New data with arsenic trioxide in leukemias and myelodysplastic syndromes

Arsenic and its derivatives have been used for medicinal purposes for thousands of years. Arsenic trioxide has demonstrated remarkable activity in the treatment of acute promyelocytic leukemia (APL), for which it can bring about complete remissions (CR) in > 80% of patients with relapsed disease, and molecular remission in 90% of those who enter a CR. Clinical trials have explored its use in the first-line setting and as part of consolidation therapy for de novo APL, for which it appears to provide an event-free and overall survival advantage. Two multicenter trials have examined its use in the treatment of the myelodysplastic syndromes; as a single agent, it yields responses in 20% of patients, and smaller trials have provided evidence for its use in non-APL acute myeloid leukemia populations in combination with other drugs such as gemtuzumab ozogamicin, ascorbic acid, and cytarabine.