One of the key messages to emerge from this week’s much-discussed findings regarding a vaccine for cocaine dependence points out that the science may be getting far ahead of its practical application. Experts agree that many hurdles need to be cleared before a marketable vaccine reaches the addiction treatment community, but they are also quick not to downplay the importance of the latest research findings.
“This research is very encouraging because it clearly shows that this strategy can work,” says Nora Volkow, M.D., director of the National Institute on Drug Abuse (NIDA), which financed the latest study. She said in an interview this week, “While I have always been very cautious when talking about a vaccine, it’s important to put on the table that it is possible.”
Published this month in the Archives of General Psychiatry and presented in an Oct. 5 teleconference sponsored by NIDA, the research involving 115 cocaine- and opiate-dependent individuals in a methadone maintenance program found that 38% of individuals receiving a cocaine vaccine attained threshold antibody levels that can result in decreased cocaine use. Moreover, it was found in weeks 9 to 16 of the 24-week study that individuals with the highest antibody levels produced significantly more cocaine-free urine samples than did individuals with lower antibody levels or those who received a placebo rather than the vaccine.
The cocaine vaccine being tested produces antibodies that block cocaine’s entry into the brain and thereby reduces cocaine-induced euphoria without causing any other psychoactive effects. Further research will be looking largely at how to improve antibody response in more individuals, says the study’s co-author, Thomas R. Kosten, MD, of the Baylor College of Medicine in Texas. Yet Kosten adds, “The only other comparable research in addictions is for a nicotine vaccine, and our results [at 38%] are better than those.”
This leaves pharmaceutical company indifference to the addiction treatment market as arguably the greatest stumbling block to availability of a cocaine vaccine. There are currently no federally approved medications to treat cocaine dependence, and while several drug companies already have vaccine technologies that are more effective than the ones examined in current addiction research, none have shown major interest in entering an addiction market seen as risky and not lucrative.
“The timing of a vaccine depends on resources and buy-in from pharmaceuticals,” says Volkow, who believes companies will have to receive incentives in order to spur participation. “If there was such a company and there were resources, we could have something in three to five years.”