Long-term efficacy and safety of arsenic trioxide for first-line treatment of elderly patients with newly diagnosed acute promyelocytic leukemia

Background: The prognosis of acute promyelocytic leukemia (APL) in the elderly is poorer than that of younger patients after treatment with all-trans retinoic acid plus chemotherapy, which is the current standard therapy for APL. A significantly higher mortality during consolidation therapy was found, which is mainly due to deaths from sepsis following chemotherapy-induced myelosuppression. Methods: A total of 33 patients aged 60 years or older with de novo APL were treated with single-agent arsenic trioxide (ATO) for remission induction and postremission therapy. The postremission therapy continued for up to 4 years. Results: Twenty-nine patients (87.9%) achieved a hematologic complete remission, and the most common adverse event during remission induction was leukocytosis (63.6%). Definite differentiation syndrome was observed in 5 patients. Nonhematologic adverse events were all manageable and reversible. Twenty-eight patients proceeded to postremission therapy. Adverse effects during postremission therapy were mild, transient, and no treatment was required. No patients died from ATO-related toxicities. With a median follow-up of 99 months, the 10-year cumulative incidence of relapse, overall survival, disease-free survival, and cause-specific survival were 10.3%, 69.3%, 64.8%, and 84.8%, respectively, which are comparable with those in the younger APL partners. No significant risks for development of chronic arsenicosis or second malignancy were observed during the follow-up period. Conclusions: The results indicate that the single-agent ATO regimen is safe and effective with long-term durable remission, and could be used as first-line treatment for elderly patients with de novo APL.