Acute promyelocytic leukemia as a paradigm for targeted therapy.

Substantial progress has occurred in the treatment of acute promyelocytic leukemia (APL) because of improved understanding of the pathophysiology of the disease and identification of a molecular target. Novel agents such as all-trans retinoic acid (ATRA) (alone or combined with chemotherapy) and, more recently, arsenic trioxide have produced complete remission in most patients with newly diagnosed APL and/or relapsed or refractory disease, respectively. Use of these targeted therapies has resulted in evolution of the disease from one that was historically one of the most fatal subtypes of acute myeloid leukemia (AML) to one that appears curable in 70% to 80% of patients. The targeted approach to treatment of this disease can serve as a paradigm for the treatment of other leukemias.