A preventive breast cancer vaccine developed by Professor Vincent Tuohy of the Cleveland Clinic will be brought forward to the FDA for permission to begin clinical trials to see if it is safe and effective for use in women.
The vaccine was shown to be completely safe and 100% effective in preventing breast cancer in three animal models, (see study in Nature Medicine), and was also found to slow the growth of tumors that had already formed. The vaccine is especially powerful in inhibiting the growth of triple-negative breast cancer, the most aggressive form of the disease with the lowest survival rate.
Triple-negative breast cancer lacks estrogen, progesterone and Her2 receptors. It occurs in approximately 15% of cases is the kind of breast cancer most common in women who carry a BRCA mutation.
The initial clinical trials, called Phase I studies, will be conducted in two groups of volunteers, women with triple-negative breast cancer who have completed their treatment and are free of disease, and women who will be vaccinated shortly before undergoing bilateral prophylactic mastectomy (typically these are women like Angelina Jolie with BRCA mutations who elect to remove their breasts to lower their risk for cancer.)
The first group of women will be studied to determine the dose and effectiveness of the vaccine; the second will be studied to make sure the vaccine does not trigger an untoward immune response in breast tissue.
The vaccine targets an unique protein normally made only by women who are breastfeeding, alpha lactalbumin (ALA). In the 12 years Tuohy spent developing and researching his vaccine, he discovered that the majority of breast tumors express, or make, ALA. Priming the immune system with a vaccine so that it attacks any cell that makes ALA is the method by which Tuohy’s vaccine works.
Because the vaccine targets ALA, a protein necessary for successful lactation in healthy women, the vaccine would not be appropriate for use in women who are still in their childbearing years.
However, the majority of women diagnosed with breast cancer in the United States and other western countries are post-menopausal: at least 60% of the cases in the United States occur in women over 55; thus, Tuohy’s vaccine holds great potential as a preventive vaccine for the majority of women.