First Cocaine Vaccine Being Tested in Humans
March 31, 2000 (Atlanta) -- An experimental vaccine to help cocaine users overcome their habit is currently being tested in humans. If it fulfills its promise, the vaccine, called TA-CD, could offer hope to millions of cocaine users who relapse, despite the desire to quit.
"TA-CD offers the potential for a completely new and highly viable approach to a very serious problem for which there are no alternative therapies," principal investigator Thomas Kosten, MD, says in a prepared statement.
"The White House's Office of National Drug Control Policy estimates that there are 3.6 million Americans who use cocaine [regularly]," Frank Vocci, PhD, tells WebMD. "That is about 2% of the U.S. adult population ? in need of treatment." Vocci is director of the Division of Treatment, Research, and Development at the National Institute on Drug Abuse (NIDA), the organization funding the Kosten study.
Kosten, a professor of psychiatry at Yale, will test TA-CD on 20 individuals, in part to determine dosage. Kosten explains that the goal of this study is to give the vaccine more regularly initially, so that levels of antibody, substances that attack foreign objects in the body, can be increased.
In his initial cocaine vaccine study, Kosten established that the vaccine was effective in producing antibodies that specifically attack cocaine; he determined that the antibodies remained circulating in the bloodstream for, at most, a year. "The results of the first study are simply that we did find antibodies," says Kosten. "[T]he higher the dose of the vaccination, the higher the level of antibodies we got. And there didn't appear to be any safety issues involved."
The vaccine works by inducing the body to create antibodies to cocaine. If a person uses the drug after being vaccinated, the antibodies would bind to the cocaine molecules and keep them from entering the brain and producing a high. The vaccine, however, does nothing to control cravings; in theory, it would be used with other forms of therapy to help patients stay clean.
"[E]ven though [cocaine] is a foreign object to the body, it [is cleared from the body] too fast for the body to recognize and [the body] doesn't have time to make antibodies against it," Kathleen Kantak, PhD, tells WebMD. She explains that when the vaccine attaches to the cocaine, "the immune system kicks in and starts making antibodies that specifically recognize that one foreign component ? which happens to be cocaine. And these antibodies are very long-lasting and circulate in the bloodstream. ? So when a person takes cocaine, before it gets into the brain, it has to get into the [bloodstream, and] these antibodies will recognize and bind to the cocaine, preventing its entry into the brain. If you slow down or reduce the amount of cocaine that gets into the brain, you are going to blunt or block its ability to [produce a 'high']."