Prognostic Value of Measurable Residual Disease in Patients with AML Undergoing HSCT: A Multicenter Study.

Allogeneic hematopoietic stem cell transplantation (HSCT) represents the best therapeutic option for many patients with acute myeloid leukemia (AML). However, relapse remains the main cause of mortality after transplantation. The detection of measurable residual disease (MRD) by multiparameter flow cytometry (MFC) in AML, before and after HSCT, has been described as a powerful predictor of outcome. Nevertheless, multicenter and standardized studies are lacking. A retrospective analysis was performed, including 295 AML patients undergoing HSCT in 4 centers that worked according to recommendations from the Euroflow consortium. Among patients in complete remission (CR), MRD levels prior to transplantation significantly influenced outcomes, with overall (OS) and leukemia free survival (LFS) at 2 years of 76.7% and 67.6% for MRD-negative patients, 68.5% and 49.7% for MRD-low patients (MRD < 0.1), and 50.5% and 36.6% for MRD-high patients (MRD ≥ 0.1) (p < 0.001), respectively. MRD level did influence the outcome, irrespective of the conditioning regimen. In our patient cohort, positive MRD on day +100 after transplantation was associated with an extremely poor prognosis, with a cumulative incidence of relapse of 93.3%. In conclusion, our multicenter study confirms the prognostic value of MRD performed in accordance with standardized recommendations.

Next-Generation DNA Sequencing-Based Gene Panel for Diagnosis and Genetic Risk Stratification in Onco-Hematology.

A suitable diagnostic classification of myeloid neoplasms and acute leukemias requires testing for a large number of molecular biomarkers. Next-generation sequencing is a technology able to integrate identification of the vast majority of them in a single test. This manuscript includes the design, analytical validation and clinical feasibility evaluation of a molecular diagnostic kit for onco-hematological diseases. It is based on sequencing of the coding regions of 76 genes (seeking single-nucleotide variants, small insertions or deletions and CNVs), as well as the search for fusions in 27 target genes. The kit has also been designed to detect large CNVs throughout the genome by including specific probes and employing a custom bioinformatics approach. The analytical and clinical feasibility validation of the Haematology OncoKitDx panel has been carried out from the sequencing of 170 patient samples from 6 hospitals (in addition to the use of commercial reference samples). The analytical validation showed sensitivity and specificity close to 100% for all the parameters evaluated, with a detection limit of 2% for SNVs and SVs, and 20% for CNVs. Clinically relevant mutations were detected in 94% of all patients. An analysis of the correlation between the genetic risk classification of AML (according to ELN 2017) established by the hospitals and that obtained by the Haematology OncoKitDx panel showed an almost perfect correlation (K = 0.94). Among the AML samples with a molecular diagnosis, established by the centers according to the WHO, the Haematology OncoKitDx analysis showed the same result in 97% of them. The panel was able to adequately differentiate between MPN subtypes and also detected alterations that modified the diagnosis (FIP1L1-PDGFRA). Likewise, the cytogenetic risk derived from the CNV plot generated by the NGS panel correlated substantially with the results of the conventional karyotype (K = 0.71) among MDS samples. In addition, the panel detected the main biomarkers of prognostic value among patients with ALL. This validated solution enables a reliable analysis of a large number of molecular biomarkers from a DNA sample in a single assay.

ASXL1 mutation as a surrogate marker in acute myeloid leukemia with myelodysplasia-related changes and normal karyotype.

Acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) are poor outcome leukemias. Its diagnosis is based on clinical, cytogenetic, and cytomorphologic criteria, last criterion being sometimes difficult to assess. A high frequency of ASXL1 mutations have been described in this leukemia. We sequenced ASXL1 gene mutations in 61 patients with AML-MRC and 46 controls with acute myeloid leukemia without other specifications (AML-NOS) to identify clinical, cytomorphologic, and cytogenetic characteristics associated with ASXL1 mutational status. Mutated ASXL1 (ASXL1+) was observed in 31% of patients with AML-MRC compared to 4.3% in AML-NOS. Its presence in AML-MRC was associated with older age, a previous history of myelodysplastic syndrome (MDS) or myelodysplastic/myeloproliferative neoplasms (MDS/MPN), leukocytosis, presence of micromegakaryocytes in bone marrow, lower number of blasts in bone marrow, myelomonocytic/monocytic morphological features and normal karyotype. ASXL1 mutation was not observed in patients with myelodysplastic syndrome-related cytogenetic abnormalities or TP53 mutations. Differences in terms of overall survival were found only in AML-MRC patients without prior MDS or MDS/MPN and with intermediate-risk karyotype, having ASXL1+ patients a worst outcome than ASXL1-. We conclude that the ASXL1 mutation frequency is high in AML-MRC patients being its presence associated with specific characteristics including morphological signs of dysplasia. This association raises the possible role of ASXL1 as a surrogate marker in AML-MRC, which could facilitate the diagnosis of patients within this group when the karyotype is normal, and especially when the assessment of multilineage dysplasia morphologically is difficult. This mutation could be used as a worst outcome marker in de novo AML-MRC with intermediate-risk karyotype.

MLL-rearranged acute myeloid leukemia: Influence of the genetic partner in allo-HSCT response and prognostic factor of MLL 3' region mRNA expression.

OBJECTIVE: MLL gene is involved in more than 80 known genetic fusions in acute leukemia. To study the relevance of MLL partner gene and selected gene's expression, in this work, we have studied a cohort of 20 MLL-rearranged acute myeloid leukemia (AML). METHODS: Twenty MLL-rearranged AML patients along with a control cohort of 138 AML patients are included in this work. By RT-PCR and sequencing, MLL genetic fusion was characterized, and relative gene expression quantification was carried out for EVI1, MEIS1, MLL-3', RUNX1, SETBP1, HOXA5, and FLT3 genes. Risk stratification and association of MLL genetic partner and gene expression to overall survival, in the context of received therapy, were performed. RESULTS: MLLr cohort showed to have an OS more similar to intermediate-risk AML. Type of MLL genetic partner showed to be relevant in allo-HSCT response; having MLLT1 and MLLT3, a better benefit from it. Expression of MLL-3' region, EVI1 and FLT3, showed association with OS in patients undergoing allo-HSCT. CONCLUSION: We show that the MLL genetic partner could have implications in allo-HSCT response, and we propose three genes whose expression could be useful for the prognosis of this leukemia in patients undergoing allo-HSCT: 3' region of MLL, EVI1, and FLT3.

Lenograstim compared to filgrastim for the mobilization of hematopoietic stem cells in healthy donors.

BACKGROUND: Recombinant human granulocyte-colony-stimulating factor (G-CSF) is used to mobilize hematopoietic stem cells for both autologous and allogeneic hematopoietic stem cell transplantation. The recombinant products clinically available are lenograstim and filgrastim, which differ from a biologic point of view as well as from their economical impact. In this regard, some studies have shown different in vitro activities although clinical studies comparing both drugs in the allogeneic transplant setting are scanty. STUDY DESIGN AND METHODS: In the current study we compare the efficacy of lenograstim and filgrastim in terms of number of circulating CD34+ cells/µL during the fifth day of G-CSF administration, the number of days of apheresis required to obtain the target cell dose, the median of CD34+ cells collected on the first day of apheresis, or the median number of total CD34+ cells collected at the end of the procedure, in a series of 146 healthy donors undergoing hematopoietic stem cell mobilization for allogeneic transplantation. RESULTS: We observed that, using a comparable dose for the two products, no significant differences were observed between the two groups. CONCLUSION: In conclusion, the current retrospective study shows that lenograstim and filgrastim are similar in terms of efficacy for the mobilization of hematopoietic stem cells in healthy donors.