Prospective assessment of NGS-detectable mutations in CML patients with nonoptimal response: the NEXT-in-CML study.

In chronic myeloid leukemia (CML) patients, tyrosine kinase inhibitors (TKIs) may select for drug-resistant BCR-ABL1 kinase domain (KD) mutants. Although Sanger sequencing (SS) is considered the gold standard for BCR-ABL1 KD mutation screening, next-generation sequencing (NGS) has recently been assessed in retrospective studies. We conducted a prospective, multicenter study (NEXT-in-CML) to assess the frequency and clinical relevance of low-level mutations and the feasibility, cost, and turnaround times of NGS-based BCR-ABL1 mutation screening in a routine setting. A series of 236 consecutive CML patients with failure (n = 124) or warning (n = 112) response to TKI therapy were analyzed in parallel by SS and NGS in 1 of 4 reference laboratories. Fifty-one patients (22 failure, 29 warning) who were negative for mutations by SS had low-level mutations detectable by NGS. Moreover, 29 (27 failure, 2 warning) of 60 patients who were positive for mutations by SS showed additional low-level mutations. Thus, mutations undetectable by SS were identified in 80 out of 236 patients (34%), of whom 42 (18% of the total) had low-level mutations somehow relevant for clinical decision making. Prospective monitoring of mutation kinetics demonstrated that TKI-resistant low-level mutations are invariably selected if the patients are not switched to another TKI or if they are switched to a inappropriate TKI or TKI dose. The NEXT-in-CML study provides for the first time robust demonstration of the clinical relevance of low-level mutations, supporting the incorporation of NGS-based BCR-ABL1 KD mutation screening results in the clinical decision algorithms.

Prognostic significance of The Wilms' Tumor-1 (WT1) rs16754 polymorphism in acute myeloid leukemia.

Acute myeloid leukemia is a genetically heterogeneous disease characterized by the accumulation of mutations in hematopoietic progenitor cells. For its heterogeneity, prognostic markers are very useful for therapeutic choice. The most important prognostic markers are age, white blood cell count, chromosomal alterations and gene mutations. Recent works have studied the prognostic significance of WT1 polymorphisms and mutations, highlighting the role of SNP rs16754 as a positive prognostic factor in AML patients. Nevertheless, the data are still unclear. To investigate the role of WT1 rs16754 polymorphism in AML, we designed a new tool for the detection using PNA directed PCR Clamping technology. Our data were able to establish a correlation between SNP rs16754 and the clinical outcome. Our results support the hypothesis that rs16754 polymorphism is an independent positive prognostic molecular marker that could be useful for therapeutic choice. In view of this, we described a novel assay faster, more sensitive and cheaper than DNA sequencing. The assay allows evaluating WT1 rs16754 polymorphism in diagnostic routine to improve prognostic information faster and without over-costing for diagnostic laboratories.

First-line therapy for chronic phase CML: selecting the optimal BCR-ABL1-targeted TKI.

Patients diagnosed with chronic myeloid leukemia (CML) and treated with BCR-ABL1 tyrosine kinase inhibitors (TKIs) have long life spans. Selection of an appropriate first-line therapy can be difficult as both the unique characteristics of each TKI and patient need to be taken into account to find the optimal match. Patient characteristics include comorbidities, concomitant medications, lifestyle, risk factors, BCR-ABL1 transcript type (e.g. b2a2 or b3a2) and additional chromosomal abnormalities. Just as patients differ, side effects, drug-drug interactions, administration plans, dosing schedules and treatment-related expenses across TKIs also vary. Alignment of these characteristics with the appropriate TKI is key to successfully initiating CML treatment. Continued success relies on communication between the patient and the healthcare team, adherence and optimization of therapy once it is initiated. In this review, we discuss these factors, in addition to TKI efficacy and safety, the cost of therapy, the future of treating CML and treatment-free remission.

Identifying and addressing unmet clinical needs in Ph-neg classical myeloproliferative neoplasms: a consensus-based SIE, SIES, GITMO position paper.

This article presents the results of group discussion among experts from SIE, SIES and GITMO societies aimed at highlighting unmet challenges in the management of Ph-neg myeloproliferative neoplasms (MPNs). The issues analyzed were: diagnosis of prefibrotic myelofibrosis; diagnosis of Ph-neg MPNs in the setting of splanchnic vein thrombosis (SVT); management of low-risk PV and low-risk ET patients with JAK2V617F mutation; molecular biomarkers in the prognostic evaluation of myelofibrosis (MF); ruxolitinib therapy in low-risk MF; therapy in patients with SVT-associated Ph-neg MPN; indications of splenectomy in MF. For each of these issues, proposals for advancement in clinical research were addressed.

Prognostic relevance of cytometric quantitative assessment in patients with myelodysplastic syndromes.

