Three years after bringing the opioid overdose reversal treatment Narcan® Nasal Spray (naloxone HCl) to market with partner Adapt Pharma, Opiant Pharmaceuticals has started working on a drug that can reverse acute cannabinoid overdose (ACO).

Whether, and how quickly, Opiant can succeed will depend on its ability to transform the oral drug into another form that can yield fast results in an emergency.

Opiant envisions developing drinabant as an injectable for use in ER settings, though a nasal spray like Narcan is another potential alternative, CEO Roger Crystal, MD, told GEN.

“There’s certainly different ways of getting it into patients, but it’s ironic that for a lot of medication, people like to think about how they can try to convert injectable medications into oral. Here, we need to do the reverse because of the state of the patient,” said Crystal, who is attending the JP Morgan 37th Healthcare Conference, being held January 7-10 in San Francisco.

Oral drinabant is simply too slow for use on patients exhibiting the symptoms associated with ACO—which can include panic and anxiety, feelings of paranoia, agitation, visual and auditory hallucinations, and nausea. ACO is most often linked to ingestion of edibles and synthetic cannabinoids.

“What we need to do is reformulate the oral as an injectable. And then we will learn how quickly it absorbs once we’ve done that reformulation,” Crystal added.

Opiant set the stage for that reformulation last month, when it acquired global development and commercialization rights from Sanofi to drinabant.

At a time when biopharmas can pay hundreds of millions of dollars or more for licensing rights, drinabant is a relative bargain. According to a regulatory filing, Opiant agreed to pay Sanofi $500,000 upfront, up to $8.1 million in development milestones, up to $36 million in sales milestones, and royalties ranging from 7% for net sales less than or equal to $150 million, to 12% for net sales of greater than $250 million.

That is comparable to what Opiant—formerly Lightlake Therapeutics—received when it outlicensed Narcan to Adapt in December 2014. Adapt agreed to pay potential development and sales milestone payments that potentially total more than $55 million, plus double-digit royalties.

Revenue from the licensing agreement for Narcan, which won FDA approval in December 2015 was approximately $8.9 million in the first nine months of 2018—accounting for most of the approximately $9.2 million in total revenue recorded by Opiant during the period.

Safety Profile Cited

Crystal said the favorable deal terms were one of two key factors in pursuing rights to drinabant. The other is its favorable safety profile. A 2010 study by Sanofi and the Centre for Human Drug Research, for example, showed drinabant (then called AVE 1625) at 20 mg and 60 mg doses to have induced maximal inhibition on heart rate, feeling high, internal and external perception, but not on body sway and alertness as measured by visual analogue scales (VAS), a 16-item assessment of subjective effect on alertness.

“Even the lowest dose of AVE1625 20 mg inhibited most of THC-induced effects,” according to the study, one of multiple trials conducted in an earlier Sanofi clinical program. Sanofi pursued numerous other indications for the drug candidate, including schizophrenia and Alzheimer’s disease.

Opiant has not offered a formal timeframe for launching studies of drinabant in ACO. Crystal envisions those studies beginning in a couple of years, adding: “If you think about timing when we would be able to file an NDA, our initial view is it would be a few years, but not 10 years.”

Crystal also offered updates on other Opiant pipeline candidates. For OPNT003 (nalmefene nasal spray), a pivotal pharmacokinetic study of the opioid overdose candidate is planned this year, with next year being targeted for the submission of an NDA.

In 2018, Opiant won a $7.4 million grant from the NIH’s National Institute on Drug Abuse to develop OPNT003 as an opioid overdose treatment, and $4.6 million from the Biomedical Advanced Research and Development Authority (BARDA) to also develop the drug as a medical countermeasure in the event of a fentanyl chemical attack.

Other pipeline updates:

  • OPNT001—Opiant remains on track to release topline clinical data from its ongoing Phase II trial of the bulimia nervosa candidate during the first quarter, Crystal said.
  • OPNT002—Opiant plans to advance development of the opioid antagonist nasal spray indicated for alcohol use disorder following positive Phase I data and supportive feedback from the FDA.

“OPNT002 gets me excited because it can open up a huge population of people who currently don’t take medication for alcohol use disorder, but I really think would be willing to use this type of approach,” Crystal said.