New HPV Vaccine Promising in Mice (HealthDay)

TUESDAY, April 15 (HealthDay News) -- Researchers say they'vecreated a synthetic vaccine that can be delivered as a nasal spray forhuman papillomavirus -- the source of the most common sexually transmitteddisease in the United States and a cause of cervical cancer.

The experimental vaccine, tested so far just with mice, also offersprotection against different strains of HPV, the researchers said.

The existing vaccine for HPV, called Gardasil, protects against fourstrains of the virus that are responsible for about 70 percent of allcervical cancers. The Gardasil vaccine requires three injections for fullprotection.

"We have been trying to produce a single vaccine that would be able toprotect patients against all cancer causing HPV types," said Richard B.S.Roden, lead researcher for the new study and an associate professor ofpathology, gynecology and obstetrics, and oncology at Johns HopkinsUniversity.

"What we have done is to try to develop a completely synthetic vaccinethat would induce antibodies that would neutralize and protect against awhole range of these cancer-causing strains," he added.

The advantages of the synthetic vaccine are that it can be synthesizedas if it were a drug, Roden said, adding that "it can be made chemicallyin the lab rather than having to use biological systems."

A synthetic vaccine also should be cheaper, Roden added. Using thisapproach, the vaccine could also be given nasally, he said.

"This may be another way to reduce the cost of vaccination, becauseyou don't have to use needles," he said.

The findings are published in the April 15-18 issue of theProceedings of the National Academy of Sciences.

In their experiments, Roden and his colleagues used a protein from oneof the strains of HPV -- HPV16 -- to create a man-made vaccine in thelaboratory. When the vaccine was given to mice either by injection ornasal spray, it protected not only against HPV16, but also againstanother strain of the virus -- HPV45.

Roden said the mice used in this experiments had special immune systemT helper cells for the vaccine to attach itself. Whether human T helpercells would work in all groups of people isn't known, he said. "Right now,that's an area we are looking at," he said.

HPV is responsible for genital warts and about 99.7 percent of allcervical cancers worldwide.

Debbie Saslow, director of breast and gynecologic cancer at theAmerican Cancer Society, said that if this vaccine could be developed, itwould represent an important advance in getting more people vaccinatedagainst HPV, especially in developing countries.

"While we have wonderful opportunities with the current vaccine, thereare limitations," she said.

One limitation is the cost of the Gardasil vaccine, an estimated $300to $500, Saslow added. "That's a limitation in this country, butparticularly in the developing world where there is so much cervicalcancer," she said.

The Gardasil vaccine also requires three shots, which is difficult indeveloping countries and among adolescents, Saslow said.

"Needle-less vaccination is the way to go for a lot of reasons," shesaid. "The current shots are extremely painful, and that's going to be adeterrent for teenage populations, as is going back and getting the threedoses."

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