Vaccine aims to help smokers quit

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Vaccine aims to help smokers quit

LONDON, Sep 10 (Reuters Health) - A British biotechnology company, already

developing a vaccine to help addicts kick cocaine, said on Monday it had

started clinical trials on a nicotine addiction vaccine.

The product, manufactured by Xenova Group Plc and given by injection into

the muscle, aims to prevent the addictive cycle of cigarette smoking by

stopping nicotine from entering the brain.

The nicotine molecule by itself is too small to generate an immune response,

Xenova's medical director, St. Clair , told Reuters Health, so

the vaccine contains nicotine bound to an existing cholera vaccine.

The combined molecule generates anti-nicotine antibodies in the bloodstream

that in turn make the nicotine too big to pass the blood-brain barrier,

thereby blocking the normal " high " generated by the drugs and potentially

helping smokers quit " cold turkey. "

Although the vaccine, called TA-NIC, is unlikely to completely block all the

nicotine from entering the brain, it will slow it down, which is more

important for preventing the nicotine 'hit' smokers get, said.

He predicted that the vaccine would need to be given in four or possibly

five doses, with booster shots required as the antibodies only last in the

bloodstream for months.

However, the initial Phase I study of TA-NIC will merely assess its safety

and tolerability at different doses, and researchers still have several

years work ahead of them to prove the efficacy of the product.

estimated that the clinical development program for the vaccine could be

completed in 4 years.

Oxlade, Xenova's chief executive, said the vaccine could eventually

have an important role to play in helping smokers quit. About one third of

smokers attempt to quit each year.

The company says the vaccine would be effective at generating an immune

response while smokers continued their habit.

Currently available smoking cessation products include nicotine replacement

therapy, delivered via skin patches or chewing gum, as well as drugs

including GlaxoKline Plc's Zyban. Last year, Boca Raton, Florida-based

pharmaceutical firm Nabi received a grant from the US National Institute on

Drug Abuse to conduct trials of their own nicotine vaccine, called NicVAX.

Xenova has a total of eight products in clinical trials, the most valuable

of which is deemed to be XR 9576, designed to fight multi-drug resistant

cancer. Xenova struck a $105 million licensing deal for XR 9576 with

Vancouver-based QLT Inc. last month.

" A nicotine vaccine would be a profound development, which would effectively

become one of the most important medicines in the response to cancer, lung

and heart disease, " said Clive Bates, director of anti-smoking group Action

on Smoking and Health. " By helping people to quit smoking we can tackle

about 50 different diseases related to smoking before they can actually

occur. "