A recombinant immunoglobulin G1 (IgG1) bispecific antibody targeting both the human T-cell surface antigen CD3 and oncofetal antigen 5T4, with potential immunomodulating and antineoplastic activities. Upon administration, anti-CD3/anti-5T4 bispecific antibody GEN1044 simultaneously targets and binds to CD3 expressed on T-cells and 5T4 expressed on tumor cells. The resulting cross-linkage may trigger a potent cytotoxic T-lymphocyte (CTL) response against the 5T4-expressing tumor cells. 5T4, a transmembrane glycoprotein, is overexpressed by a variety of cancer cell types; its expression is correlated with increased invasiveness.