Optimal approach for high-risk acute promyelocytic leukemia

Clinical outcomes for patients with acute promyelocytic leukemia (APL) have improved dramatically in the last 25 years, but a small proportion still die early during induction or relapse after achieving remission. This review examines features that define increased risk of treatment failure in APL, and summarizes strategies that are currently available to minimize that risk.

In the last few years, a targeted approach has progressively been adopted in the initial therapy of APL, with increasing reliance on the combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). The goals of treatment are to minimize early and late disease-related and therapy-related complications, and to ultimately eliminate relapses and resistant disease entirely. The relative contributions of treatment-induced terminal differentiation and leukemia-specific fusion protein degradation in the elimination of APL have also been clarified.

High-risk APL, traditionally defined by an initial white cell count exceeding 10 × 10⁹/l, has proven to be almost as amenable to disease eradication as low-risk and intermediate-risk APL, provided treatment includes ATRA, ATO and some chemotherapy. Improved understanding of the pathogenesis of APL and the associated coagulopathy has the potential to further minimize the risk of failure by reducing induction deaths and relapses.