When we think vaccines, it's usually as a defense against infection from a nasty bug like the new H1N1 flu virus or even HIV.
But researchers say they're making progress on a vaccine to fight dependence on cocaine. You read that right--a vaccine that would help people curb cocaine use.
How would it work? A vaccine could prompt the production of antibodies to grab cocaine in the bloodstream and keep it from the triggering pleasure in the brain. Do that, the researchers hypothesized, and you might dull the interest in a cocaine fix, making it easier to shake the habit.
Results of a study comparing a five-shot regimen of an experimental vaccine and a placebo in 115 drug users also taking methadone showed promise and problems.
A high level of antibodies against cocaine was associated with a significant reduction in cocaine use. Yet just 38 percent of the study subjects achieved the desired level of antibodies, and the protection lasted for only a couple of months. So a stronger, longer-lasting vaccine would help.
Side effects from the vaccine were mild or moderate and not significantly different in the groups that got vaccine or placebo.
What's next? We asked Dr. Thomas Kosten, senior investigator on the study, now at the Michael E. DeBakey Veterans Affairs Center in Houston. In an email, he told a broader test of the vaccine at multiple sites is slated to start in Jan. 2010.
Any product is still long way off because Celtic Pharma, the owner of the current vaccine, doesn't have deep enough pockets to fund the phase III studies that would be required for FDA approval.
"Perhaps we can get Big Pharma interested," Kosten wrote, "but they will need legal protection from lawsuits from overdoses and various other complications that are unrelated to the vaccine."
Separately, the researchers have been testing in animals a more potent from of the vaccine that uses technology from Merck. But that has lots of hurdles to clear before a human test is even possible, Kosten wrote.
Work on the cocaine vaccine was supported by the National Institute on Drug Abuse, Celtic Pharma and the Veterans Administration medical centers in West Haven, Conn., and Houston.