idelalisib + obinutuzumab

Idelalisib + obinutuzumab is a combination of two antineoplastic agents, each with a distinct mechanism of action, under clinical investigation for B-cell malignancies. Idelalisib is an oral small molecule inhibitor of phosphoinositide 3-kinase delta (PI3Kδ), which blocks survival, proliferation, and homing signals essential for B-cell malignancies by targeting the delta isoform highly expressed in leukocytes. Obinutuzumab is an intravenously administered, humanized type II monoclonal antibody against CD20, a B-cell surface antigen, and induces B-cell depletion through direct cytotoxicity and antibody-dependent cellular cytotoxicity. The combination has been evaluated primarily for treatment of chronic lymphocytic leukemia (CLL) and Waldenström macroglobulinemia, though development in previously untreated CLL was terminated at the phase 3 stage due to safety concerns[1][5][9].