Effects of docetaxel on the in vitro growth of human myeloid progenitors

Haemotoxicity is usually the primary and dose-limiting side-effect of docetaxel (TXT) a semysyntetic analogue of paclitaxel which has acquired an important role in anticancer treatment. This research presents the results of an in vitro toxicity study of TXT on myeloid progenitors obtained from healthy volunteers and assayed as CFU-GM. Peripheral blood mononucleated non-adherent cells (MNAC) were incubated for 24 h at standard conditions with increasing concentrations of TXT and then cultured for CFU-GM assay. At every concentration severe CFU-GM growth inhibition was observed. In a second set of experiments MNAC were sequentially exposed to TXT and then to doxorubicin or cisplatin or vinorelbine or etoposide at appropriate concentrations. In a third set the sequence of exposure was reversed. No difference of CFU-GM growth inhibition was observed between the alternate sequences. These findings suggest that the toxicity on CFU-GM in vitro growth of TXT combinations with other anticancer drugs is sequence-independent.