The experiments were carried out on chronic myeloid leukemia (CML) cell lines, both sensitive (K562 and LAMA-84) and the derived drug-resistant, P-gp- and BCRP-over expressing cell lines (K562-RC and K562-RD), where it was determined that 0.25 μM elacridar combined with various imatinib concentrations decreased cell viability in a dose- and time-dependent manner [48]. This evidence concerns the gene PGP and chronic myelogenous leukemia, BCR-ABL1 positive.