With so many people dying from diseases related to nicotine addiction and cigarette smoking, pharmaceutical companies are motivated to develop drugs to help smokers kick the habit. Approaches such as nicotine gum and patches have been approved for general use, but they have not been effective in helping people quit smoking. Up to 70% of all smokers try to quit each year, but only about 5% succeed (Volpp et al., 2009).

One line of research focuses on developing a vaccine for nicotine addiction. Kim Janda’s laboratory at the Scripps Research Institute has been working on developing vaccines for various abused drugs since the 1980s. Because of the large potential market, pharmaceutical companies seem most interested in a nicotine vaccination, but a vaccine approved by the U.S. Food and Drug Administration has yet to materialize.

Figure 4.1

LABORATORY EXPLORATION FIGURE 4.1 Nicotine vaccine. The concept of the nicotine vaccine involves the binding of the nico­tine with the antibody so that the new complex is too large to cross the blood–brain barrier.

As seen in Laboratory Exploration Figure 4.1, the idea behind drug vaccinations is that a given drug molecule is injected into the bloodstream so that antibodies are formed and attach to any subsequent molecules of that specific drug (in this case, nicotine) that are presented to the body. Because the nicotine molecule is so small, Janda and his colleagues developed a hapten (a small molecule that modifies the nicotine molecule so that it will elicit an immune response) that would latch onto the nicotine molecule and make it larger so it would be noticed by the immune system (Moreno et al., 2010). If the presence of nicotine eventually prompts self-generated antibodies to latch on to the nicotine–hapten molecule, then the overall complex becomes too large to cross the blood–brain barrier. If nicotine is restricted from entering the brain, then the nicotine user fails to experience the reinforcing psychological effects that would otherwise sustain an addiction. In a sense, the reward faucet is cut off in these individuals. At least, that is the way this treatment is supposed to work.

Although Janda’s findings with animal models have been difficult to transfer to the human clinical population because of more variable levels of nicotine antibodies in the blood serum of humans compared with rats, some predict that his career-long efforts directed toward this single cause will one day succeed (Lockner et al., 2015; Roiko et al., 2008). It is interesting to consider how a vaccination strategy to treat addiction, expanded to other drugs, could change attitudes toward addiction (Long, 2011; Quenqua, 2011). Will nicotine vaccinations, as well as cocaine and heroin vaccinations, become a standard part of our children’s vaccinations some­day? If so, will motivated users simply look for new drug variations to cross the blood–brain barrier? For the approxi­mately 25% of the U.S. population currently using nicotine and 6 million smokers worldwide who will die of smoking-related effects each year (Substance Abuse and Mental Health Services Administration, 2014; World Health Orga­nization, 2011), the short-term possibility of finding help in fighting nicotine addiction outweighs these unknown long-term consequences.