"A vaccine against cervical cancer being developed by Inovio Pharmaceuticals Inc. of Blue Bell Pa. produced positive results in a small sample of  women. The vaccine prompted their bodies to produce T cells  a type of white blood cells  that in a separate lab test recognized cells with tumor proteins and killed them. The researchers including a team from the University of Pennsylvania say the paper in the journal Science is the first to show that a DNA vaccine alone produced a high level of immunity in people. At the same time the researchers acknowledged that a working vaccine faces more trials and remains years away from an actual product. Cervical cancer is the second most common type  after breast cancer  in women worldwide. Every year about  women are diagnosed with cervical cancer. About half of them mostly in developing countries eventually die. Unlike other cancers it is caused by infection  in this case some types of human papillomavirus which also causes genital warts. Vaccines to prevent HPV infection have been developed  Gardasil by Merck Co. and Cervarix by GlaxoSmithKine. The problem is the vaccines dont protect or help women who are already infected with the virus said J. Joseph Kim CEO of Inovio which funded the study. He and several Inovio scientists participated in it. In the United States only about three in  teenage girls  the target group  are fully vaccinated and many fewer in developing countries. Plus many women were infected before the two vaccines were developed. Researchers have estimated that between  million and  million women worldwide have precancerous HPV infections. In the initial trial for the Inovio vaccine called VGX  women who had been treated previously for lesions were injected with a vaccine made of DNA carrying a genetic code targeted to prompt the body to make a specific kind of T cell. Those T cells were then removed and combined in a test tube with other cells from the women that displayed the tumor protein. In the lab setting the T cells attacked and killed the other cells. The results were exciting for David B. Weiner a Penn professor of pathology and laboratory medicine who also participated in the study. The T cells ability to recognize and kill those targets in the lab suggests that they would now be able to do this against the womens own cancer cells in their bodies he said. Weiners lab pioneered the use of DNA vaccines a research field that looked promising  years ago partly because things that may have side effects can be eliminated. They are nonlive so theres no risk of them causing the disease. They dont replicate in the body. But in the late s interest in the new vaccines flagged. In tests on larger animals and humans the immune response was disappointing. Now said Weiner basically this is the first paper that were aware of that demonstrates that a DNA vaccine on its own in humans could produce this quality or magnitude of immunity. It opens up a lot of exciting avenues of study he added. In the paper Weiner reported compensation from Inovio and other drug companies. One of the differences this time is that the vaccine was delivered along with a small electric pulse believed to greatly increase the efficiency of the vaccine. Stanley A. Plotkin an emeritus professor at Penn whose career has been in vaccine development said the study is important because vaccines have traditionally been prophylactic preventing the disease before it occurs. In this case he said were talking about therapeutic vaccines used in people who already have a disease in order to eliminate it or to control it. Also he said the current research goes a long way toward making a DNA vaccine practical and useful in humans rather than only in animal models. Plotkin a codiscoverer of the rotovirus vaccine is a consultant to vaccine manufacturers including Inovio but was not involved in the study. Most side effects of the vaccine were minimal and deemed unrelated to the treatment the Science paper reported. After nine months  the official conclusion of the study  the participants were still producing T cells Kim said. However he said the effect seems to be more durable than that. Tests up to three years later showed the vaccination was still working. Inovio is currently conducting phase II trials on about  women worldwide who have untreated precancerous lesions. Kim said the results of that study are expected by the end of . Kim said it could be four to six years before the vaccine if it ultimately proves effective could be commercially available."