NicVAX

NicVAX is a nicotine conjugate vaccine intended to reduce or eliminate physical addiction to nicotine. According to the National Institute on Drug Abuse, NicVAX can potentially be used to inoculate against addiction.^[1] This proprietary vaccine is being developed by Nabi Biopharmaceuticals^[2] with the aid of the University of Houston-Clear Lake and University of Minnesota. NicVAX consists of the hapten 3'-aminomethylnicotine which has been conjugated (attached) to Pseudomonas aeruginosa exoprotein A. ^[3]

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NicVAX is still under development; it is currently in phase IIB of testing. As of October 12, 2006, Nabi has finished enrolling patients to test the vaccine.^[4] The testing was completed by May when Nabi issued a press release indicating that phase IIB testing was a success, with a large number of test subjects having abstained during the trial period.^[5]

Administration and effects

NicVAX is administered via an injection into the arm; the 3'-aminomethylnicotine molecule found in the vaccine^[3] instigates an immune response in which anti-nicotine antibodies are created. The antibodies bind to nicotine molecules, causing the merged molecules to be too large to enter the brain; this prevents nicotine from being able to affect the body. The idea behind the drug is that since often even a single cigarette can deliver enough nicotine to the brain to reinstate the addiction, blocking the entry of nicotine into the brain might prevent this renewed dependence.^[6] This treatment works for nicotine addiction from any source.^[7] Clinical Pharmacology & Therapeutics considers this method "attractive," since the antibody does not enter the brain; as a result, side effects on the central nervous system are not expected. Additionally, the antibodies produced bond only with nicotine.^[3]

However, while this drug may curtail addiction, it does not prevent psychological cravings; in fact, a user could potentially smoke heavily to compensate for the nullifying effects of NicVAX.^[7] However, a study performed indicated that this did not happen among the test subjects.^[8]

Studies

Initial tests, involving injections of nicotine-specific immunoglobulin G into laboratory rats in the early 2000s, resulted in nicotine levels in the brain cut by up to 65%.^[3]

A study, performed in 2005 for 38 weeks by the University of Minnesota Cancer Center's Transdisciplinary Tobacco Use Research Center and published in Clinical Pharmacology & Therapeutics, involved 68 smokers, none of whom had known health problems or intended to quit smoking in the next month. The test subjects were injected four times throughout the trial: when it began, and after four, eight and 26 weeks with either one of three dosages of NicVAX or a placebo. At the conclusion of the study, it was concluded that NicVAX was "safe and well-tolerated", with side effects including headaches, colds, and upper respiratory tract infections. While most of the test subjects continued to smoke, six people from the high dosage group, one person from the medium dosage group, no one from the low dosage group, and two people from the placebo group quit smoking. They did not start again for at least thirty days.^[8]

A one-year study, which started in June 2006, is being conducted by the University of California, San Francisco's Habit Abatement Clinic. UCSF is one of nine testing centers.^[9]

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