STI571 and vincristine.

Isobolograms of simultaneous exposure to STI571 and vincristine (VCR) in (A) KU812, (B) K-562, (C) TCC-S, and (D) TCC-Y cells. Data are presented as mean values of at least 3 independent experiments; the SEMs were less than 20% and were omitted. In all 4 cell lines, most data points fell in the area of supra-additivity. The observed data were significantly smaller than the predicted minimum values in KU812, TCC-S, and TCC-Y cells (P < .02, .05, and .05, respectively), suggesting synergistic effects. The observed data were not significantly smaller than the predicted minimum values in the K562 cells (P > .05), suggesting additive to synergistic effects.