Single-agent arsenic trioxide in the treatment of newly diagnosed acute promyelocytic leukemia: long-term follow-up data

Abstract

Purpose: We previously reported our results with a single-agent arsenic trioxide (ATO) –based regimen in newly diagnosed cases of acute promyelocytic leukemia (APL). The concern remained about the long-term outcome of this well-tolerated regimen. We report our long-term follow-up data on the same cohort. Patients and Methods: From January 1998 to December 2004, 72 patients with PML/RARα+ APL were enrolled. All patients were treated with a single-agent ATO regimen. Results: Overall 62 (86.1%) achieved a hematologic remission (complete remission). After the initial report, an additional seven patients have relapsed for a total of 13 relapses. There were no additional toxicities to report on follow-up. At a median follow-up 60 months, the 5-year Kaplan-Meier estimate (± SE) of event-free survival, disease-free survival, and overall survival (OS) was 69% ± 5.5%, 80% ± 5.2%, and 74.2% ± 5.2%, respectively. The OS in the good risk group as defined by us remains 100% over this period. Conclusion: Single-agent ATO as used in this study in the management of newly diagnosed cases of APL is safe and is associated with durable responses. Results in the low-risk group are comparable to that reported with conventional therapy while additional interventions would probably be required in high-risk cases.