Uptake of imatinib-loaded polyelectrolyte complexes by BCR-ABL(+) cells: a long-acting drug-delivery strategy for targeting oncoprotein activity.

Rationale & Aim: Imatinib mesylate (IM), a selective tyrosine kinase inhibitor of the oncoprotein BCR-ABL, is the 'gold standard' for patients with chronic myeloid leukemia (CML) but the drug does not eliminate CML stem cells, leading to disease relapse on drug discontinuation. At present, much effort is focused on delivery carriers that can increase the intracellular retention and antileukemic impact of IM. We previously validated IM-loaded polyelectrolyte microcapsules as effective purging agents to eradicate BCR-ABL(+) cells from CML patient autografts.