February 1, 2011

Vaccine for Cocaine Addiction Discovered

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Currently, only psychosocial therapies exist for addiction; however, researchers have developed a vaccine to immunize mice from the effects of cocaine. The researchers were scientists from Weill Cornell Medical College, the University, and the Scripps Research Institute.

According to Prof. Ronald G. Crystal, genetic medicine, Weill, “Next to heroin, cocaine is probably the leading cause of recreational drug addiction.”

The challenge with making a vaccine for most addictive substances is that the molecules are too small for the human immune system to detect. The cold virus, in contrast, produces a strong reaction from the immune system, so researchers attached a cocaine analog to the virus. The immune system then produced antibodies to cocaine.

Previously, other researchers have explored this method by attaching addictive substances to certain proteins, but these were not as immunogenic as the cold virus.  As Crystal put it, the “fundamental trick” the researchers used was the strong immune response cold viruses cause.

When cocaine was administered to the mice after the vaccine was given, they were unaffected. Without the vaccine, the mice demonstrated excitement. Giving mice the vaccine prior to giving them cocaine “was like giving them water,” Crystal said.

A dose of the vaccine works to intercept the reaction cocaine has when it enters the bloodstream and travels to the brain (which takes about six seconds from when it enters). The researchers have replicated the study many times and are now doing studies with rats, which show similar results.

Such a vaccine has the potential to change drug rehabilitation methods in humans. Crystal made it clear that “humans are not just big mice.” To move to humans, safety needs to be established. Furthermore, efficacy in large animals would be necessary, especially in non-human primates. If no adverse affects are displayed in animals, research will be geared towards cocaine addicts looking to abandon the habit.  If all goes well, the researchers could be working with humans in one to two years.

“Assuming this approach works, this is a platform strategy that can be used to attach any addictive molecules […] It should work for nicotine and heroin or amphetamines. Preliminary data for nicotine shows that similar results were produced,” Crystal said.

Original Author: Katerina Athanasiou