Multisite Controlled Trial of Cocaine Vaccine

This 18-week, placebo-controlled randomized clinical trial among 300 cocaine dependent patients is designed to test the efficacy of a newly developed active vaccine against cocaine (TA-CD). TA-CD vaccine consists of succinylnorcocaine (SNC) coupled to a recombinant cholera toxin B subunit (rCTB) and is designed to raise anti-cocaine antibodies in the circulation to bind to cocaine entering the bloodstream, following administration by intravenous or intranasal routes or by smoking. The antigen-antibody complexes will be too large to cross the blood-brain barrier, preventing high concentrations of cocaine reaching the brain's nucleus accumbens thereby blocking the pleasurable response to cocaine and reducing rates of drug use. The effectiveness of the vaccine is dependent on inducing sufficient levels of anti-cocaine antibodies to match the challenge from a subsequent dose of cocaine. Because TA-CD takes several weeks to generate an antibody response, we plan to use contingency management in this interval to sustain treatment engagement. Furthermore, since TA-CD may prove most effective in patients where the antibodies can prevent a cocaine slip from turning into a binge (or return to regular use) by attenuating the priming effect, we are complementing the vaccine by using cognitive behavioral therapy (CBT) to teach patients how to cope with this priming effect and prevent a full relapse.