The invention relates to a new crystalline form of the methanesulfonic acid addition salt of 4-(4-methylpiperazin-1-ylmethyl)-N-[4-methyl-3-(4-pyridin-3-yl)pyrimidin-- 2-ylamino)phenyl]-benzamide of formula 1, which may be used for example for tumour therapy. ##STR00001##