Highly effective combinations of a compound of formula A (a PI3Kδ selective inhibitor) and anti-CD20 antibodies are provided herein for the treatment and amelioration of PI3Kδ and/or CD20 mediated diseases and disorderes. In particular, the combination can be used to treat cancers and autoimmune diseases. More particularly, the invention provided for a combination of a compound of formula A, or stereoisomers thereof, and ublituximab for the treatment and/or amerioration of hematological malignancies such as leukemia and lymphoma.
