SNS-032 potently induced apoptosis in CLL cells. (A) Induction of apoptosis in CLL cells isolated from 6 patients at 6-hour (■) and 24-hour (●) exposure to SNS-032. Cell death was measured by annexin V/PI double staining and quantitated by flow cytometry analysis (mean ± SD). (B) SNS-032 is selective against CLL cells. Cell death induced by SNS-032 was compared between the averages of 8 CLL cells (●) to mononuclear cells isolated from 3 healthy donors (■). (C) SNS-032 induced similar cell death regardless of patient characteristics and treatment history. Cell death induced by 0.3 μM SNS-032 after 24-hour incubation was compared in CLL cells from patients with favorable or poor prognostic factors. A P value of less than .05 was considered significant. Induced cell death was calculated as the difference between cell death in drug-treated samples minus that of time-matched controls. DMSO alone at highest concentration used here (0.01%) did not show toxicity to the CLL cells. *Sample number was too small to give a reliable P value.