New therapeutic vaccines help kick drug habits

Jun 23 2007

A pair of new vaccines designed to combat cocaine and methamphetamine dependencies not only relieve addiction but also minimize withdrawal symptoms, according to study results presented by Baylor College of Medicine (BCM) researchers at the Annual Meeting of the College on Problems of Drug Dependence in Quebec City, Canada.

The vaccines stimulate the body to produce antibodies which then attack the drug while it is in the blood stream. This prevents the drug from reaching the brain and creating the reactions that contribute to dependency.

"These are therapeutic, not preventative, vaccines," said lead investigator Dr. Thomas Kosten, Jay H. Waggoner Professor of Psychiatry & Behavioral Sciences at the Menninger Department of Psychiatry at BCM and research director of the Veteran Affairs national Substance Use Disorders Quality Enhancement Research Initiative. "They are meant for those who are already suffering from drug addiction."

Kosten stresses that while the vaccines have been shown to help overcome drug addictions, they do not necessarily curb relapse.

"This is not a stand-alone treatment," Kosten said. "There is a reason drugs were used in the first place, and that needs to be dealt with either through counseling or behavioral therapies."

TA-CD, the cocaine vaccine, works through a series of injections over a three-month period. Study participants began to respond favorably to the vaccine after about a month. TA-CD has one more large scale human study scheduled before it is ready for the FDA approval process.

"The vaccine slowly decreases the amount of cocaine that reaches the brain," Kosten said. "It's a slow process, and patients do not go through any significant withdrawal symptoms."

Antibody production was sustained for another nine months following the vaccine treatment. Additional injections were subsequently administered every four to eight weeks, if needed at all.

The methamphetamine vaccine, still in early stages of development, has produced similar results as TA-CD. While both vaccines spur antibody production, each has a unique protein composition that help the body target the different drugs.