Olorinab (APD371) is a drug being developed by Arena Pharmaceuticals for the treatment of gastrointestinal pain associated with Crohn's disease and irritable bowel syndrome.

[2][3] Initial Phase IIa exploratory clinical trials have been successful in patients with quiescent Crohn's disease.

[4] Arena initiated the Phase IIb Captivate[5] trial in late July 2019[6] in patients with irritable bowel syndrome related pain, in constipation and diarrhea predominant sub-types.

[8][9] In 2019, a study showed that Olorinab reduces Visceral Hypersensitivity in the TNBS-induced colitis animal model, attempting to control for its mechanism of action by using a CB2 antagonist (SR-144,528).

Also, SR-144528 prevented olorinab-induced inhibition of colonic nociceptor hypersensitivity, further validating the role of the CB2 receptor in nociception.