A 'Vaccine For Addiction' Is No Simple Fix

Aug 15, 2017
Originally published on August 11, 2017 10:23 pm

It's always appealing to think that there could be an easy technical fix for a complicated and serious problem.

For example, wouldn't it be great to have a vaccine to prevent addiction?

"One of the things they're actually working on is a vaccine for addiction, which is an incredibly exciting prospect," said Dr. Tom Price, secretary of Health and Human Services.

He was talking to reporters earlier this week, after the White House discussed the recommendations from a government commission tasked with suggesting ways to cope with the nation's opioid epidemic.

But, as is so often the case, there's no quick fix on the horizon for an epidemic that is now killing more Americans than traffic accidents.

Researchers have been working on vaccines against addictive drugs, including nicotine, cocaine and heroin, for almost two decades.

"Like any other vaccine, you inject the vaccine and you use your immune system to produce antibodies," says Dr. Ivan Montoya, acting director of the division of Therapeutics and Medical Consequences at the National Institute on Drug Abuse. "In this case, the antibodies are against the drugs of abuse."

So antibodies generated by a heroin vaccine, for instance, would prevent the molecules that cause euphoria from getting into the brain. (The vaccine actually targets morphine and a related chemical, since heroin breaks down into those components before crossing into the brain, Montoya says. It doesn't block endogenous opioids — the brain's built-in painkillers.)

The trick would be getting your body to produce enough antibodies to soak up a surge of drug injected into the bloodstream. "That is the biggest challenge, to get enough antibodies," Montoya tells NPR.

That's apparently a major reason that previous attempts to make a nicotine vaccine for smokers failed, he says. "The second challenge is getting the person to be vaccinated on a regular basis."

These vaccines aren't like the measles vaccine that you receive once or twice for a lifetime of immunity. Multiple shots per year would likely be required. So the strategy would only work in people who were actively trying to recover from a drug addiction. And people addicted to heroin who decide to get high could switch to some other opioid — like fentanyl, carfentanil, or oxycodone.

Kim Janda, a professor of chemistry at the Scripps Research Institute, says he's thinking about developing a vaccine that targets both heroin and fentanyl. But his first priority is to test a heroin vaccine in people. So far, he's used funding from the National Institutes of Health to test his potential vaccine in rodents and monkeys.

Human trials will cost tens of millions of dollars. The NIH generally doesn't fund that kind of study and hasn't made an exception for the opioid crisis. So Janda is hoping to get the money he needs from a pharmaceutical company, as other opioid vaccine developers have done.

He's optimistic that human tests could begin in 18 months once he has funding, though it would take much longer than that to find out whether the vaccine is actually safe and effective.

Janda knows that a vaccine would supplement, rather than replace, the current approaches to treating addiction.

"I think we need to look at other ways of treating opioid addiction," he says, "and I think this can help."

Researchers at the Walter Reed Army Institute of Research and at the University of Minnesota are also developing vaccines against opioids, but so far none has been tried in people.

You can reach Richard Harris at rharris@npr.org.

Copyright 2017 NPR. To see more, visit http://www.npr.org/.

AUDIE CORNISH, HOST:

President Trump says he'll declare the opioid epidemic a national emergency. It's not clear yet how that will change how the federal government approaches the crisis. Earlier this week, Health and Human Services Secretary Tom Price said the government's already doing things, like funding important medical research.

(SOUNDBITE OF ARCHIVED RECORDING)

TOM PRICE: One of the exciting things that they're actually working on is a vaccine for addiction, which is incredibly exciting - prospect.

CORNISH: That vaccine is at best many years away. NPR's science correspondent Richard Harris has more.

RICHARD HARRIS, BYLINE: Researchers have been working on vaccines against addictive drugs including nicotine, cocaine and heroin for almost two decades. Ivan Montoya at the National Institute on Drug Abuse says the concept is simple, the same as other vaccines.

IVAN MONTOYA: Like any other vaccine, you get the vaccine, and you use your immune system to produce antibodies. In this case, the antibodies are against the drugs of abuse.

HARRIS: So a heroin vaccine, for instance, would prevent the molecules that cause euphoria from getting into the brain. The trick is getting your body to produce enough antibodies to soak up a surge of drug injected into the bloodstream.

MONTOYA: That is the biggest challenge - to get enough antibodies.

HARRIS: And Dr. Montoya's says that's apparently a major reason that previous attempts to make a nicotine vaccine for smokers failed.

MONTOYA: The second challenge is getting the person motivated to be vaccinated on a regular basis.

HARRIS: These vaccines aren't like the measles vaccine that you can get once for a lifetime of immunity. Multiple shots per year will probably be required. So the strategy will only work in people who are actively trying to recover from a drug addiction. And addicts who decide to get high could switch to some other opioid, like fentanyl, carfentanil or oxycodone.

Kim Janda, professor at the Scripps Research Institute, says he's thinking about developing a vaccine that targets both heroin and fentanyl. But his first priority is to test a heroin vaccine in people. So far, he's used federal research dollars to test his potential vaccine in rodents and monkeys.

KIM JANDA: We do have money from the NIH, but this is going to cost, to do something like this, tens of millions of dollars.

HARRIS: The National Institutes of Health typically doesn't fund that kind of research and has not made an exception for the opioid crisis. So Janda is hoping to make a deal with a pharmaceutical company. He's optimistic that human tests could begin in 18 months once he has funding, though it would take much longer to find out whether the vaccine is actually safe and effective. Janda knows that a vaccine would supplement rather than replace the current approaches to treating addiction.

JANDA: I think we need to look at some other ways of treating opioid addiction. And I think this can help.

HARRIS: Researchers at the Walter Reed Army Institute of Research and at the University of Minnesota are also developing vaccines against opioids. But so far, they haven't been tried in people. Richard Harris, NPR News. Transcript provided by NPR, Copyright NPR.