Short-term in vitro sensitivity testing in acute leukemia.

To detect sensitivity or resistance of leukemic cells to chemotherapy prior to treatment, a short-term incubation method was employed. Blast cells from the peripheral blood or bone marrow of adult patients with different forms of acute leukemia were analyzed for in vitro responsiveness to cytostatic agents in terms of suppression of nucleoside precursor (3H-uridine, 3H-deoxyuridine) incorporation into the cells. Retrospectively, the in vitro data were compared to the clinical response of the patients to polychemotherapy. In the majority of patients, in vitro cytotoxic effectiveness of doxorubicin and ara-C reflected the in vivo situation. The levels of in vitro inhibition that could distinguish between drug-sensitive and drug-resistant diseases appeared to be 30% for doxorubicin and 20% for ara-C. No correlation was found between the doxorubicin effect in vitro and the proliferative state of the leukemic cell populations. Serial in vitro testing during the course of the disease of various patients proved the ability of the test system to detect acquired resistance to chemotherapeutic agents. Studies with established cell lines (HL-60, Raji) indicated that the short-term test in its present form is probably not suited to monitor the effect of drug combinations in vitro.