VERAPAMIL TESTS FOR ASSESSMENT OF DRUG-RE SISTANCE OF LEUKEMIA BLASTS

To determine prognostically unfavourable groups of acute leukemia pati ents, 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 tre atment. It was found that H-3-Vcr accumulation in the blasts of some p atients resistent to induction chemotherapy increases with verapamil a ddition to culture medium (Vrp+cells). ADR inclusion into Vrp+cells wa s the same as that into Vrp-cells. The inclusion of H-3-Ara-C into S-p hase 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 th at evaluation of Vrp effect on H-3-Ver accumulation under short-term c ulturing is able to indicate groups of patients with low probability o f achieving complete remissions in response to standard regimens of Vc r, Ara-C and anthracyclines treatment.