MicroRNA expression profiles discriminate childhood T‐ from B‐acute lymphoblastic leukemia

MicroRNAs (miRNAs) play a critical role on biological and cellular processes; the search for functional markers may be of importance for differential diagnosis, prognosis, and development of new therapeutic regimens. In this context, we evaluated the bone marrow miRNA profile of Brazilian children exhibiting T‐ or B‐cell acute lymphoblastic leukemia (T‐ALL or B‐ALL), using massive parallel sequencing, using the HiSeq 2500 platform (Illumina). The differential expression analysis was conducted considering a leave‐one‐out approach and FDR ≤ 0.05. Machine learning algorithms were applied to search for the disease subset biomarkers. Target prediction, functional enrichment, and classification of biological categories were also performed. Sixteen miRNAs were differentially expressed between T‐ and B‐ALL, of which 10 (miR‐708‐5p, miR‐497‐5p, miR‐151a‐5p, miR‐151b, miR‐371b‐5p, miR‐455‐5p, miR‐195‐5p, miR‐1266‐5p, miR‐574‐5p, and miR‐425‐5p) were downregulated and six (miR‐450b‐5p, miR‐450a‐5p, miR‐542‐5p, miR‐424‐5p, miR‐629‐5p, and miR‐29c‐5p) were upregulated in childhood T‐ALL. These miRNAs may be used for distinguishing childhood lymphoblastic leukemia subtypes, since it provided the clear separation of patients in these two distinct groups. Six relevant biological pathways were identified according to their role in leukemia, namely, viral carcinogenesis, cell cycle, and B‐cell receptor signaling pathways for induced miRNAs and TGF‐beta signaling, apoptosis, and NF‐kappa B signaling for the repressed miRNAs, of which several miRNA gene targets participate in cell differentiation and hematopoiesis processes. Machine learning analysis pointed out miR‐29c‐5p expression as the best discriminator between childhood T‐ and B‐ALL, which is involved in calcium signaling, critical for B‐cell lymphocyte fate. Further studies are needed to assure the role of the 16 miRNAs and miR‐29c‐5p on acute lymphoblastic leukemia subtypes and on disease prognosis.     

The arginine metabolome in acute lymphoblastic leukemia can be targeted by the pegylated‐recombinant arginase I BCT‐100

Arginine is a semi‐essential amino acid that plays a key role in cell survival and proliferation in normal and malignant cells. BCT‐100, a pegylated (PEG) recombinant human arginase, can deplete arginine and starve malignant cells of the amino acid. Acute lymphoblastic leukemia (ALL) is the most common cancer of childhood, yet for patients with high risk or relapsed disease prognosis remains poor. We show that BCT‐100 is cytotoxic to ALL blasts from patients in vitro by necrosis, and is synergistic in combination with dexamethasone. Against ALL xenografts, BCT‐100 leads to a reduction in ALL engraftment and a prolongation of survival. ALL blasts express the arginine transporter CAT‐1, yet the majority of blasts are arginine auxotrophic due to deficiency in either argininosuccinate synthase (ASS) or ornithine transcarbamylase (OTC). Although endogenous upregulation or retroviral transduced increases in ASS or OTC may promote ALL survival under moderately low arginine conditions, expression of these enzymes cannot prevent BCT‐100 cytotoxicity at arginine depleting doses. RNA‐sequencing of ALL blasts and supporting stromal cells treated with BCT‐100 identifies a number of candidate pathways which are altered in the presence of arginine depletion. Therefore, BCT‐100 provides a new clinically relevant therapeutic approach to target arginine metabolism in ALL.     

Chimeric antigen receptor‐engineered cytokine‐induced killer cells overcome treatment resistance of pre‐B‐cell acute lymphoblastic leukemia and enhance survival

Pre‐emptive cancer immunotherapy by donor lymphocyte infusion (DLI) using cytokine‐induced killer (CIK) cells may be beneficial to prevent relapse with a reduced risk of causing graft‐versus‐host‐disease. CIK cells are a heterogeneous effector cell population including T cells (CD3⁺ CD56^?), natural killer (NK) cells (CD3^?CD56⁺) and natural killer T (T‐NK) cells (CD3⁺ CD56⁺) that exhibit non‐major histocompatibility complex (MHC)‐restricted cytotoxicity and are generated by ex vivo expansion of peripheral blood mononuclear cells in the presence of interferon (IFN)‐γ, anti‐CD3 antibody, interleukin‐2 (IL‐2) and interleukin‐15 (IL‐15). To facilitate selective target‐cell recognition and enhance specific cytotoxicity against B‐cell acute lymphoblastic leukemia (B‐ALL), we transduced CIK cells with a lentiviral vector encoding a chimeric antigen receptor (CAR) that carries a composite CD28‐CD3ζ domain for signaling and a CD19‐specific scFv antibody fragment for cell binding (CAR 63.28.z). In vitro analysis revealed high and specific cell killing activity of CD19‐targeted CIK/63.28.z cells against otherwise CIK‐resistant cancer cell lines and primary B‐ALL blasts, which was dependent on CD19 expression and CAR signaling. In a xenograft model in immunodeficient mice, treatment with CIK/63.28.z cells in contrast to therapy with unmodified CIK cells resulted in complete and durable molecular remissions of established primary pre‐B‐ALL. Our results demonstrate potent antileukemic activity of CAR‐engineered CIK cells in vitro and in vivo, and suggest this strategy as a promising approach for adoptive immunotherapy of refractory pre‐B‐ALL.     

