A humanized monoclonal antibody directed against the CD40 receptor with potential antineoplastic activity. Dacetuzumab specifically binds to and inhibits the CD40 receptor, thereby inducing apoptosis and inhibiting cellular proliferation via antibody-dependent cellular cytotoxicity (ADCC) in cells that overexpress this receptor. The CD40 receptor, a member of the tumor necrosis factor (TNF) receptor super-family, is highly expressed on most B lineage hematologic malignancies including multiple myeloma, non-Hodgkin's lymphoma, chronic lymphocytic leukemia, Hodgkin's disease and acute lymphoblastic leukemia.