STI571 and recombinant IFN-α.

Isobolograms of simultaneous exposure to STI571 and recombinant IFN-α in (A) KU812, (B) TCC-S, and (C) TCC-Y cells. Data are presented as mean values of at least 3 independent experiments. The SEMs were less than 25% and were omitted. In all 3 cell lines, all or most data points of the combinations fell in the area of supra-additivity. The observed data were significantly smaller than the predicted minimum values by Wilcoxon signed-rank test in the KU812 and TCC-S cells (P < .01 and P < .05, respectively), suggesting synergistic effects. The observed data were not significantly smaller with the predicted minimum values in the TCC-Y cells (P > .05), suggesting additive to synergistic effects.