Opiant Pharmaceuticals Announces Completion of Enrollment in Phase 2 Clinical Trial of Nasal Naltrexone in Patients With Alcohol Use Disorder

Opiant Pharmaceuticals, Inc. recently announced the last patient has been enrolled in the Phase 2 clinical trial of OPNT002, nasal naltrexone, for patients with Alcohol Use Disorder (AUD). The total trial duration per patient is 20 weeks, with the last patient enrolled expected to complete the study in early 2023 and with top line data anticipated to follow mid-year.

“We are pleased to have completed patient enrollment ahead of schedule and are looking forward to concluding the treatment phase of this study and releasing top-line data next year,” said Roger Crystal, MD, President and Chief Executive Officer of Opiant. “This study is a critical step in our effort to develop alternative therapeutic treatment options to improve the lives of people suffering from alcohol use disorder.”

Opiant launched its Phase 2 clinical study of OPNT002 for the treatment of alcohol use disorder in January 2022. The multi-center, double-blind, randomized, placebo-control Phase 2 study is being conducted in Europe, and is designed to evaluate OPNT002 efficacy, safety, and tolerability in 300 patients with AUD. The trial is being conducted using a Sequential Parallel Comparison Study Design, which is useful in psychiatric studies to reduce the impact of the placebo effect on the assessment of treatment response. The primary end point will be measured by the proportion of patients showing an improvement in World Health Organization (WHO) Risk Levels of Alcohol Consumption consisting of a 2-level reduction from baseline to end of treatment.

Clinical and preclinical studies have shown that alcohol releases endorphins, which are the brain’s endogenous opioids. These endorphins are thought to activate opioid receptors, which contribute to alcohol’s reinforcing and addictive properties. Current naltrexone treatments work to block mu-opioid receptors when administered orally or through injection. However, converging lines of evidence indicate that activation of delta-opioid receptors also contributes to the reinforcing properties of alcohol. The effective blockade of delta‐opioid receptors requires much higher plasma naltrexone concentrations than is achieved by currently approved naltrexone products.

Opiant is developing OPNT002 to rapidly increase plasma concentrations of naltrexone following dosing and thereby block mu and delta-opioid receptors. In previous research, OPNT002 has demonstrated rapid nasal absorption, delivering high levels of naltrexone yet with a short half-life. Results from Phase 1 studies demonstrate that OPNT002 produces maximum plasma concentrations that are approximately 50% higher than orally administered naltrexone. This feature, along with a very rapid onset and a short plasma half-life, are characteristics ideally suited to developing OPNT002 for ‘as needed’ nasal dosing in anticipation of drinking, or once drinking has started.

Alcohol use disorder is a chronic relapsing brain disease characterized by compulsive use of alcohol and the inability to control intake. It is the third leading preventable cause of death in the US, and according to the WHO, harmful use of alcohol is responsible for 5.1% of the global burden of disease. A report by the Centers for Disease Control and Prevention, found that deaths from alcohol use increased by 43% from 2006 to 2018. Currently, less than 10% of individuals with AUD seek treatment for their drinking problems, and many individuals with AUD who do not seek alcohol treatment report not wanting to stop drinking as their primary reason for not seeking treatment. Individuals with AUD who do not initially accept an abstinence goal may find treatment more appealing if it is focused on reductions in drinking.

Opiant Pharmaceuticals, Inc., the company that developed NARCAN Nasal Spray, is building a leading franchise of new medicines to combat addictions and drug overdose. For more information, visit www.opiant.com.