Miriam Fauzia | The Dallas Morning News (TNS)
A fentanyl vaccine developed by University of Houston researchers is expected to enter clinical trials mid-next year, hoping to be a breakthrough solution to a deadly crisis.
The vaccine, which has been proven effective in animal studies, is designed to block the highly addictive opioid from entering the brain and causing an overdose. Biopharmaceutical startup Ovax acquired the license to produce and test the vaccine in November 2023 and raised more than $10 million for the effort in June.
“We’re all incredibly excited,” said Collin Gage, the startup’s co-founder and CEO. He added that his company is starting from scratch, but he’s confident that one day a fentanyl vaccine will be available to the public.
That day may be a long way off. While public health emergencies, such as the COVID-19 pandemic, can accelerate vaccine development, testing a new vaccine can take five to 10 years, sometimes longer.
Meanwhile, fentanyl overdose deaths are on the rise in Texas, from fewer than 80 in 2014 to nearly 2,300 in 2023, according to the Texas Department of State Health Services. The synthetic opioid — manufactured illegally but also available by prescription — is 50 times more potent than heroin and 100 times more potent than morphine, making it the deadliest drug in the opioid crisis.
For fentanyl vaccines, adjuvants are essential
The idea of creating an opioid vaccine has piqued scientists’ interest since the 1970s. Unlike bacteria or viruses, opioids are not recognized by our immune system as foreign invaders. But the immune system can be trained to produce antibodies in response to an opioid like fentanyl through a vaccine that links fragments of the drug to fragments of noninfectious bacteria and uses substances called adjuvants.
Adjuvants are designed to enhance the immune response and are particularly important in vaccines targeting substance use disorders. Past attempts to make such vaccines have failed in part because the adjuvants weren’t effective enough, said Jay Evans, director of the University of Montana’s Center for Translational Medicine. Evans is also the chief scientific and strategic officer of Inimmune, a Montana-based biotech company that is developing and testing a variety of vaccines, including those targeting fentanyl and heroin addiction.
The adjuvant in the University of Houston fentanyl vaccine is an enterotoxin, a chemical produced by the Escherichia coli bacteria and modified to be noninfectious. It was first developed at Tulane University in Louisiana in the early 2000s and has been used in a variety of vaccines, said Colin Haile, a research associate professor of psychology at the University of Houston who led the development of the fentanyl vaccine. Haile is also a co-founder and advisor to Ovax.
“It’s been through 15 human clinical trials in combination with other vaccines,” he said, referring to the adjuvant used in his team’s vaccine. “Studies in infants have shown fantastic results, with virtually no side effects.”
Other researchers such as David Dowling and Dr. Ofer Levy, both co-founders of Ovax, are using adjuvants that have not been tested in humans but appear to effectively enhance the immune response to vaccines targeting substance use disorders, at least based on animal studies, Dowling said.
Clinical trials fraught with pitfalls
Phase 1 clinical trials of the University of Houston vaccine are expected to begin in the second quarter of 2025. Ovax is also in licensing negotiations with Boston Children’s Hospital for a fentanyl vaccine developed by Dowling and Levy. If those negotiations are successful, phase 1 clinical trials could begin in early 2026.
The trials will aim to determine the vaccine’s safety, potential side effects and the optimal dosage. Finding people willing to participate will be a challenge, Evans said.
“Compared to a normal infectious disease clinical trial, it’s going to be more difficult. The FDA is adamant that you don’t want to test this vaccine in healthy individuals who don’t already have some form of opioid addiction,” he said. “So we have to target patients in Phase 1 who have a history of opioid use disorder, and that’s a harder population to recruit. It’s going to take longer; the patient population is going to have more adverse events because they’re addicted, and they’re going to be harder to follow.”
Evans added that the stigma surrounding addiction and drug use could make people reluctant to disclose their condition and participate in a clinical trial.
Ovax has not yet decided where it plans to conduct its Phase 1 clinical trials, Gage said, but it has studied sites in Australia and the Netherlands.
“We are also studying in the United States,” he said, “but it is difficult to find the right patient population.”
Future clinical trials will need to determine how effective the vaccine is, who would benefit most and how long immunity would last.
Vaccines as part of the solution
Some critics of fentanyl vaccines say they take resources away from existing treatments for opioid addiction, such as buprenorphine, methadone and naltrexone. Some question whether people will seek the vaccine.
“People have to say they want to get vaccinated, and they have to choose to come back for every shot or infusion,” Keith Humphreys, a professor of psychiatry and behavioral sciences at Stanford University, told The Washington Post in 2023. “Vaccines do nothing to reduce need or deprivation or motivate anyone to come back for more care.”
For Haile, a fentanyl vaccine is not the only solution, but an additional weapon in the fight against the opioid crisis. He and his colleagues at the University of Houston conducted animal studies to determine how the vaccine affects treatment with buprenorphine, a medication commonly prescribed to manage withdrawal symptoms and drug cravings. The results have not yet been published, but are “pretty impressive,” Haile said, noting that fentanyl vaccines could improve the effectiveness of existing treatments.
“The most important thing to keep in mind is that we are moving as quickly as possible.[…]“We need to get something to market as quickly as possible to solve this terrible problem,” Haile said. “The ultimate goal is to protect people and save lives.”
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