Cancer Vaccines Are Proving Their Mettle

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In a third presentation, a team at the University of Pittsburgh School of Medicine say they've developed a vaccine that uses parts of the immune system to target p53, which is a protein that suppresses tumor growth. The scientists used the vaccine to treat head and neck cancer cells.

"In cancer, p53 is either mutated or altered," Theresa Whiteside, a professor of pathology, immunology and otolaryngology, said during the teleconference. By targeting the unchanged parts of altered p53 cells with a vaccine that activates the immune process, her team was able to produce killer cells that destroyed tumor cells. The vaccine also boosted the supply of immune "helper cells," which help the killer cells do their job.

"We can generate killer cells and helper cells in patients with head and neck cancer," Whiteside said. "On the basis of this study, we have initiated a phase I clinical trial in patients with head and neck cancer," she said.

In two other presentations, researchers presented data on the benefit of widely publicized vaccines that prevent most cervical cancer. The vaccines do so by preventing infection with the major strains of human papillomavirus (HPV), thought to be the cause of most cervical malignancies.

In the first report, Dr. Stanley Gall, a professor of obstetrics and gynecology at the University of Louisville, and colleagues reported that a new HPV vaccine made by GlaxoSmithKline was safe and effective.

"The vaccine was 100 percent effective in preventing precancerous lesions from HPV types 16 and 18 for up to five to six years," Gall said during the teleconference. These types of HPV account for about 72 percent of all cervical cancers, he said.

Overall, the vaccine showed 68 percent efficacy regardless of the type of cancer-causing HPV virus, Gall said. "The protection goes beyond what is expected from a vaccine that is targeted to type 16 and 18 alone," he said. "It protected against type 45 and 31 and also extended protection up to five years," he said.

In the other report, Dr. Darron R. Brown, a professor of medicine and infectious disease, at the Indiana University School of Medicine, and colleagues showed that the currently available vaccine, Gardasil, made by drug giant Merck, is 99 percent to 100 percent effective in preventing cervical cancer from HPV types 16 and 18. The study involved more than 12,000 women.

"In addition, 241 women who received Gardasil five years ago are still 100 percent protected from HPV 16 and 18 and have high sustained antibody levels," Brown said during the teleconference. "This is very encouraging," he said.

More information

For more information on cancer vaccines, visit the American Cancer Society.