Monday, June 1, 2009

Cocaine Treatment Drug Flunks the Test

Vigabatrin fails in clinical trials.

It wasn’t the Last Best Hope, or the Holy Grail, but it had stirred up great excitement as possibly the first effective treatment medication for cocaine addicts. So it was nobody’s idea of happy corporate news when Catalyst Pharmaceutical Partners of Coral Gables, Florida, announced last Friday that its drug Vigabatrin, known as CPP-109, had failed as a cocaine treatment in Phase II clinical trials.

Brian Bandell of the South Florida Business Journal reported that during the 12-week study, the drug did not help drug addicts stay cocaine-free, compared to a placebo group.

In a press release, CEO Patrick McEnany said “we are not ready to abandon our view that CPP-109 has the potential for use in treating cocaine addiction, which still represents a significant unmet medical need.” Vigabatrin is sold overseas as Sabril by a Belgian company, but is not approved for use in the United States. Earlier animal testing and two limited early-stage studies on human addicts in the 2003-2004 had convinced the company that Sabril diminishes cravings for stimulants. It may also blunt the euphoric effect of meth and cocaine.

Catalyst’s stock, traded on NASDAQ, fell 57 percent to 90 cents a share on the news. The company started operations in 2006. According to the Miami Herald, Catalyst raised $21 million in its initial public offering on a single drug “with huge potential.” McEnany told the Herald he was uncertain why the drug had failed, but added that “cocaine addicts are a very unpredictable group.” He said the company would be analyzing the data over the next few months. “The data is immense. We’re trying to get our arms around it.”

Ovation Pharmaceuticals (now Lundbeck, Inc.), which hopes to market the drug under the trade name Sabril in the U.S., had also promised to push forward with clinical trials.

Edward H. Nash of Merriman Curhan Ford, a San Francisco financial research firm, downgraded Catalyst’s stock on Friday. “Unfortunately, we do not believe Catalyst has the opportunity and the right technology in hand,” he said, adding that the firm “no longer represents a viable biotech investment.”

Vigabatrin attracted initial interest because of its ability to dampen neuronal responses to excess amounts of dopamine produced by chronic cocaine use. As noted earlier (FDA Puts Coke/Meth Treatment on Fast Track), the U.S. Food and Drug Administration (FDA) had given “Fast Track” designation to vigabatrin, an anticonvulsant, for evaluation as an anti-craving drug for cocaine and methamphetamine addiction.

However, potential side effects threatened to derail the trials almost before they started. The FDA was already on record with its concern about reports of retinal damage in patients overseas. (See “Drug For Cocaine Addicts Causes Weight Loss”).

Graphic Credit: Addiction Treatment Forum


Peter O'Loughlin said...

Perhaps if we focused on treating the addicted, rather than a single entity of addiction, we might make more progress.

Anonymous said...

Perhaps methamphetamine and cocaine users might find treatment more attractive if we offered agonist replacement therapy, (such as supervised oral doses of lysine-dexamphetamine).

Withdrawl from dependent use of stimulants is difficult. Symptoms such as dysthemia, anhedonia, lack of energy/enthusiasm, and problems with mood, memory and concentration make relapse a common occurance.

Providing a low level agonist substitute in supervised oral doses would allow the person to continue functioning normally. This option would attract many more users into treatment and would have a much higher retention rate than antagonist or non-medical treatments.

I agree with Peter that we need to look at a "whole of person" approach. The stability of a prescribed regime would allow many users to stabilise or improve their life circumstances to the point where abstinence becomes a realistic and desirable goal. Gradual reduction of dose to abstinence is (in my humble experience) the least disruptive way to address heavy dependence on cocaine or amphetamines. Most dependent users trying this at home are unable to maintain a consistent dose, or a consistent reduction. Medical supervision and prescription of agonist therapy would make dealing with cocaine or amphetmaine dependence much simpler and cheaper for all concerned.

Dr Jane.

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