The Food and Drug Administration (FDA) has granted Fast Track designation to OPNT003 (nasal nalmefene) for the treatment of opioid overdose.

OPNT003 is being developed as an alternative to naloxone to reverse the effects of opioids, including respiratory depression, sedation, and hypotension. According to a pilot phase 1 study ( Identifier: NCT03129347), the investigational intranasal formulation of nalmefene demonstrated a more rapid onset and longer duration of action compared with naloxone. 

Additionally, the pharmacokinetics of OPNT003 3mg nasal spray were compared with intramuscular nalmefene hydrochloride injection 1mg in 68 healthy participants in a phase 1 study ( Identifier: NCT04759768). Results showed that OPNT003 achieved significantly higher plasma concentrations compared with the intramuscular injection (P <.0001). OPNT003 achieved maximum plasma concentrations in approximately 15 minutes, with a plasma half-life of approximately 11 hours.

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The Company is currently comparing OPNT003 to nasal naloxone in an ongoing pharmacodynamic study. The pharmacokinetic and pharmacodynamic data will support the New Drug Application submission for OPNT003 using the 505(b)(2) regulatory pathway.

“Opioid overdoses in the United States are a public health crisis with rates at the highest level in history and particularly powerful synthetic opioids like fentanyl, being the main driver,” said Dr Roger Crystal, President and CEO, Opiant. “The designation of Fast Track status by the FDA underscores the potential for OPNT003 to represent a major advance in opioid overdose treatment that can help communities better respond to this escalating crisis.”


  1. Opiant receives FDA Fast Track designation for OPNT003, nasal nalmefene, for treatment of opioid overdose. News release. Opiant Pharmaceuticals, Inc. Accessed November 10, 2021.
  2. Opiant Pharmaceuticals announces positive top-line results of confirmatory pharmacokinetic (PK) study for OPNT003, nasal nalmefene, a novel investigational treatment for opioid overdose. News release. Opiant Pharmaceuticals, Inc. July 6, 2021. Accessed November 10, 2021.

This article originally appeared on MPR