A murine immunoglobulin G1 (IgG1) monoclonal antibody directed against the CD37 antigen with potential antineoplastic activity. Upon administration, lilotomab both activates the immune system to induce an antibody-dependent cell-mediated cytotoxicity (ADCC) against CD37-overexpressing tumor cells and induces apoptosis in these tumor cells. CD37 is a transmembrane glycoprotein expressed at high-levels on B-cells and to a lesser extent on T-cells and myeloid cells, and is frequently overexpressed in certain B-cell malignancies.