In vivo efficacy of AT9283 in BCR-ABL⁺ cell line xenograft. Nude mice bearing either BaF3/wt-BCR-ABL^p210 (A) or BaF3/T315I (B) xenografts were administered the indicated doses of AT9283 by the intraperitoneal route. Vehicle (♦) and 12.5 mg/kg AT9283 (□) was dosed twice daily for 5 days followed by a 2-day break. The dose cycle was repeated twice in each case. Nude mice bearing human CML cells, K562 (C) xenografts were also administered the indicated doses of AT9283 by the intraperitoneal route. Vehicle (♦), 12.5 mg/kg (■), 10 mg/kg (□), and 7.5 mg/kg (♦) AT9283 was dosed twice daily for 5 days followed by a 2-day break. The dose cycle was repeated twice in each case. Mean growth curves ± SEs are shown for groups of 8 mice in each instance.