Abstract: The present invention relates to a combination comprising (a) a phosphatidylinositol 3-kinase inhibitor selected from 5-(2,6-di-morpholin-4-yl-pyrimidin-4-yl)-4-trifluoromethyl-pyridin-2-ylamine, (S)-Pyrrolidine-1,2-dicarboxylic acid 2-amide 1-({4-methyl-5-[2-(2,2,2-trifluoro-1,1-dimethyl-ethyl)-pyridin-4-yl]-thiazol-2-yl}-amide) or a pharmaceutically acceptable salts thereof, and (b) a microtubule destabilizing agent for simultaneous, separate or sequential use for the treatment of a tumor disease; a pharmaceutical composition comprising such combination; a method of treating a subject having a tumor disease comprising administration of said combination to a subject in need thereof; use of such combination for preparation of a medicament for the treatment of a tumor disease; and a commercial package thereto.