Best views, weather, etc. How to test them 👓 SC, Ala. sites look back Betty Ford honored
NEWS

In cervical cancer fight, 1 shot could be enough

Laura Ungar
The (Louisville, Ky.) Courier-Journal
Two University of Louisville cancer researchers, Drs. A. Bennett Jenson and Shin-je Ghim, have helped to develop a vaccine that has proved to be effective against two strains of a virus that can lead to the development of types of cervical cancer.
  • Reducing number of shots required could be helpful in developing nations and poor areas of U.S.
  • Doctors caution that more research needs to be done
  • Two HPV vaccines are licensed for females 9 through 26

LOUISVILLE — A national study released Monday suggests that one shot may be enough to prevent cervical cancer — opening the possibility of cheaper and easier vaccinations in the future.

Reducing the number of doses from the three shots now required could be particularly helpful in developing nations and poverty-stricken U.S. regions such as Appalachia, where patients get cervical cancer at high rates but face difficulties accessing health care and paying for the vaccine.

The three-shot series costs $130 per shot in the United States, while the cheapest international price is $13 per shot.

"This is really exciting for resource-poor countries and areas like ... Appalachia," said Mahboobeh Safaeian, an investigator in the National Cancer Institute's Division of Cancer Epidemiology and Genetics. "The implications are humongous for those settings."

Safaeian and other researchers involved in the NCI-funded study, published in the journal Cancer Prevention Research, examined the immune response in blood samples of women who got one, two or three doses of vaccine. They found that all the samples had antibodies against human papillomavirus types 16 and 18, which are sexually transmitted and cause most cervical cancer.

Dr. A. Bennett Jenson — one of two University of Louisville researchers, along with Dr. Shin-je Ghim, who helped develop the cervical cancer vaccine — said he hopes the one-shot results hold up. He's been working with colleagues in India on efforts to reduce the enormous burden of cervical cancer there, where it is the biggest cancer killer of women.

Jenson said women worldwide would be more likely to get the vaccine if they only needed one dose, meaning more lives, money, time and effort would be saved. "In places like India, if it works, it would really be great," he said.

But Jenson and others expressed reservations about the NCI study's findings, saying more research is needed before any changes are made.

Two HPV vaccines, GlaxoSmithKline's Cervarix and Merck's Gardasil, are now licensed by the U.S. government for females 9 through 26. Both are administered with three doses over six months. Jenson said the first shot provides some immunity, the second one increases immunity and the third is a booster shot.

"Maybe they could get by with two," Jenson said. "Still, I'm very much for (reducing doses) if it works."

Attacking a killer

Cervical cancer strikes about 12,000 American women each year and kills about 4,000.

Kentucky has the eighth-highest incidence rate in the nation — 8.6 per 100,000 women in 2010, compared with 7.4 per 100,000 nationally — and the rate in the state's Appalachian region is 9.7 per 100,000.

But more than 85% of cervical cancers occur in developing countries, which lack routine Pap smear screenings that detect precancerous lesions so they can be removed before they become cancerous.

Overall, a relatively small percentage of American females 13 to 17 get all three shots — just 33%, according to a recent federal study. The study also said 54% of females in that age group got only the first shot.

Safaeian said that reality drove the research.

Researchers used data from a clinical trial testing the effectiveness of the Cervarix vaccine in Costa Rican women. Although the research called for three doses, 20% of the women in the study received fewer doses for various reasons.

The researchers found that antibody levels were lower among women who got only one dose than among women who received all three. But the levels in the one- and two-dose groups were five to 24 times higher than the levels of antibodies in women who were not vaccinated but had been infected previously by HPV.

Safaeian said scientists don't know the exact level needed to protect against cervical cancer. But researchers said the levels in women getting one dose appeared stable, suggesting the immune responses are lasting.

More study needed

Still, Safaeian cautioned that, "while our findings are quite intriguing and show promise, additional data are needed before policy guidelines can be changed."

Doctors and drug company executives agreed.

Deb Wambold, a Merck spokeswoman, said tests leading to the licensing of Gardasil looked only at the effectiveness of the three-dose regimen, and "it's too early to say" whether other regimens would be as effective.

She pointed to a study in the Journal of the American Medical Association suggesting a two-dose regimen in 9- to 13-year-olds conferred an immune response no worse than the three-dose regimen, but also saying more research is needed.

"It has turned out to be an exceptionally robust vaccine," said Dr. Robert Hilgers, a gynecological oncologist in Louisville who runs the Women's Global Cancer Alliance. "The problem is the studies have not been long-term."

Hilgers said it would be wonderful if a one- or two-dose regimen is shown to work. But he pointed out that there are other barriers to more widespread vaccination. For example, the vaccine remains controversial in the United States and abroad, with some parents expressing concerns about its safety or whether it gives tacit approval to sexual behavior in teens.

According to the U.S. Centers for Disease Control and Prevention, the vaccine is safe. Post-licensure safety monitoring shows that about 22,000 "adverse events" were reported out of 57 million doses of vaccine distributed between June 2006 and March 2013. Ninety-two percent were classified as nonserious problems, such as fainting or headache.

CDC scientists also studied specific events such as Guillain-Barre syndrome, stroke and seizures, and concluded none were more common after HPV vaccination than after inoculation with other vaccines.

As monitoring continues, efforts are underway to provide lower-cost vaccine to the developing world.

Merck and GlaxoSmithKline, for instance, plan to offer vaccine for less than $5 a dose in certain developing countries through a program with the GAVI Alliance, which was created with a grant from the Bill and Melinda Gates Foundation.

Safaeian said her ultimate hope is that poor regions throughout the world gain more access to vaccination. She said easier vaccination means saving women in the prime of life, "when they still have kids and families to take care of. The implications for them are great."

Cervical cancer symptoms

Early cervical cancers usually don't cause symptoms. When the cancer grows larger, women may notice:

• Bleeding between regular menstrual periods

• Bleeding after sexual intercourse, douching or a pelvic exam

• Menstrual periods that last longer and are heavier than before

• Bleeding after going through menopause

• Increased vaginal discharge

• Pelvic pain

• Pain during sex

Source: National Cancer Institute

MAP:Cervical cancer incidence rates by state, 2010 from the Centers for Disease Control and Prevention

Featured Weekly Ad