A 4-day chemosensitivity assay in vitro reliably predicts clinical response of patients with acute leukemia

To assess the individual chemosensitivity of human acute leukemias to anticancer agents, a rapid in vitro assay based on 125[I]-5-iodo-2'-deoxyuridine (125IUdR) incorporation into the DNA of neoplastic cells was tested. It was found that: a) the assay reflects the higher in vivo responsiveness of acute lymphoid leukemias with respect to acute non-lymphoid leukemias; b) samples from responder patients were more sensitive in vitro to antileukemic agents than were samples from non-responder patients; c) the assay in this study had an 86% accuracy in predicting response and a 90% accuracy in predicting resistance.