A low-fucose, human-mouse chimeric IgG1 monoclonal antibody directed against the ganglioside GD3, a surface antigen expressed on many malignant melanoma cells, with potential antineoplastic activity. Ecromeximab binds to GD3-positive cells, thereby initiating antibody-dependent cytotoxicity against GD3-positive cells. This agent is prepared by fusing murine immunoglobulin (Ig) light and heavy variable regions derived from the murine IgG3 antibody KM-641 to a human constant (Fc) region. The low fucose content of the oligosaccharide side chains of this antibody may enhance binding of the antibody Fc region to lymphocyte Fc receptors.