According to the 2016 WHO classification, AML-MRC encompasses an heterogeneous group of acute myeloid leukemias (AML) comprising: AML emerged from a previous myelodysplastic syndrome (MDS) or myeloproliferative /myelodysplastic disease (group 1), AML with MDS-defining cytogenetic abnormalities (group 2), or acute myeloid leukemia (AML) with dysplasia in at least 2 cell lineages without the above mentioned (group 3). In spite that AML-MRC has been considered a high-risk entity with poor prognosis, little is known on the relationship of clinical and biological characteristics with outcomes in these three groups. The aim of this study was to describe the clinical and biological characteristics of patients with AML-MRC and analyze their prognostic variables and outcomes.

We retrospectively analyzed AML-MRC cases diagnosed between January-2009 and December- 2018 in two institutions. Descriptive variables were studied to compare the three AML-MRC groups. AML cytogenetic risk and response were defined according to the European Leukemia Net recommendations. Overall survival (OS) was considered as the time from the diagnosis to the last visit. Survival analysis were performed with Kaplan Meier method and comparisons with the log-rank test.

Among 575 cases of AML identified, 186 (32.3%) met AML-MRC criteria and were included in the study. The main patient characteristics are shown in Table1. Median age was 72 (range, 22-88) years and 32% were female. Adverse karyotype was present in 29% of patients, being more prevalent in the AML-MRC group 2. Sixty one patients (33%) received an intensive chemotherapy approach and 36 (19%) an allogeneic stem cell transplantation. Patients in group 3 exhibit a higher probability of achieving a complete response than groups 1 and 2 (Table 2). After a median follow-up for survivors of 28.5 months (range, 5-130), 149 (80%) died in this period. Three years Overall Survival (OS) for patients in groups 1, 2 and 3 was 3 (0-117), 5 (0-93) and 10 (0-130) months, respectively (p=0.012) (Figure 1). Type of treatment (intensive, non intensive or best supportive care) and cytogenetic risk also showed impact on OS. Multivariant analysis adjusting these factors showed that patients in group 3 also presented better OS than patients in group 1 (HR=0,42 [IC95% 0,18-0,84], p=0,02), both with around a 30% of patients with adverse cytogenetics.

To conclude the present study suggests that group 3 of AML-MRC, for which the diagnosis is based solely on morphologic findings, showed better prognosis than the other groups. A more detailed molecular characterization might contribute to improve prognostic stratification of this heterogeneous AML entity, particularly in patients with non-high risk cytogenetics.

Disclosures

Salamero:Pfizer: Honoraria; Daichii Sankyo: Honoraria; Celgene: Honoraria; Novartis: Honoraria. Valcárcel:Jazz Pharmaceuticals: Honoraria; Novartis: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Other: spouse is an employee in the company, Speakers Bureau; Pfizer: Honoraria. Bosch:AstraZeneca: Honoraria, Research Funding; Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding; F. Hoffmann-La Roche Ltd/Genentech, Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Honoraria, Research Funding; Kyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Author notes

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Asterisk with author names denotes non-ASH members.