No smoke with NicVAX

Nabi Biopharmaceuticals, of Rockville, MD, has reported positive Phase II clinical results for NicVAX (Nicotine Conjugate Vaccine), a vaccine that is being developed to prevent and treat nicotine addiction by acting as an aid to stop smoking.

The results indicated a 33% quit rate in smokers who received NicVAX at the highest dose level versus 9% in the placebo group. The results represented a vaccine-only effect, as patients were only given NicVAX without any supplemental treatments, behavioral support or counselling. The objectives of the study were to show that NicVAX was able to safely generate nicotine- specific antibodies in smokers, and to assess its potential use as an aid in stopping smoking among smokers who wanted to quit.

NicVAX is designed to cause the immune system to produce antibodies that bind to nicotine and prevent it from entering the brain, thereby preventing the 'rush' that occurs when nicotine binds to receptors in the brain. This 'rush' is believed to be the main physical reason that most people cannot stop smoking.

In addition, results showed a substantial reduction in average cigarette consumption in smokers who received the highest dose of NicVAX versus lower doses or placebo. Smoking cessation was confirmed by cotinine and carbon monoxide levels, which are biochemical markers of smoking. Nicotine dependency was measured by a questionnaire and also showed a substantial reduction at the top dose of NicVAX as compared with placebo or the lower dose levels. Nabi said NicVAX was very well tolerated and side effects were similar between the active dose levels and the placebo group. The outside clinical costs for the trial were funded by a grant from the National Institute on Drug Abuse, under the US National Institutes of Health.

'The vaccine-only effect that we saw in this trial is truly impressive,' said Dr Henrik Rasmussen, senior vice president clinical, medical and regulatory affairs, Nabi Biopharmaceuticals. Dr Rasmussen continued: 'If these results could be repeated in a larger study, it would make NicVAX potentially one of the most efficacious approaches to smoking cessation available. The 33% efficacy rate that we saw at the high dose level is particularly remarkable when one takes into consideration that this was a vaccine-effect only and that psychological counselling or other behavioral interventions were not provided.'