Immunized against addiction

Can a simple vaccine kill the appetite for cocaine? Researchers may soon find out.

Published April 26, 2000 4:00PM (EDT)

The 10 years of hardcore drug use are a blur to Janet -- the weeks she barely ate or slept, the many times she avoided seeing her parents, the ways she went about getting crystal meth and coke. But one thing is clear: On a summer morning two years ago, she woke up and quit. And then she left every reminder of her old life, including her husband, her job, her town.

"I did the coke to be more outgoing," says the 30-year-old, who asked that her real name not be used. "The first high of it was positive, but then you start to lose that and you want more, and if you can't get it, you kind of crash out of society."

Doctors have long been baffled why some people, like Janet, can quit drugs on their own and others can't, even with the help of toll-free hot lines, counselors and countless 12-step programs. But a new form of treatment for addicts could help when other attempts fail -- and change the way we look at addiction.

Researchers at Yale University recently completed the first human tests of a cocaine vaccine. Scientists also are experimenting with immunizations against addiction to methamphetamine, PCP and nicotine. It's unlikely such vaccines would ever be added to the list of routine inoculations, like the polio vaccines given to all kids. But if anti-drug vaccines proved effective, it might trigger a hunt for other biochemical approaches to addiction.

"I think it's one of the most promising treatments," says Alan Leshner, director of the National Institute on Drug Abuse. "If it is done well and we figure out all the issues, it will be an important addition to the clinical toolbox."

In the Yale study, psychiatrist Thomas Kosten found that the cocaine vaccine caused no major side effects. Now he is testing its effectiveness on cocaine addicts at an outpatient clinic. Called TA-CD, the vaccine is being developed by England-based Cantab Pharmaceuticals. It would be administered every six to nine months, Kosten says.

The implications of a vaccine to prevent abuse of a drug like cocaine are tremendous. Medical historians point to the possibility of court-ordered shots for drug abusers. And the availability of a medical approach like a vaccine might persuade the public that addiction is actually a disease, not the mark of bad behavior that should be punished.

"People should recognize that the use of cocaine that first time was something that was purely a matter of volition, but once cocaine is being used, the drive to use it again is part of your normal biology," says Donald Landry, an associate professor of medicine at Columbia University who is doing research in this field. "It's all well and good to say they should solve it with willpower, but it is an insidious mechanism that is designed to imprint behavior on an individual."

Vaccines, of course, are not the first medical approach to addiction. Methadone, used to treat heroin abuse, is effective -- but also happens to be addictive. Critics have undercut its value by deeming it a drug swap. (And obviously, methadone has not eliminated heroin addiction.) While vaccines can escape that accusation, they do come with baggage. Increasingly, they have come under attack because of safety concerns.

Researchers say immunization is the way to go with cocaine addiction, in part because they have failed to develop a classical blocker that would prevent the drug from binding to cells in the brain. Theoretically, immunization would stop the cocaine in the bloodstream before it reached the brain.

Cocaine is also a good target because of its popularity and its potentially disastrous effects in heavy users -- it's one of the most highly addictive drugs available. Researchers say that anyone can develop an appetite for the drug, which binds to the normal dopamine transporter. Even lab animals get hooked after they've experienced cocaine highs. "Every mouse will self-administer cocaine; they will press the bar to the exclusion of food, or sex; they will press it until they die," says Kim Janda, professor of chemistry at Scripps Research Institute in La Jolla, Calif.

But repeated use is not simply a habit; cocaine alters brain function. "Opiates don't make you stop thinking correctly, but cocaine and amphetamines and methamphetamines actually change the way your brain works," says David Musto, professor of child psychiatry and the history of medicine at Yale. "And so you can get extremely paranoid that people are still after you." Janet knows this well: Two years after she quit taking drugs, she says, she still stays home many days because of intense anxiety attacks around people.

Scientists are investigating two immunization techniques. Active immunization works as a conventional vaccine does: It triggers the body to produce antibodies that bind to the cocaine and neutralize it. The second approach, passive immunization, uses injected antibodies that bind to the cocaine and break, or "catalyze," it into harmless fragments.

Janda and his colleagues recently completed a study on rats showing that a combination of the two techniques works best, and has less risk of relapse than using the active method alone. Janda's findings will be reported soon in the Proceedings of the National Academy of Sciences. And he will begin testing his approach on people in the next few months, in collaboration with Drug Abuse Sciences, a pharmaceutical company in Menlo Park, Calif.

Even if they turn out to work well, these immunization approaches have limitations. If users don't get the high they want, they might take more cocaine to override the effects of the vaccine. (With passive immunization with a catalytic antibody, researchers say, this shouldn't happen as easily.) Moreover, it takes several months to create the needed antibodies -- for example, two months for Kosten's vaccine -- which might be enough time for someone to give up on the treatment.

And if the pleasure of cocaine is blocked, a user can always jump to other drugs. "The thing I have learned about drugs is that if you're not getting the high that you want out of it, then you look for alternatives," Janet says. It's also important not to underestimate the craving that addicts have for substances like cocaine, even if they have been clean for years. If, as happened to Janet recently, a former user is in the same room with someone who has cocaine, it can trigger an intense yearning for the drug.

The difficulty in treating people who are trying to kick any drug habit goes beyond just biology. No matter how successful a vaccine is, addiction will still be a struggle for many people, researchers say. Typically, complicated psychological, social and personal histories interplay with drug abuse.

"Many have organized their lives around their addiction, and then when that is stopped, they have to find a new way of reorganizing their lives," says Don DesJarlais, director of research for Beth Israel Medical Center's Chemical Dependency Institute in New York.

Janet snorted her first line of cocaine when she was 18, just after being told she would never be able to have children because of an accident. She was already carrying a heavy emotional burden, she says, having been molested at age 4 and raped by several men at age 11.

When she looks back on the beginning of her habit and wonders if anything could have stopped her, Janet says that perhaps if she'd been living at home and her parents had dragged her to get vaccinated, and had monitored her, then maybe she would have stopped. But she insists, as do the researchers developing these vaccines, that all the medical attention in the world won't eliminate drug addiction. The key to quitting is having the desire, and the will, to quit.

By Dawn MacKeen

Dawn MacKeen is a former senior writer for Salon, and author of a forthcoming book about her grandfather’s survival of the Armenian Genocide, "The Hundred-Year Walk: An Armenian Odyssey" (Houghton Mifflin Harcourt, January 2016).

MORE FROM Dawn MacKeen

Related Topics ------------------------------------------