Some patients with acute myeloid leukemia (AML) who are in complete remission after induction chemotherapy harbor persisting pre-leukemic clones, carrying a subset of leukemia-associated somatic mutations. There is conflicting evidence on the prognostic relevance of these clones for AML relapse. Here, we characterized paired pre-treatment and remission samples from 126 AML patients for mutations in 68 leukemia-associated genes. Fifty patients (40%) retained ≥1 mutation during remission at a VAF of ≥2%. Mutation persistence was most frequent in DNMT3A (65% of patients with mutations at diagnosis), SRSF2 (64%), TET2 (55%), and ASXL1 (46%), and significantly associated with older age (p < 0.0001) and, in multivariate analyses adjusting for age, genetic risk, and allogeneic transplantation, with inferior relapse-free survival (hazard ratio (HR), 2.34; p = 0.0039) and overall survival (HR, 2.14; p = 0.036). Patients with persisting mutations had a higher cumulative incidence of relapse before, but not after allogeneic stem cell transplantation. Our work underlines the relevance of mutation persistence during first remission as a novel risk factor in AML. Persistence of pre-leukemic clones may contribute to the inferior outcome of elderly AML patients. Allogeneic transplantation abrogated the increased relapse risk associated with persisting pre-leukemic clones, suggesting that mutation persistence may guide post-remission treatment.

Key Points• AML patients with isolated trisomy 13 have a very poor clinical outcome • Isolated trisomy 13 in AML is associated with a high frequency of mutations in SRSF2 (81%) and RUNX1 (75%)In acute myeloid leukemia (AML), isolated trisomy 13 (AML113) is a rare chromosomal abnormality whose prognostic relevance is poorly characterized. We analyzed the clinical course of 34 AML113 patients enrolled in the German AMLCG-1999 and SAL trials and performed exome sequencing, targeted candidate gene sequencing and gene expression profiling. Relapse-free (RFS) and overall survival (OS) of AML113 patients were inferior compared to other ELN Intermediate-II patients (n5855) (median RFS, 7.8 vs 14.1 months, P 5 .006; median OS 9.3 vs. 14.8 months, P 5 .004). Besides the known high frequency of RUNX1 mutations (75%), we identified mutations in spliceosome components in 88%, including SRSF2 codon 95 mutations in 81%. Recurring mutations were detected in ASXL1 (44%) and BCOR (25%). Two patients carried mutations in CEBPZ, suggesting that CEBPZ is a novel recurrently mutated gene in AML. Gene expression analysis revealed a homogeneous expression profile including upregulation of FOXO1 and FLT3 and downregulation of SPRY2. This is the most comprehensive clinical and biological characterization of AML113 to date, and reveals a striking clustering of lesions in a few genes, defining AML113 as a genetically homogeneous subgroup with alterations in a few critical cellular pathways. Clinicaltrials.gov identifiers:

Relapse of malignant disease remains the major complication in patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) after hematopoietic cell transplantation (HCT) with reduced-intensity conditioning (RIC). In this study, we investigated the predictive value of disease-specific markers (DSMs), donor chimerism (DC) analysis of unsorted (UDC) or CD34 þ sorted cells and Wilms' tumor gene 1 (WT1) expression. Eighty-eight patients with AML or MDS were monitored after allogenic HCT following 2 Gy total-body irradiation with (n ¼ 84) or without (n ¼ 4) fludarabine 3 Â 30 mg/m 2 , followed by cyclosporin A and mycophenolate mofetil. DSMs were determined by fluorescence in situ hybridization (FISH) and WT1 expression by real-time polymerase chain reaction. Chimerism analysis was performed on unsorted or CD34 þ sorted cells, by FISH or short tandem repeat polymerase chain reaction. Twenty-one (24%) patients relapsed within 4 months after HCT. UDC, CD34 þ DC and WT1 expression were each significant predictors of relapse with sensitivities ranging from 53 to 79% and specificities of 82-91%. Relapse within 28 days was excluded almost entirely on the basis of WT1 expression combined with CD34 þ DC kinetics. Monitoring of WT1 expression and CD34 þ DC predict relapse of AML and MDS after RIC-HCT.

