Syndromes predisposing to leukemia are a major cause of inherited cytopenias in children.

Prolonged cytopenias are a non-specific sign with a wide differential diagnosis. Among inherited disorders, cytopenias predisposing to leukemia require a timely and accurate diagnosis to ensure appropriate medical management, including adequate monitoring and stem cell transplantation prior to the development of leukemia. We aimed to define the types and prevalences of the genetic causes leading to persistent cytopenias in children. The study comprises children with persistent cytopenias, myelodysplastic syndrome, aplastic anemia, or suspected inherited bone marrow failure syndromes, who were referred for genetic evaluation from all pediatric hematology centers in Israel during 2016-2019. For variant detection, we used Sanger sequencing of commonly mutated genes and a custom-made targeted next-generation sequencing panel covering 226 genes known to be mutated in inherited cytopenias; the minority subsequently underwent whole exome sequencing. In total, 189 children with persistent cytopenias underwent a genetic evaluation. Pathogenic and likely pathogenic variants were identified in 59 patients (31.2%), including 47 with leukemia predisposing syndromes. Most of the latter (32, 68.1%) had inherited bone marrow failure syndromes, nine (19.1%) had inherited thrombocytopenia predisposing to leukemia, and three each (6.4%) had predisposition to myelodysplastic syndrome or congenital neutropenia. Twelve patients had cytopenias with no known leukemia predisposition, including nine children with inherited thrombocytopenia and three with congenital neutropenia. In summary, almost one third of 189 children referred with persistent cytopenias had an underlying inherited disorder; 79.7% of whom had a germline predisposition to leukemia. Precise diagnosis of children with cytopenias should direct follow-up and management programs and may positively impact disease outcome.

Sequential treatment with FLAG-IDA/treosulfan conditioning regimen for patients with active acute myeloid leukemia.

Sequential protocols combining salvage chemotherapy with reduced intensity conditioning (RIC) and allogeneic hematopoietic cell transplantation (alloHCT) for high-risk acute myeloid leukemia (AML) have been studied more than a decade. Purpose of this retrospective analysis was to evaluate the anti-leukemic efficacy and toxicity of FLAG-IDA protocol (fludarabine, cytarabine, and idarubicin) followed by treosulfan-based conditioning for patients with active AML. From January 2014 to November 2019, a total of 29 active AML patients [median age, 64 years (range, 23-73)] were treated. All patients completed protocol regimen and were transplanted. Five patients (17%) had grade 3-4 toxicities; therefore, treosulfan was substituted with total body irradiation (TBI) non-myeloablative conditioning. Six (20%) patients died within 30 post-transplant days, all from infectious complications. Out of 23 evaluable patients on day 30, 22 (96%) achieved complete hematologic remission with full donor chimerism. Non-relapse mortality (NRM) rates at 1 and 3 years were 22% and 49%, respectively. Median overall survival (OS) was 12 (95% CI, 4-20) months. OS and disease-free survival were 50% and 46% at 1 year and 28% and 17% at 2 years, respectively. Age, gender, disease burden, number of previous lines, and comorbidity score did not predict survival. Sequential strategy combining FLAG-IDA and treosulfan may offer a salvage option for few selected patients with active AML; however, high NRM presents a major obstacle to treatment success. Future efforts should focus on reducing NRM by moderating regimen intensity and by better selection of patients.