Abstract: The present invention relates to a combination which comprises (a) a phosphatidylinositol 3-kinase inhibitor selected from the group consisting of a compound of formula (I) or a compound of formula (II), or pharmaceutically acceptable salt thereof, (b) a 17?-Hydroxylase/C17,20-lyase inhibitor (CYP17 inhibitor), specifically abiraterone acetate and 1-(2-Chloro-pyridin-4-yl)-3-(4-methyl-pyridin-3-yl)-imidazolidin-2-one or pharmaceutically acceptable salt thereof, for simultaneous, separate or sequential use for the treatment of a tumor disease; a pharmaceutical composition comprising such combination; use of such combination for the treatment of a tumor disease; a commercial package or product comprising such combination; and to a method of treating a patient having a tumor disease comprising administration of said combination to a patient in need thereof.