September 22, 2003
UPTON, NY - Using an experimental addiction treatment first investigated at the U.S. Department of Energy's Brookhaven National Laboratory, a team of scientists from Brookhaven, the New York University (NYU) School of Medicine, and a national addiction treatment center in Mexico report prolonged abstinence and the elimination of drug craving in eight out of 20 hard-core, long-term cocaine addicts who enrolled in the study. This is the first human clinical data showing that gamma vinyl-GABA (GVG, vigabatrin) holds promise as a pharmacological treatment for cocaine addiction. The results will appear in the December 1, 2003, issue of the journal Synapse, available online September 22, 2003.
"It is extremely gratifying to see these early human results bear out what we've observed in our extensive preclinical animal studies with GVG," said Brookhaven neuroanatomist Stephen Dewey, who has been using animal models and brain imaging techniques to investigate GVG's effects on neurochemistry and addictive behavior for more than ten years. These animal experiments have shown that GVG can block drug-induced increases in brain dopamine (a chemical associated with reward and pleasure, which is elevated by all addictive drugs), drug-seeking behavior, drug self-administration and sensitization, and drug craving - even that triggered by environmental cues (see detailed information about GVG ).
"This promising work on a potential treatment for drug addiction illustrates the value of the Department of Energy's basic research in physics, chemistry, and imaging sciences," said Secretary of Energy Spencer Abraham. "The advanced technologies developed in the DOE laboratories are being applied to a number of critical national health issues, including the problem of drug abuse."
Said lead author Jonathan Brodie, a psychiatrist and biochemist at NYU who also collaborated on the animal experiments, "These human clinical data support the need for a larger double-blind placebo-controlled trial that will more carefully examine the risk/benefit relationship for GVG in the treatment of cocaine addiction - a life-threatening disease for which there are currently no effective pharmacological treatments."
The study was conducted in June and July of 2003 at a Mexican-government-designated addiction treatment center in Baja California (the Clinica Integral de Tratamiento Contra Las Adicciones in Mexicali, B.C.) at the suggestion of Emilia Figueroa, a physician familiar with Dewey's preclinical work on GVG. GVG is approved for use in the treatment of epilepsy in Mexico (and many other countries), but not in the United States because it can sometimes cause a reduction in the field of vision. The protocol was approved by the state of Baja California and the Mexican federal government.
Twenty daily cocaine abusers who expressed an interest in breaking their drug dependence were enrolled and given an escalating daily dose of GVG, starting with one gram twice a day, and reaching two grams twice a day by day seven of the trial. The subjects were treated as outpatients, allowed to return home each day and go about their normal lives. They were encouraged to participate in group and individual therapy programs, and all were required to provide urine samples for drug screening twice weekly and complete daily questionnaires on drug use and craving.
Eight subjects dropped out within the first 10 days, stating that they did not wish to stop their cocaine use. Of the 12 who continued treatment with GVG, eight achieved periods of abstinence of more than 28 consecutive days, the duration set as a benchmark for successful treatment. All eight were tapered off GVG after completion of the trial, and remained drug-free at the time of publication. Four other patients stayed in the trial for periods ranging from 25 to 43 days but continued to use cocaine, albeit in significantly reduced amounts. None of the study participants reported any visual disturbances.
Those who completed the study reported that their craving for cocaine was eliminated within two to three weeks. They showed profound behavioral gains in self-esteem, family relationships, and work activities.
"The success rate achieved in this small study - 8 out of 20 remaining in the trial and drug-free - is comparable to that of other experimental cocaine addiction treatment protocols. But the prolonged duration of abstinence far exceeds what other pharmacological treatments have achieved," said Dr. Frank Vocci, Director, Division of Treatment Research and Development, National Institute on Drug Abuse.
"The results are particularly impressive considering that the study subjects remained in the same neighborhood, where the drug is readily available, and with all the cues and social pressures that supported their addiction for so many years," said Figueroa.
The scientists hope that larger scale trials on GVG will be conducted at NIDA-sponsored addiction research centers in the U.S. to investigate its efficacy as a treatment for addiction as well as any side effects.
In October 2002, Catalyst Pharmaceutical Partners of Coral Gables, Florida, received an exclusive worldwide license from Brookhaven Science Associates, operator of Brookhaven National Laboratory, for the use of the drug vigabatrin for its application in treating drug addiction.
This work was funded by the Biochemical Psychiatry Fund at the NYU School of Medicine, the Office of Biological and Environmental Research within the U.S. Department of Energy's Office of Science, and the National Institute on Drug Abuse.
2003-206 | Media & Communications Office