Preferential inhibition by cytarabine of CFU‐GM from patients with chronic granulocytic leukemia

Abstract

Granulocyte‐macrophage colony‐forming (CFU‐GM) cells from peripheral blood of normal subjects and patients with chronic granulocytic leukemia (CGL) were cultured in soft agar. Drugs under study were added in a liquid overlay 2 days after initiation of cultures, providing prolonged exposure to these agents thereafter. Dose‐dependent inhibition of colony growth was recorded with each of eleven agents examined, and at the higher concentrations tested, colony formation was often completely suppressed. Cytarabine showed selectivity against CFU‐GM from patients in the chronic stage of CGL (P = 0.006); the median 50% inhibitory concentration for 12 such patients was 3.4 ng/ml versus 11.8 ng/ml for 15 healthy subjects. Such selectivity was not found with busulfan, hydroxyurea, mercaptopurine, thioguanine, daunorubicin, vincristine, vinblastine, methotrexate, desacetylmethylcolchicine, and trimethylcolchicinic acid. One other group has also reported a preferential effect of cytarabine against colony‐forming cells from patients with CGL, and this appears to be the only drug for which such selective activity has been recorded to date. Cancer 59:197–202, 1987. Copyright © 1987 American Cancer Society