Antitumor activity of teclistamab in xenograft models. (A) In the H929 prophylactic model, teclistamab had antitumor efficacy with significant reduction of tumor formation and growth compared with PBS-treated control mice, at dose levels of either 0.5 or 1 µg per animal; BCMAxNull and NullxCD3 bispecific antibodies, however, failed to suppress tumorigenesis in the model. (B) In the established RPMI 8226 model, teclistamab displayed antitumor effects at both the 10 and 50 µg per animal dose compared with PBS-treated control mice. Human pan-T cells were activated and expanded in vitro by using a T-cell activation and expansion kit (Miltenyi Biotec) and grown in medium containing IL-2 (0.1 µg/µL). Results are presented as average tumor volume, expressed in mm³ ± SEM of each group. Tumor volume was calculated by using the following formula: tumor volume (mm³) = (a × b²/2), where a represents the length and b the width of the tumor as determined by caliper measurements.