Anti-CD20-interferon-alpha fusion protein has superior in vivo activity against human B-cell lymphomas compared to rituximab and enhanced complement-dependent cytotoxicity in vitro.

3024 Background: We previously reported an anti-CD20-interferon (IFN)-alpha fusion protein able to induce apoptosis and promote in vivo eradication of a human CD20-expressing mouse B cell lymphoma (Xuan et al, Blood 2010). We now report the activity of a recombinant anti-CD20-human IFNα fusion protein against human non-Hodgkin B cell lymphomas (NHL). Methods: Anti-CD20-hIFNα was evaluated against a panel of human Burkitt, diffuse large B cell (DLBCL), and mantle cell lymphoma cell lines. Proliferation was measured by [3H]-thymidine, complement-dependent cytotoxicity (CDC) by PI flow cytometry, and antibody-dependent cellular cytotoxicity (ADCC) by LDH release using PBMC effectors. NHL xenografts were grown in SCID mice. Results: Anti-CD20-hIFNα induced stronger growth inhibition than rituximab, particularly against Burkitt and germinal center-type DLBCL NHLs. Tumor growth inhibition by anti-CD20-hIFNα was associated with substantial apoptosis in some cell lines. Anti-CD20-hIFNα exhibited potent ADCC activ...