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Positive Phase I Study Results Show Promise for Potential Acute Pain Therapy, Mitigating Major Risks of Existing Opioids

Image Credit: © putilov_denis –

Elysium Therapeutics has announced positive results from a Phase I study (O2P-001) investigating the company’s proprietary Oral Overdose Protected (O2P™) hydrocodone prodrug for the treatment of moderate-to-severe acute pain, according to a press release.1

“Because non-opioid options are ineffective and existing opioids have no protection against their inherent risks, moderate-to-severe acute pain (e.g., post-operative pain) is not adequately managed in greater than 80% of patients in the US and is associated with increased morbidity, functional and quality-of-life impairment, delayed recovery time, prolonged duration of opioid use, higher healthcare costs, and is predictive of the development of chronic pain,” said Greg Sturmer, co-founder and CEO of Elysium Therapeutics in the press release. “As shown in our human study, our SMART opioids, led by O2P hydrocodone, mitigate the major risks associated with existing prescription opioids without sacrificing their superior analgesic efficacy, especially when compared to currently marketed non-opioid alternatives and those in development.”

The randomized, open-label, two-part Phase I trial enrolled a total of 93 subjects. Some of the key findings from the study include safety with no serious adverse events reported, efficacy showing effective management of acute pain and longer duration of action than traditional hydrocodone, and oral overdose protection with lower hydrocodone exposures.

“The results from the O2P-001 study indicate that Elysium’s O2P technology could yield safer opioids that address the key issues inherent in current opioids that have fueled the opioid crisis, while providing patients with highly effective pain relief,” said Leela Vrishabhendra, MD, principal investigator for the O2P-001 study in the press release.

“The vast majority (>90%) of acute use opioid abuse is via ingesting multiple intact tablets in excess of the prescribed dose,” said Tom Jenkins, PhD, co-founder and chief scientific officer of Elysium Therapeutics and inventor of trypsin-activated opioid prodrugs and concomitant use of trypsin inhibition to govern opioid exposure in the press release. “Results from our O2P hydrocodone Phase I study address key issues of existing opioids that too often lead to abuse, addiction, and death by providing meaningful protection against oral overdose; and significantly reducing the number of tablets prescribed.”

According to Sturmer, Elysium Therapeutics plans to meet with FDA to discuss next steps and finalize dosing for remaining studies.


  1. Elysium Therapeutics Announces Compelling Human Proof-of-Concept Data for its SMART™ Opioid, O2P™ Hydrocodone Prodrug for Acute Pain that Could Disrupt the Industry by Establishing New Standards for Opioid Safety. News release. March 5, 2024. Accessed March 5, 2024.