In vitro chemosensitivity of newly diagnosed and relapsing acute non-lymphoid leukemia patients

We evaluated the in vitro sensitivity of circulating blasts from 25 newly diagnosed and 7 relapsing ANLL patients to drugs employed in vivo for inducing remission. Ten of the 14 newly diagnosed complete responders were in vitro sensitive to cytosine arabinoside and daunorubicin, whereas 10/11 non-responders were resistant to both agents. Although cells from all 7 relapsing patients were in vitro sensitive to the remission inducing agents, only 4 entered complete remission. Even if only indicative, these findings suggest that the poor prognosis of relapsing patients may be due, at least in part, to factors other than drug resistance. Moreover, the chemosensitivity test adopted is a better predictor in newly diagnosed than relapsing patients, as indicated by the concordance between in vitro and in vivo results.