Fentanyl Vaccine Candidate Could Change Opioid Epidemic

A pre-clinical vaccine candidate targeting the dangerous synthetic opioid fentanyl (FEN) was recently found to block its ability to enter the brain, thus eliminating the drug's "high."

The breakthrough discovery by researchers led by the University of Houston could have significant implications for the nation's opioid epidemic by becoming a relapse prevention agent for people trying to quit using opioids.

While research reveals Opioid Use Disorder (OUD) is treatable, an estimated 80% of those dependent on the drug suffer a relapse. 

Over 150 people die daily from overdoses of synthetic opioids, including fentanyl, which is 50 times stronger than heroin and 100 times stronger than morphine.

The consumption of about 2 milligrams of fentanyl is likely to be fatal, depending on a person's size. 

These researchers previously showed that FEN-CRM+dmLT generated significant amounts of anti-FEN antibodies associated with significant blockade of FEN's analgesic effects in mice.

The current study was conducted to extend the assessment of FEN-CRM+dmLT to male and female rats.

And expand upon the behavioral tests of nociception to determine if it also blocks FEN-induced disruption of schedule-controlled responding and depression of physiological measures associated with overdose.

The study also showed anti-FEN antibody specificity and the ability of the vaccine to prevent FEN from entering the brain.

The findings, published in the peer-review journal Pharmaceutics, could not be timelier or more in demand. 

The team plans to manufacture clinical-grade vaccines in the coming months, with clinical trials in humans planned soon.  

"We believe these findings could have a significant impact on a very serious problem plaguing society for years – opioid misuse," said the study's lead author Colin Haile, a research associate professor of psychology at UH and the Texas Institute for Measurement, Evaluation and Statistics.

"Our vaccine (candidate) can generate anti-fentanyl antibodies that bind to the consumed fentanyl and prevent it from entering the brain, allowing it to be eliminated from the body via the kidneys."

"Thus, the individual will not feel the euphoric effects and can 'get back on the wagon' to sobriety."

In another positive finding, the vaccine did not cause any adverse side effects in the immunized rats involved in lab studies.

Fentanyl is an especially dangerous threat because it is often added to street drugs like cocaine, methamphetamine, and other opioids, such as oxycodone and hydrocodone/acetaminophen pills, and even to counterfeit benzodiazepines like Xanax.

These counterfeit drugs laced with fentanyl add to the number of fentanyl overdoses in individuals who do not ordinarily consume opioids.  

"The anti-fentanyl antibodies were specific to fentanyl and a fentanyl derivative and did not cross-react with other opioids, such as morphine."

"That means a vaccinated person would still be able to be treated for pain relief with other opioids," said Haile. 

The vaccine tested contains an adjuvant derived from E. coli named dmLT.

An adjuvant molecule boosts the immune system's response to vaccines, a critical component for the effectiveness of anti-addiction vaccines.

The adjuvant was developed by collaborators at the Tulane University School of Medicine and has proven vital to the vaccine's efficacy.

Current treatments for OUD are methadone, buprenorphine, and naltrexone, and their effectiveness depends upon formulation, compliance, medication access, and the specific misused opioid.  

Therese Kosten, professor of psychology and director of the Developmental, Cognitive & Behavioral Neuroscience program at UH, calls the new vaccine a potential "game changer."  

"Fentanyl use and overdose is a particular treatment challenge that is not adequately addressed with current medications because of its pharmacodynamics and managing acute overdose with the short-acting naloxone is not appropriately effective as multiple doses of naloxone are often needed to reverse fentanyl's fatal effects," said Kosten, senior author of the study. 

The Department of Defense funded the study through the Alcohol and Substance Abuse Disorders Program managed by RTI International's Pharmacotherapies for Alcohol and Substance Use Disorders Alliance, which has funded Haile's lab for several years to develop the anti-fentanyl vaccine.  

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