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Doctors may eventually have a new tool to wield in working with people struggling with opioid use disorder, a vaccine that targets heroin and fentanyl.
Researchers at Virginia Commonwealth University are evaluating the vaccine and are submitting their work for publication this week and in January. Vaccines would complement existing treatments including naltrexone buprenorphine and methadone, according to Matthew Banks, an associate professor in the VCU School of Medicine’s Department of Pharmacology and Toxicology.
Fentanyl and heroin are commonly mixed together in drugs sold on the street. Fentanyl is a synthetic opioid that’s up to 100 times more powerful than morphine. It accounted for most of the overdose deaths in the United States in 2016, according to a report released Wednesday by the Centers for Disease Control and Prevention. Fentanyl was linked with 18,355 overdose deaths for that year, about 29 percent of overall overdose fatalities. Heroin was second, accounting for 15,961 deaths, or about 25 percent.
The vaccine is similar to a flu vaccine, Banks says. It includes a substance that looks to the body like fentanyl or heroin, and that in turn stimulates the body to make antibodies against the opioids. The antibodies keep the drug molecules from crossing into the central nervous system, blocking the high, according to a university release.
“We’re taking the concept and adding a new wrinkle to it,” Banks says.
Current medications available in treating opioid use disorder have limitations. For instance, they don’t work in all patients with the abuse diagnosis, may be limited in the length of time in which they work, may be abused by users, or may have serious side effects of their own. Methadone, for instance, may cause respiratory problems. Naltrexone may be problematic because it acts to block drugs that are abused, but it also blocks the receptors for drugs used to treat pain. A vaccine would only target the specific drug or drugs being abused.
“[Clinicians] need better tools,” Banks says.
One potential downside to a vaccine targeting specific abused drugs is that a patient may switch to something else, say Percocet, to gain a high, he adds.
The VCU team is evaluating the effectiveness of vaccines compared with the treatments that are already clinically approved. Banks says he expects to receive feedback by spring or summer following publication of the study.
A vaccine holds the potential to last longer and have fewer side effects than current treatments, says Banks. A vaccine won’t produce abuse effects because it doesn’t bind in the same place, and it may be effective for three to six months. The longer a vaccine works, the less frequent the need for someone in treatment to visit a doctor, he notes.
The current round of testing involved a heroin vaccine and a fentanyl vaccine. The next phase may involve a combined vaccine. The vaccine was developed by the Scripps Research Institute campus in La Jolla, California, according to a VCU release.