A major breakthrough in vaccines could raise hope for treating aggressive breast cancer
Results of a small clinical trial of a vaccine against an aggressive form of breast cancer have been presented at a conference, and researchers say there is reason for optimism. All 16 patients in the trial received three doses of the vaccine, and most developed a strong immune response and no major side effects were reported.
Triple negative breast cancer (TNBC) accounts for only about 10-15 percent of breast cancer cases overall, but these tumors tend to grow faster and there are fewer treatment options available for them. This cancer can also have a high risk of recurrence, even after successful treatment.
The term “triple negative” refers to the fact that cancer cells lack receptors for two hormones, progesterone and estrogen, and do not overproduce a protein called HER2. This means that many traditional breast cancer drugs, which target HER2 or the hormonal system, do not work.
Therefore, new treatment options for TNBC are urgently needed, so news back in 2021 that a vaccine was entering clinical trials was welcomed. This vaccine targets a protein called α-lactalbumin, which is found in the vast majority of TNBC tumors.
The goal of this early human trial was to determine the maximum dose that people could tolerate, and to check whether it produced the immune response that researchers were looking for.
Sixteen patients previously successfully treated for TNBC were enrolled in the trial. They received three doses of the vaccine, with each dose spaced two weeks apart. Their immune responses were assessed by measuring two markers of T-cell immune response (proteins called interferon-γ and interleukin 17), as well as antibodies produced by B cells.
When given the maximum tolerated dose established by the study, none of the participants reported any major adverse effects from the vaccine, such as flu-like symptoms. The only side effect was skin irritation at the injection site. The vaccine also successfully elicited a T-cell immune response in 75% of study volunteers, although an antibody response was only observed at higher doses.
“The data from our Phase 1 trial so far has exceeded our expectations, and we are pleased with the progress we have made,” Dr. Amit Kumar, chairman and CEO of vaccine developer Anixa Biosciences, said in a press release. “This vaccine is designed to direct the immune system to destroy TNBC cancer cells through a mechanism that has not been used before in cancer vaccine development.”
Anixa, in collaboration with the Cleveland Clinic, is currently recruiting for another trial to test a combination of this vaccine and an immunotherapy drug called pembrolizumab, which is already used to treat various types of cancer. They will trial this combination therapy in patients with TNBC who still show evidence of disease after surgery and chemotherapy.
A second trial is also being planned to test the safety of the vaccine in patients planning preventive mastectomies due to a higher risk of developing breast cancer in the future.
“Now, this is a difficult group to study because it’s not a large group,” explained Dr. J. Thomas Budd, MD, a medical oncologist at the Cleveland Clinic, in a conversation with CancerNetwork®. “It will take a long time for patients to develop cancer, and of course there are surgical options nowadays. But it will be a very exciting approach, and we are really looking forward to trying to get funding to do these additional trials.”
Budd continued in the press release: “There is a significant unmet need for the prevention of TNBC, an aggressive form of breast cancer with few targeted treatment options available. (…) Our hope is that future studies will demonstrate that antigen-specific T cell responses Which we noticed translates into preventing the recurrence of breast cancer.
The results were presented at the 2023 San Antonio Breast Cancer Symposium.