New vaccine to aid immunity to cancer
by Diana De Leon, Feature Editor

    A vaccine designed to build immunity against certain viruses that cause cervical cancer has proved effective in recent studies.

   The vaccine could be offered to young women who are sexually active and to those women deemed at high risk for sexually transmitted diseases.

   "We are tremendously excited about the possibility of cancer prevention," Dr. Dawn B. Willis, director of research promotion and communication for the American Cancer Society, said.

   Cervical cancer is caused by the human papilloma virus (HPV), which sexually transmitted.

    HPV was discovered to be the trigger for cervical cancer in 1983, and more than 80 different types of HPVs have been identified.

   "The ACS supported several basic science researchers studying HPV over the years whose discoveries were pivotal in making this vaccine possible," she said.

   Many types of HPVs are considered low-risk because they rarely cause cancer, but those types that do cause cancer are referred to as cancer-associated types of HPVs.

   "Only 30 strains can be transmitted genitally, and infections with most of these are fairly rare and unapparent," she said.

   Cervical cancer is a condition in which cells of the cervix become abnormal and start to grow rapidly.

   It is a slow-growing cancer; the cells go from normal to pre-cancerous to cancer over a period of several years.

   "The proof of principal, that a vaccine can be made that provides 100 percent protection against an HPV strain, has been established," she said.

   Vaccines are currently in trials in several different countries including the United States.

   In the United States, preliminary studies found one vaccine to be successful in preventing HPV-16 from causing pre-cancerous changes, Willis said.

   "The United States has phase III trials in progress," she said. "Trails of a 16, 18, 6 and 11 combination are underway and should be completed in two to three years."

   Willis explained that the FDA does have responsibilities whenever a new drug, or in this case a vaccine, is developed.

   Phase III trials are usually sponsored by drug companies these days, Willis said.

    "The FDA will probably grant fast-track approval within a year after trials, then another year for companies to gear up production and distribution making public use five years away," she said.

   A vaccine being developed at the Ludwig Institute for Cancer research in San Paulo, Brazil, has proved effective against four types of HPVs, but researchers do not know how long the vaccine protects against these cancer causing HPVs.

   In a trial study of more than 1,000 women between the ages of 16 and 23 in Brazil, those who received the vaccine developed a strong immunity against the virus.

   Women experienced virtually no side effects from the vaccine, and each was injected three times over a period of six months.

   "Our FDA requirements may slow things down so that the Brazil vaccine may be available before the U.S. vaccine," she said.

   A woman already infected will not benefit from the vaccine.

   The ACS currently is spending $13.6 million in grants on research related to cervical cancer or HPV and $2.78 million for vaccine development, Willis said. The ACS does not do the research; the organization funds it through grants.

   "Prevention is always better than treatment or even early detection," she said.

   The United States has a lower incidence of cervical cancer because of preventive measures such as the Pap test, which is not available in some countries.

   The lack of wide-spread preventive measures makes cervical cancer second only to breast cancer in the number of deaths each year worldwide, with most deaths attributed to developing countries.