Use of Venetoclax in Patients with Relapsed or Refractory Acute Myeloid Leukemia: The PETHEMA Registry Experience.

The effectiveness of venetoclax (VEN) in relapsed or refractory acute myeloid leukemia (RR-AML) has not been well established. This retrospective, multicenter, observational database studied the effectiveness of VEN in a cohort of 51 RR-AML patients and evaluated for predictors of response and overall survival (OS). The median age was 68 years, most were at high risk, 61% received ≥2 therapies for AML, 49% had received hypomethylating agents, and ECOG was ≥2 in 52%. Complete remission (CR) rate, including CR with incomplete hematological recovery (CRi), was 12.4%. Additionally, 10.4% experienced partial response (PR). The CR/CRi was higher in combination with azacitidine (AZA; 17.9%) than with decitabine (DEC; 6.7%) and low-dose cytarabine (LDAC; 0%). Mutated NPM1 was associated with increased CR/CRi. Median OS was 104 days (95% CI: 56-151). For the combination with AZA, DEC, and LDAC, median OS was 120 days, 104 days, and 69 days, respectively; p = 0.875. Treatment response and ECOG 0 influenced OS in a multivariate model. A total of 28% of patients required interruption of VEN because of toxicity. Our real-life series describes a marginal probability of CR/CRi and poor OS after VEN-based salvage. Patients included had very poor-risk features and were heavily pretreated. The small percentage of responders did not reach the median OS.

Prognostic significance of FLT3-ITD length in AML patients treated with intensive regimens.

FLT3-ITD mutations are detected in approximately 25% of newly diagnosed adult acute myeloid leukemia (AML) patients and confer an adverse prognosis. The FLT3-ITD allelic ratio has clear prognostic value. Nevertheless, there are numerous manuscripts with contradictory results regarding the prognostic relevance of the length and insertion site (IS) of the FLT3-ITD fragment. We aimed to assess the prognostic impact of these variables on the complete remission (CR) rates, overall survival (OS) and relapse-free survival (RFS) of AML patients with FLT3-ITDmutations. We studied the FLT3-ITD length of 362 adult AML patients included in the PETHEMA AML registry. We tried to validate the thresholds of ITD length previously published (i.e., 39 bp and 70 bp) in intensively treated AML patients (n = 161). We also analyzed the mutational profile of 118 FLT3-ITD AML patients with an NGS panel of 39 genes and correlated mutational status with the length and IS of ITD. The AUC of the ROC curve of the ITD length for OS prediction was 0.504, and no differences were found when applying any of the thresholds for OS, RFS or CR rate. Only four out of 106 patients had ITD IS in the TKD1 domain. Our results, alongside previous publications, confirm that FLT3-ITD length lacks prognostic value and clinical applicability.

Liquid biopsy: a non-invasive approach for Hodgkin lymphoma genotyping.

The Hodgkin lymphoma (HL) genomic landscape is hardly known due to the scarcity of tumour cells in the tissue. Liquid biopsy employing circulating tumour DNA (ctDNA) can emerge as an alternative tool for non-invasive genotyping. By using a custom next generation sequencing (NGS) panel in combination with unique molecule identifiers, we aimed to identify somatic variants in the ctDNA of 60 HL at diagnosis. A total of 277 variants were detected in 36 of the 49 samples (73·5%) with a good quality ctDNA sample. The median number of variants detected per patient was five (range 1-23) with a median variant allele frequency of 4·2% (0·84-28%). Genotyping revealed somatic variants in the following genes: SOCS1 (28%), IGLL5 (26%), TNFAIP3 (23%), GNA13 (23%), STAT6 (21%) and B2M (19%). Moreover, several poor prognosis features (high LDH, low serum albumin, B-symptoms, IPI ≥ 3 or at an advanced stage) were related to significantly higher amounts of ctDNA. Variant detection in ctDNA by NGS is a feasible approach to depict the genetic features of HL patients at diagnosis. Our data favour the implementation of liquid biopsy genotyping for the routine evaluation of HL patients.

Identification of relapse-associated gene mutations by next-generation sequencing in low-risk acute myeloid leukaemia patients.

Recommended genetic categorization of acute myeloid leukaemias (AML) includes a favourable-risk category, but not all these patients have good prognosis. Here, we used next-generation sequencing to evaluate the mutational profile of 166 low-risk AML patients: 30 core-binding factor (CBF)-AMLs, 33 nucleophosmin (NPM1)-AMLs, 4 biCEBPα-AMLs and 101 acute promyelocytic leukaemias (APLs). Functional categories of mutated genes differed among subgroups. NPM1-AMLs showed frequent variations in DNA-methylation genes (DNMT3A, TET2, IDH1/2) (79%), although without prognostic impact. Within this group, splicing-gene mutations were an independent factor for relapse-free (RFS) and overall survival (OS). In CBF-AML, poor independent factors for RFS and OS were mutations in RAS pathway and cohesin genes, respectively. In APL, the mutational profile differed according to the risk groups. High-risk APLs showed a high mutation rate in cell-signalling genes (P = 0·002), highlighting an increased incidence of FLT3 internal tandem duplication (ITD) (65%, P < 0·0001). Remarkably, in low-risk APLs (n = 28), NRAS mutations were strongly correlated with a shorter five-year RFS (25% vs. 100%, P < 0·0001). Overall, a high number of mutations (≥3) was the worst prognostic factor RFS (HR = 2·6, P = 0·003). These results suggest that gene mutations may identify conventional low-risk AML patients with poor prognosis and might be useful for better risk stratification and treatment decisions.

