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BU medical school discovers vaccine for cocaine addiction

Jan. 23, 2008

By Shannon Daily
Staff writer

After years of work, Baylor College of Medicine researchers have brought a cocaine vaccine to its final stages of testing.

With the number of cocaine addicts in the United States reaching around 2.4 million in 2005, researchers have been working to find a medical treatment to assist counseling and rehabilitation programs already in place.

"Behavioral interventions are helpful in treating cocaine addiction, but currently there are no approved medications to treat this disorder, despite over 60 medications having been investigated," according to "Therapeutic options and challenges for substances of abuse," an article co-written by Dr. Thomas Kosten and Dr. Tracie Gardner, two Baylor College of Medicine researchers.

Kosten, a professor of psychiatry, neuroscience and addictions at the college, has been working on the vaccine for 12 years.

"I see drug abuse as a very treatable and curable chronic relapsing disease of the brain," Kosten said. "Medications and these immunotherapies can make more impact on public health in young, promising people than any other medical intervention since we first started vaccinating for smallpox."

The cocaine vaccine uses the same basic principle as the smallpox, flu and polio vaccines.

With the polio vaccine, "what Dr. Jonas Salk did was disable the polio virus so it can't hurt you," said Dr. Jim Patton, a professor in the department of psychology and neuroscience.

However, this process doesn't work for cocaine.

Cocaine molecules aren't recognized by the immune system as foreign particles because they're small -- therefore they're able to make it to the brain to create a high.

The researchers attached the cocaine molecules to a larger protein molecule, an inactive cholera protein, and this combination is what the body learns to attack.

Once the cocaine/cholera complex gets recognized, antibodies attach to all parts of it. Some of this mixture of antibodies attaches only to the cholera part and some attach only to the cocaine part and some to both, Patton said.

The immune system is then able to recognize the cocaine by itself since some antibodies now recognize cocaine alone and therefore will clean it out of the blood, preventing it from reaching the brain to create the high.

The vaccine, however, isn't 100 percent effective.

"It doesn't work on everybody. Not all of us have equally robust immune systems," Patton said.

Tomas said while 35 percent of the test subjects produced a good antibody response that blocked the cocaine fully, 25 percent of the subjects didn't produce enough antibodies for the vaccine to work.

The remaining subjects produced reasonable amounts of antibodies -- some stopped completely and other reduced their cocaine use.

With the development of the vaccine, a suggestion the vaccine be used as a preventive measure has also come up.

"As with any medical breakthrough, there's the possibility of people seeing it as a silver-bullet type thing," said Dr. Doug Matthews, an associate professor of neuroscience.

As to whether or not parents should be able to give their children the cocaine vaccine, Matthews said, "Parents should use the platform that God's given them with their children. In my opinion it's not the best route."

Kosten is now waiting for approval from the Food and Drug Administration to begin further testing.

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