A rapid in vitro drug-sensitivity assay in acute nonlymphocytic leukemia

Leukemic myeloid, myelomonocytic, and monocytic cells will incorporate radiolabeled sulfate into newly synthesized macromolecules. We developed a liquid culture technique to examine the in vitro effects of chemotherapeutic agents on the incorporation of radiolabeled sulfate into cells of patients with acute nonlymphocytic leukemia (ANLL). Cells recovered from bone marrow or peripheral blood of 25 patients with ANLL were incubated in vitro for one hour with saline (control) or a variety of chemotherapeutic agents. Cells were washed free of the drug and grown in liquid cultures containing nutrient medium and 35SO4. The percent of 35SO4 incorporated into the drug treated as compared with control cells was determined after one, three, and seven days of culture. Patients whose drug-treated cells incorporated less than 30% of 35SO4 when compared with the control after three or seven days of culture achieved a complete response to these agents in vivo (P less than .05). Thus, the in vitro effects of various chemotherapeutic agents on the incorporation of 35SO4 into cells obtained from patients with ANLL may help predict clinical response to these agents in vivo.