Trispecific antibodies. (A) Trispecific T-cell engagers, with 1 binding domain for the myeloma antigen and 2 for the T-cell antigens, which include CD3 and a costimulatory antigen. These schematics are representative of trispecifics and not the actual constructs. (B) Trispecific NK-cell engager with 2 myeloma antigen-binding domains and 1 NK-cell antigen domain.