An experimental vaccine developed by Cleveland Clinic offers new hope for women affected by triple-negative breast cancer: the most difficult type of breast cancer to treat.
There’s fresh hope for women affected by a cancer known as triple-negative breast cancer (TNBC), which accounts for 10-15% of all breast cancer cases. This type of cancer is more common in young patients (under the age of 50) and is known to be one of the hardest cancers to beat.
The hope comes in the form of a vaccine developed by Cleveland Clinic: a major centre for biomedical trials in the United States. After lengthy studies, the vaccine was tested on a small group of women for the first time, with results that look promising.
The term “triple negative” refers to the absence of two specific types of receptors (proteins on the external wall of cancer cells that “hook onto” oestrogens and progesterone) and the lack of mutation of a gene called HER2, which, in contrast, is often found in other types of breast cancer.
These three “factors” (HER2 mutation, as well as oestrogen and progesterone receptors) are the key targets of many types of drugs currently available to oncologists treating breast cancer. However, the absence of all three makes it much harder to “attack” TNBC, which has a greater tendency than other types of cancer to recur and develop resistance.
All eyes are on a lactation protein
In the absence of the “classic” targets, the vaccine created by Cleveland Clinic targets a protein that’s normally only present during lactation: alpha-lactalbumin, which is produced by most triple-negative cancers.
The US researchers came up with the idea of using a vaccine to “train” the immune system to identify this molecule, thus activating a fast and effective response to protect against any cancer cells producing it.
The vaccine took two decades to prepare and it was only after extensive experimentation on laboratory animals with triple-negative cancers that the researchers decided to start testing it on a small group of women. The Cleveland Clinic immunologists selected 26 patients of three different types:
All participants were given the vaccine, to assess its toxicity and determine the best doses.
As presented at the recent Society for Immunotherapy of Cancer meeting and published in the Journal for ImmunoTherapy of Cancer, the trial identified optimal doses in various scenarios, leading to a better understanding of the potential toxic effects, such as injection site reactions, ulceration or other symptoms, which can therefore be treated promptly should they occur. Above all else, however, the tests proved that the vaccine works, because it produces specific antibodies if and when alpha-lactalbumin-producing cancer cells appear.
2025 marks a new trial phase
All the data collected has provided a solid foundation for progression to phase two, in which the researchers will study larger patient cohorts and start assessing the vaccine’s efficacy against this type of cancer. This phase is expected to begin in 2025 and will last around three years.
If this treatment’s efficacy is confirmed, it will be used primarily in women at high risk, such as those with variants of the BRCA1 and BRCA2 genes (the most famous case being that of the actress Angelina Jolie), which make the onset of cancer more likely, even at a young age.