N-(4-Trifluoromethylphenyl)-2-cyano-3-hydroxycrotonamide, 2-Cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]-2-beuteamide, LEF-M; Teriflunomide; Leflunomide EP Impurity B; Aubagio; A1726; (2Z)-2-Cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]-2-butenamide; Femorix; HMR 1726; SU 20

Teriflunomide (Leflunomide EP Impurity B) is the active metabolite of Leflunomide, a potent disease-modifying antirheumatic drug used in the treatment of rheumatoid arthritis. LEF-M interferes with dendritic cell function. The second Phase III study evaluating the efficacy of Genzyme’s teriflunomide therapy against relapsing forms of multiple sclerosis found the once-daily oral drug to be no less effective than injectable interferon beta 1a..