This invention relates to methods and compositions for treatment of inv(16) leukemia and particularly to treatment of acute myeloid leukemia. Disclosed is a method of treating inv(16) leukemia comprising the step of administering to a subject in need thereof a therapeutically effective combination of a) a compound of the formula (1) and b) a chemotherapeutic agent selected from the group consisting of pirarubicin, aclarubicin, mitoxantrone, doxorubicin, daunorubicin, idarubicin, epirubicin, cytarabine, pharmaceutically acceptable salts and mixtures thereof. The therapeutically effective combination synergistically inhibits proliferation of inv(16) leukemia cells. This invention also relates to pharmaceutical compositions comprising a therapeutically effective combination of the compound of formula (1) and the chemotherapeutic agent and a pharmaceutically acceptable excipient.