Apilimod is a small molecule that inhibits IL-12 and IL-23 production - cytokines that are involved in autoimmune diseases - through the prevention of nuclear translocation of c-Rel. Synta Pharmaceuticals Corp is developing apilimod for the potential treatment of Crohn's disease (CD) and other autoimmune diseases. Preclinical studies demonstrated the successful inhibition of IL-12 and IL-23 production by the drug. In the clinical setting, apilimod has been generally well tolerated, with mild-to-moderate side effects reported, including headaches and nausea. Patients with CD responded within 14 days of treatment with apilimod and, after 28 days, the drug significantly reduced the Crohn's disease activity index (CDAI). Apilimod is currently in phase II clinical trials for rheumatoid arthritis, common variable immunodeficiency and CD. From the data available to date, apilimod appears to be a promising treatment for CD, and the oral formulation of this compound provides an advantage for apilimod over injectable therapies.