In vitro sensitivity to the liposomal preparation, DaunoXome in CLL

In older to determine the efficacy of liposomal encapsulated daunorubicin ( DaunoXome; DNX) in chronic lymphocytic leukaemia, the sensitivities of cell s from 10 patients with this disease were assessed and compared with that o f free drug using the MTT assay. There was a marked variation in effect bet ween patients for both drug preparations. Despite this, there was a small b ut significant enhancement of cytotoxicity afforded by rite liposomal prepa ration (median 2.8-fold, p<0.01). The cells from 2 of the patients appeared to be resistant to free daunorubicin. However, incubation for 96h in DNX a ppeared to cir circumvent this resistance. This increase in sensitivity for resistant cells could not be demonstrated in an MDR positive cell line (K5 62AR) suggesting that another mechanism of resistance may be involved We co nclude that it is feasible to assess sensitivity to DNX using the MTT assay in fresh cells from patients with CLL using a continuous drug exposure of 96h. Furthermore, DNX appears more effective than free drug in this disease .