Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=221969
Story Retrieval Date: 4/23/2014 4:40:40 AM CST
A vaccine to block cocaine users from getting high could be available for trials in humans within the year, but questions remain about its effectiveness to “cure” those with a history of addiction, according to researchers at Weill Cornell Medical College in New York.
Dr. Ronald G. Crystal, chairman of the Department of Genetic Medicine at Weill Cornell Medical College, and his colleagues have completed pre-clinical trials of a novel strategy for fighting cocaine addiction: Using particles of the common cold virus.
“I got the idea from my experience in gene therapy,” he said. “I figured if we could hook particles that mimic the structure of cocaine to the common cold virus and trick the immune system into thinking that the drug was actually part of the virus, the immune system would develop a resistance.”
A cocaine high is achieved when the drug reaches the brain and accumulates in its nerve endings, preventing dopamine receptors from recycling. As a result, these receptors remain active, leaving users with a feeling of euphoria.
The vaccine would interfere with this process by preventing cocaine from reaching the brain in the first place.
“The question is, of course, can we create an immunity defense strong enough to hold up in humans,” said Crystal, who so far has only conducted safety studies on rats and primates. “We’re moving up in size,” he added, noting that it would likely take several weeks to a month for the vaccine to kick in, and would need to be re-administered every six months or so.
Another hurdle to overcome is the human element. Crystal pointed out that if he advances the vaccine to human trials, he first plans to administer it to those who actively want to stop using, since they won’t crave the positive effects as much those who have a history of addiction.
“People with addiction for the most part are people who had the illness and used other things before they used drugs – overeating, serial relationships, interpersonal drama, etc. – all things that have been shown to increase midbrain dopamine tone,” said addiction expert Dr. Howard Wetsman, chief medical officer at Townsend Addiction Treatment Centers in New Orleans. These people typically move onto drugs like cocaine because they develop a tolerance to their previous addictions.
“So what happens if you take such a person and make their drug not work? They feel bad, not better,” Wetsman, author of “Questions and Answers on Addiction,” explained. “They need more drug, not less. Rats in a cage can’t just switch to pot; it’s not available.”
This is why the vaccine alone shouldn’t be looked at as a silver bullet for curing cocaine addiction, according to Ramsen Kasha, executive director at Hazelden Addiction Treatment Center in Chicago. “What we have found is that the best way to affect long-term recovery is to focus on all aspects of addiction, such as social and spiritual – not just psychological,” he said.
The silver bullet factor is a risk that accompanies most all psychopharmacological interventions, because most addicts, by nature, are looking for a quick fix.
“Nobody wants to hear that they have to commit to a 12-step program in addition to a vaccine for cocaine,” Kasha said. “Having said that, I do feel a vaccine could be excellent if used as an adjunct to longer-term treatment.”
According to the American Society of Addiction Medicine, which altered its definition of addiction 2011, addiction is now recognized as not just a choice, but a neurological condition.
“Addiction is a chronic brain disorder and not simply a behavioral problem involving too much alcohol, gambling or sex,” according to the ASAM release.
Ethical issues may also arise since, unlike cocaine itself, traces of the vaccine may last in a person’s systems for weeks, or even months, Kasha said. This could lead to problems in the workplace if, for example, urinalysis is required for random drug tests.
Crystal concluded that a similar concept to the cocaine vaccine could work in a similar fashion for other addictive molecules, such as heroin and amphetamines.
Wetsman added that while “the whole vaccine idea is great if the problem is really ‘normal people’ – those who want to use cocaine mainly to have more than their fair share of fun’ – using drugs, but it’s pretty much useless if the problem if a disease called addiction was there before the drugs.”