Comparative antitumor activity of ADCT-402 in the human CD19-expressing Burkitt lymphoma-derived Ramos model. (A) In vivo antitumor activity of ADCT-402 in SC implanted Ramos xenograft model. ADCT-402 was administered IV at a group mean tumor volume of 120 mm³ as a single dose at 0.33, 0.66, or 1 mg/kg. (B) In vivo antitumor activity of ADCT-402 in SC implanted Ramos xenograft model in comparison with ADC RB4v1.2-DM4 and hBU12-mc-MMAF. All 3 ADCs were compared at a single dose of 1 mg/kg; in addition, RB4v1.2-DM4 and hBU12-mc-MMAF were tested at 3.3 mg/kg every 4 days × 2 and 3 mg/kg every 4 days × 4, respectively. (C) In vivo antitumor activity of ADCT-402 in SC implanted Ramos xenograft model where ADCT-402 was administered at a single dose of 1 mg/kg or fractionated dosing of 0.33 mg/kg given either every week × 3 or every 4 days × 3. (A-C) Data are shown as mean ± SEM from animal group sizes of 10 mice. (D) In vivo antitumor activity of ADCT-402 in a disseminated Ramos model. Kaplan-Meier survival plots show percentage animal survival over 91 days in an experiment in which ADCT-402 was administered at a single dose of 0.33 mg/kg or 1 mg/kg in comparison with vehicle or nontargeting ADC administered as a single dose of 1 mg/kg (each group, n = 10). PBS, phosphate-buffered saline; SEM, standard error of the mean.