Every new year, thousands of addicts make the resolution to quit. However, intention is often weaker than craving. Rushing to the rescue, researchers have been working on a variety of vaccines that spur the body's immune system to help even when the pleasure centers clamor for another hit. On the cutting edge of this effort is Dr. Tom Kosten, from the Baylor College of Medicine, who recently announced in press releases that he is confident that his cocaine vaccine will move into Phase III trials in Spring of this year and obtain FDA approval not long after.
Drug vaccines have begun to show promise in the past few years. In November, we reported on the encouraging but not spectacular results of a trial for NicVAX. NicVax was not universally helpful, but for the third of subjects that did produce substantial numbers of nicotine antibodies, their chance of quitting was doubled. The cocaine vaccine developed by Dr. Kosten, TA-CD, looks like it may be at least as effective. In a double-blinded placebo controlled test of 114 subjects, those given TA-CD had a 50% increase in cocaine free days. Phase III trials, drawing from pools of subjects at multiple sites, are required to prove that TA-CD is ready for use, but a long string of prior experiments have already demonstrated that the vaccine is safe (the worst observed side-effect was brief and minor twitching) and has the desired effect in humans.
TA-CD works by making the immune system associate cocaine molecules with a substance that is easily recognized as an invader. Inactivated cocaine is bonded to inactivated cholera and injected into the bloodstream. For months after the vaccination, cocaine is destroyed before it reaches the brain. Cocaine can still be consumed, but it will not cause a high. While it might be biologically possible for addicts to take enough to overwhelm their antibodies, this is unlikely. For starters, that amount of cocaine is unaffordable to anyone but the wealthiest users.
A cocaine vaccine would be a great boon, but there are some risks to consider. If someone was desperate enough to acquire a sufficient amount of cocaine to overwhelm their immune system, they might overdose. Or they might give up cocaine and move onto other drugs for the high they need. In addition to health risks, there is an ethical question that our society must deal with if the vaccine is approved. Should some people be forced to take the vaccine? Courts might be tempted to order vaccinations instead of rely on the word of addicts that they will reform. Parents might insist that their children receive the vaccine, even if there is no evidence of abuse. Companies might insist that their employees take it to ensure productivity does not suffer. The strength of the vaccine—that it does not rely on voluntary decisions—may also create troubling dilemmas.
We should be happy if we have to grapple such questions, because it will mean that a working vaccine is available. There are many people who have the desire and strength to make the initial step towards abstinence, but then relapse once and get sucked back into the drug’s thrall. Vaccines, along with therapy, may protect former addicts from long-term cravings and spontaneous mistakes.
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