Research with a new nicotine vaccine shows that the vaccine is safe and well tolerated, with higher doses producing a greater rate of abstinence.

“We were pleased to see that because that indicates this vaccine does indeed have a significant impact on smoking behavior,” said Dr. Dorothy K. Hatsukami of the Tobacco Use Research Center in Minneapolis. The finding of increased abstinence, she added, was “surprising.”

The next step, Hatsukami said, will be to conduct studies to identify the optimum dose and scheduling for administering the vaccine. She noted that the vaccine could be a useful tool to help smokers quit, although in order to kick the habit it will likely be necessary for them to address behavioral aspects of smoking. “It’s not going to be a miracle cure.”

Hatsukami and her colleagues report results of the study in the November issue of Clinical Pharmacology and Therapeutics.

The “encouraging results” reported in the current study, as well as other recent research on nicotine vaccines, must be confirmed, Dr. Jacques Le Houezec of Amzer Glas in Rennes, France writes in an editorial accompanying the study.

The vaccine could be useful for smokers trying to quit, former smokers hoping to ward off relapse, and could also be used to prevent adolescents from taking up smoking, he noted, adding that giving the vaccine to teens would raise ethical questions as “it will be the first time that a vaccine is used not to prevent a disease but to prevent a behavior.”

The nicotine vaccine works by triggering production of antibodies that bind to nicotine, creating a complex that is too large to pass through the blood-brain barrier.

Hatsukami and her colleagues tested the experimental vaccine called NicVAX in 68 smokers. This preliminary study was designed primarily to test the safety of the vaccine.

Volunteers received placebo or 50, 100 or 200 micrograms of the vaccine at days 0, 28, 56 and 182 and were followed for 38 weeks. They were not instructed to quit, unless they expressed a desire to do so.

Fifty-six people completed the study.

While withdrawal symptoms and craving were considered a potential side effect, none of the study participants experienced these symptoms. This was likely because antibody concentrations rose relatively slowly, Hatsukami and her team note. There was also no sign that smokers increased their cigarette consumption to compensate for the vaccine’s effects.

Adverse effects were generally mild and were not markedly different from those given placebo.

Six of the study participants on the highest dose of the vaccine abstained from smoking for 30 days, compared to one on the 100-microgram dose, none on the 50-microgram dose, and two participants on placebo. Patients on the highest dose also took the least time to achieve 30-day abstinence.

SOURCE: Clinical Pharmacology and Therapeutics, November 2005.