Nabi Biopharmaceuticals has completed enrolment for its European-based NicVAX (Nicotine Conjugate Vaccine) Phase II dose-ranging study in smokers. NicVAX is a novel, innovative, and proprietary investigational vaccine being developed to prevent and treat nicotine addiction.

According to a company release, the study, designed to evaluate NicVAX's safety, antibody response to nicotine, and measure smoking cessation/nicotine dependency, is a randomized dose-ranging study in smokers. The four NicVAX dose levels, 100, 200, 300, and 400 mcg per injection, will be given over a six-month period with 10 patients included per dose group. Based on clinical trial results generated to date, Nabi Biopharmaceuticals has observed no significant toxicity through the 200 mcg dose level, hence the current study is designed to evaluate whether higher doses of NicVAX could further increase anti-nicotine antibody levels without increasing toxicity.

Thomas H. McLain, chairman, chief executive officer and president says, "Nabi Biopharmaceuticals' NicVAX is potentially advantageous in three important and commercially strategic ways: The vaccine appears to be very well tolerated, even at 200 mcg, the highest dose level tested, allowing us to explore higher and potentially even more efficacious doses; our unique and proprietary mechanism of action for NicVAX, using the same carrier protein as we use in StaphVAX, is based on an established mechanism of action; and, we believe NicVAX is the most advanced smoking cessation product of its kind in development.”

“By the end of 2005, we intend to announce preliminary results from this European Phase II study, be in a position to initiate a European Phase III pivotal trial, and begin to manufacture commercial scale material in our own vaccine manufacturing facility in Boca Raton, Florida," he added.

In September 2004, Nabi Biopharmaceuticals announced the results from a US Phase II trial with NicVAX that indicated a 33 per cent quit rate in smokers who received NicVAX at the highest dose level versus 9 per cent in a placebo group. This was a NicVAX-only effect without any additional interventions, supplemental treatments, behavioural support or counselling.

The objectives of the US 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 smoking cessation.

NicVAX is designed to cause the immune system to produce antibodies that bind to nicotine and prevent it from entering the brain. It is believed that these nicotine antibodies will act like a "sponge" soaking up nicotine as it circulates in the bloodstream and preventing it from reaching the brain. The positive stimulus in the brain that is normally caused by nicotine would then no longer be present, thereby taking away the physical motivation for smoking, consequently helping people to quit, says the release.