Treatment of Acute Promyelocytic Leukemia With No or Minimal Chemotherapy: Now a Reality in Common Clinical Practice

Osman et al1 report the consensus opinion among the clinicians at the University of Chicago Medical Center when treating patients with newly diagnosed acute promyelocytic leukemia (APL). The treatment of APL has evolved dramatically over the past several decades and has led to the disease becoming one of the most curable forms of acute leukemia.2 However, as the authors quite correctly indicate, failure to recognize the entity early and delay in initiation of all-trans retinoic acid (ATRA), as well as inadequate management of coagulopathy and complications of therapy such as differentiation syndrome, still lead to high mortality during the initial period of therapy.3 The practical considerations provided by the authors, although not universally agreed on by APL experts, provide practicing clinicians with additional suggestions for further reducing potential complications of modern regimens, including the chemotherapy-free regimens. A preponderance of data suggests that the best strategy for treating standard-risk APL (including Sanz low- and intermediate-risk groups) is the combination of ATRA and arsenic trioxide in induction and consolidation.4-6 This regimen, pioneered at MD Anderson and proven to be superior to ATRA plus chemotherapy by the APL0406 trial, is associated with lower mortality and improved event-free survival and overall survival, and possibly lower risk of long-term complications, such as therapy-related myeloid disorders and cardiotoxicity.7 Although formal randomized data in high-risk disease are limited, the authors agree that long-term follow-up of MD Anderson trials, as well the United Kingdom AML17 (Acute Myeloid Leukemia 17) trial, has demonstrated the benefit of gemtuzumab ozogamicin in this setting.4,6 Other practical points tackled by the authors are the optimal dose and schedule of ATRA and arsenic trioxide. Although there is some degree of variability in the reported trials, the authors recommend that the standard dose and schedules of both drugs should be adhered to, with the exception of situations in which toxicity or intolerability, or the presence of other comorbid conditions, mandate dose adjustments. Careful monitoring for known significant adverse effects, such as differentiation syndrome and QT interval prolongation, and adherence to practical guidelines on how to best manage these complications are of paramount importance to achieve the best outcomes for all patients with this disease. The use of gemtuzumab ozogamicin or idarubicin to control leukocytosis can reduce the complications, such as hemorrhage and