A group of researchers is developing a vaccine that would block the effects of fentanyl in an effort to combat the overdose crisis.
But experts worry the drug could be used coercively and distracts from solutions that already work, including medication-assisted treatment for opioid addiction and a safer supply of drugs.
A team at the University of Houston is currently working on a vaccine that would create anti-fentanyl antibodies in a person, preventing them from feeling high if they consumed the synthetic opioid. The drug has already been shown to be effective in lab rats, with minimal side effects, according to a paper published in Pharmaceutics in October. Scientists are now hopeful that the FDA will approve starting clinical trials in humans.
If approved, a patient would receive one dose of the vaccine and two boosters.
“If an individual consumes fentanyl, those antibodies will bind to the fentanyl to prevent the drug from entering the brain, where it stimulates euphoric centers,” said lead researcher Dr. Colin Haile, a research associate professor of psychology at University of Houston and the Texas Institute for Measurement, Evaluation, and Statistics (TIMES). He said the vaccine could be a tool to help people recovering from opioid addiction.
Haile believes the vaccine, which is being funded by the Department of Defense, could be a game-changer in light of record overdoses in the U.S. Over 100,000 Americans died of a drug overdose last year, with more than 71,000 deaths linked to illicitly-manufactured fentanyl, according to the Centers for Disease Control and Prevention.
“What we're doing now is not working so we need a novel treatment strategy. And I think this fentanyl vaccine could be that,” Haile said.
But not everyone agrees with him.
Dr. Ryan Marino, medical director of toxicology and addiction medicine at University Hospitals in Cleveland, said while he supports giving people more treatment options, there’s already a drug on the market that blocks opioids from working—naltrexone. Naltrexone is an opioid antagonist; administered by injection, it binds to opioid receptors to block the effects of the drug.
However, Marino said you can override naltrexone by taking a big enough dose of opioids, which can also increase the risk of overdose.
Haile said a similar scenario played out during a clinical trial for an anti-cocaine vaccine, where people managed to override the effects of the vaccine by doing enough cocaine.
“That's something that we want to avoid. We see this as a tool for somebody that really wants to quit,” he said.
Drugs like methadone and buprenorphine, which reduce cravings and withdrawal because they’re also opioids, are the gold standard in treating opioid use disorder. Marino said rather than trying for a “moon shot” idea like a anti-fentanyl vaccine, more resources should go towards making sure methadone and buprenorphine are more widely accessible.
Claire Zagorski, graduate research assistant in translational science at the University of Texas College of Pharmacy, said she’d like to see funding go toward increasing the availability of naloxone—the agent that reverses opioid overdoses—and creating more safe drug consumption sites.
“All of these things have really beautiful reams of evidence that they work really well. They're embraced by people who use drugs, the community is excited about them, and they want to see them,” she said.
Zagorski said she’s also worried that people could be ordered to take the vaccine, potentially in jail, or via parole programs or drug treatment courts. She said naltrexone has already been used coercively, particularly in the prison system.
“Any time treatment is mandated and people are coerced into receiving treatment for substance use, it tends to work really, really poorly because that's a terrible place to start for any kind of behavioral modification,” she said.
Both Zagorski and Marino also raised concerns about blocking the effects of fentanyl, which is frequently used in hospitals for pain management and anesthetic purposes. Haile said people who received the vaccine would still be able to feel the effects of other opioid painkillers.
“One anesthesiologist said, ‘If we start vaccinating people with this, it will be a nightmare.’ Those were his words. And my response to that is we're already in a nightmare,” Haile said.
While Haile said he envisions the ideal candidate for the fentanyl vaccine being someone who wants to be abstinent and avoid relapse, he also said it’s possible people who use drugs like cocaine would want it as a means of avoiding overdose from contaminated products.
“We know people are being exposed to fentanyl unknowingly and dying. So if it can do some good to this population, then, that would be a good thing to prevent death,” he said.
Marino said while he can understand why the vaccine would appeal to coke users, the larger unaddressed issue is still the toxic drug supply.
“We're just kind of acknowledging we have a contaminated drug supply that people don't want and that is dangerous,” he said.
Although a vaccine could be years away, interventions targeting the toxic drug supply are needed urgently, according to Dr. Paxton Bach, co-medical director at the British Columbia Centre on Substance Use. He prescribes patients with opioid use disorder a safe supply of drugs—in B.C., people who are addicted to opioids can access prescription heroin and fentanyl as an alternative to street drugs.
“We need to leverage all options as quickly as possible to aim to reduce deaths,” Bach said.
Haile said his team is currently making a clinical grade vaccine after which they’ll do toxicology studies in rats and submit an application to the FDA to test clinical trials. If things progressed smoothly, he said a fentanyl vaccine could be on the market within two to three years.
Similar vaccines targeting drug addiction have been in the works for years and so far none have come to market. But Haile believes because the main components of this vaccine are already used in other vaccines and are proven to be safe and effective, he’s hopeful the FDA will approve the application.
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