IDELALISIB IS AN INHIBITOR OF PI3K? KINASE, WHICH IS EXPRESSED IN NORMAL AND MALIGNANT B-CELLS. IDELALISIB INDUCED APOPTOSIS AND INHIBITED PROLIFERATION IN CELL LINES DERIVED FROM MALIGNANT B-CELLS AND IN PRIMARY TUMOR CELLS. IDELALISIB INHIBITS SEVERAL CELL SIGNALING PATHWAYS, INCLUDING B-CELL RECEPTOR (BCR) SIGNALING AND THE CXCR4 AND CXCR5 SIGNALING, WHICH ARE INVOLVED IN TRAFFICKING AND HOMING OF B-CELLS TO THE LYMPH NODES AND BONE MARROW. TREATMENT OF LYMPHOMA CELLS WITH IDELALISIB RESULTED IN INHIBITION OF CHEMOTAXIS AND ADHESION, AND REDUCED CELL VIABILITY.