MONDAY, Aug. 2 (HealthDay News) -- An experimental vaccine based on an encephalitis virus may be able to block tumor growth in some advanced cancers by stimulating an immune response -- even when an immune system has been suppressed, according to a study published online Aug. 2 in the Journal of Clinical Investigation.
Michael A. Morse, M.D., of the Duke University Medical Center in Durham, N.C., and colleagues treated 28 patients with advanced cancer, or cancer that had been unresponsive to treatment, with a vaccine created by removing replication genes from the Venezuelan equine encephalitis virus (an alphavirus) and replacing them with genes for the production of carcinoembryonic antigen, found in cancer cells. Over three months, the patients received up to four vaccine injections plus booster shots.
The researchers found that the vaccine generated an immune response against the tumor cells in some patients. Two patients with no evidence of disease remained in remission, two patients maintained stable disease, and one patient with pancreatic cancer had a lesion on his liver disappear. The remaining patients did not respond to the therapy. Patients with the smallest amount of tumor appeared to benefit most from the therapy.
"These data suggest that virus-like replicon particle-based vectors can overcome the presence of neutralizing antibodies to break tolerance to self antigen, and may be clinically useful for immunotherapy in the setting of tumor-induced immunosuppression," the authors write.
Several study authors disclosed employee relationships with Alphavax.
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