Arsenic Trioxide as Effective Therapy for Relapsed Acute Promyelocytic Leukemia

The standard of treatment for newly diagnosed patients with acute promyelocytic leukemia (APL) is all-trans retinoic acid (ATRA) plus anthracycline-based cytotoxic chemotherapy, a combination that is highly effective for remission induction. However, 20%-30% of patients relapse and require salvage therapy. Reports from China on the striking efficacy and safety of arsenic trioxide in patients with APL led to clinical trials in the United States, which culminated in U.S. Food and Drug Administration approval in September 2000. Trisenox® (Cell Therapeutics, Inc., Seattle, WA) is an injectable formulation of arsenic trioxide indicated in the treatment of refractory or relapsed APL. The common side effects of Trisenox therapy are mostly mild and self-limiting and do not require interruption of therapy. Serious adverse effects that can occur include hyperleukocytosis, electrocardiographic abnormalities, and APL differentiation syndrome. These effects can be prevented or managed successfully with careful patient monitoring during treatment. Trisenox has no known cross-resistance with ATRA or other anticancer agents. It does not cause hair loss and is not myelosuppressive in patients with APL. Oncology nurses can play a major role in educating patients about this new drug, explaining its clinical benefits and side effects and the precautions that are necessary for its use.