Vaccine shows lasting effects against fentanyl addiction in rats
A vaccine combining a fentanyl antigen with a tetanus toxoid has been shown to be effective in reducing fentanyl choices and increasing food choices with effects that may last for several months in rats. These results suggest that the vaccine could not only reduce the dangerous behaviors associated with taking drugs, but also increase the behaviors maintained by healthier non-drug alternatives. The results are presented in the journal Neuropsychopharmacology.
The anatoxic fentanyl-tetanus vaccine tested in this study was developed by Kim D. Janda of Scripps Research. Fentanyl alone can not stimulate antibody production. Scripps researchers have developed a cocktail of vaccines to trigger an immune response against the family of synthetic fentanyl opioids. Researchers at the Virginia Commonwealth University School of Medicine then investigated the effectiveness of this vaccine in reducing fentanyl self-administration and increasing self-feeding in male and female rats.
Corresponding authors Matthew L. Banks and Kim D. Janda suggest: "More effective and readily available treatments for opioid use disorder are needed to cope with the current crisis." One strategy is to use targeted opioid vaccines to induce antibody production by the immune system that recognizes and blocks the passage of a specific opioid into the brain and peripheral organs / tissues. "
The study was based on a behavioral procedure in which rats chose to receive injections of fentanyl or food. Prior to vaccination, rats chose a large amount of fentanyl, but within four weeks of their vaccination, fentanyl choices decreased and food choices increased. The effect was similar to that observed in rats chronically treated with naltrexone, a treatment currently approved by the FDA for opioid dependence. In response to only two vaccinations at weeks one and three, the choice of fentanyl was reduced for 15 weeks, after which a third vaccine renewed the effect of the vaccine, suggesting a long-lasting vaccine effect. Vaccination also prevented an increased choice of fentanyl over foods normally seen after fentanyl withdrawal.
The results suggest that immunopharmacotherapies, which target the drug itself, may have the potential to prevent the development of opioid dependence and subsequent weaning. These results also suggest that the vaccine could provide protection against the inadvertent overdose of fentanyl. Further evaluation of current preclinical evidence in laboratory and human clinical trials is needed to confirm the efficacy of the vaccine in humans.
The authors point out that immunopharmacotherapies present unique challenges compared to currently approved treatments. First, the vaccine is based on the individual's ability to generate a sufficient immune response to the drug, which can be difficult for some individuals, such as those with weakened immune systems. In addition, all vaccines, including the fentanyl vaccine used in this study, take several weeks to reach maximum effectiveness. This delay may leave subjects vulnerable to the effects of targeted opioid during this induction period of the vaccine.
