If America's 50 million smokers could vaccinate themselves against nicotine addiction or pop a pill to eliminate their cravings, drug researchers are betting they would.
The race for a smoking wonder drug has major pharmaceutical companies and small startups competing to make nicotine addiction as treatable - and lucrative- as erectile disfunction, high cholesterol and acid reflux disease.
In a marketplace dominated by nicotine patches, gums, lozenges and sprays, researchers see great promise for a nicotine-free way to stop smoking addiction at the chemical level.
"It's the biggest addiction market there is," said Dr. Herbert D. Kleber, a psychiatry professor and addiction researcher at Columbia University. "Is it realistic to be able to help addicts stop smoking and remain off with a pill? I think the answer is yes and we're working on a number of them."
While patches and gums help wean smokers off cigarettes by slowly reducing their dependance on nicotine, researchers are tailoring drugs to mimic or block nicotine's chemical reactions with the body.
In Connecticut, researchers at Pfizer Inc. identified a brain receptor that nicotine binds to and designed a drug, varenicline, that latches to the same site. Varenicline is in Phase III testing, normally the last step before a company applies for approval from the Food and Drug Administration.
Researchers hope that with the chemical reaction complete, the overpowering cravings won't kick in when patients stops smoking. And if they do reach for a cigarette, the drug will be sitting in nicotine's favorite parking spot, lessening its effect on the brain.
"It's an unmet medical need," said Dr. Karen Reeves, executive director of clinical development for Pfizer. "The morbidity and mortality rate is so high, and doctors and smokers really have not had enough in their armamentarium to help smokers stop smoking."
The French pharmaceutical company Sanofi-Synthelabo said it will ask for FDA approval this year for the drug rimonabant, which it would market under the name Acomplia as a way to help stop smoking and overeating.
Acomplia targets circuitry in the brain that encourage smokers to keep lighting up. If the body's chemical reward system is blocked, smoking might not be as pleasurable or as addictive.
Researchers have high hopes for the drug, saying it might also treat alcohol and drug abuse.
Then there's NicVax, a drug that Florida-based Nabi Pharmaceuticals claims could be used as a nicotine vaccine. NicVax triggers the production of antibodies that seek out and bind with nicotine molecules, making them too big to react with the brain's receptors.
NicVax, which was developed primarily using grants from the National Institute on Drug Abuse, has shown promise in early trials and could begin Phase III testing late this year, the company said.
A similar drug, called Ta-Nic, is in early testing by the Xenova Group in England.
"Everyone has been looking for the magic bullet," said Thomas Glynn, director of cancer science and trends for the American Cancer Society.
Whether one will be found remains uncertain, he said. It's more likely, doctors agree, that scientists will develop a number of successful drugs that will prove effective, but no single pill will "cure" smoking.
Doctors with high hopes have been let down before. In 1997, the FDA approved bupropion, commonly sold under the name Zyban, as an anti-smoking drug.
The drug, which was originally marketed as an anti-depressant, has proven successful for some smokers but was never the industry blockbuster some expected.
Dr. Cheryl Oncken, associate professor of medicine at the University of Connecticut, said the new drugs being developed represent the next generation of medicine. Oncken will present a research study this weekend on varenicline, which in an earlier Pfizer study was shown to help nearly half of smokers quit within seven weeks - compared to about 33 percent with bupropion.
Investors are proceeding cautiously. Scott Henry, a Pfizer analyst at Oppenheimer & Co., said it's too early to tell whether there is a smoking wonder drug in development. He said varenicline has shown promise, but like all drugs going through clinical testing, there are many unanswered questions.
"Is it truly a revolutionary new treatment, or is just another bell and whistle?" he said.
By Matt Apuzzo