Cervical cancer vaccine shows promise

October 12, 2012 by Sandy Bauers

A vaccine against cervical cancer, being developed by Inovio Pharmaceuticals Inc. of Blue Bell, Pa., produced positive results in a small sample of 18 women.

The vaccine prompted their bodies to produce - a type of - that, in a separate lab test, recognized 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 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.

is the second most common type - after - in women worldwide. Every year, about 470,000 women are diagnosed with cervical cancer. About half of them, mostly in , eventually die.

Unlike other cancers, it is caused by infection - in this case, some types of , which also causes .

Vaccines to prevent HPV infection have been developed - Gardasil, by & Co., and Cervarix, by GlaxoSmithKine.

"The problem is, the vaccines don't 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 10 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 28 million and 40 million women worldwide have pre-cancerous HPV infections.

In the initial trial for the Inovio vaccine, called VGX-3100, 18 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 . 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 women's own cancer cells in their bodies," he said.

Weiner's lab pioneered the use of DNA vaccines, a research field that looked promising 20 years ago, partly because things that may have side effects can be eliminated. They are nonlive, so there's no risk of them causing the disease. They don't replicate in the body.

But in the late 1990s, 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 we're 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, "we're 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 co-discoverer 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 150 women worldwide who have untreated precancerous lesions. Kim said the results of that study are expected by the end of 2013.

Kim said it could be four to six years before the , if it ultimately proves effective, could be commercially available.

Explore further: Cervical disease sufferers could benefit from HPV vaccine

Related Stories

Cervical disease sufferers could benefit from HPV vaccine

March 28, 2012
Women who are diagnosed with pre-cancerous cervical conditions after receiving the HPV vaccine can still benefit from a considerably reduced risk of reoccurring disease, a study published today in the British Medical Journal ...

Partnership sees cervical vaccines for poorer countries

November 17, 2011
A major campaigner in vaccines for poorer countries announced plans on Thursday for innoculating up to two million women and girls against cervical cancer by 2015.

Mayo Clinic receives FDA approval for ovarian and breast cancer vaccines

August 17, 2011
Mayo Clinic has received investigational new drug approval from the Food and Drug Administration for two new cancer vaccines that mobilize the body's defense mechanisms to destroy malignant cells. The vaccines are among the ...

Recommended for you

African Americans face highest risk for multiple myeloma yet underrepresented in research

November 23, 2017
Though African-American men are three times more likely to be diagnosed with multiple myeloma, a type of blood cancer, most scientific research on the disease has been based on people of European descent, according to a study ...

Encouraging oxygen's assault on iron may offer new way to kill lung cancer cells

November 22, 2017
Blocking the action of a key protein frees oxygen to damage iron-dependent proteins in lung and breast cancer cells, slowing their growth and making them easier to kill. This is the implication of a study led by researchers ...

One-size treatment for blood cancer probably doesn't fit all, researchers say

November 22, 2017
Though African-American men are three times more likely to be diagnosed with a blood cancer called multiple myeloma, most scientific research on the disease has been based on people of European descent, according to a study ...

One in four U.S. seniors with cancer has had it before

November 22, 2017
(HealthDay)—For a quarter of American seniors, a cancer diagnosis signals the return of an old foe, new research shows.

Combination immunotherapy targets cancer resistance

November 22, 2017
Cancer immunotherapy drugs have had notable but limited success because in many cases, tumors develop resistance to treatment. But researchers at Yale and Stanford have identified an experimental antibody that overcomes this ...

Researchers discover specific tumor environment that triggers cells to metastasize

November 21, 2017
A team of bioengineers and bioinformaticians at the University of California San Diego have discovered how the environment surrounding a tumor can trigger metastatic behavior in cancer cells. Specifically, when tumor cells ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.