Comparison of induction therapy in non-high risk acute promyelocytic leukemia with arsenic trioxide or in combination with ATRA

Background: Acute promyelocytic leukemia (APL) is a curable form of acute myeloid leukemia; in recent years, the use of new treatment strategies, such as combination therapy, have led to improved APL outcomes. Here, outcomes of patients treated with a combination of arsenic trioxide (ATO) and all-trans-retinoic acid (ATRA) are compared against patients treated with single ATO therapy.

Patients and methods: In total, 67 patients with non-high-risk APL were evaluated. A group of 30 patients received ATO, and another group of 37 patients received ATO plus ATRA. ATO infusion at a dose of 0.15 mg/kg/day was continued till complete remission was achieved or till 60 days of consumption, and after 28 days of rest, second ATO course was initiated for 28 days as consolidation. Four courses separated by 28-day rest were planned. In the second group, 45 mg/m²/day ATRA was added to ATO protocol.

Results: All patients except one in the ATO group and all patients in the ATO plus ATRA group were alive after a median follow-up of 18 and 17 months, respectively; 2.5-year overall survival in the ATO group was 86% (p-value = .32). Five patients in the ATO group experienced relapse, and 2.5-year leukemia-free survival in this group was 60%. No relapse occurred in the ATO plus ATRA group (p-value = .01). Differences in the mean of white blood cell (p-value = .67), platelet (p-value = .15), liver (p-value = .37), and renal (p-value = .95) dysfunctions were not significant.

Conclusion: Although ATO has been considered a first-line therapy in patients with APL, several studies have reported improved outcomes with a combination of ATO plus ATRA. This study demonstrated a significant decrease in relapse with this combination compared with single ATO therapy and supported the importance of ATRA in APL treatment.