Vaccine Against Opioids Successful in Preclinical Trials

A novel vaccine that blocks the psychoactive effects of heroin was observed to be successful in non-human primates. This is the first anti-opioid vaccine found to be effective in preclinical trials, according to a study published by the Journal of the American Chemical Society.

"This validates our previous rodent data and positions our vaccine in a favorable light for anticipated clinical evaluation," said senior study author Kim Janda, PhD.

The vaccine works by exposing the immune system to a portion of the structure of heroin, which then creates antibodies against the drug. The antibodies render the drug ineffective and inhibit feelings of euphoria, according to the study.

The authors believe that inhibiting the psychoactive effects of heroin may dissuade patients with a history of substance misuse from relapsing. When patients relapse, many experience an overdose and potentially death.

The experimental vaccine has been in development for more than 8 years. Previously, the authors successfully tested the vaccine in rodent models.

In the new study, the authors redesigned the vaccine to more closely resemble heroin and then explored its efficacy in 4 rhesus monkeys. They revised the vaccine to bolster a more significant immune system attack.

The monkeys received 3 doses of the vaccine, which was observed to effectively neutralize various doses of the drug. This result was found to be most significant during the first month after vaccination, but prolonged for more than 8 months, according to the study.

The authors did not observe any negative side effects during the trial.

Additionally, all of the vaccine components have either already been approved by the FDA or have been observed to be safe in previous clinical trials, according to the study.

"We believe this vaccine candidate will prove safe for human trials," Dr Janda said.

The authors noted that 2 of the monkeys had received the vaccine 7 months prior for pilot testing. They discovered that the primates had a more significant response to the vaccine during the second vaccination.

These findings suggest that their immune system remembered the vaccine and produced the same antibodies months later, the authors noted. If validated in humans, the vaccine may provide a long-term solution to ensure patients avoid relapsing, according to the study.

"We were really encouraged to see the vaccine produce such lasting effects in non-human primate models," said first study author Paul T. Bremer, PhD.

Vaccines against other drugs have been previously tested in humans without testing in primate trials and resulted in failure. This is the first to successfully inhibit heroin in these animals, the authors reported.

The authors said that the experimental vaccine is successful because they closely analyzed the chemistry of the vaccine to determine how the antibodies would bind to drug molecules, according to the study.

"These steps let us put our best foot forward when we went into the primate study," Dr Bremer said.

While the vaccine was effective against heroin, the authors warn that it has not been tested for other opioids. The vaccine also has not been tested in emergency situations, such as overdose.

Next, the authors will license the vaccine and partner to conduct clinical trials, the study concluded.