When Chase Johnson was 31 years old, her dog started acting strange. He was worried, did not leave her side, and once nuzzled her chest. Johnson felt a hard lump.
“I wasn't someone who was good at self-examination, I don't think I would have found it otherwise,” said Johnson, now 36, of Cary, North Carolina. “I had no family history of breast cancer.”
In February 2021, Johnson was diagnosed with triple negative breast cancer, an aggressive type of the disease. tends to grow and spread quickly to other parts of the body.
Breast cancer treatment determined in part by whether certain proteins are present on tumor cells, including estrogen receptors and progesterone receptorsas well as a protein called HER2. Treatments can target these three proteins. Breast cancer, which has no receptors and produces little or no HER2, is considered triple negative, making it difficult to treat.
Johnson underwent four months of intravenous chemotherapy and surgery to remove the tumor and lymph nodes. After that, she had to undergo another six months of oral chemotherapy and 24 courses of radiation.
Her treatment was considered successful, and after that she began looking for ways to prevent the cancer from returning. ABOUT 40% of women with triple negative breast cancer relapses occur within five years of treatment, and approximately 30% of these women have cancer repeats itself in the brain. This may also reappear in the lungs, liver and lymph nodes.
In December 2022, Johnson took part in an early-stage clinical trial at the Cleveland Clinic, which is testing a new vaccine that researchers hope can stop the recurrence of triple-negative breast cancer and, in some women, stop the cancer from developing altogether.
“I’m literally doing everything I can to make sure this doesn’t come back,” Johnson said. “Resources for triple negative are so limited that if traditional treatments don't work, you're simply out of luck.”
The vaccine targets a protein called α-lactalbumin, which is present in about 70% of triple-negative breast cancers and is found on the surface of tumor cells. If successful, the vaccine will train the immune system to produce T cells that attack and destroy cells using a protein.
The latest results from the phase 1 clinical trial, which included 35 women, were presented Thursday at San Antonio Breast Cancer Symposium in Texas.
The study tested whether the vaccine was safe and produced an immune response in three groups of patients. (It did not take into account how the vaccine affected outcomes.) Johnson's first group included women who had recovered from early-stage, triple-negative breast cancer and were tumor-free but at high risk of recurrence. The second were women who were treated at an early stage of the disease and who were left with tumor cells. The third group had not yet been diagnosed with breast cancer, but they had genetic predispositionsuch as the BRCA gene, which puts them at high risk of developing triple negative cancer.
The researchers found that 74% of women developed an immune response to the vaccine, although what this result means for reducing relapses or preventing the disease is still unknown.
“We don't yet know whether this immune response will reduce the risk of recurrence or prevent breast cancer,” said study leader Dr. J. Thomas Budd, a breast cancer medical oncologist at the Cleveland Clinic Cancer Institute.
The vaccine also appeared to be safe, with women reporting redness or a bump at the injection site, but no serious side effects.
One concern was whether the vaccine would cause an autoimmune reaction, in which the immune system mistakenly attacks the body. Women naturally produce alpha-lactalbumin while breastfeeding, and the vaccine can train the body to attack it. For this reason, Budd said he does not recommend that women who wish to breastfeed participate in the study.
The Phase 1 results, while promising, represent only an early step in determining whether the vaccine will be successful.
The phase 2 study is expected to begin late next year. The trial will be the first to look at whether the vaccine can reduce the risk of recurrence of triple negative breast cancer. If all goes well, future trials will test the prevention in patients at genetic risk, Budd said.
Justin Balko, co-director of the breast cancer research program at Vanderbilt-Ingram Cancer Center, said the vaccine's most promising use would be to prevent the first occurrence or recurrence of cancer, rather than targeting remaining cancer cells.
That's because, over time, tumor cells can learn to hide targeted proteins from the immune system, Balko said. New cancer cells are less likely to develop this ability, he added.
Research into a vaccine for triple-negative breast cancer is a long-awaited goal, said Dr. Larry Norton, founding medical director of the Evelyn H. Lauder Breast Center at Memorial Sloan-Kettering Cancer Center in New York. The most effective targeted treatments for breast cancer require the presence of estrogen receptors or HER2 in tumors.
“There’s no triple negative either, so all we’re left with is chemotherapy,” Norton said.
Even if a vaccine targeting alpha-lactalbumin doesn't prove effective in phase 2 trials, Norton said scientists are getting better at identifying the abnormal molecules found in different tumor cells. These abnormalities serve as targets for new treatments.
“There was a time when we said HER2 was the worst type of breast cancer there was, then treatments came out that targeted HER2, and now suddenly one of the worst prognostic markers is one of the best,” Norton said. “This could be the story of triple-negative breast cancer if we find a target for it.”
