FDA clears nasal opioid reversal drug, lifting Indivior

The FDA has approved a new intranasal therapy for treating opioid overdose developed by Opiant Pharma, giving a boost to its new UK owner Indivior.

The US regulator has cleared the nalmefene nasal spray Opvee as an emergency treatment for individuals aged 12 or over who are suspected of having taken an overdose of natural or synthetic opioids.

It is the first intranasal nalmefene therapy to be cleared for marketing in the US, and offers an alternative to naloxone-based products like Emergent BioSolutions’ Narcan – recently approved as an over-the-counter (OTC) product in the US – and Hikma Pharma’s Kloxxado.

FDA Commissioner Robert Califf said the approval “places a new prescription opioid reversal option in the hands of communities, harm reduction groups, and emergency responders.” The FDA cleared the drug after a priority review.

According to official figures, the US is still firmly in the grip of the opioid epidemic, with more than 103,000 reported fatal overdoses occurring in the 12-month period ending in November 2022, primarily driven by highly potent synthetic drugs like illicit fentanyl.

Fentanyl is 50 to 100 times more potent than morphine and was responsible for around 71,000 of the 108,000 drug overdose deaths in the US in 2021.

Nalmefene could be a useful option because it has a rapid onset, typically acting within 2.5 to 5 minutes to reverse the respiratory depression that can be fatal in an overdose situation.

It also has a longer duration of action than naloxone, which means it can continue to protect people who have taken a high dose of opioids that can take a long time to clear the system. That may also mean that opioid withdrawal effects last for longer with nalmefene, however, which may be viewed as a disadvantage compared to naloxone.

Indivior completed its $145 million acquisition of Opiant in February, with Opvee the primary asset in the deal. The UK company reckons it has sales potential of $150 million to $250 million a year, and could have to pay another $50 to $60 million to Opiant shareholders in the form of a contingent value right (CVR) if Opvee meets certain sales objectives.

Narcan was also developed by Opiant, and reached peak sales of around $430 million – mainly from the US – before generics reached the market at the end of 2021. Last year, its nasal naloxone franchise brought in $373 million, a fall of 14%.

Opvee is an important product for Indivior, which is grappling with the loss of patent protection for Suboxone, an oral film formulation of buprenorphine/naloxone that approached $1 billion in sales at its peak before succumbing to generic competition.

The UK company has softened the blow by switching its focus to Sublocade (buprenorphine extended release), a subcutaneous injection used as both treatment for opioid use disorder and as a rescue medication in overdose, which grew 67% to $408 million last year.