Maintenance therapy with all-trans retinoic acid and arsenic trioxide improves relapse-free survival in adults with low- to intermediate-risk acute promyelocytic leukemia who have achieved complete remission after consolidation therapy.

BACKGROUND: Currently, the optimal maintenance therapy for patients with acute promyelocytic leukemia (APL) who have achieved complete remission (CR) after completing consolidation chemotherapy remains controversial. The comparative effectiveness of the all-trans retinoic acid (ATRA) plus arsenic trioxide (As2O3) maintenance strategy with classic ATRA plus chemotherapy has not been evaluated. In this study, we compared the efficacy and toxicity of maintenance therapy with ATRA plus As2O3 and classic ATRA plus chemotherapy in low- to intermediate-risk APL patients reaching the first CR after induction and consolidation therapy.

METHODS: A retrospective review of 58 adult patients diagnosed with APL was conducted. After receiving consolidation therapy and achieving CR, 30 patients were administered maintenance therapy with an ATRA plus As2O3 regimen (ATRA+As2O3 group), whereas 28 patients were administered 3-monthly cycles of an ATRA plus chemotherapy regimen (ATRA+chemotherapy group).

RESULTS: Grade 3-4 neutropenia was significantly more frequent in the ATRA+chemotherapy group (N=9, 32.1%) than in the ATRA+As2O3 group (N=0) (P=0.001). At a median follow-up of 49.1 months (range: 9.7-97.4 months) from the completion of consolidation, no relapses were observed in the ATRA+As2O3 group, whereas seven relapses occurred in the ATRA+chemotherapy group. The risk of relapse in the patients administered ATRA+As2O3 maintenance was significantly lower than that in those administered ATRA+chemotherapy maintenance (P=0.004). Based on log-rank analysis, only maintenance therapy with ATRA and As2O3 was associated with a significantly higher relapse-free survival (P=0.0159).

CONCLUSION: Maintenance therapy with ATRA and As2O3 was beneficial in low- to intermediate-risk APL patients who were effectively treated to achieve CR. Further clinical trials with reliable designs are needed to confirm these observations.