Intranasal Nalmefene Gets Priority Review for Opioid Overdose Treatment

OPNT003 is an intranasal formulation containing the high affinity opioid antagonist, nalmefene.

The Food and Drug Administration (FDA) has accepted for Priority Review the New Drug Application (NDA) for OPNT003 (nasal nalmefene) for the treatment of opioid overdose.

OPNT003 is an intranasal formulation containing the high affinity opioid antagonist, nalmefene. The investigational treatment is being developed as an alternative to naloxone to reverse the effects of opioids, including respiratory depression, sedation, and hypotension.

The NDA was submitted through the FDA’s 505(b)(2) regulatory pathway and is supported by data from a pharmacokinetic (PK) study ( Identifier: NCT04759768) comparing OPNT003 3 mg nasal spray to an intramuscular injection of nalmefene hydrochloride 1 mg. Results showed that OPNT003 achieved significantly higher plasma concentrations compared with the intramuscular injection (P <.0001). Maximum plasma concentrations were observed in approximately 15 minutes, with a plasma half-life of approximately 11 hours.

The application also included data from a second PK study ( Identifier: NCT05219669) comparing 3 dosing regimens of OPNT003. Findings showed dose proportional plasma concentrations whether the treatment was administered as a single dose in each nostril or as 2 doses in a single nostril.

Additionally, a pharmacodynamic study ( Identifier: NCT04828005) comparing intranasal nalmefene to Narcan® (naloxone HCl) nasal spray 4 mg met its primary endpoint of noninferiority. Nasal nalmefene produced a greater reversal of remifentanil-induced respiratory depression that was nearly twice that produced by nasal naloxone at 5 minutes.

“We are delighted to announce that the FDA has accepted Opiant’s NDA for OPNT003 for filing and designated it priority review status,” said Roger Crystal, MD, President and CEO of Opiant. “The acceptance of the OPNT003 NDA filing is an important milestone as it brings us 1 step closer to the potential approval and US commercial launch of OPNT003. We believe the data supporting this NDA indicates that OPNT003 can potentially offer first responders and communities an important treatment option in tackling the very serious opioid overdose crisis. We look forward to working with the FDA during the review process.”

The FDA previously granted Fast Track designation to OPNT003 for this indication. A Prescription Drug User Fee Act (PDUFA) target date of May 22, 2023 has been set for the application.

This article originally appeared on MPR


Opiant Pharmaceuticals announces FDA acceptance and Priority Review of NDA for OPNT003, nasal nalmefene, for opioid overdose. News release. Opiant Pharmaceuticals. Accessed January 19, 2023.