Acute promyelocytic leukemia: state-of-the-art management

Abstract

Acute promyelocytic leukemia (APL) is driven by the promyelocytic leukemia (PML) -retinoic acid receptor (RAR) α fusion protein generated by the chromosomal translocation t (15;17) which affects both nuclear receptor signaling and PML nuclear body (NB) assembly. The advent of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) as molecular targeted therapies directed against PML-RARα has been a major breakthrough in APL treatment. ATRA and ATO target RARα and PML, respectively, and elicit PML-RARα degradation, leading to the reformation of normal NBs and cell differentiation. In several multicenter trials, more than 90% of newly diagnosed APL patients treated with ATRA and chemotherapy achieved complete remission, of whom 20%-30% subsequently relapsed; the overall survival was approximately 80% in these studies. However, several major clinical problems continue to account for treatment failure including early death due to hemorrhage, infection during consolidation, disease relapse, and secondary malignancies. These issues are associated mainly with anticancer agents used in combination with ATRA. Combination therapy using ATRA and ATO is the current standard therapy for untreated patients with APL in Western countries. The current problems in patients with APL treated with ATRA and ATO are APL differentiation syndrome and high risk of relapse in patients with an initial leukocyte count of more than 10×109/l.