The present invention relates to methods of treating or preventing a proliferative disease in a patient in need thereof by orally administering a therapeutically effective amount of an alpha-isoform selective phosphatidylinositol 3-kinase inhibitor compound of formula (I) or a pharmaceutically acceptable salt thereof for at least two five-consecutive day cycle, wherein said compound is not administered to the patient for a period of about two days to about three days between said five-consecutive day cycles； the use of said compound of formula (I) or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for treating or preventing a proliferative disease administered in accordance with said dosage regimen； therapeutic regimen comprising administration of said compound of formula (I) or a pharmaceutically acceptable salt thereof in accordance with said dosage regimen； and related pharmaceutical compositions and packages thereof.
