Combinations of BI 836826 that effectively kill CLL cells

What is it about?

BI 836826 is a novel antibody directed against the cell surface antigen CD37. Antibodies as single agents and in combination were tested on tumor cells isolated from the blood of patients with chronic lymphocytic leukemia (CLL). BI 836826 killed CLL cells more efficiently than clinically admitted CD20 antibodies. Combinations of BI 836826 with conventional chemotherapeutic agents (chlorambucil, fludarabine or bendamustine) and with PI3K inhibitors (idelalisib, copanlisib) as representatives of targeted agents showed enhanced cell killing compared to both combination partners.

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Why is it important?

The direct cytotoxic activity against chronic lymphocytic leukemia (CLL) cells of the CD37 antibody BI 836826 was assessed in combinations with chemotherapeutic agents and PI3K inhibitors. As determined via phosphatidylserine exposure of freshly isolated CLL cells, BI 836826 reduced CLL cell survival much more strongly than clinically used CD20 antibodies, and significantly enhanced the cytotoxicity of chlorambucil, fludarabine or bendamustine and of the PI3K inhibitors idelalisib and copanlisib (BAY 80-6946). Combination of BI 836826 with chemotherapeutic agents and PI3K inhibitors at clinically achievable concentrations led to mutual enhancement and reduced the mean percentage of viable CLL cells below 30 %.