COKE VACCINE TRIALS TO START |
A vaccine which prevents cocaine from affecting the brain has been proven successful
in animal models and will be tested on human beings beginning later this year. After months of anticipation, ImmuLogic Pharmaceutical Corporation of Waltham, MA announced last summer that it had received a $700,000 grant from the National Institute on Drug Abuse (NIDA) to fund the human trials. The vaccine introduces an antibody into the bloodstream that neutralizes the effect of cocaine. An antibody is usually a protein manufactured by the body in response to an "antigen," some foreign substance entering the bloodstream. Typically, antibodies play an important role in enabling the immune system to resist disease. ImmuLogic claims that preclinical studies have shown that "vaccine-induced antibodies inhibit the passage of cocaine to the brain," and that "treatment with cocaine-specific antibodies eliminates the effect of cocaine in rats" which had been induced to self-administer the drug. The successful results were reported in 1995 in both Science News and in a Chemical And Engineering News article by ImmuLogic vice president Barbara Fox. In NIDA's February 1996 report on basic research, institute director Alan Leshner previewed the vaccine, commenting, "One of the country's greatest needs in dealing with its drug problem is a medication for cocaine addiction, since we have none." A somewhat similar existing method involves dosing alcoholics with disulfiram (marketed by Wyeth under the trade name Antabuse), a drug which makes people violently sick when combined with alcohol. In theory, the unsatisfying response to indulgence in alcohol will, after a few negative experiences, attenuate the craving for alcohol. While the ImmuLogic vaccine may not produce similar nauseating effects, it is assumed that when addicts discover that cocaine no longer has any effect on them, their craving will likewise diminish over time. By forcibly preventing relapse into addiction, the vaccine should greatly enhance client compliance with treatment. According to Fox, ImmuLogic is "optimistic that it is going to be either a stand-alone pharmacotherapy or a therapy that could be used in conjunction with other therapies." ImmuLogic plans to develop similar vaccines for other drugs, beginning with nicotine. Neither NIDA nor ImmuLogic has so far suggested that such a vaccine is likely for marijuana. The development of biotechnology to block the effects of THC is problematic. However, a 1993 article in the Proceedings Of The National Academy Of Sciences reported progress on identification of an antibody that enhances natural anti-THC antibodies. Anandamides, the natural brain substances which trigger specific nerve receptors to produce the characteristic effects of marijuana, may actually inhibit the pharmacological effects of THC in the brain, according to a 1994 report in the Journal of Pharmacology and Experimental Therapeutics by Dr. Raphael Mechoulam of Israel. Though this is somewhat different from the way an anticocaine vaccine would work, it might present one possible way to block THC effects in the brain. ImmuLogic notes that out of over two million "heavy" cocaine users in the United States, about 400,000 seek medical assistance for treatment every year. The vaccine, they say, is envisioned for use only with these consenting treatment clients. At its present level of development, it will require frequent booster shots, perhaps every six to 12 months, rendering it quite costly to, for example, preventively vaccinate "at-risk" youths and provide them boosters at regular intervals. Technological innovations often have unintended or unforeseen consequences. Advocates of drug-policy reform often argue for medical distribution of cocaine, or other forms of regulated availability, as a way to eliminate or reduce drug-related crime and black-market profits. Opponents express reasonable concern over possible addiction problems that could result. If clinical trials are successful, a cocaine vaccine might provide additional protection for society from any increased cocaine use that might follow introduction of regulated availability of the drug. ImmuLogic has also developed products to treat allergies to cats and ragweed, and is developing a treatment for multiple sclerosis with the German firm Schering AG. The proprietary work at ImmuLogic should not be confused with research at the Scripps Institute in La Jolla, CA, by Kim Janda, Rocco Carrera and George Koob. The Scripps workers have treated rats with an analog (a chemically similar substance) of cocaine, which enabled them to produce their own natural antibodies to prevent the drug from operating on the central nervous system. |