Enhanced cytotoxic effect of ABT-737 combined with a proteasome inhibitor in MCL (HBL-2). (A) Percentage of cells killed compared to control for each treatment group (± SD). ABT-737 was given for up to 72 hours. Model of in vitro exposure is shown on the upper left. (B) Multiple comparison analysis for ABT-737 at 10 nM in combination with bortezomib at 6 nM or carfilzomib at 6 nM or 10 nM for 24 hours; 3 different schedules for each drug combination are compared. Statistically superior group (P < .05) is shown in a gray box. Probability values for comparisons of all averages proved (P values). (C) Comparison of each combination to each drug alone; superior treatment group is shown in parentheses. A = ABT-737, B = bortezomib, C = carfilzomib.