Nicotine Vaccine Shows Early Promise

Study found NicVAX helped 38% stay away from smoking for 30 days

By Amanda Gardner
HealthDay Reporter

WEDNESDAY, Nov. 2 (HealthDay News) -- A nicotine vaccine, a ray of hope for millions of smokers wanting to quit, has come one step closer to reality.

Researchers presenting at the American Association for Cancer Research meeting in Baltimore on Wednesday reported strong safety and efficacy results for NicVAX.

"We saw a significant effect," said lead author Dorothy K. Hatsukami, the Forster Family Professor in Cancer Prevention at the University of Minnesota's School of Medicine, in Minneapolis.

The effects were significant enough to merit moving on to a full-blown clinical trial, she added.

"It's absolutely worth it," Hatsukami stated. "There's a lot of promise for this vaccine, not just because of our study, but also because of other studies."

NicVAX is now the frontrunner in the field, most likely to be the first to get results to the U.S. Food and Drug Administration for possible approval.

"They're getting close to phase 3, which is the final step before presenting to the FDA," said Thomas J. Glynn, director of Cancer Science and Trends at the American Cancer Society. "We're still talking a couple of years, but they are pretty far ahead of the other two. It's a serious effort. It's no fly-by-night."

The other two nicotine vaccines under development may be as much as four to six years away from market, Glynn added.

The market for such a vaccine is huge, with about 50 million people in the United States still smoking. The habit contributes to a host of diseases and is the number one preventable risk factor for cancer. Lung cancer is the leading cause of cancer-related deaths, causing more deaths than the other five top cancers combined.

"This vaccine opens up a world of possibilities," Glynn said.

At least two other vaccines are in development. In addition, Varenicline and Rimonabant, which are not vaccines, have reported about 50 percent quit rates at 12 weeks, and may be approved by the FDA within a year.

The basic principles across the different vaccines are similar: The vaccine stimulates the body's immune system to produce antibodies that then attach to the nicotine molecule. In animal studies, this has been shown to slow delivery of nicotine to the brain while also decreasing the amount reaching the brain. The reason? The nicotine/antibody compound is too big to cross the blood-brain barrier.

"It's such a novel way of treating an addiction because it's not targeting any part of the brain," Hatsukami said. "It's targeting the molecule itself."

The current study, supported by the National Institute of Drug Abuse and Nabi Biopharmaceuticals, was designed to look at safety, as well as levels of antibodies produced.

Sixty-eight smokers were randomly assigned to receive different doses of the vaccine or a placebo. The participants were not recruited because they had expressed an interest in quitting.

Although the study was not specifically designed to look at cessation, quit rates were impressive: 38 percent of the participants quit smoking for 30 days.

"That's pretty good for people coming in for non-treatment," Hatsukami said. "We didn't even provide counseling unless they asked for it."

Higher vaccine doses elicited better antibody responses. Participants receiving the highest dose were more likely to abstain from cigarettes for 30 days.

"Far more people quit in the highest dose," Hatsukami said. "It looks like vaccines do have promise in terms of helping people quit smoking."

Some participants reported aches and tenderness at the injection site, while some also reported headaches, malaise and muscle pain. Most of these side effects went away within a few days, the researchers said.

There were no differences in withdrawal symptoms between those receiving the vaccine and those receiving a placebo.

There also appeared to be no "compensatory smoking behavior," meaning vaccine recipients did not puff harder or smoke more cigarettes to compensate for the effect.

Several questions still remain, Glynn pointed out: How long will the vaccine be effective? Will smokers need a booster? Will it be a relapse preventer? And is this something that could be given to a 9-year-old to prevent him or her from taking up the habit, much like the measles vaccine prevents measles?

"The big question is, is this one of the magic bullets? My heart says yes and my head says no," Glynn said. "[But] it will enable us to start tailoring treatment even more for cessation."

More information

To learn more about nicotine addiction, visit the National Institute on Drug Abuse.

