Thanks to a major milestone from a recent clinical trial, a breast cancer vaccine to protect healthy patients may be available within the next several years.
This encouraging message comes from Saranya Chumsri, MD, associate professor of medicine at Mayo Clinic in Jacksonville, Florida, who worked with a patient who saw incredible results after receiving the vaccine, which targets the HER2 protein.
How Does the Breast Cancer Vaccine Work?
Several outlets have reported that the treatment essentially cured Lee Mercker’s stage 0 breast cancer (confined within her ducts) before she underwent surgery. The truth? The immunotherapy “did not eradicate all of her cancer,” Dr. Chumsri tells Florence Health. However, it did seem to eliminate one of Mercker’s three tumors, which is “really exciting,” she adds.
“We were able to see there were T cells attacking her tumor in the breast,” Dr. Chumsri explains. “In past studies [in stage 2 and 3 breast cancer after surgery], we only detected the T cells in the peripheral blood. We didn’t quite know whether we could generate T cells that actually attack the cancer. Now, we’re able to see it … but it’s very early. The trial is still ongoing.”
The current phase includes 43 stage 0, pre-surgery patients. One coming up will focus again on stage 2 and 3 patients post-surgery. Stage 4 patients have not yet participated.
The ultimate goal is that the vaccine will prevent cancer entirely and be available “off the shelf” like a flu shot. After all, they work in a similar fashion, Dr. Chumsri says: “A flu shot stimulates your body to attack the virus, and ours stimulates an immune response to attack cancer cells and the HER2 protein.”
What’s Special About the Vaccine?
Dr. Chumsri highlights that her vaccine is low toxicity (unlike chemo and other cancer treatments), requires no intensive procedures and will work in more patients than previous cancer vaccines.
“With some of the previous vaccines, we have to draw patients’ peripheral blood, take out the white blood cells, stimulate them outside and put it back into the patient,” Dr. Chumsri says.
In addition, her peptide-based vaccine combines four different peptides, making it effective in 97 percent of patients. Other vaccines using one peptide work in only about half the population.
What’s Next for the Breast Cancer Vaccine?
Before the vaccine can hit hospitals, private practices and clinics, a few more years of research lie ahead.
“We have to make sure it’s really safe before we think about using it on a healthy patient without breast cancer. That’s still probably several years from now,” Dr. Chumsri says. “But so far patients are doing really well. Side effects are minimal.”
Immunotherapy treatments for other types of cancer are also in the works at Mayo Clinic’s Jacksonville campus. Recently, several patients in a trial focusing on stage 4, triple-negative breast cancer had “a complete response,” Dr. Chumsri notes.
There’s an ongoing CAR-T study on patients with blood malignancy, as well.
Chumsri adds that cancer vaccine trials across Mayo Clinic facilities are in need of participants. She encourages clinicians interested in referring patients to contact Mayo Clinic’s Clinical Trials Referral Office at 1-855-776-0015.
Trial vaccine wipes out breast cancer in Florida patient, Fox 10 Phoenix.
Interview Oct. 18, 2019, Saranya Chumsri, MD, associate professor of medicine Mayo Clinic.