Compound (I) and compositions and use in therapy as CSBP/RK/p38 kinase inhibitor. 3-[2-{[3-(diethylamino)propyl]amino}-8-(2,6-difluorophenyl)-7-oxo-7,8-dihydropyrido[2,3-d]pyrimidin-4-yl]-5-fluoro-4-methyl-N (1-methylethyl)benzamide or a salt thereof