An immunoconjugate consisting of milatuzumab, a humanized monoclonal antibody against CD74, conjugated to the anthracycline antibiotic doxorubicin with potential antineoplastic activity. The milatuzumab moiety of this antibody-drug conjugate (ADC) selectively binds to CD74 on tumor cell surfaces; upon internalization, the doxorubicin moiety is released, where it intercalates between base pairs in the DNA helix and inhibits topoisomerase II, thereby preventing DNA replication and increasing double-strand breakage. As a result, this agent may inhibit the proliferation of cancer cells that overexpress CD74. CD74, an integral membrane protein and tumor associated antigen (TAA), is overexpressed in certain cancer cells and promotes survival in rapidly proliferating tumor cells.