The invention relates to solid pharmaceutical compositions comprising (Z)-2-cyano-3-hydroxy-but-2-enoic acid-(4′-trifluoromethylphenyl)-amide, as well as a process for the preparation of the same, methods of using such compositions to treat subjects suffering from autoimmune diseases in particular systemic lupus erythematosus or chronic graft-versus-host disease, multiple sclerosis or rheumatoid arthritis.