Chromothripsis Is a Recurrent Genomic Abnormality in High-Risk Myelodysplastic Syndromes.

To explore novel genetic abnormalities occurring in myelodysplastic syndromes (MDS) through an integrative study combining array-based comparative genomic hybridization (aCGH) and next-generation sequencing (NGS) in a series of MDS and MDS/myeloproliferative neoplasms (MPN) patients. 301 patients diagnosed with MDS (n = 240) or MDS/MPN (n = 61) were studied at the time of diagnosis. A genome-wide analysis of DNA copy number abnormalities was performed. In addition, a mutational analysis of DNMT3A, TET2, RUNX1, TP53 and BCOR genes was performed by NGS in selected cases. 285 abnormalities were identified in 71 patients (23.6%). Three high-risk MDS cases (1.2%) displayed chromothripsis involving exclusively chromosome 13 and affecting some cancer genes: FLT3, BRCA2 and RB1. All three cases carried TP53 mutations as revealed by NGS. Moreover, in the whole series, the integrative analysis of aCGH and NGS enabled the identification of cryptic recurrent deletions in 2p23.3 (DNMT3A; n = 2.8%), 4q24 (TET2; n = 10%) 17p13 (TP53; n = 8.5%), 21q22 (RUNX1; n = 7%), and Xp11.4 (BCOR; n = 2.8%), while mutations in the non-deleted allele where found only in DNMT3A (n = 1), TET2 (n = 3), and TP53 (n = 4). These cryptic abnormalities were detected mainly in patients with normal (45%) or non-informative (15%) karyotype by conventional cytogenetics, except for those with TP53 deletion and mutation (15%), which had a complex karyotype. In addition to well-known copy number defects, the presence of chromothripsis involving chromosome 13 was a novel recurrent change in high-risk MDS patients. Array CGH analysis revealed the presence of cryptic abnormalities in genomic regions where MDS-related genes, such as TET2, DNMT3A, RUNX1 and BCOR, are located.

Deregulation of genes related to iron and mitochondrial metabolism in refractory anemia with ring sideroblasts.

The presence of SF3B1 gene mutations is a hallmark of refractory anemia with ring sideroblasts (RARS). However, the mechanisms responsible for iron accumulation that characterize the Myelodysplastic Syndrome with ring sideroblasts (MDS-RS) are not completely understood. In order to gain insight in the molecular basis of MDS-RS, an integrative study of the expression and mutational status of genes related to iron and mitochondrial metabolism was carried out. A total of 231 low-risk MDS patients and 81 controls were studied. Gene expression analysis revealed that iron metabolism and mitochondrial function had the highest number of genes deregulated in RARS patients compared to controls and the refractory cytopenias with unilineage dysplasia (RCUD). Thus mitochondrial transporters SLC25 (SLC25A37 and SLC25A38) and ALAD genes were over-expressed in RARS. Moreover, significant differences were observed between patients with SF3B1 mutations and patients without the mutations. The deregulation of genes involved in iron and mitochondrial metabolism provides new insights in our knowledge of MDS-RS. New variants that could be involved in the pathogenesis of these diseases have been identified.

The cellular origin and malignant transformation of Waldenström macroglobulinemia.

Although information about the molecular pathogenesis of Waldenström macroglobulinemia (WM) has significantly advanced, the precise cell of origin and the mechanisms behind WM transformation from immunoglobulin-M (IgM) monoclonal gammopathy of undetermined significance (MGUS) remain undetermined. Here, we undertook an integrative phenotypic, molecular, and genomic approach to study clonal B cells from newly diagnosed patients with IgM MGUS (n = 22), smoldering (n = 16), and symptomatic WM (n = 11). Through principal component analysis of multidimensional flow cytometry data, we demonstrated highly overlapping phenotypic profiles for clonal B cells from IgM MGUS, smoldering, and symptomatic WM patients. Similarly, virtually no genes were significantly deregulated between fluorescence-activated cell sorter-sorted clonal B cells from the 3 disease groups. Interestingly, the transcriptome of the Waldenström B-cell clone was highly different than that of normal CD25(-)CD22(+) B cells, whereas significantly less genes were differentially expressed and specific WM pathways normalized once the transcriptome of the Waldenström B-cell clone was compared with its normal phenotypic (CD25(+)CD22(+low)) B-cell counterpart. The frequency of specific copy number abnormalities [+4, del(6q23.3-6q25.3), +12, and +18q11-18q23] progressively increased from IgM MGUS and smoldering WM vs symptomatic WM (18% vs 20% and 73%, respectively; P = .008), suggesting a multistep transformation of clonal B cells that, albeit benign (ie, IgM MGUS and smoldering WM), already harbor the phenotypic and molecular signatures of the malignant Waldenström clone.

