Vaccine may block tumor growth for some cancers

An experimental vaccine may be able to block tumor growth in some forms of cancer even when an immune system has become suppressed, a recent Journal of Clinical Investigation study has revealed.

Dr. Michael A. Morse of the Duke University Medical Center in Durham, N.C., said that the experimental vaccine is based on an encephalitis virus, ModernMedicine.com reports.

Morse and his colleagues treated 28 patients with advanced cancer or cancers that had been unresponsive to treatment. The patients were treated with a vaccine that was created by removing replication genes from the Venezuelan equine encephalitis virus and switching them with genes used for the production of carcinoembryonic antigen, which is found in cancer cells.

The test subjects received four vaccinations, plus booster shots, over a three-month story, according to ModernMedicine.com.

The researchers found that the vaccine caused an immune response against the tumor cells in several patients. Two patients stayed in remission and two maintained stable disease. Another patient who had pancreatic cancer had a lesion on his liver disappear.

The remaining subjects did not respond to the therapy. Furthermore, patients with the least amount of tumor appeared to benefit the most from the treatment.

“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 of the study wrote, ModernMedicine.com reported.