In vivo efficacy of ABT-737 combined with a VXL treatment regimen. NOD/SCID mice were inoculated with ALL-7 (A) or ALL-19 (B), monitored for engraftment, and treated with vehicle control (Con; thin lines), ABT-737 (737; bold dotted lines), a combination of vincristine, dexamethasone, and L-ASP (VXL; thin dotted lines), or VXL plus ABT-737 (VXL + 737; bold lines). Drugs were administered by intraperitoneal injection: vincristine (Sigma-Aldrich, Castle Hill, Australia), 0.15 mg/kg in saline every 7 days for 4 weeks; dexamethasone (Sigma-Aldrich), 5 mg/kg in saline Monday to Friday for 4 weeks; L-ASP (Aventis, Lane Cove, Australia), 1000 IU/kg in saline Monday to Friday for 4 weeks; and ABT-737, 25 mg/kg in DMSO (final concentration < 1%), 30% propylene glycol, 5% Tween 80, and 65% dextrose (pH 4-5), Monday to Friday for 4 weeks. The EFS of mice was quantified as the time taken from the initiation of treatment until leukemia cells reached 25% in the peripheral blood, or for mice to be killed due to treatment-related toxicity. Each line represents the proportion of mice remaining event-free over time.