Front-Line Therapy with Arsenic Trioxide/All-Trans-Retinoic Acid Combination and Chemotherapy Improves Cure Rates in Newly Diagnosed Patients with Acute Promyelocytic Leukemia

BACKGROUND: In this study, we analyzed the clinical benefit and safety of upfront use of all-trans-retinoic acid (ATRA), arsenic trioxide (ATO) and chemotherapy in patients with newly-diagnosed acute promyelocytic leukemia (APL) during Apr 2001 and Dec 2005.

METHODS: A total of 85 patients were treated with ATRA and ATO as induction therapy, followed by consolidation/maintenance therapy composed of ATRA, ATO and chemotherapy. All patients were followed-up to evaluate the long-term efficacy and safety.

RESULTS: A total of 81 (95.3%) patients entered complete remission (CR) with a median of 27 days. Among these 81 patients, 4 patients relapsed and 2 patients died from the disease with a median follow-up of 70 months (15–87). The 5-year leukemia-free survival (5-yr-LFS) and overall survival (5-yr-OS) for all patients were 89.2±3.4% and 91.7±3.0% while for patients who achieved CR (n=81), the 5-yr-LFS and 5-yr-OS were 96.2±2.1% and 96.2±2.1% respectively. With careful monitoring of in vivo arsenic levels in 33 evaluable long-term survivors, we demonstrated that the serum and urine arsenic concentrations were within safety limits, although a slight but significantly increase in arsenic levels was observed as compared to healthy donors. Overall, no obvious arsenic associated long-term toxicity was documented in these patients.

CONCLUSIONS: Use of up-front ATRA/ATO/chemotherapy combination treatment in newly-diagnosed APL has proven relatively safe and has lead to a significant improvement in long-term LFS/OS.