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13 May, 2013 18:57

Anti-cocaine vaccine to be tested on humans

Anti-cocaine vaccine to be tested on humans

Cocaine addicts may soon have a ‘cure’ for their unhealthy dependence: researchers have successfully created a vaccine that prevents cocaine particles from reaching the brain and inducing feelings of euphoria, thereby helping users break their addiction.

“The vaccine eats up the cocaine in the blood like a little Pac-Man before it can reach the brain,” Dr. Ronald G. Crystal, the lead investigator of the Weill Cornell Medical College study said in a press release.

“We believe this strategy is a win-win for those individuals, among the estimated 1.4 million cocaine users in the United States, who are committed to breaking their addiction to the drug,” he added. “Even if a person who receives the anti-cocaine falls off the wagon, cocaine will have no effect.”

Cornell researchers have successfully administered the vaccine to non-human primates and are now much closer to launching human clinical trials. Human testing is expected to begin within a year, Dr. Crystal believes.

Cocaine blocks the recycling of dopamine – a neurotransmitter that is responsible for feelings of pleasure. The drug prevents the reuptake of dopamine by the neuron that releases it, causing higher concentrations of dopamine to remain in the synapse and create a ‘high’.

“You get this massive flooding of dopamine and that is the feel good part of the cocaine high,” Dr. Crystal said.

The new vaccine prevents dopamine accumulation at the brain’s nerve endings. The vaccine consists of particles of the common cold virus and particles that mimic the structure of cocaine. Once the body receives an injection, it recognizes the cold virus and creates an immune response against both the common cold and the cocaine ‘impersonator’.

“The immune system learns to see cocaine as an intruder,” Dr. Crystals said.

In order to feel the drug high that cocaine users seek to achieve, at least 47 percent of the dopamine transporter needs to be occupied by cocaine. The Cornell researchers found that in vaccinated primates, cocaine occupied less than 20 percent of dopamine receptors – making it impossible for the animals to be affected by the drug. 

Researchers expect that the vaccine will work in humans, but do not know how often it needs to be administered to maintain its effect. The vaccine continued to work effectively for 13 weeks in mice and seven weeks in primates.

“An anti-cocaine vaccination will require booster shots in humans, but we don’t know yet how often these booster shots will be needed,” Dr. Crystal said. “I believe that for those people who desperately want to break their addiction, a series of vaccinations will help.”

There are about 1.9 million current and past-month cocaine users in the US, 1.4 million of which are considered addicts or abusers, according to the latest data from the National Institute on Drug Abuse. About one in five people who use cocaine will become addicted. There are about 2 million visits to US emergency departments for drug abuse each year, 480,000 of which come are a result of cocaine use.

A vaccine preventing cocaine-induced feelings of euphoria would help drug users break free from their addiction, thereby drastically reducing emergency room visits and health problems in the US.

“Cocaine addiction is a major social problem. It causes changes to behavior, it’s expensive and it’s illegal,” Dr. Crystal told LiveScience in 2012. “It’s very difficult to stop. If we could successfully develop a cocaine vaccine it would really be a very positive social advance.”