NOV 14, 2022 3:30 PM PST

Experimental Opioid Vaccine Could Prevent Overdose Deaths

WRITTEN BY: Annie Lennon

Researchers have developed a vaccine that may be able to block the opioid fentanyl from reaching the brain. They note that the vaccine may be a 'hame changer' for treating fentanyl use and overdose. The corresponding study was published in Pharmaceutics

Every day, over 150 people die from synthetic opioid overdoses from drugs, including fentanyl, an opioid that is 50 times stronger than heroin and 100 times stronger than morphine. While doctors can prescribe pharmaceutical fentanyl to treat severe pain from surgery or advanced cancer, most cases of fentanyl-related overdose are linked to illicitly manufactured versions of the drug. 

Illicitly manufactured fentanyl is often added to drugs such as heroin, cocaine, and methamphetamine. It can also be made into pills that resemble other opioids. Just 2mg of fentanyl is suffiicent to be lethal. An analysis by the Drug Enforcement Administration (DEA) found that counterfeit pills may contain quantities of fentanyl ranging from 0.02mg- 5.1 mg, with 42% of pills containing at least 2mg of the drug. 

In the current study, researchers tested a previously developed experimental fentanyl vaccine alongside an adjuvant derived from E.coli known as dmLT. Adjuvants are substances that boost the immune system’s response to vaccines. 

After immunization, male and female rats produced significant levels of anti-fentanyl antibodies. These antibodies, wrote the researchers, were highly effective in neutralizing fentanyl-induced pain relief. Immunization also reduced levels of the drug in the brain following drug administration and prevented decreases in physiological measures such as oxygen saturation and heart rate. The researchers noted that the vaccine did not result in adverse side effects.

Lead author of the study, Colin Haile, a research associate professor of psychology at UH and the Texas Institute for Measurement, Evaluation and Statistics (TIMES), and a founding member of the UH Drug Discovery Institute, said: 

"We believe these findings could have a significant impact on a very serious problem plaguing society for years -- opioid misuse. Our vaccine is able to generate anti-fentanyl antibodies that bind to the consumed fentanyl and prevent it from entering the brain, allowing it to be eliminated out of the body via the kidneys. Thus, the individual will not feel the euphoric effects and can 'get back on the wagon' to sobriety.” 

Further tests demonstrated that while the anti-fentanyl antibodies attached to fentanyl and sufentanil- an opioid used to induce anesthesia in labor delivery and to treat severe, acute pain- they did not bind to morphine, methadone, buprenorphine or oxycodone. This, said the researchers, means that vaccinated patients may still be treated for pain relief with other opioids. 

The researchers hope their findings translate into an alternative strategy for treating fatal fentanyl overdoses, as current treatments, such as naloxone, are often inadequate. Towards this, they plan to manufacture clinical-grade versions of the vaccine for human clinical trials. 


Sources: Science DailyPharmaceutics

About the Author
Bachelor's (BA/BS/Other)
Annie Lennon is a writer whose work also appears in Medical News Today, Psych Central, Psychology Today, and other outlets.
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