The Truth About the "New" Coke Vaccine

By Walter Armstrong 03/23/11

Scientists are heralding the novel cocaine vaccine as a landmark anti-addiction drug. But how well does it really work?

A shot in the arm for addiction treatment? ThinkStock

Addiction is hell. Addicts can trace its every detail in their sleep, while scientists are left to stumble around in the dark. Margaret Haney, a neurobiologist who heads Columbia University’s substance-abuse research center, has been mapping the particular hell of cocaine addiction for over 15 years. She displays a fitting humility in the face of its mysteries. One of the leading researchers at work on cocaine vaccine development, she frequently fields desperate phone calls from people asking how they can get the treatment for a friend or family member.

They can’t, because none exists. The most advanced candidate, dubbed TA-CD (“therapy for addiction—cocaine addiction”), is still in clinical trials. Its performance in rats is brilliant; in humans, not so much. “People have a mistaken view of how a vaccine might work, thinking of it as magic, where what it’s doing, at best, is blunting the effects,” Haney told the Washington Post in January. “They get very excited, and it’s heartbreaking."

This is the experimental drug about which Time magazine blared, “New Hope for an Anti-Cocaine Vaccine,” in January. Likewise, many media reports accentuated the positive to be found in the latest TA-CD data published in the Archives of General Psychology. It was left to Newsweek to play the skeptic, acidly retorting, “Forget the Coke Vaccine.” The truth, as banal it sounds, lies somewhere between Time and Newsweek’s version of events.
The take-home from the study is that 20 percent of the addicts who were treated with the vaccine were able to cut their consumption of cocaine by half or more. That sounds hopeful enough, but the specifics of the study guard against too much optimism. The study was small (115 people) and relatively brief (24 weeks). The vaccine worked in only 11 of 55 cases; it took two months to kick in, and after two more months, its benefits had fizzled out.
TA-CD first made headlines way back in the mid-'90s, so progress has been halting. The field of addiction treatment has yielded many buds but little fruit, for several reasons: science, money, and stigma. Vaccines, which tend to be one-time shots rather than daily meds, aren’t major moneymakers for Big Pharma. (One notable exception is nicotine addiction—drug companies are racing to bring a number of competing late-stage version to market.) In addition, the well-being of people hooked on illegal substances isn’t exactly a top priority on the nation’s health agenda. Antabuse and methadone, the most widely used drugs for alcoholism and heroin addiction, respectively, have both been around for more than 50 years. Plus, the infinitely complex workings of the brain remain a riddle to science—and to any addict who, despite the best intentions, relapses on the road to recovery.
With its status as the first vaccine against an illegal substance to advance into late-stage clinical trials, TA-CD is a landmark drug. An enormous investment (of dollars, decades, reputations, etc.,) is at stake in its success or failure. Notably, the National Institute on Drug Abuse has backed its development with millions in grants. Equally important, approval of TA-CD would validate the vaccine-for-addiction model, helping some 200 versions for cocaine, heroin, meth, and even alcohol attract backing. So, in the absence of any other medication for cocaine addiction, odds are that TA-CD will manage, with its middling benefits, to make it to market. Finally Haney would have more than a mere promise to offer desperate callers.
If TA-DC were magic, as many people believe when they hear the words cocaine vaccine, it would end relapses by blocking the insidious cravings and triggers that can, in a flash, turn a sane, sober ex-addict into his wild-eyed coke-fiend alter ego. But the mechanisms that flip the switch from no to yes in the addict’s brain, apparently stealing every last ounce of impulse control, remain a black box awaiting some future Nobel Prize winner. Current TA-CD researchers like Haney are no slouches, however, and their strategy is to do an end run around the brain-driven sources of relapse by developing a vaccine that simply keeps cocaine from entering the brain in the first place. If you were to slip up, the Bolivian marching powder’s amazing rush and buzz would be blunted, if not blocked entirely, by the vaccine. Without that reward, your cravings and triggers would start to fade, gradually tipping the scales in favor of your sober self over your inner cokehead.
TA-CD operates like any other vaccine—you get a shot that exposes you to a harmless amount of the target (whether it’s the flu virus or the cocaine molecule), and your immune system mounts a defense, using antibodies primed to attack that specific intruder. But as fate would have it, the cocaine molecule is exceedingly small, even for a molecule. That’s another reason that it has taken so long to get a cocaine vaccine into human trials. The antibodies can’t find the coke molecules, which your bloodstream ferries from your nose straight into your brain’s reward pathways.

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