Pubdate: Wed, 2 Jan 2008
Source: Houston Chronicle (TX)
Copyright: 2008 Houston Chronicle Publishing Company Division, Hearst Newspaper
Contact:  http://www.chron.com/
Details: http://www.mapinc.org/media/198
Author: Todd Ackerman
Bookmark: http://www.mapinc.org/coke.htm (Cocaine)
Bookmark: http://www.mapinc.org/heroin.htm (Heroin)
Bookmark: http://www.mapinc.org/meth.htm (Methamphetamine)
Bookmark: http://www.mapinc.org/rehab.htm (Treatment)

HOUSTON SCIENTISTS SEE HOPE IN COCAINE VACCINE

Baylor Doctors Say Shots Block the Drug's High

The needle may be one of addiction's enduring symbols, but two 
Houston researchers hope injections of modified cocaine actually 
provide the first-ever medication for people hooked on the destructive drug.

The Baylor College of Medicine scientists have developed a cocaine 
vaccine, currently in clinical trials, that stimulates the immune 
system to attack the real thing when it's taken.

As a result, cocaine no longer provides a kick.

"For people who have a desire to stop using, the vaccine should be 
very useful," said Dr. Tom Kosten, a psychiatry professor who was 
assisted in the research by his wife, Therese, a psychologist and 
neuroscientist. "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."

Kosten, who joined Baylor 18 months ago, asked the Food and Drug 
Administration in December to green-light a multi-institutional trial 
to begin in the spring. It presumably would be the final clinical 
hurdle before the vaccine might be approved for treatment.

Approval would mark a breakthrough in the treatment of cocaine 
addiction, which now mostly involves psychiatric counseling and 
12-step programs. Over the years, Kosten notes, more than 50 
pharmaceutical options have been investigated and found wanting.

The vaccine also could raise interesting ethical questions involving 
who should get inoculated and what happens if confidential 
information about those receiving it becomes known. Although 
developed for therapeutic purposes - the number of cocaine addicts in 
this country is estimated at more than 2 million - the vaccine 
eventually is expected to be used for prevention, as well.

The questions include whether parents would be allowed to have their 
children inoculated; whether it would amount to coercion to make it a 
condition for lighter criminal sentences; whether employers might 
happen upon such information and use it discriminatorily; and whether 
to use it on pregnant addicts to protect the fetuses.

The questions don't just reverberate about this vaccine: Tom Kosten 
also is at work on vaccines for methamphetamine, heroin and nicotine. 
Two other nicotine vaccines are being investigated by other scientists.

"Anti-drug vaccines may provide an important weapon against 
addiction," said Frank Vocci, director of treatment research and 
development at the National Institute of Drug Abuse, which funded 
much of the research. "We're starting to see progress. We just need 
to see more."

Concept Called 'Clever Idea'

No one denies the extent of the problem. Federal estimates put the 
number of Americans classified with substance abuse or dependence at 
22.2 million and the cost to the country at $484 billion a year - 
almost three times the cost of cancer.

The Kostens' cocaine vaccine has been more than a decade in the making.

In concept, the idea seems simple. Cocaine (and many other drug) 
molecules are so small the immune system fails to recognize them and 
make the antibodies necessary to mount an attack. To help the immune 
system, Kosten attached inactivated cocaine to the outside of 
inactivated cholera proteins.

In response, the immune system not only makes antibodies to the 
combination, which is harmless, but also recognizes the potent naked 
drug when it's ingested. The antibodies bind to the cocaine and 
prevent it from reaching the brain, where it normally would generate 
the highs that are so addictive.

"It's a very clever idea," says David Eagleman, a Baylor 
neuroscientist. "Scientists have spent the last few decades figuring 
out reward pathways in the brain and how drugs like cocaine hijack 
the system. It turns out those pathways are difficult to rewire once 
they've seen the drug. But the vaccine just circumvents all that."

Kosten says the idea goes back to the 1950s, when scientists devised 
a vaccine to treat potentially fatal overdoses of the then-popular 
heart medication digitalis, and the 1970s, when researchers 
experimented with a heroin vaccine before abandoning it.

Kosten took up the idea in the mid-1990s, figuring cocaine was a 
better candidate because the enzyme for breaking it down is in the 
bloodstream, not the liver, like most drugs. While they were at Yale, 
he led the clinical trials and his wife conducted the animal experiments.

The most impressive result involved a study at Columbia University in 
New York, where users who had no interest in being treated were paid 
to be vaccinated. Those who got a low dose saw little change. Those 
who got a high dose reduced their drug use by more than 50 percent. 
In Kosten's words, "it didn't do what it used to do."

But one expert warns against expecting too much.

"Addiction vaccines are a promising advance, but it's unlikely any 
treatment in this field will work for everyone," said Dr. David 
Gorelick, a senior investigator at the National Institute on Drug 
Abuse. "Still, if they prove successful, they will give those working 
in drug addiction an important option."

To be sure, the vaccine is still a work in progress.

There also are questions about dedicated users' ability to overcome 
the vaccine if they ingest more cocaine than the immune system can 
fight off, and whether they'll simply switch drugs once they stop 
getting a high from cocaine.

FDA May Act in a Few Years

Kosten acknowledges those are concerns. But he also notes that most 
users would have a hard time affording the amount of cocaine 
necessary to override the immune response, and that study 
participants didn't switch drugs when the cocaine lost its effect. 
Vaccines also could be combined - as is done with mumps, measles and 
rubella - if the concept pans out.

Vaccines' ethical concerns have occasioned academic papers, committee 
investigations and conferences. In a 2004 report, the National 
Academy of Sciences' Center for Studies of Behavior and Development 
lauded the new method's promise, but cautioned that it "poses 
distinct behavioral, ethical, legal and social challenges that 
require careful scrutiny."

"There are certainly important issues there, but I don't think any 
are insurmountable," said Dr. Peter Cohen, a Georgetown law professor 
and chairman of the District of Columbia Medical Society's physician 
health committee. "Overall, the benefits to society of such vaccines 
would outweigh the risks."

Addicts also will benefit from other treatment at the same time, such 
as behavioral therapies or counseling, says Kosten. Emphasizing that 
there was a reason drugs were used in the first place, he says the 
vaccine is not meant as "a stand-alone treatment."

Still, FDA approval could come within a few years, Kosten speculates, 
if he gets the go-ahead to conduct the Phase III trial next year and 
it succeeds. The trial would enroll about 300 patients at six sites 
around the country, one in Houston.

So, what will it mean to Kosten if and when that approval comes down?

"It'll be great," he said. "It'll also mean a new opportunity to make 
more vaccines and move on to more addiction problems."
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MAP posted-by: Richard Lake