The present invention is based on the finding that combined use of a multispecific antibody comprising: (1) a cancer-specific antigen-binding domain, (2) a CD3-binding domain, and (3) a domain comprising an Fc region having decreased Fcγ receptor-binding activity with a tumor necrosis factor (TNF) receptor superfamily agonist antibody can reduce side effects such as liver injury observed when the agonist antibody is prescribed alone, and achieve effective therapeutic effects.
