Grünenthal Completes Phase I Trial for Novel NOP Agonist Pain Therapy
Grünenthal has successfully completed a Phase I trial for its proprietary nociceptin receptor (NOP) agonist, demonstrating safety and tolerability in 113 healthy volunteers. The company plans to advance the novel pain therapy into a Phase II trial later this year, with results expected in the second half of 2027.
Grünenthal announced today that the company successfully concluded a Phase I trial evaluating the safety and tolerability of its proprietary nociceptin receptor (NOP) agonist. The trial, which involved 113 healthy participants, demonstrated that the investigational compound was safe and well tolerated, with no dose-dependent adverse event pattern observed.
The company is now planning to progress its NOP agonist into a Phase II trial that aims to enrol 400 US-based patients undergoing bunionectomy – a well-established model for evaluating the efficacy and safety of a compound as a treatment for acute pain. The Phase II trial will commence later this year, with results expected in the second half of 2027.
Through its specific selectivity for the nociceptin receptor, the NOP agonist features a unique mechanism of action for the treatment of acute and chronic pain and may present a first-in-class therapy option. The compound has the potential to deliver robust pain relief in a broad range of conditions without the side effects commonly associated with opioids. During the Phase I trial, no adverse events such as somnolence, constipation, or respiratory depression, or events suggesting any abuse liability potential were observed.
Bunionectomy is the surgical procedure for removing a bunion and is accepted by regulatory authorities as a postoperative hard tissue pain model in which the analgesic effect of an investigational compound may be evaluated as a treatment for acute pain. The nociceptin/orphanin receptor (NOP) is a G protein-coupled receptor whose natural ligand is the 17-amino-acid neuropeptide nociceptin. NOP agonists have been shown to act as potent analgesics without the potential for abuse liability in pre-clinical models.
Grünenthal is a global leader in pain management and related diseases, headquartered in Aachen, Germany, with affiliates in 28 countries across Europe, Latin America, and the U.S. The company's products are available in approximately 100 countries. In 2025, Grünenthal employed around 4,100 people and achieved revenues of €1.8 billion.