A neutralizer for nose candy? - October 06, 2009
A vaccine that takes the “yay” out of llello has shown some success in decreasing use in cocaine addicts, researchers reported 5 October in Archives of General Psychiatry. But the reduction was short-lived and only occurred in a subset of patients.
Similar to your standard vaccine, the cocaine vaccine induces the body to produce antibodies to cocaine. When a person snorts, smokes, chews or injects cocaine and it enters the bloodstream, the antibodies sop some of it up before it can make it to the brain and give the user an addictive, euphoric high. Then, while it’s trapped in the blood, an enzyme called cholinesterase finishes the job by degrading the chemical. The idea is that the vaccine, used in conjunction with other treatments like cognitive behavioural therapy, would help curb relapses and ultimately break dependency.
The Phase IIb study focused on people who were addicted to cocaine and opiates and were enrolled in an outpatient methadone treatment programme. These patients were ideal because people on methadone maintenance tend to show up for treatment fairly reliably, so the participants could be followed throughout the entire course of study (24 weeks, including the follow-up period).
Of the 115 (mostly white, mostly crack-smoking) users, 94 stuck with the whole trial. Of the 55 who received the vaccine injections, 38% developed antibody levels high enough to be effective, as determined by animal studies. After antibody production had peaked (about 8 weeks after the first injection), these high-antibody users were doing significantly less cocaine than users who received placebo or who produced lower levels of antibody — 45% of their urine samples were cocaine-free, compared with 35% of placebo or low-antibody users. No one was completely abstinent.
But by week 16 (a month after the last vaccine injection), cocaine use in these high-antibody addicts was back to the level of the other users. Lead author Thomas Kosten said in a press briefing that the optimal treatment would include boosters every two to three months for at least two years. He also mentioned that this was a “first-generation vaccine”, and that he might get better results from a better adjuvant or a better carrier (this vaccine used aluminium hydroxide as an adjuvant and a cholera subunit as the carrier).
More coverage
Vaccines for Drug Addiction Show Promise - LA Times
Cocaine vaccine may reduce ‘use' - BBC
Cocaine Vaccine Is the Real Thing - ABC News
Hopes high for cocaine-addiction vaccine - The Age
Image: Wikimedia Commons
Comments
Cocaine has MW = 303.35 while antibodies run about 150,000 (two light chains each ~25,000 and two heavy chains, each ~50,000). Intercepting 0.1 g of cocaine would require 25-49 grams of antibody. Direct interdiction is ridiculous.
Posted by: Uncle Al | October 6, 2009 11:36 PM