Sensitivity of human CFU-GM to mafosfamide : analysis of the factors affecting individual variations

A study of CFU-GM sensitivity to mafosfamide was carried out in 67 candidates for ABMT. A lethal dose 95 (LD 95 ) was calculated from the dose-response curve. Despite standardized treatment conditions of marrow buffy-coat cells, LD 95 values that were normally distributed (median 100 μg/ml; mean±SEM 95.6±4.0 μg/ml) varied considerably from patient to patient (range 30-160 μg/ml). Three independent factors appeared to confer greater sensitivity of CFU-GM: low patient age, low CFU-GM rate in treated cells and prolonged delay of CFU-GM sensitivity test from last chemotherapy course. In contrast, sex, pathology, disease status, number of previous chemotherapies and use of CY before the test did not influence CFU-GM sensitivity