BCR and chronic myelogenous leukemia, BCR-ABL1 positive: The same team used the PCL loaded NPs with imatinib in combination with doxorubicin loaded sensitive polyelectrolyte complexes (PECs) which allowed a down-regulation of BCR–ABL in a sustained manner as well as significant CML stem cell death as both drugs worked in a synergistic manner with maximized cytotoxicity with minimized probability of cell resistance to any of these drugs [82].