Thursday, Dec. 6, 2018
Vaccinations against opioid abuse are potential new strategies for preventing overdose. The therapeutics would have the advantage of not interfering with existing treatments (methadone, naltrexone, buprenorphine and naloxone) and could be longer lasting.
Virginia Commonwealth University researchers are testing a vaccine against opioid abuse developed by the Scripps Research Institute in California. The vaccine is meant to block the effects of heroin and fentanyl in patients with opioid use disorder.
Matthew Banks, Pharm.D., Ph.D, associate professor in the Department of Pharmacology and Toxicology in the VCU School of Medicine, is leading the testing efforts. Researchers at the Minneapolis Medical Research Foundation and Walter Reed Army Institute of Research are testing other anti-heroin and anti-oxycodone vaccines, Banks said.
The Scripps vaccine and other immunotherapies work by prompting the immune system to make antibodies that prevent drug molecules, such as heroin or fentanyl, from crossing the blood brain barrier into the central nervous system, blocking the effects of opioids.
In an interview with VCU News, Banks explained the workings of the vaccine and how it could impact substance abuse treatment.
How is this particular vaccine different from others being tested or on the market?
No vaccine is currently on the market and approved for opioid use disorder treatment. The vaccine being evaluated at VCU and at other institutions is basically the same concept, but with slightly different carrier proteins, opioid haptens, and adjuvants. Preclinical research should screen and select the most clinically viable candidate vaccine.
Can a person still overdose when they have had the vaccine?
If the person was able to purchase and consume enough of the opioid to saturate all of the antibodies, there would be the potential for overdose. However, this risk of overdose with the vaccine is no different than the risk of overdose for currently used treatments such as naltrexone and buprenorphine.
How quickly could this be on the market?
Difficult to say. Although the preclinical data look promising, the vaccine needs to be evaluated for treatment efficacy in humans. Once treatment efficacy and safety in humans has been demonstrated, the approval process generally moves quickly.
What individuals would most benefit from this vaccine?
These vaccines would be most useful for individuals in rehab, or patients who have relapsed more than once, to provide one layer of therapeutics that could potentially be combined with other current treatments (e.g. naltrexone or buprenorphine).
What are potential downfalls of the vaccine?
Vaccine selectivity can be a good thing or a downside depending on your perspective. High vaccine specificity allows for good antibody-drug binding, but would leave the person vulnerable to switching to another abuse opioid.
Do you see a new wave of vaccinations being created for other drugs? What other nonbiological threats can vaccines be engineered to protect against?
Vaccinations are being created for other abused drugs, such as cocaine, nicotine and methamphetamine. The focus is on opioids because of the current opioid crisis. Potentially, vaccines could be developed for other small nonbiological compounds such as ricin. However, this is outside my expertise.
The vaccine piggybacks off the tetanus shot. Are there any other clinically available vaccines that could also serve as a vehicle?
There are carrier proteins other than tetanus toxoid that have been evaluated and are used by other researchers. The Scripps Research Institute discovered that the tetanus toxoid was the best carrier protein in boosting an immune response.
What about "inoculating" people who abuse other substances, as a protective measure?
That is controversial and engages a lot of ethics questions about how we would predict a person would develop a substance use disorder. In general, there are more effective strategies (e.g. social support, strong family connections, etc.) that should be considered and utilized as protective measures.