SCIENTIFIC ADVANCES

Arsenic Compound Improves Survival of Adults with Uncommon Form of Leukemia

A phase III intergroup led by the CALGB trial demonstrated a positive benefit from consolidation therapy with arsenic trioxide ( As₂O₃) on event-free survival and overall survival among patients with newly diagnosed acute promyelocytic leukemia (APL). Between June, 1999 and March, 2005, 582 patients were enrolled on this study. Patients were randomized to receive two courses of As₂O₃ for 5 days each week for 5 weeks as a first consolidation regimen if they achieved remission after induction therapy with oral tretinoin (ATRA), daunorubicin, and cytarabine. Subsequent consolidation included two courses of ATRA and daunorubicin. Patients in complete remission were then randomized to 1 year of ATRA maintenance (7days repeated every other week) with or without 6-mercaptopurine (daily) plus methotrexate (weekly). Event-free survival, the primary endpoint, was 77 percent at 3 years on the As₂O₃ arm (median, not reached) compared to 59 percent at 3 years on the standard arm (median, 63 months). Overall survival was 86 percent on the As₂O₃ arm compared to 77 percent on the standard arm at 3 years. This study demonstrates that the addition of two courses of As₂O₃ consolidation therapy following remission induction significantly improves event-free survival and overall survival in adults with APL.

Stock W, Moser B, Powell BL, Appelbaum FR, Tallman MS, Larson RA, Feusner JH, Bloomfield CD, Willman C, Gallagher RE. Prognostic significance of initial clinical and molecular genetic features of acute promyelocytic leukemia (APL): Results from the North American Intergroup Trial, C9710. J Clin Oncol2007: ASCO Annual Meeting Proceedings (Post-Meeting Edition) 25;7016.