Prognostic factors influencing outcomes of allogeneic HCT for AML with monosomal karyotype.

Monosomal karyotype (MK) comprises chromosomal abnormalities defined as either one single autosomal monosomy with structural abnormalities (MK1) or two or more distinct autosomal monosomies (MK2). MK is a predictive factor for extremely poor prognosis in patients with acute myeloid leukemia (AML), and not all patients are eligible for allogeneic hematopoietic cell transplantation (HCT). Using registry data from the Japan Society for Transplantation and Cellular Therapy, we retrospectively analyzed 892 AML patients with MK who underwent initial HCT between 2000 and 2017. The median follow-up among surviving patients was 3.1 years (range, 0.1-13.8 years). The 3-year overall survival (OS) rate was 26% for the 284 MK1 patients, which was significantly higher than the 10% observed in the 608 MK2 patients (P < 0.001). Multivariate analysis showed that MK subtype, disease status at time of HCT, patient age at HCT, sex, performance status, and year of HCT significantly affected OS. Notably, MK1 was associated with better OS than MK2 in both patients in complete remission (CR) and non-CR patients. Molecular pathogenesis may be different between MK1 and MK2, and further investigation is required to gain biological insight into the impact of MK subtype on post-HCT outcomes.