NIDA Grant Backs Development of an Overdose-Resistant Opioid Painkiller

The National Institute on Drug Abuse has awarded Ensysce Biosciences a $5.3 million installment to continue developing an opioid painkiller engineered to resist overdose, the clinical-stage company said this week. The payment is the third consecutive year of funding under a multi-year federal grant totaling roughly $15.1 million, and it completes the award, which supports both the nonclinical and clinical development of the company's opioid-safety platform.

The money will go toward finishing a clinical study of the lead candidate, PF614-MPAR, and running the long-term nonclinical studies needed before Ensysce can file a New Drug Application with the Food and Drug Administration. The candidate has already received Breakthrough Therapy designation, a status intended to speed development of treatments that may substantially improve on existing options for serious conditions.

A different approach to opioid safety

Most abuse-deterrent opioids are built to make pills hard to crush, dissolve, or inject. That design does little to stop an overdose when someone simply swallows several intact tablets. Ensysce's MPAR technology — short for Multi-Pill Abuse Resistance — targets that oral-overdose gap directly, using a chemical mechanism the company likens to a built-in safety switch: it maintains normal opioid exposure at a prescribed dose but restricts the release of additional drug when too many pills are taken at once, whether through intentional misuse, accidental overconsumption, or a dosing error.

PF614-MPAR pairs that overdose-protection layer with PF614, a prodrug that stays inactive until it reaches the small intestine and meets the digestive enzyme trypsin, which makes it harder to abuse through snorting or injection. Together the two mechanisms are meant to address both manipulation-based abuse and oral overdose. Ensysce is developing the drug first for patients with severe pain who cannot be adequately treated with non-opioid options, and CEO Lynn Kirkpatrick called the continued NIDA support a step "toward setting a new standard for opioid safety."

The work is unfolding against a grim backdrop: nearly 80,000 people die from opioid overdoses in the United States each year, with prescription opioids still contributing to the toll. PF614-MPAR remains investigational and has not been approved; further studies will be required to establish its safety and effectiveness. The company has also floated adapting the same chemistry to methadone and amphetamine medications, which could extend the approach to treatment for opioid use disorder and ADHD down the line.