Vaccine pharmacotherapy for the treatment of cocaine dependence.

BACKGROUND

Cocaine abuse has no established pharmacotherapy, but active immunotherapy with a cocaine vaccine shows promise as a therapeutic intervention.

METHODS

An open label, fourteen week, dose-escalation study evaluated the safety, immunogenicity, and clinical efficacy of a novel human cocaine vaccine (TA-CD) in eighteen cocaine dependent subjects. Ten subjects (400 microg total dose group) received four-100 microg injections over the course of eight weeks. Subsequently, eight subjects (2000 microg total dose group) received five-400 microg vaccinations over twelve weeks. Intent to treat analysis of thrice weekly urine toxicologies and cocaine antibody titers were compared.

RESULTS

Sixteen of 18 subjects completed the study. There were no serious adverse reactions and the vaccine was well tolerated. The 2000 microg total dose group had a significantly higher mean antibody titer response (2000 units) as compared to the 400 microg total dose group (1000 units) (p = .05). The 2000 microg group was more likely to maintain cocaine free urines than those in the 400 microg group (Z = -3.12, p = .002). Despite relapse in both groups, most reported an attenuation of cocaine's usual euphoric effects at the six month follow-up time points (63% in the 400 microg and 100% in the 2000 microg groups).

CONCLUSIONS

The conjugated cocaine vaccine was well tolerated and cocaine specific antibodies persisted at least six months. The likelihood of using cocaine decreased in subjects who received the more intense vaccination schedule.