An experimental vaccine, called CYT002-NicQb, to treat nicotine addiction has achieved proof of efficacy..

CYT002-NicQb is a therapeutic vaccine in development for the treatment of nicotine addiction.
Vaccination with CYT002-NicQb induces high levels of nicotine-specific antibodies that bind nicotine in the blood.
As the complex of nicotine attached to an antibody is too large to pass the blood-brain-barrier, nicotine uptake into the brain and the subsequent stimulation of nicotine-perceptive neurons in the brain is believed to be significantly reduced or even prevented.
In this way the addiction-driving and satisfaction-inducing stimulus of nicotine is minimized.

The study, randomized, double blind, placebo-controlled, multicenter, assessed safety, tolerability and efficacy of the vaccine candidate.
It was carried out at the Kantonsspital St. Gallen, the Centre Hospitalier Universitaire Vaudois ( CHUV ) Lausanne, and the Lung Center Hirslanden Zurich, all in Switzerland.
The study was conducted in 341 healthy male and female smokers, aged 18-70 who have been smoking between 10 and 40 cigarettes per day for at least 3 years and who were motivated to quit smoking. 5 injections of the vaccine or placebo were given at monthly intervals at month 0, 1, 2, 3, and 4.
All participants received smoking cessation counselling by the study collaborators at each visit during three months.
One month after the first injection, the participants were asked to make a serious attempt to quit smoking.
Smoking behaviour was recorded by the participants in personal diaries, and independent biochemical validation was performed by measuring carbon monoxide in exhaled air ( a by-product of cigarette burn that remains in the blood for up to 24 hours ).
Efficacy of the vaccine was determined by continuous abstinence from smoking between week 8 and 24 after treatment start.
Two thirds of the smokers received the vaccine, whereas one third received placebo.
All smokers who received the vaccine mounted an anti-nicotine antibody response, which corresponds to an immunological response rate of 100%.
Based on the measured levels of antibodies, the vaccine-treated smokers were grouped into a high, a medium, and a low responder group.
All smokers who received placebo had no measurable anti-nicotine antibodies in their blood.
The difference of continuous abstinence between the high responder group and the placebo group was highly significant ( p=0.004 ).
Overall cigarette consumption in the high responder group was less than half of that seen in the placebo group ( p=0.004 ).
Moreover, the average cigarette consumption by those people who did not achieve continuous abstinence was also lower in the high responder group than in the placebo group ( p=0.16 ).

The vaccine was safe and generally well tolerated with common side effects being local injection site reactions and flu-like symptoms, which usually resolved within 24 hours.

” I am very excited about the outcome of this study, as the data clearly suggest that antibodies against nicotine are effective in helping people quit smoking, “ Jacques Cornuz, of the Centre Hospitalier Universitaire Vaudois ( CHUV ) Lausanne, commented. “ There is certainly no doubt that new approaches such as vaccination are urgently needed. Despite the fact that smoking causes 30% of all cancer deaths, including 87% of deaths from lung cancer, there are 1.3 billion smokers worldwide. And each smoker looses on average more than 10 years of lifetime as a result from this serious addiction. I believe that the vaccine approach has the potential to dramatically alter the way how we will treat smoking addiction in the future.”

Nicotine, an alkaloid derived from tobacco leaves, has been shown to be the principal addictive component of tobacco.
Upon inhalation of cigarette smoke, nicotine passes into the bloodstream and within seconds penetrates through the blood-brain barrier, where it stimulates specific neurons in the brain.
Stimulation of these neurons leads to the release of messenger molecules, which give rise to an almost immediate reward and a feeling of pleasure.
This sensory stimulus is critical to the addictive properties of nicotine and causes a high relapse rate after quitting attempts.
Although nearly 75% of smokers in the U.S. report that they want to quit smoking, less than 5% of those who try quitting are able to stay tobacco-free for 3 to 12 months ( Surgeon's General Report, USA, 2004 ).

Source: 41st Annual Meeting of the American Society of Clinical Oncology ( ASCO ), 2005


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