A group of 300 people is taking part in research to determine the efficacy and safety of a nicotine "vaccine" that helps smokers quit by blocking the drug's pleasurable effects, the Associated Press reported July 27.

NicVax, from Nabi Biopharmaceuticals, is being tested among smokers in Madison, Wis., Minneapolis, Minn., Omaha, Neb., San Francisco, Los Angeles, Boston and New York City. The drug is on a fast track to possible FDA approval, and the National Institute on Drug Abuse recently gave Nabi $4 million to research NicVax.

"It's going to be a very good way to keep people from relapsing," said Frank Vocci, director of medications development at  NIDA. "When [smokers] have that first cigarette, if they really enjoy it, they're at high risk of relapse. If you can make that cigarette not so good, you've really got something."

NicVax would be administered via injection, a few weeks apart over the course of a year, to study participants. Test subjects also will receive stop-smoking counseling.

The vaccine works by binding to nicotine molecules, making most too big to pass from the bloodstream into the brain. The small amount of the drug that does get to the brain will help ease withdrawal, researchers said.