The vaccine itself does not destroy cocaine molecules, rather it induces antibodies that bind to it, making the opiate lose its ability to pass through the blood–brain barrier—and thus unable to trigger a high.
To test the vaccine's effectiveness in humans, researchers (with some help and financial backing from Celtic Pharma) enlisted 94 subjects who had enrolled in a methadone treatment program for opiate addiction—and who also regularly used cocaine—for a placebo-controlled, double-blind study. (They decided on this group because methadone programs historically have better retention rates than programs for cocaine abuse only.) One group received a placebo, another a low dosage of vaccine, whereas a third was administered a high dosage over a series of 12 weeks with five total injections.
More than half of the subjects in the high-dosage group (53 percent) appeared to have laid off the cocaine for more than half of the trial period, the researchers report after tracking traces of the drug in urine samples collected three times a week. Just less than a quarter of subjects with the low dosage had the same track record, according to the results published online yesterday in the Archives of General Psychiatry. A drop in cocaine usage across all groups may also be attributed to a curb in opiate drug consumption from the methadone treatment.
Link | Image: U.S. Department of Health and Human Services