SOURCES: Dorothy K. Hatsukami, Ph.D., Forster Family Professor in Cancer Prevention, University of Minnesota School of Medicine, Minneapolis; Thomas J. Glynn, Ph.D., director, Cancer Science and Trends, and director, International Tobacco Programs, American Cancer Society, Washington, D.C.; Nov. 2, 2005, presentation, American Association for Cancer Research meeting, Baltimore

Misconceptions Still Shroud Smoking

The right information can help smokers quit, study finds

By Ed Edelson
HealthDay Reporter

TUESDAY, Nov. 1 (HealthDay News) -- Mistaken beliefs -- most often about nicotine -- often hurt smokers who are trying to give up the habit.

That was the underlying message of a presentation by smoking-cessation expert Virginia Reichert, director of the Center for Tobacco Control at North Shore-Long Island Jewish Health System in Great Neck, N.Y. She made her remarks Tuesday at the American College of Chest Physicians meeting in Montreal.

For example, many smokers are reluctant to use nicotine patches or gum because they think nicotine causes cancer, Reichert said.

A study of over 1,100 middle-aged smokers who enrolled in the center's program found that nicotine-cancer misconception much more common among women, with 72 percent of them believing it, compared to 60 percent of men, Reichert said. And the same percentage of women smoke "light" cigarettes, mistakenly believing them to be less harmful, compared to 63 percent of the men, she said.

Nicotine is dangerous, but not for any link to cancer, which does not exist, Reichert said. It does its damage by addicting people to tobacco, "and when you're smoking you're inhaling 4,000 chemicals a day," she said. Many of those chemicals are carcinogenic.

"Nicotine is the most addictive chemical we know, more addictive than heroin or cocaine," and too many physicians who try to help smokers underestimate that addictive power, Reichert said. "You've got to do more than give them a brochure and walk away."

The data on misinformation came from a six-week program involving heavy smokers in their mid-40s, averaging a pack and a half a day, she said. At the start of the program, participants filled out a questionnaire to gauge their knowledge and beliefs about smoking.

Women were more likely than men to worry about smoking giving them cancer -- 75 percent versus 64 percent. They were also more likely than men to worry that quitting would cause them to gain weight -- 41 percent vs. 15 percent -- and to worry about being able to handle stress without cigarettes -- 63 percent to 55 percent.

With a program that includes medical management, behavior modification, use of nicotine patches and/or gum and diet, "most smokers who quit can expect to avoid withdrawal symptoms and minimize weight gain," Reichert said.

The program was equally successful for men and women, with a quit rate of 59 percent for women and 55 percent for men, she said.

A major reason for that success is the ability to wean smokers away from getting nicotine from tobacco, Reichert said. Patches, gums and even nicotine inhalers can still supply "the drug they are addicted to in small amounts," she said.

The amounts should be small because nicotine does pose dangers, said Dr. Diane Stover, director of the pulmonary service at Memorial Sloan-Kettering Cancer Center in New York City. It constricts blood vessels and promotes formation of blood clots that can lead to heart attacks and other major cardiovascular problems, she said. Still, nicotine replacement "is a bridge to stop smoking, and then you take away the nicotine," Stover said.

Despite all the evidence about the ill effects of smoking, it is still necessary to spell them out for many people, Stover said. "When you talk to people about the dangers of smoking, they'll say, 'I knew it was not healthy to smoke, but I really didn't know why,' " she said.

Another report at the meeting provided new information about one of the leading problems of smoking -- lung cancer. It gave some comfort to women, finding that they survive longer than men with the disease, even without treatment.

Researchers from Mount Sinai School of Medicine in New York City reviewed nearly 19,000 cases of lung cancer and found that women not only had significantly better survival rates than men when treated, they also had a 21 percent decreased risk of death compared to men without treatment.

The study "suggests that the progression of lung cancer has a biological basis, with the disease being more aggressive in men than women," the researchers said.

More information

Smokers who want help in quitting can get it from the U.S. Centers for Disease Control and Prevention.

SOURCES: Virginia Reichert, NP, director, Center for Tobacco Control, North Shore-Long Island Jewish Health System, Great Neck, N.Y.; Diane Stover, M.D., chief of pulmonary service, Memorial Sloan-Kettering Cancer Center, New York City; Nov. 1, 2005 presentation, American Academy of Chest Physicians, Montreal

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