Heroin and its opioid cousins have wreaked havoc on humankind for centuries. On one hand, treatments such as methadone or other MATs have been developed, and on the other, detoxification, opioid blockade, and abstinence based therapies. New approaches and research are starting to gain traction and get attention. When faced with other plagues where there is no cure available, scientists look to the next best thing—vaccination. The problem with heroin and with most drugs of abuse is that they are very small and simple molecules, and, as such, undetected by the normal immune responses.
For the past eight years, investigators at the Scripps Institute have been looking for a workaround to this obstacle. They may have succeeded. By binding key fragments of heroin molecules to larger, immune-provoking protein conjugate, they were able to provoke a strong antibody response designed to breakdown the heroin before it could reach the brain, thus reducing the drug’s psychoactive effect by fifteen-fold. The initial trials in rodents were successful in neutralizing the effects of heroin. But previous such approaches that showed promise in rodents were later unsuccessful in human trials.
To further test their hypothesis, the researchers tweaked their vaccine to more closely resemble heroin and gave it to rhesus monkeys with the goal of provoking a stronger immune response to further neutralize this opioid. The vaccine produced an effective immune response and neutralized varying doses of heroin in addicted primates. This effect was predictably stronger in the first month post-vaccination but lasted for over eight months. This is, in fact, the first vaccination against heroin to succeed in primate trials.
Because many of the conjugates have been FDA approved, moving forward to human trials could be sooner than later.
Although the technology had opened the door to more research, the vaccine for heroin will not produce an immune response against other opioids. But, that too could change as we learn more about the process at the molecular level.
Why Does This Matter?
Relapse for opioid addiction is common. Recent advances with partial agonists/ antagonist and opioid replacement agents have been marginally successful. Baylor’s Tom Kosten and other NIDA-funded researchers are working smart and hard to develop vaccines. A viable vaccine that could be administered and monitored as part of an overall continuing care model may be helpful in sustaining recovery.