OBJECTIVES: Morphology and cytogenetics are currently used to define prognosis in myelodysplastic syndromes (MDS). However, these parameters have some limits. Flow cytometry has been recently included in the diagnostic panel for MDS, and its prognostic significance is under evaluation. METHODS: Marrow aspirates from 424 MDS patients were analyzed by flow cytometry to evaluate the impact of bone marrow cell immunophenotype on overall survival (OS) and leukemia-free survival (LFS). The immature compartment of myeloblasts was analyzed by the quantitative expression of CD34 (<3% vs. ≥3%), CD117, and CD11b(-) /CD66b(-) (<5% vs. ≥5%); myeloid maturation was analyzed by the expression of CD11b(+) /CD66b(++) (<15% vs. ≥15%) and CD11b(+) /CD66b(+) (<25% vs. ≥25%). RESULTS: In univariate analysis, the expression of immaturity markers (CD34(+) , CD117(+) , and CD11b(-) /CD66b(-) ) was associated with shorter LFS and OS (P < 0.0001); higher expression of differentiation markers (CD11b(+) /CD66b(++) and CD11b(+) /CD66b(+) ) was associated with longer LFS (P < 0.0001 and P = 0.0002, respectively) and OS (P < 0.0001). In multivariate analysis, expression of CD34(+) (P = 0.007), CD117(+) (P = 0.013), and CD11b(+) /CD66b(++) (P = 0.023) retained independent prognostic value for OS, while only the expression of CD34(+) was a prognostic factor for LFS (P = 0.0003). Two different risk groups were defined according to the presence of 0-1 or ≥2 of these factors with significant different LFS and OS (P < 0.0001). This score showed prognostic value in predicting survival even in subanalysis according to IPSS and WHO subgroups. CONCLUSIONS: Flow cytometric analysis in MDS may provide meaningful prognostic information. Blast percentage expressed as CD117(+) or CD34(+) cells and the quantitative assessment of myeloid maturation showed prognostic value for survival.

Quantitative assessment of WT1 gene expression after allogeneic stem cell transplantation is a useful tool for monitoring minimal residual disease in acute myeloid leukemia.

INTRODUCTION: WT1 overexpression is described in several oncological diseases including acute myeloid leukemia (AML). Quantification of WT1 in bone marrow samples may be useful as a marker of minimal residual disease (MRD) and may predict the relapse of AML after allogeneic hematopoietic stem cell transplant (HSCT). METHODS AND RESULTS: The quantitative expression of WT1 was measured in 38 AML patients (16 males and 22 females) at diagnosis, at the time of transplant and after the allogeneic HSCT (at precise time points). All cases showed high WT1 expression levels at diagnosis with a mean of 4189 (SD 3325) and a median of 3495 (range 454-13923) copies WT1/10(4)Abl. At transplant, 25 patients (66%) were in complete cytologic remission (CcR) and 13 (34%) had refractory or relapsed AML. Bone marrow samples from patients transplanted in CcR showed significantly lower WT1 expression levels during HSCT compared with the samples from patients with a relapsed or refractory AML (P = 0.004). After HSCT, a rapid decline in WT1 expression levels was observed in all patients who attained or maintained a condition of CcR. Six of 38 patients (13%) relapsed after HSCT and all of them had an increase in WT1 expression at/or before relapse. Five of these six patients died of leukemia and one was successfully reinduced with donor lymphocyte infusion (DLI) + chemotherapy with a rapid reduction of WT1 levels. Besides, we found a complete concordance between WT1 expression levels and other disease markers (when available). CONCLUSIONS: In our experience, there was a complete concordance between WT1 expression levels (measured by quantitative RT-PCR at precise time points) and status of AML before and after allogeneic HSCT. WT1 may be useful as a non-specific leukemia marker for monitoring MRD and as a predictor of AML clinical relapse. Based on these results, cases with increase of WT1 levels after HSCT and without graft vs. host disease may be candidate to discontinuation of immunosuppression and/or DLI therapy.

Rational approaches to the design of therapeutics targeting molecular markers: the case of chronic myelogenous leukemia.

Progress in understanding the molecular basis of signal transmission and transduction has contributed substantially to clarifying the mechanisms of leukemogenesis and of leukemia progression and has led to the identification of a number of specific molecular targets for treatment. Chronic myeloid leukemia (CML) has provided one of the best models, as the identification of a leukemia-specific hybrid tyrosine kinase (BCR-ABL, p210, p190) has led to the identification and the successful therapeutic application of a powerful tyrosine kinase inhibitor, imatinib. The BCR-ABL fusion gene is the result of a reciprocal translocation between the long arms of chromosomes 9 and 22, t(9;22)(q34;q11), which characterizes more than 95% of the cases of CML. The resulting chimeric proteins (P210 and P190), which retain a constitutively activated tyrosine kinase activity, have a causative role in the genesis of the leukemia process. In agreement with this observation, BCR-ABL tyrosine kinase inhibitors have recently emerged as powerful new therapeutic tools, obtaining extraordinary results in early chronic-phase CML as well as in more advanced phases of the disease. Although these results represent a remarkable breakthrough, there are still numerous issues, such as the emergence of resistance, that remain unsolved and that will need further investigation. In spite of its low incidence, CML remains a paradigmatic model for understanding the pathogenesis and therapeutic options of human leukemias.

Usefulness of quantitative assessment of Wilms tumor suppressor gene expression in chronic myeloid leukemia patients undergoing imatinib therapy.

The Wilms tumor suppressor gene (WT1) is overexpressed in a number of human hematological malignancies, including chronic myeloid leukemia (CML). Although at present, the biological significance of WT1 expression in CML in still unclear, this marker could represent a useful tool for molecular monitoring of CML patients prior to and post imatinib therapy. In fact, the use of real-time polymerase chaine reaction (PCR) to quantitatively measure the WT1 transcript amount may be a predictor of patient response to imatinib therapy.