Definition

A trispecific immunoglobulin G (IgG)-like T-cell engaging antibody targeting the two tumor-associated antigens (TAAs) cluster of differentiation 19 (CD19) and CD20, and the T-cell surface antigen CD3, with potential immunostimulating and antineoplastic activities. Upon administration, anti-CD3/CD19/CD20 trispecific antibody 1A46 binds to CD19- and/or CD20-expressing tumor B cell and CD3 antigen on cytotoxic T lymphocytes (CTLs). This activates and redirects CTLs to CD19- and/or CD20-expressing tumor cells, resulting in CTL-mediated killing of tumor cells. Both CD19 and CD20 are B-cell-specific cell surface antigens overexpressed in B-cell lineage malignancies. Targeting both CD19 and CD20 may prevent tumor cell antigen escape and relapse.