Figure 1.

(A) Romidepsin alone inhibited cell viability in a time- and dose-dependent manner in Hut-78 and Karpas-299 cells (see Table 1 for IC₅₀ values of romidepsin). (B) Lenalidomide alone slightly inhibited cell viability in TCL cell lines, but did not reach the IC₅₀ even after 72 h of treatment. (C) Isobologram analysis of combination treatment with both romidepsin (0.5, 1, 2.5 nM) and lenalidomide (2, 4, 10 µM) for 24 hours (see Table 2 for combination index values) and cell viability from cell lines treated with romidepsin (2.5 nM) and lenalidomide (10 µM) either alone and in combination for 24 hours (*P < 0.003; **P < 0.001; ***P < 0.02; ****P < 0.002). (D) Cell viability from PBMCs from 3 healthy subjects treated with romidepsin (2.5 nM) and lenalidomide (10 µM) alone and in combination. (E) Cytotoxicity of TCL cells after treatment with romidepsin (2.5 nM) for 6 hours followed by washout and the addition of lenalidomide (10 µM) for 24 hours.