Comparison of maintenance regimens in Acute Promyelocytic Leukemia patients.

Maintenance therapy in APL is still a standard especially in high-risk patients treated with chemotherapy+ATRA combination whereas the role of the maintenance therapy in low-risk patients is controversial. This study aims to compare the efficacy and toxicity of ATRA monotherapy and ATRA+MTX+ 6-MP combination as the maintenance treatment for 2 years in APL patients who achieved molecular complete response after induction and consolidation with ATRA+chemotherapy. A total of 71 patients from 4 different centers were included in this study. After a median follow-up of 54 months (5-180 months), the 5-year RFS was 89 % in the ATRA monotherapy arm, the 5-year RFS was 78.5 % in the combined treatment arm (p = 0.643, HR:1.3, 95 % CI: 0.35-5.3). Hematological toxicity in all grades and Grade III/IV hematological toxicity was observed significantly more in the combined treatment arm than in the ATRA monotherapy arm (All grades: 76.9 % vs 18.9 %, p < 0.001; Grade III/IV: 20.5 % vs. 3.1 %, p = 0.035). Hepatotoxicity at all levels was significantly higher in the combined treatment arm than in the ATRA monotherapy arm (61.5 % vs 25 %, p = 0.002). Our study concluded that two years of ATRA monotherapy and combined maintenance therapy, both of which were found to be similar in terms of disease control and long term survival, ATRA Monotherapy could be a safer maintenance treatment option since both hematological and non-hematological toxicities were observed less often in the ATRA monotherapy arm.