Survival benefit of maintenance therapy in AML patients after complete remission in northeast Iran oncology centers with limited access to oral azacitidine.

Abstract

123 Background: Acute myeloid leukemia (AML) is associated with high relapse rates even in patients who achieve a complete remission with initial treatment. Maintenance therapy with cytotoxic agents has been considered a strategy to prolong disease-free survival (DFS) and overall survival (OS). The lack of availability of oral Azacitidine in some countries limits its use. This study aimed to compare the DFS and OS rates of AML patients with and without maintenance therapy using subcutaneous cytarabine or oral thioguanine. Methods: This retrospective cohort study reviewed the charts of non-m3 AML patients treated in oncology centers in northeast Iran from February 2015 to February 2021. The study included patients aged 15-60 who experienced complete remission following induction and then consolidation chemotherapy and did not receive Allogeneic Hematopoietic Stem Cell Transplantation (allo-HSCT). Patients were categorized based on receiving maintenance therapy (MT) after the first-line treatment and those who were only followed up (FU). Patients’ demographic information, pathology and lab findings, date of relapse and/or death, and first-line and maintenance treatments regimens were extracted. For each of the MT and FU groups, the frequency of main outcomes (death and/or relapse) was calculated, and the Median (95%CI) of DFS and OS was estimated. The log-rank test was used to compare the DFS and OS between groups. Results: A total of 100 patients (50 MT and 50 FU) met the study inclusion criteria. There were no significant differences between the two groups regarding patients’ demographic characteristics, pathology and lab findings, and ELN’s risk category. The relapse rate in the FU and MT groups was 76% (n=38) and 60% (n=30) respectively (p=0.09). 39 individuals (78%) in the FU group and 26 individuals (54.2%) in the MT group died between complete remission and Feb 2022(p=0.01). The Median (95% CI) of DFS in FU and MT groups were 11 (8.6-13.3) and 18 (7.3 -28.6) months respectively (P=0.03). The median OS (95% CI) was 16 (10.8 - 21.1) months in the FU group and 23 (10.8 - 35) months in the MT group (P=0.04). Further comparisons between patients who received subcutaneous cytarabine and oral thioguanine revealed no significant differences regarding DFS and OS. Conclusions: The study results suggest that maintenance therapy with subcutaneous cytarabine or oral thioguanine after complete remission in non-m3 AML patients is associated with improved DFS and OS. Further randomized controlled trials and cost-utility studies are recommended to consider these available cytotoxic agents as maintenance therapy alternatives in regions where Azacitidine is not available.