An experimental vaccine against nicotine is “safe” and “promising,” researchers report.
The vaccine is called NicVax. It’s designed to make the body produce antibodies against nicotine.
So far, studies of NicVax have focused on the vaccine’s safety and effects on the immune system. The vaccine’s effectiveness will be directly tested later.
Still, early test results hint that the vaccine might help people quit smoking, says researcher Dorothy Hatsukami, PhD, in a news release.
Hatsukami directs the University of Minnesota Cancer Center’s Transdisciplinary Tobacco Use Research Center.
The study, published in Clinical Pharmacology & Therapeutics, was partially funded by Nabi Pharmaceuticals, which developed NicVax.
Testing the Vaccine
The study included 68 smokers with no known health problems. Most smokers reported smoking at least 16 daily cigarettes. None planned to quit smoking in the next month.
The smokers were followed for 38 weeks. They got shots of NicVax or a placebo (a shot with no medicine) four times: at the study’s start, and after four, eight, and 26 weeks.
Three different doses of NicVax were tested. Participants didn’t know what dose they’d gotten or if they’d gotten the placebo.
Previous tests, done on rats, had shown that vaccination cuts nicotine levels in the brain, the researchers note.
NicVax was safe and well-tolerated, write Hatsukami and colleagues.
Immune responses to the vaccine varied among the NicVax groups. The strongest response was seen in those that got the highest dose of the vaccine.
As expected, immune response was stronger in the later rounds of shots, the researchers report.
They note no serious side effects among any of the groups. The most frequent adverse events included colds, headaches, and infections of the upper respiratory tract.
Most people kept smoking during the study. After all, they had all told the researchers at the study’s start that that was their intention.
However, a few quit smoking, anyway. They included:
--Six people from the high-dose vaccine group
--One person from the medium-dose vaccine group
--No one from the low-dose vaccine group
--Two people from the placebo group
Those people quit smoking and didn’t start again for 30 days. Blood tests appeared to confirm that.
The tests screened for a chemical called cotinine, which stems from nicotine’s breakdown. NicVax might affect cotinine levels, the researchers note.
Nicotine cravings didn’t spike during the study. The smokers reportedly weren’t compensating by getting more puffs from each cigarette.
More Work Ahead
“More research needs to be done, but at this point, our results show the vaccine is safe and well-tolerated,” Hatsukami says in a news release.
She adds that the vaccine specifically targets nicotine and has no expected effect in the brain or central nervous system.
Meanwhile, there are other ways to quit smoking.
Reams of studies have linked smoking to a wide range of health risks, including cancer and heart disease, two leading killers of men and women alike.
Smokers who decide to quit may want to be patient with themselves. Many people try several times before quitting the cigarette habit for good. It’s worth the effort, health experts say.
By Miranda Hitti, reviewed by Louise Chang, MD
SOURCES: Hatsukami, D. Clinical Pharmacology & Therapeutics, November 2005; vol 78: pp 456-467. News release, University of Minnesota.