It’s possible that clinicians could someday use a vaccine to prevent heroin abuse among high-risk individuals. Not unlike the old-school flu shot, the heroin vaccine creates antibodies that prevent the drug from becoming active in the body's receptors.
“This type of intervention has the potential for prevention, but we’re not there yet,” said Nora D. Volkow, MD, director of the National Institute on Drug Abuse (NIDA), in an exclusive interview with Addiction Professional at the National Rx Drug Abuse Summit in Atlanta.
Development of the vaccine is still in early stages, limited to laboratory trials on rats. The next steps would be to progress to human trials then to FDA approval. If the vaccine ultimately receives approval—although that’s many years and billions of dollars away—it could become a standard part of treatment.
“We have three different projects working on heroin vaccines,” she said. “We are pressuring them to move forward because the data is showing a good response to the vaccines.”
Volkow said right now there is interest in one particular project advancing to human trials.
NIDA is funding research for multiple investigations with different techniques to generate the vaccine to increase the chances that one will show enough promise to lead to FDA approval. In the past, vaccines for nicotine and cocaine, for example, failed to move forward because they did not create enough antibodies to be effective in humans.
Investing in the future
It’s also a challenging undertaking because too many researchers simply publish their findings and don’t move the preclinical testing on to human trials, Volkow said. She said there must be more incentives to continue the work, so NIDA is creating new mechanisms for funding research on the heroin vaccine.
“Until we go into human trials, we will not know if they will work,” she said. “They work great in rats. They stop taking the drug, they don’t feel bad about it, and the drug is not getting into the brain.”
In rats, the vaccine targets heroin and its psychoactive breakdown-products in the bloodstream, preventing them from reaching the brain, and thus preventing addiction and the compulsion to use. Addicted rats that were vaccinated and had subsequent access to self-administer heroin at will (with a lever in the cage) did not seek the drug, according to studies.
“I have no doubt we will succeed, but what I’m hesitant about is the time it will take us to succeed,” Volkow said. “And that time is determined by the amount of investment we can have.”
She compared the investment to that of HIV drug therapies and how awareness led to funding the science required to ultimately bring those drugs to market. And it happened quickly.
“It paid off,” she said. “The science is there. But we don’t have that level of investment at all in substance use disorders.”
She said the main barrier to overcome is stigma, and it’s frustrating because of the high death toll attributed to addiction.