A post-hoc analysis of outcomes of patients with acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) who received oral azacitidine (Oral-AZA) maintenance therapy in the QUAZAR AML-001 study.

6522 Background: AML-MRC represents 25%–34% of all AML cases, and patients with this AML subtype generally have poor outcomes. In this subanalysis of the QUAZAR AML-001study, we report outcomes of patients with AML-MRC who received Oral-AZA vs placebo (PBO). Methods: QUAZAR AML-001 was a phase 3 study of Oral-AZA maintenance therapy in patients with AML in first remission after intensive chemotherapy who were not eligible for hematopoietic stem cell transplantation (HSCT). Patients ≥ 55 years of age with AML and intermediate- or poor-risk cytogenetics received Oral-AZA 300 mg or PBO QD for 14 d per 28-d cycles. In this analysis, WHO 2008 criteria were used to identify patients with secondary AML and/or patients with AML-MRC (both groups are referred to as AML-MRC in this analysis). Data on mutational profiles at diagnosis were not available. Overall survival (OS) from time of randomization to time of death from any cause after censoring for HSCT, and relapse-free survival (RFS) from time of randomization, were calculated using the Kaplan–Meier method. Duration of measurable residual disease (MRD) negativity achieved on treatment was calculated from the first MRD-negative assessment. Results: Overall, 101/472 patients had AML-MRC; 56/238 (23.5%) patients in the Oral-AZA arm and 45/234 (19.2%) patients in the PBO arm. Karyotype/cytogenetics data at diagnosis were available for 87/101 (86.1%) patients with AML-MRC and 331/371 (89.2%) patients with non-AML-MRC. A greater proportion of AML-MRC than non-AML-MRC patients had poor-risk cytogenetics (20/101 [19.8%] vs 46/371 [12.4%]), del(5q) (10/87 [11.5%] vs 9/331 [2.7%]), and monosomy 7/del(7q) (9/87 [10.3%] vs 14/331 [4.2%]). Median OS did not significantly differ in patients with AML-MRC vs non-AML-MRC in either treatment arm (Oral-AZA: 19.9 mo vs 25.1 mo, P = 0.2694; PBO: 14.8 mo vs 14.9 mo, P = 0.2099). In both treatment arms, the median RFS was inferior for patients with AML-MRC vs non-AML-MRC (Oral-AZA 7.5 mo vs 10.5 mo, P = 0.0430; PBO: 3.7 mo vs 4.9 mo, P = 0.0109). Oral-AZA significantly prolonged median OS and RFS, and the duration of MRD negativity for patients with AML-MRC compared with PBO (Table). Conclusions: Oral-AZA significantly improved OS and RFS compared with PBO for patients with AML-MRC indicating that Oral-AZA maintenance is an effective treatment option for these patients with particularly poor prognosis. Clinical trial information: NCT01757535 . [Table: see text]