Researchers at the University of Wisconsin-Madison have found that a majority of back-pain patients they tested who were taking opioid painkillers produced anti-opioid antibodies. The anti-opioid antibodies may contribute to some of the negative side effects of long-term opioid use. Existing antibodies may also limit the benefit a patient receives from an anti-opioid vaccine. The future goal of the researcher’s anti-opioid vaccine would be to stimulate an immune response against opioids to reduce the harm of opioid abuse. However, future research is needed to identify the population of patients that will respond well to that treatment.
Cody Wenthur, professor at the UW-Madison School of Pharmacy, led the work with collaborators at the Scripps Research Institute and Scripps Health in San Diego. Their research was announced at the American Chemical Society Fall 2020 virtual meeting.
The researchers found antibodies against protein-bound opioids in 10 of 19 patients who took opioids to treat chronic lower back pain. Patients who had taken higher doses of opioids had a stronger antibody response. A control group of three patients who did not take opioids for their back pain had only very low levels of anti-opioid antibodies. For this initial study, Wenthur's team could only identify three patients with chronic pain who had not previously taken opioids, which spoke to the ubiquitous nature of these medications.
"Opioid use disorder and opioid overdoses continue to be a major epidemic in this country," says Wenthur. "A relatively new therapeutic approach entering clinical trials is what in shorthand we call an opioid vaccine, where the immune system generates a response against the drugs. But for this approach to be successful, we need to identify the people who would benefit from that approach."
The team hopes to develop a vaccine that produces viable antibodies capable of neutralizing the drugs. Such capabilities would help combat addiction by reducing the pleasurable feelings the drugs produce in the brain.