Cocaine addiction is a problem affecting more than one million Americans, leading them to physical and financial ruin. But a new hope is in the works to prevent addicts from falling off the wagon. Researchers at Weill Cornell medical College in New York City have just completed trials on primates, showing that after vaccination and cocaine treatment, the drug never made it to the brain. The results were published in the Nature journal Neuropsychopharmacology.

Cocaine is a small molecule drug that comes from the coca plant and is used as a recreational drug to induce feelings of happiness and energy. The drug works by bliocking the recycling of dopamine, the pleasure neurotransmitter, in the brain.

"The vaccine eats up the cocaine in the blood like a little Pac-man before it can reach the brain... 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. Even if a person who receives the anti-cocaine vaccine falls off the wagon, cocaine will have no effect," said the study's lead investigator, Dr. Ronald G. Crystal, chairman of the Department of Genetic Medicine at Weill Cornell Medical College.

The vaccine combines parts of the flu virus and a molecule the mimics the physical structure of cocaine. When the modified cold virus is injected, the immune system reacts to it and to the cocaine mimic as well, creating antibodies against the mimic. The antibodies are then present in the blood and stick to cocaine molecules preventing them from crossing the blood brain barrier and making people high.

The first set of experiments on the vaccine was performed on mice, a key step before human trials that the researchers hope to start later this year. Researchers developed a technique that would use a short-lived radioisotope to bind to the dopamine transporter receptor in the brain. A positron emission tomography (PET) scan of the primates was able to detect that there was a large drop in the detection of the tracer in nonvaccinated test subjects but not vaccinated subjects. This means that the vaccine prevented cocaine from entering the brain and binding to receptors.

"This is a direct demonstration in a large animal, using nuclear medicine technology, that we can reduce the amount of cocaine that reaches the brain sufficiently so that it is below the threshold by which you get the high... an anti-cocaine vaccination will require booster shots in humans, but we don't know yet how often these booster shots will be needed. I believe that for those people who desperately want to break their addiction, a series of vaccinations will help," said Dr. Crystal.

Maoz A, Hicks M, Vallabhjosula S. Adenovirus Capsid-based Anti-cocaine Vaccine Prevents Cocaine from Binding to the Nonhuman Primate CNS Dopamine Transporter. Neuropsychopharmacology. 2013; doi:10.1038. Accessed May 10, 2013.