The present invention relates to the fumarate salt of 4-[[4-[[4-(2-cyanoethenyl)-2,6-dimethylphenyl]amino]-2-pyrimidinyl]amino]benzonitrile, pharmaceutical compositions comprising as active ingredient said salt and to processes for their preparation.Sel de fumarate de 4-[[4-[[4-(2-cyanoéthényl)-2,6-diméthylphényl]amino]-2-pyrimidinyl]amino]benzonitrile, compositions pharmaceutiques comprenant le sel précité servant de principe actif et ses procédés de préparation.