What’s the News: Researchers at the Scripps Research Institute have now created a vaccine that prevents a heroin high in rats. The vaccine, detailed in a recent study in the Journal of Medicinal Chemistry, stimulates antibodies that can stop not only heroin but also its derivative psychoactive compounds from reaching the brain. How the Heck:
Developing a vaccine for heroin addiction has been a goal of research for some time, but a major issue has been that the drug quickly metabolizes into 6-acetylmorphine, morphine, and the much less active 3-monoacetylmorphine, so any vaccine must work against all four of the compounds.
This research team solved the problem by creating a drug cocktail that slowly degrades in the body, all the while exposing the immune system to the different psychoactive metabolites of heroin. They also created a control vaccine that only targeted morphine.
When the researchers injected several booster shots of the dynamic vaccine into rats, the rodents rapidly developed antibodies to the compounds. When given the opportunity, only three out of seven rats self-administered heroin (by pressing on a lever) after they received the new vaccine; all of the control rats self-administered the drug.
What’s the Context:
Scientists at the Weill Cornell Medical College recently created a seemingly effective vaccine against cocaine addition in mice, though there are still many levels of testing before it can be used in human trials. In a different cocaine addiction study, scientists found that the vaccine TA-CD was able to prevent the cocaine high, but not the craving, leading some addicts to take more cocaine than they normally would.
A couple of anti-heroin treatments have come out over the past few years, though none have been vaccines. Last year, the FDA approved the drug Vivitrol, a natltrexone injection, as a way of curbing heroin addiction. Similar to the current study's vaccine, an injection of Vivitrol prevents people from getting high on heroin, but the treatment must be administered once a month.
Not So Fast:
While over half of the addicted rats opted out of taking heroin after being vaccinated, there were still only seven of them injected in the trial. Ideally, the researchers need a larger pool of test rats to really see the effectiveness of their vaccine.
It’s unclear if the vaccine is preventing both the heroin high and the craving, or just the high. If tested in human addicts (still a long way off), would some of them up their heroin doses to try to override the vaccine, as cocaine addicts did with TA-CD?
Vaccines don’t always affect people the same way, particularly those with immunological deficiencies, so it's unlikely that it would work for all addicts.