Curative strategies for high-risk acute promyelocytic leukemia

Purpose of review Patients with acute promyelocytic leukemia (APL) who present with leukocytosis are considered high-risk due to lower relapse-free survival when treated with all-trans retinoic acid (ATRA) and anthracycline-based chemotherapy. The discovery and incorporation of arsenic trioxide (ATO) in therapeutic regimens for high-risk patients have led to improved survival, but there is no consensus on the optimal treatment approach. This review addresses reduction in early death and explores questions of regimen selection, including the choice of induction, consolidation, and maintenance, as well as the use of prophylactic adjunctive therapies, while examining clinical trial and real-world evidence. Recent findings ATRA-ATO combined with idarubicin (IDA) or gemtuzumab ozogamicin are highly effective compared to ATRA-IDA-based chemotherapy in clinical trials and real-world studies. Improved survival and early death reduction can be seen in the randomized controlled APOLLO study and in data from the recently published HARMONY and HERO analyses. Summary ATRA-ATO-based combinations, including ATRA-ATO-IDA and ATRA-ATO-GO, are current standards of care in high-risk APL. Further studies should seek to clarify the choice between these and other regimens and to more clearly show the benefit of maintenance therapy and of additional therapies such as for differentiation syndrome and CNS prophylaxis with these highly effective induction/consolidation regimens.