Semapimod (INN), formerly known as CNI-1493, is an investigational new drug which has anti-inflammatory,[1] anti-cytokine,[2] immunomodulatory,[3] antiviral[4] and antimalarial[5] properties.

[1] Subsequently, it was found that suppression of nitric oxide synthesis occurred even at semapimod concentrations 10-fold less than required for inhibition of arginine uptake, suggesting that this molecule was a more general inhibitor of inflammatory responses.

[10] A subsequent phase I trial in humans failed to show an increase in the tolerated dose of IL-2, although indications of pharmacological activity as an inhibitor of tumor necrosis factor production were observed.

[11] In a preliminary clinical trial of semapimod in patients with moderate to severe Crohn's disease, positive clinical changes were observed, including endoscopic improvement, positive responses in some patients not responding to infliximab, healing of fistulae, and indications for tapering of steroids; no significant adverse effects were observed.

Semapimod is synthesized by reacting 3,5-diacetylaniline[14] with sebacoyl chloride in the presence of pyridine, followed by reaction of the resulting tetraketone with aminoguanidine hydrochloride.