N E W
Y O R K, Aug. 7 — Forget the patch,
the nicotine chewing gum and the cold turkey approaches to quitting
smoking.
A shot in the arm might
someday be able to stop the craving for cigarettes experienced by 60
million Americans each year.
Scientists at the “Tobacco Or Health”
conference, going on in Chicago this week, are reporting their results
with a vaccine against tobacco that aims to reduce the amount of
nicotine that gets to the brain in the hope of making it less
addictive.
Dr. Paul Pentel, an investigator at the
Hennepin County Medical Center in Minneapolis; David Malin, Ph.D., a
professor of psychology and neuroscience with the University of
Houston-Clear Lake; researchers at the National Institute of Drug
Abuse; and Nabi, Inc., a biotechnology company in Boca Raton, Fla.,
are collaborating in the development of this new vaccine, called
NicVAX.
Stimulates
the Immune System
The vaccine works by stimulating the body’s own immune system, the
researchers say. Although nicotine itself is too small a chemical to
produce an antibody response, when it is joined to another substance
the two create a molecule-a vaccine — that induces antibodies to
nicotine alone. When the antibodies and nicotine bind in the
bloodstream, the new molecule is too large to enter the brain, where
the addictive effects of nicotine occur.
The vaccine, which currently is being tested
in rats, might be able to prevent people from getting hooked on
cigarettes and could help people get off the cycle of dependence on
nicotine, the scientists say. Clinical trials in humans may begin as
early as next year.
Possible
Preventive and Treatment
The vaccine has been able to prevent the actions of nicotine in the
rats, explains Malin. It reduces nicotine’s effect on blood
pressure, it limits the withdrawal effects the rats experience, it
reduces their activity level and it stops the rats from selecting
nicotine when given a choice.
Given intravenously to the rats, the dose of
nicotine is analogous to what humans consume. The vaccine has been
able to reduce from one-third to two-thirds the amount of free
nicotine in the bloodstream, Pentel says.
“The goal is to bind up nicotine,” Pentel
explains. “Much of it depends on how much antibody is present, how
well-immunized the animal is and how much nicotine is given.”
Humans
Different than Rats
But smoking in humans is more complex than it is in rats. Smokers who
might be treated with the vaccine could conceivably smoke more to
compensate for the effects of the vaccine. “The amount of nicotine
intercepted needs to be high enough so that even if someone were to
smoke more cigarettes the effects of nicotine would not be felt,”
Malin says.
Pentel says the vaccine probably wouldn’t
reduce the craving that someone has after nicotine has left their
body, which is why it would be only one part of a program to treat
nicotine addiction.
A nicotine vaccine could have a huge market
as only 3 percent of smokers in the United States quit each year.
“After all, 435,000 people die prematurely every year because of
their nicotine addiction,” says Dr. Alan I. Leshner, the director
NIDA, which is supporting the vaccine development.
Other companies, including Cantab, in
England, are developing similar tobacco vaccines. Vaccines against
cocaine also are in development.
ABCNEWS’ Deborah Amos and Maria A. Flores and ABCNEWS.com’s
Robin Eisner contributed to this report.
Variety
of New Treatments
Ray Aldrich
began smoking when he was 13 years old and was soon up to
three packs a day. He has tried to quit several times —
and several times he has failed.
“What happens is you see someone
else smoking, you smell it, you think, ‘I’ll just have
one,’” says Aldrich, “and then you’re hooked again.”
Studies show that people who try to
quit smoking using willpower alone have only about a 7 percent
longterm success rate.
But new treatment guidelines, based
on a review of nearly 6,000 studies, show how smokers can more
than double or triple their odds of kicking the habit.
“The difference between what
smokers and doctors had just a few years ago and today is that
we now have options and different approaches,” says Dr.
Michael Fiore of the University of Wisconsin Medical School.
As for medications, the latest
research suggests that the nicotine patch, gum, nasal spray,
inhaler and the antidepressant, Zyban, taken separately or in
combination, are the most effective — what doctors call
first-line treatments.
“There are now five medications,
all approved by the FDA, that will at least double your
success rate if you’re committed to quitting,” Fiore says.
Researchers also say that adding
counseling can further improve your odds — one-on-one
sessions, whether in person or on the phone. At least six
states now offer telephone-based counseling: a toll-free
number that connects smokers to trained specialists who
provide ongoing advice.
“We know the telephone counseling
works,” says Dr. Richard Hurt of the Mayo Clinic. “We
should make it available and widely available through our
health plans throughout the country.”
Smoking is the single biggest risk
factor for cancer, heart disease and a variety of other health
programs. The addiction can be so strong it takes the average
smoker five serious attempts to quit before finally
succeeding.
For Ray Aldrich, after counseling and
three different nicotine products, he has now been
tobacco-free for 10 months.
“I just take it one day at a
time,” he says. It’s still a struggle, but one made easier
by a variety of new treatments.
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W E
B L I N K S 
Nabi,
Inc.
National
Institute on Drug Abuse
Hennipin
County Medical Center
University
of Houston-Clear Lake
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