DNA-Based Cervical Cancer Vaccine Shows Promise in Small Trial

October 12, 2012 — Women with types of the human papillomavirus that can lead to cervical cancer produced a strong immune response against precancerous cells after they received an experimental DNA-based vaccine, according to a small study published online in the journal Science Translational Medicine, the New York Times reports (Rabin, New York Times, 10/10).

The vaccine -- known as VGX-3100 and manufactured by Inovio Pharmaceuticals -- was designed to encourage the production of large quantities of immune system cells, or T-cells, that could target two HPV-specific, cancer-causing genes called E6 and E7 oncogenes, according to Reuters (Steenhuysen, Reuters, 10/10).

For the study, which involved just 18 women, researchers examined the effects of three doses of VGX-3100 by electroporation, in which an electronic pulse accompanies the injection. Each of the women already had received standard treatment for precancerous conditions associated with HPV Type 16 and Type 18. According to the Times, some women who have precancerous lesions associated with the two strains produce high levels of T-cells that fight off the infection without medical intervention (New York Times, 10/10).

Key Findings

The researchers found that 14 of the women produced significant T-cells, which lasted for two years. Lab tests also showed that more than 90% of the women who responded to the vaccine developed T-cells that were able to kill the target cell, which suggests that the vaccine could work as a treatment, according to Reuters. The researchers noted that there were no major side effects to the vaccine (Reuters, 10/10).

Next, the researchers plan to test whether VGX-3100 can successfully eliminate or control precancerous cervical lesions in patients who have not received treatment. Those results are expected by the end of 2013 (New York Times, 10/10).

The researchers said the study is the first to demonstrate that a DNA vaccine alone can produce a high level of immunity in humans, although they noted that they are years away from bringing a product to market (Bauers, Philadelphia Inquirer, 10/11).