Therapeutic vaccines for nicotine dependence

Abstract

Smoking remains the leading cause of preventable death worldwide. Despite the development of a number of drugs for smoking cessation, overall efficacy of these substances is limited and the majority of smokers fail to quit smoking long-term. These drugs aim to help people quit by either replacing nicotine with an alternative source of nicotine (eg, patches or gums) or by reducing the withdrawal symptoms. A vaccine against nicotine has a different strategy: by inducing sufficient nicotine-specific antibodies, it is possible to sequester the drug in the blood and prevent it from entering the brain. In this way, the addictive properties of cigarettes are eliminated and smokers attempting to quit may be able to smoke one or two cigarettes without becoming hooked again. Essentially, a vaccine against nicotine targets the progression from lapses to full relapse rather than withdrawal symptoms. Recent research with vaccines against nicotine has clearly demonstrated in animals that antibodies can interfere with the addictive properties of nicotine in different settings. The first phase II clinical trial has confirmed the validity of the concept and shown that a vaccine against nicotine can be efficacious for smoking cessation in humans provided anti-nicotine antibody levels are sufficiently high.