Anti smoking vaccine soon in the U.S.

Vaccine injection to prevent smoking relapse among smokers trying to quit is in the "pipeline" of the industry for almost ten years. There are three firms which are positioned in this market today.

In a few months, we'll know if it can be cleared for sale. Indeed, the British pharmaceutical group GlaxoSmithKline (GSK) announced Monday it had signed a licensing agreement for exclusive worldwide distribution of NicVAX, a candidate vaccine against nicotine addiction.

After years of encouraging animal trials, then initially disappointing in humans, GSK has initiated the Phase 3 trials expected to determine actual effectiveness of the vaccine on smokers.

Tobacco dependence is due to nicotine, a natural drug also produced by the brain. Present in cigarette smoke, when inhaled into the lungs, it travels to the alveoli,  passes into arterial blood and is found almost instantly in the brain.

It stimulates there the dopaminergic neurons that produce the sensation of pleasure and ...addiction. The problem is that nicotine is a small molecule that easily passes the blood-brain barrier.

The aim of GSK is to prevent nicotine from passing into the brain and reduce the urge or need to smoke. The three laboratories have combined with a viral protein or cholera toxin, genetically amended, so that it is not dangerous.

When all nicotine-toxin is injected into the body, it is recognized as foreign by the immune system that directs the cells to produce antibodies. The antibodies circulate in the blood, recognize nicotine tobacco and stick to it. This makes a molecule so large that it becomes unable to cross the barriers that protect the brain.

The three competing firms have progressed at different pace. When the British company Xenova (since absorbed by Celtic Pharma) has launched the development of this type of vaccine in late 1999, results on rats were immediately very interesting.

And the first human trials known as Phase 1 started in 2001 on sixty volunteer smokers and nonsmokers, have shown that the product was well tolerated. In 2005, the Cytos vaccine, tested by Jacques Cormuz, Switzerland tobaccologist in University Hospital Lausanne had taken a step ahead.

A positive test was presented at the Congress of the American Society of Clinical Oncology in Orlando on 300 heavy smokers aged 18 to 70 years who had quit smoking for 8 weeks. A third of the vaccinated volunteers had high antibody production and 57% of these subjects had not relapsed six months after vaccination.

As for the vaccine of GSK-Nabi: if the phase 3 trials are positive, it could be quickly approved by the Food and Drug Administration. Several problems remain to be overcome: 70% of vaccinees make an acute influenza-like illness. The antibodies have a short half-life. Thus, it will therefore require repeated injections in case of relapse. Finally, an ethical problem is for adolescents that would be vaccinated to prevent them from starting to smoke.

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