Vaccination against nicotine: an emerging therapy for tobacco dependence.

Tobacco dependence is an addiction characterised by compulsive drug-seeking and drug-taking behavior and intensive craving in the absence of tobacco. Nicotine is the major addictive component of tobacco and acts on the reward system in the brain. Together with strong conditional reinforcements, unaided smoking cessation attempts are notoriously unsuccessful and even the most recently introduced pharmacotherapy, varenicline, only achieves a 23% continuous abstinence rate after 1 year. Vaccination against nicotine represents a promising novel concept for treating nicotine addiction. Antibodies against nicotine inhibit the passage of nicotine to brain and thus inhibit its addiction-reinforcing activities. There are three nicotine vaccines that are in clinical development. The first proof-of-concept study in smoking cessation with the vaccine NicQb (Cytos Biotechnology), a nicotine vaccine based on virus-like particles, demonstrated that continuous abstinence rates can be significantly increased by vaccination; however, as expected from the mode of action, a sufficient antibody level had to be achieved. Antibody level dependence of abstinence was also observed with the nicotine vaccine NicVAX (Nabi Biopharmaceuticals). Vaccination against nicotine has the potential of becoming an important therapy against tobacco dependence.