Experimental vaccine may block tumor growth in advanced cancers
The study, led by Michael Morse, MD, associate professor of medicine at Duke University Medical Center, involved the use of an experimental vaccine developed by scientists who removed the genes that enable an alphavirus to replicate itself and replaced them with genes that make CEA, a biomarker present in many malignant colon, breast, and lung cells. Included in the study were 28 patients with advanced cases of lung, colon, breast, appendix, or pancreatic cancers who had already been treated with multiple courses of chemotherapy but whose cancers kept recurring. Over a 3-month period, participants received up to four injections plus booster shots of the vaccine.
Researchers found that at the end of the study, two patients with no evidence of disease remained in remission, two patients were able to maintain stable disease, and one patient with pancreatic cancer saw a lesion in his liver disappear. According to the researchers, those who seemed to benefit the most were those who had the smallest amount of tumor.
“Remember, these were patients with very advanced disease that nothing else had been able to stop,” said Dr. Morse. “We believe that in this small number of patients, the vaccine was able to stimulate the body's defense system to destroy significant numbers of cancer cells despite the presence of any army of neutralizing antibodies and regulatory T cells.”