The clinical utility and prognostic value of multiparameter flow cytometry immunophenotyping in light-chain amyloidosis.

The clinical value of multiparameter flow cytometry (MFC) immunophenotyping in primary or light chain amyloidosis (AL) remains unknown. We studied 44 consecutive bone marrow samples from newly diagnosed patients with amyloidosis; 35 patients with AL and 9 with other forms of amyloidosis. Monoclonal plasma cells (PCs) were identifiable by MFC immunophenotyping in 34 of 35 (97%) patients with AL, whereas it was absent from all but 1 of the 9 (11%) patients with other forms of amyloidosis. Quantification of bone marrow plasma cells (BMPCs) by MFC immunophenotyping was a significant prognostic factor for overall survival (OS) (≤ 1% vs > 1% BMPC cutoff; 2-year OS rates of 90% vs 44%, P = .02). Moreover, detecting persistent normal PCs at diagnosis identifies a subgroup of patients with AL with prolonged OS (> 5% vs ≤ 5% normal PC within all BMPC cutoff, 2-year rates of 88% vs 37%, P = .01). MFC immunophenotyping could be clinically useful for the demonstration of PC clonality in AL and for the prognostication of patients with AL.

Soluble and membrane levels of molecules involved in the interaction between clonal plasma cells and the immunological microenvironment in multiple myeloma and their association with the characteristics of the disease.

Clonal plasma cells (PC) from different types of monoclonal gammopathies (MG) display distinct phenotypes consistent with an increased antigen-presentation and T-cell costimulation in MG of undetermined significance that deteriorates in malignant conditions. Expression of other cell surface and soluble molecules (e.g. adhesion/proliferation molecules) involved in the interaction between clonal PC and the bone marrow (BM) microenvironment has also been related to malignant PC, although the exact clinical significance of their expression remains largely unknown. Analysis of cell surface levels of several of these molecules in multiple myeloma (MM) patients shows an association between lower expression on BMPC of the HLA-I and beta2-microglobulin antigen-presenting molecules, the CD126 and CD130 IL6 receptor (IL6R) chains, and CD38, and adverse prognostic features of the disease. Likewise, patients showing higher soluble levels of antigen-presenting molecules (HLA-I and beta2-microglobulin), IL6R and CD95 tended to be associated with more aggressive disease behavior. In contrast, CD40, CD86, CD56, CD19, and CD45 were not associated with patients' outcome. Interestingly, upon considering the ratio between the soluble and PC membrane expression of each molecule, an increased adverse prognostic impact was observed for both HLA-I and beta2-microglobulin, but not for the other molecules. Multivariate analysis confirmed the independent prognostic value of cell surface expression of CD126 on BMPC together with serum beta2-microglobulin and LDH. In summary, our results show an abnormal distribution of the cellular and soluble compartments of the HLA-I, IL6R, and to a lower extent, CD95 molecules, in MM, associated with the clinical characteristics and behavior of the disease.

Peripheral blood dendritic cell subsets from patients with monoclonal gammopathies show an abnormal distribution and are functionally impaired.

Objectives. The information currently available about dendritic cells (DCs) in patients with different types of monoclonal gammopathy (MG) is limited and frequently controversial. In the present study, we analyzed the ex vivo distribution as well as the phenotypic and functional characteristics of peripheral blood (PB) DCs from different types of MG. Methods. For this purpose, 61 untreated patients in total with MG were analyzed-MG of undetermined significance (MGUS), 29 cases; multiple myeloma (MM), 28 cases; and plasma cell leukemia (PCL), 4 cases-in comparison with a group of 10 healthy controls. Results. Our results show an absolute overall higher number of all subsets of PB DCs in PCL, together with lower numbers of myeloid DCs in MM patients. From a phenotypic point of view, PB DC subsets from all types of MG expressed significantly higher levels of HLA molecules and altered patterns of expression of the CD2, CD11c, CD16, CD22, CD62L, and CD86 molecules, in association with altered patterns of secretion of inflammatory cytokines. Conclusion. In summary, we show the existence of significant abnormalities in the distribution, phenotype, and pattern of secretion of inflammatory cytokines by different subsets of PB DCs from patients with MGs, which could reflect a potentially altered homing of DCs, together with a greater in vivo activation and lower responsiveness of PB DCs, which are already detectable in MGUS patients.