Opiant's nasal opioid overdose drug clears clinical test ahead of planned FDA filing

Opiant CEO Roger Crystal (Opiant)

A clinical trial has found nasal nalmefene delivery achieves significantly higher plasma concentrations than intramuscular injections, advancing Opiant Pharmaceuticals’ hopes of filing for approval around the end of the year.

Opiant is developing nalmefene as a treatment for opioid overdose. An injectable formulation of the drug won FDA approval in the 1990s but was removed from the market in 2008. Since then, the rise of synthetic opioids and the challenges they pose for existing opioid overdose drug naloxone has led Opiant to seek to return nalmefene to the market in a nasal spray formulation.

The pharmacokinetic clinical trial was designed to support approval of nasal nalmefene OPNT003 via the 505(b)(2) regulatory pathway. Investigators enrolled 68 healthy subjects and administered 3 mg of nalmefene in a nasal spray and 1 mg in an intramuscular injection in a randomized crossover study. 

Maximum plasma concentration was significantly higher in the nasal spray data set, causing the study to hit one of its primary endpoints with a p-value of less than 0.0001. It took around 15 minutes for recipients of the nasal spray to reach maximum plasma concentration, and the plasma half-life was 11 hours. The half-life of naloxone is around two hours.

“A rescue agent with a rapid onset and a long half-life is critical to saving lives from overdose,” Opiant CEO Roger Crystal said in a statement.

The trial provides Opiant with some of the evidence it needs to seek FDA approval. Opiant is running a pharmacodynamic study to generate the rest of the evidence. The study is expected to deliver data in the fourth quarter, setting Opiant up to seek approval around the end of the year. The Biomedical Advanced Research and Development Authority is supporting development of OPNT003.