Researchers at the University of Cincinnati think they may have identified a pill that could prevent recurrence of breast cancer.
In an animal study published in the Jan. 8 issue of Molecular Therapy, a collaborative research team from the University of Cincinnati Cancer Institute and the National Institutes of Health tested vaccines based on two different strains of adeno-associated virus (AAV) and found that, when administered orally, they produced a two-pronged immune system attack on cancer cells.
AAV is being investigated as a platform for gene therapy because it’s demonstrated the ability to kill cancer cells without causing disease. That’s been a challenge to researchers who in the past have worked on oral breast vaccines using bacteria, which can be harmful to humans, according to a University of Cincinnati news release about the study.
The researchers tested two strains of recombinant AAV: one that stayed in the stomach, and another that escaped the stomach and moved into the bloodstream. They also tested two different methods of delivery to see whether oral administration or intramuscular injection was more effective.
“Normally, you introduce a virus by mouth and it is broken down in the stomach,” said lead author Jason Steel in a statement. “[This] virus is resistant to breakdown, which opened up the possibility of administering it orally as a cancer vaccine.”
The team found that the strain that remained in the stomach was most effective; the animals that received that strain did not develop tumors in the year after administration. And the subjects developed more antitumor antibodies when it was delivered orally than when it was delivered via intramuscular injection.
“With this virus, we get both an antibody and a tumor-killer T-cell response,” Steel said.
Much more testing is needed on the vaccine, but the researchers say it may have potential as a prevention tool in individuals who have been treated for certain kinds of breast cancer, or those at increased risk for the disease.
Breast cancer has perhaps seen more vaccine development activity than any other kind of cancer. Neuvax, a vaccine developed by Galena Biopharma to prevent recurrence, is in phase 3 clinical trials and there are many more candidates in the early stage pipeline from pharma giants like GSK to startups like Immunophotonics. Oral vaccines are being studied as well by researchers at Mercer University and Swiss-German biotech company VAXIMM AG, which enrolled the first clinical trial of its oral therapeutic cancer vaccine last fall.
The UC team expects to begin preclinical testing of the oral vaccine in prevention of other cancers including lung cancer in 2013.