Monday, January 14, 2008

Cocaine Vacine?

Have not yet formulated an opinion on this but worthy of watching for updates I suppose.- Chy

A husband and wife team based at Baylor College of Medicine (BCM) in Houston, Texas, have developed a cocaine vaccine that is currently undergoing clinical trials. The vaccine, which is based on an inactivated form of the drug, teaches the immune system to fight real cocaine and stop it getting to the brain and delivering the expected "high".

Developing a vaccine to free millions of addicts from dependency on substances such as cocaine, methamphetamine and nicotine, has been a long term goal of Tom and Therese Kosten for more than 30 years. They were ice skating partners as teenagers, and both went to Yale, he to complete his medical training and she to do a PhD in psychology and neuroscience. They joined BCM's Menninger Department of Psychiatry & Behavioral Sciences 18 months ago after relocating from Connecticut.

Tom Kosten, who is now psychiatry professor at the college told the Houston Chronicle the vaccine should help people who want to stop using cocaine:

"At some point, most users will give in to temptation and relapse, but those for whom the vaccine is effective won't get high and will lose interest," he explained.

Tom Kosten recently asked the US Food and Drug Administration (FDA) to give the go ahead to a phase III clinical trial of the vaccine. All being well, the multi-centre study will begin in the spring, although full FDA approval may take several years after that. The trial involves 300 participants in six locations around the US, including Houston.

Speaking in an interview shortly after they joined BCM, Tom Kosten said he and his wife were both:

"Interested in developing medications to treat addictions."

"One attraction for me is the immense social implications of the area," he added.

The Substance Abuse and Mental Health Services Administration estimated that in 2005 some 22.5 million Americans were classed as substance dependent.

The habit has a large price tag, costing the nation over 480 billion dollars a year, according to the National Institute on Drug Abuse. This is almost three times as much as cancer, with considerable social implications.

When under the influence of drugs, and often for up to a week after stopping, some abusers become sociopathic, and homicidal. As Kosten explained to online college magazine BCM Solutions last summer, drugs hijack the normal brain pathways that are needed for normal social functioning:

"Through brain imaging studies, we have learned that many abusers can be insensitive to feelings and emotions in others. The abuser's brain just doesn't register that another person is in pain or that the abuser may be causing that emotional, and in extreme cases, that physical pain."

Many drugs like cocaine are made of small particles that are too small for the immune system to react to and then destroy with antibodies. What was needed thought Tom and Therese, was something bigger that the immune system could react to and at the same time "learn" to fight cocaine.

The solution, which seems obvious now, but has taken nearly ten years to perfect, is very clever. Take an inactive cholera toxin protein and attach inactivated cocaine to its surface. This "tricks" the immune system into making antibodies against cocaine. The immune system "sees" the inactivated cholera toxin and also the cocaine pattern and makes antibodies against both substances.

Then, when the vaccinated patient ingests cocaine, the antibodies made in response to the inactivated version attack the real thing by binding to it and stopping it reaching the brain. The expected "high" doesn't occur, the reinforcement pattern is broken, and the patient eventually loses interest. Or that's the theory that needs to be tested.

Should the vaccine get through clinical trials (assuming the FDA give the go ahead), it will be a significant breakthrough in the treatment of cocaine addiction, which currently comprises psychiatric help and a 12 step programme.

Some experts have urged people excited by the idea not to expect too much. Not only may it be some time before a vaccine hits the market, it may not work for every one.

As with all new treatments there are a number of ethical and other questions to resolve. Who should get the treatment? What type of support will people need? And what if hardened addicts just take a lot more of the substance as a way to overcome the ability of the immune system to respond? What effect might that have on their sociopathic tendencies, quite apart from the medical implications?

According to law professor and chairman of the District of Columbia Medical Society's physician health committee, Peter Cohen, interviewed by the Houston Chronicle, these issues are not unsurmountable:

"Overall, the benefits to society of such vaccines would outweigh the risks."

Click here to read full story in Houston Chronicle.

Sources: Houston Chronicle, BCM Solutions.

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