University of Washington breast cancer vaccine shows promise in clinical trials.
Image: Images: Shutterstock Graphics: Vicky Leta

Scientists at the University of Washington School of Medicine are winners of the 2023 Gizmodo Science Fair for their experimental breast cancer vaccine.

The Question

Can you train the immune system to target cancers on the verge of returning—or even prevent them from forming in the first place?

The Results

The team’s vaccine should work by training the body to develop a specific type of immune response to the HER2 protein, a protein that’s naturally found in many cells but is overproduced by roughly 30% of breast cancers. The theory is that this response, known as a cytotoxic (cell-killing) response, will target these cancers but not harm the body otherwise.


In November, the researchers published data from a Phase I safety trial of their vaccine, which involved 66 women with advanced stage breast cancer. The women had undergone treatment that either put their cancer into complete remission or largely contained it, but they remained at high risk of it aggressively reemerging. The volunteers were tracked for a median length of about 10 years.

In the trial, the vaccine showed no signs of serious long-term health risks, with the most common side effects being acute and short-lasting symptoms like redness at the injection site and fever. The volunteers also developed the immune responses that researchers hoped the vaccine would generate. And though Phase I trials are not meant to prove that a treatment works—only that it is safe—there was a clearly encouraging indicator of its effectiveness. About 80% of the vaccinated women were still alive after 10 years, well above the 50% five-year survival rate typically seen for people with similar cancers.


Why They Did It

“We’re aiming to cure cancer, one vaccine at a time. And I know that might sound kind of flippant to say that, but so much has happened in the world of immunology, and in the world of vaccines, and in the world of cancer [in recent years],” said Nora Disis, the project’s lead researcher and director of the Cancer Vaccine Institute at the University of Washington. “I think we’ve come to a tipping point for cancer vaccines.”

Why Their Breast Cancer Vaccine Is a Winner

As Disis notes, there have been major successes of late in the field of what’s known as immunotherapy—medicines designed to boost the immune system’s defenses against cancer. There are now approved drugs that remove the checkpoints that keep immune cells from targeting some tumors, for instance, as well as treatments that genetically transform T-cells into potent cancer killers. There are several therapeutic cancer vaccines already approved, but these have only shown modest effectiveness against very specific types of cancer. The vaccines in development now are expected to be more effective in general and able to treat a variety of cancers. And they might not only target hardy tumors that are likely to return but even those that haven’t yet emerged. Another promising approach is the use of these vaccines in combination with other immunotherapies.


The HER2 vaccine developed by Disis and her colleagues is far from the only one being studied at the UW Cancer Vaccine Institute, but it is the furthest along in clinical trials. And in many ways, it’s the culmination of 30 years of work by Disis in particular.

Image for article titled An Experimental Breast Cancer Vaccine Might Already Be Saving Lives
Illustration: Vicky Leta

“I think the early challenge, years ago, was just that people didn’t think that the immune system played any role in cancer eradication,” she said. “But now, really, the biggest challenge is not creating the vaccine or manufacturing the vaccine—it’s being able to find patients to enroll in clinical trials.”


Studies have found that as little as 5% or fewer of cancer patients enroll in clinical trials generally, not just those testing out new vaccines.

“One of the other areas we’re working on is trying to increase the diversity of the patients that are represented in clinical trials—to make efforts to reach different parts of our community,” said Kiran Dhillon, executive director of the UW Cancer Vaccine Institute.


What’s Next

The team is already conducting Phase II trials of the HER2 vaccine and two other candidates for breast cancer. They’ve also developed experimental vaccines against ovarian, colon, lung, bladder, and prostate cancers.

Speaking of the field more broadly, Disis predicts that a therapeutic cancer vaccine will reach the public within the next five years.


The Team

“Oh, we’re talking about hundreds,” said Disis when asked how many people it took to get this vaccine off the ground. “Oftentimes, people think of scientists as one person in some type of lab toiling to the wee hours of the night. But even in the group I work in, it’s like 40 people toiling into the wee hours of the night. And each person has a unique role to play in vaccine development. It isn’t like there’s one leader telling everyone what to do.”

“Another thing unique to our Institute as well—that makes it a little bit different from other academic labs—is that we do discovery work, translation work, and clinical trials under one roof,” said Dhillon. “So you’re not waiting for a collaborator to catch up to you for the next phase of the project. Everybody here is at the table.”


See the full list of Gizmodo Science Fair winners