VERAPAMIL TESTS FOR ASSESSMENT OF DRUG-RESISTANCE OF LEUKEMIA BLASTS

To determine prognostically unfavourable groups of acute leukemia patients, the authors studied the in vitro accumulation of H-3-vincristine (Vcr) and adriamycin (ADR) as well as inclusion of H-3-cytosar (Ara-C) into marrow blast DNA from patients showing different effects of treatment. It was found that H-3-Vcr accumulation in the blasts of some patients resistent to induction chemotherapy increases with verapamil addition to culture medium (Vrp+cells). ADR inclusion into Vrp+cells was the same as that into Vrp-cells. The inclusion of H-3-Ara-C into S-phase cell DNA in the cells Vrp+ was 3 time that in the cells Vrp-. All the responders to cytosar treatment had Vrp- blasts. It is evident that evaluation of Vrp effect on H-3-Ver accumulation under short-term culturing is able to indicate groups of patients with low probability of achieving complete remissions in response to standard regimens of Vcr, Ara-C and anthracyclines treatment.