Unlike recent vaccines, such as Gardisil and Cervarix, which target strains of human papilomavirus (HPV) responsible for the infections that cause cervical cancer, the new vaccine trains the immune system to detect and target cancer cells in women who have already been infected with HPV.
“The problem is, these [other] vaccines don’t protect or help women who are already infected with the virus,” said Joseph Kim, CEO of Inovio pharmaceuticals, which funded the study
Three injections of the vaccine, developed by Inovio Pharmaceuticals, prompted the production of T cells, white blood cells that kill tumour proteins, in 14 of the 18 women whose cancers had already been treated surgically. The killer cells were detected to have lasted for two years in these patients.
“These T cells were not only abundant in number; they were able to do what they were designed to do. They were able to seek out and kill the target cells,” Kim said.
Early trials showed that 90 per cent of the women who responded to the vaccine were able to develop T cells that killed the cancer causing cells with no major side effects noted. The findings, published in the journal Science Translational Medicine, suggest the drug could provide a viable cancer treatment.
David Weiner, a Penn Professor of Pathology and Laboratory Medicine, who participated in the study was excited by the results: “This is the first paper that we’re aware of that demonstrates that a DNA vaccine on its own in humans could produce this quality or magnitude of immunity” he said.
Cervical cancer is the second most common cancer, after breast cancer, affecting women across the globe. Annually there are 493,000 new cases diagnosed and 274,000 women succumb to the disease every year.
Phase two trials of the Inovio cervical cancer vaccine have now begun for 150 women with previously untreated pre-cancerous lesions, with results from these trials expected by the end of next year. Researchers, including a team from the University of Pennsylvania, said it could be four to six years before the drug could be provided commercially.