OREX-1019: A novel treatment of opioid use disorder and relapse prevention

David R. Maguire, Lisa R. Gerak, Gerta Cami-Kobeci, Stephen M. Husbands, Charles P. France, Barbara Belli, Peter Flynn

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


There is an urgent need for new pharmacological treatments for substance use disorders, including opioid use disorder, particularly for use in relapse prevention. A combination of buprenorphine with naltrexone has shown particular promise, with clinical studies indicating a substantial improvement over treatment with naltrexone alone. OREX-1019 (formerly BU10119) is a compound that mimics the pharmacology of the buprenorphine/naltrexone combination. This study evaluated, in rhesus monkeys, the therapeutic potential of OREX-1019 for treating opioid use disorder. Pretreatment with OREX-1019 (0.01-0.3 mg/kg s.c.) dose-dependently decreased responding for the m opioid receptor agonist remifentanil in rhesus monkeys but did not maintain levels of responding above vehicle when it was available for self-administration. OREX-1019 (0.01-1.0 mg/kg s.c.) also decreased cue- plus heroin-primed reinstatement of extinguished responding in monkeys that self-administered remifentanil but did not alter cue- plus cocaine-primed reinstatement of responding in monkeys that self-administered cocaine. OREX-1019 (0.3 mg/kg s.c.), like naltrexone (0.1 mg/kg s.c.), increased heart rate and blood pressure, produced overt observable signs, and eliminated food-maintained responding in monkeys treated chronically with morphine. These results confirm that OREX-1019 has little or no efficacy at m opioid receptorsand has low abuse potential, and, combined with promising safety (clean profile vs. other off-target proteins including the hERG (human ether-a-go-go-related gene) K1 channel) and pharmacokinetic data (supporting administration by subcutaneous or sublingual routes, but with low oral bioavailability), suggest it could be a safe and effective alternative to current treatments for opioid use disorders particularly as applied to relapse prevention.

Original languageEnglish (US)
Pages (from-to)205-215
Number of pages11
JournalJournal of Pharmacology and Experimental Therapeutics
Issue number2
StatePublished - Feb 2020

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology


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