Comparison of the activity of SNS-032, flavopiridol, and roscovitine in CLL cells. The inhibition of uridine incorporation after 6 hours (A) and inhibition of cell survival measured by annexin V/PI staining after 24 hours (B) were compared among SNS-032 (●), flavopiridol (■), and roscovitine (▲) with concentrations that ranged between 0.01 and 100 μM. Data (mean ± SD) represent measurements from 3 to 5 individual patient samples.