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We retrospectively compared the incidence of virus infections and outcome in the context of immune reconstitution in two different HLA-haploidentical transplantation (haplo-HSCT) settings. The first was a combined T-cell-replete and T-cell-deplete approach using antithymocyte globulin (ATG) prior to transplantation in patients with hematological diseases (cTCR/TCD group, 28 patients; median age 31 years). The second was a T-cell-replete (TCR) approach using high-dose posttransplantation cyclophosphamide (TCR/PTCY group, 27 patients; median age 43 years). The incidence of herpesvirus infection was markedly lower in the TCR/PTCY (22 %) than in the cTCR/TCD group (93 %). Recovery of CD4+ T cells on day +100 was faster in the TCR/PTCY group. CMV reactivation was 30 % in the TCR/PTCY compared to 57 % in the cTCR/TCD group, and control with antiviral treatment was superior after TCR/PTCY transplantation (100 vs 50 % cTCR/TCD). Twenty-five percent of the patients in the cTCR/TCD group but no patient in the TCR/PTCY group developed PTLD. While 1-year OS was not different (TCR/PTCY 59 % vs cTCR/TCD 39 %; p = 0.28), virus infection-related mortality (VIRM) was significantly lower after TCR/PTCY transplantation (1-year VIRM, 0 % TCR/PTCY vs 29 % cTCR/TCD; p = 0.009). On day +100, predictors of better OS were lymphocytes>300/μl, CD3+ T cells >200/μl, and CD4+ T cells >150/μl, whereas the application of steroids >1 mg/kg was correlated with worse outcome. Our results suggest that by presumably preserving antiviral immunity and allowing fast immune recovery of CD4+ T cells, the TCR approach using posttransplantation cyclophosphamide is well suited to handle the important issue of herpesvirus infection after haplo-HSCT.

In acute myeloid leukemia (AML), internal tandem duplications (ITDs) of FLT3 are frequent mutations associated with unfavorable prognosis. At diagnosis, the FLT3-ITD status is routinely assessed by fragment analysis, providing information about the length but not the position and sequence of the ITD. To overcome this limitation, we performed cDNA-based high-throughput amplicon sequencing (HTAS) in 250 FLT3-ITD positive AML patients, treated on German AML Cooperative Group (AMLCG) trials. FLT3-ITD status determined by routine diagnostics was confirmed by HTAS in 242 out of 250 patients (97%). The total number of ITDs detected by HTAS was higher than in routine diagnostics (n = 312 vs. n = 274). In particular, HTAS detected a higher number of ITDs per patient compared to fragment analysis, indicating higher sensitivity for subclonal ITDs. Patients with more than one ITD according to HTAS had a significantly shorter overall and relapse free survival. There was a close correlation between FLT3-ITD mRNA levels in fragment analysis and variant allele frequency in HTAS. However, the abundance of long ITDs (≥75nt) was underestimated by HTAS, as the size of the ITD affected the mappability of the corresponding sequence reads. In summary, this study demonstrates that HTAS is a feasible approach for FLT3-ITD detection in AML patients, delivering length, position, sequence and mutational burden of this alteration in a single assay with high sensitivity. Our findings provide insights into the clonal architecture of FLT3-ITD positive AML and have clinical implications.

In acute myeloid leukemia (AML), assessment of minimal residual disease (MRD) by flow cytometry (flow MRD) after induction and consolidation therapy has been shown to provide independent prognostic information. However, data on the value of earlier flow MRD assessment are lacking. Therefore, the value of flow MRD detection was determined during aplasia in 178 patients achieving complete remission after treatment according to AMLCG (AML Cooperative Group) induction protocols. Flow MRD positivity during aplasia predicted poor outcome (5-year relapse-free survival (RFS) 16% vs 43%, P<0.001) independently from age and cytogenetic risk group (hazard ratio for MRD positivity 1.71; P=0.009). Importantly, the prognosis of patients without detectable MRD was neither impacted by morphological blast count during aplasia nor by MRD status postinduction. Early flow MRD was also evaluated in the context of existing risk factors. Flow MRD was prognostic within the intermediate cytogenetic risk group (5-year RFS 15% vs 37%, P=0.016) as well as for patients with normal karyotype and NPM1 mutations (5-year RFS 13% vs 49%, P=0.02) or FLT3-ITD (3-year RFS rates 9% vs 44%, P=0.016). Early flow MRD assessment can improve current risk stratification approaches by prediction of RFS in AML and might facilitate adaptation of postremission therapy for patients at high risk of relapse.

Midazolam was applied transmucosally in 47 children randomly assigned to three different groups. Group N received 0.2 mg.kg-1 nasally, group R 0.5 mg.kg-1 rectally, and group S 0.2 mg.kg-1 sublingually. All groups were treated 60 min prior to a planned i.v. puncture with EMLA. Reliable and valid psychological parameters (such as emotional situation, shivering, awareness, respiratory rate and facial colour) were scored after premedication and before and after i.v. puncture, 20 min after premedication and until induction. A blood sample was drawn 10, 30 and 60 min after premedication and the levels of midazolam, alpha-hydroxy-midazolam, ACTH, glucose and cortisol were measured. In all three groups the plasma levels of midazolam 10 min after premedication were higher than 70 ng.ml-1 (accepted as a sedative level). 30 min after premedication the midazolam level in the sublingual group was statistically significantly higher than in the nasal group and the psychological parameters in all three groups were significantly changed (10 min after premedication). The psychological parameters were not significantly different between the three groups over the whole study. Sublingual premedication has some advantages (most readily accepted, highest plasma levels and lowest deviations) and could be the first choice in premedication of children. All three transmucosal applications are safe and well accepted, although nasal application was rejected by two of the children.