L‐asparaginase treatment in acute lymphoblastic leukemia

Asparaginases are a cornerstone of treatment protocols for acute lymphoblastic leukemia (ALL) and are used for remission induction and intensification treatment in all pediatric regimens and in the majority of adult treatment protocols. Extensive clinical data have shown that intensive asparaginase treatment improves clinical outcomes in childhood ALL. Three asparaginase preparations are available: the native asparaginase derived from Escherichia coli (E. coli asparaginase), a pegylated form of this enzyme (PEG‐asparaginase), and a product isolated from Erwinia chrysanthemi, ie, Erwinia asparaginase. Clinical hypersensitivity reactions and silent inactivation due to antibodies against E. coli asparaginase, lead to inactivation of E. coli asparaginase in up to 60% of cases. Current treatment protocols include E. coli asparaginase or PEG‐asparaginase for first‐line treatment of ALL. Typically, patients exhibiting sensitivity to one formulation of asparaginase are switched to another to ensure they receive the most efficacious treatment regimen possible. Erwinia asparaginase is used as a second‐ or third‐line treatment in European and US protocols. Despite the universal inclusion of asparaginase in such treatment protocols, debate on the optimal formulation and dosage of these agents continues. This article provides an overview of available evidence for optimal use of Erwinia asparaginase in the treatment of ALL. Cancer 2011. © 2010 American Cancer Society.     

Evidence of long‐lasting anti‐CD19 activity of engrafted CD19 chimeric antigen receptor–modified T cells in a phase I study targeting pediatrics with acute lymphoblastic leukemia

Ninety percent of relapse/refractory B‐cell acute lymphatic leukemia (R/R B‐ALL) patients can achieve complete remission (CR) after CD19‐targeting chimeric antigen receptor T (CAR‐T) cell therapy. However, around 50% of them relapse in 1 year. Persistent CAR‐T cell engraftment is considered as the key to remain durable remission. Here, we initiated a phase I study to treat 10 pediatric B‐ALL patients using a CD19‐targeted second generation CAR with a 4‐1BB intracellular costimulatory domain. All patients received a standard fludarabine and cyclophosphamide (FC) preconditioning regiment, followed by a CAR‐T infusion with a median number of 0.5 (0.3‐1.58) × 10⁶ CAR+ T cells/kg. The pretreatment tumor burdens were high with a median bone marrow (BM) blasts percentage of 59.2% (7.31%‐86.2%), excluding one patient only with brain infiltration of leukemia cells (0% BM blasts). The initial CR rate was 80% (n = 8/10). Four patients (40%) experienced serious (grade > 2) cytokine release syndrome (CRS) and three patients (30%) with obvious neurotoxicity. Monthly assessments of CD19+ minimal residual disease (MRD) and CAR‐T engraftment demonstrated the anti‐CD19 activity of long‐term engrafted CAR‐T cell clones in one patient for more than 2 years.     

Phase I and Extension Study of Clofarabine Plus Cyclophosphamide in Patients With Relapsed/Refractory Acute Lymphoblastic Leukemia

BackgroundClofarabine is a nucleoside analogue with activity in children with acute lymphoblastic leukemia (ALL). Based on the hypothesis that clofarabine inhibits DNA repair after exposure to DNA-damaging agents, we designed a phase I and extension study to evaluate the combination of clofarabine and cyclophosphamide in adult patients with relapsed/refractory ALL.MethodsThe continual reassessment method (CRM) was used to define the maximum tolerated dose (MTD).ResultsFifty patients with a median age of 30 years (range, 21-72 years) were enrolled, 30 of whom were part of the phase I group. Clofarabine 40 mg/m² intravenously daily × 3 days and cyclophosphamide 200 mg/m² intravenously every 12 hours × 3 days were established as the MTDs. Dose limiting toxicity (DLT) included diarrhea, transaminase elevations, and skin rashes. The response rate of the whole study group was 14%, including 10% of patients who achieved complete remission (CR) or CR without platelet recovery (CRp). Three responses occurred in patients with primary refractory disease. Early mortality (< 30 days) was 6%. The median duration of response was 69 days (range, 5-315 days). Median overall survival was about 3 months. Compared with day 1 (cyclophosphamide alone), H2AX phosphorylation was increased on day 2 when clofarabine and cyclophosphamide were administered as a couplet (n = 8).ConclusionThe combination of clofarabine plus cyclophosphamide at the doses used in this study in a group of heavily pretreated patients with ALL is only moderately effective. Other doses, alternative schedules, or a more favorable patient population may achieve better results.     

The role of long non‐coding RNAs and downstream signaling pathways in leukemia progression

The study of long non‐coding RNAs (lncRNA) is a newly established field and our knowledge about them is rapidly growing. These kinds of RNAs are unchanged parts of the genome throughout evolution, that modulate cell growth, differentiation, and apoptosis during diverse physiological and pathological processes including leukemia development. They have the capability to be useful biomarkers for the diagnosis, clinical typing, prognosis, as well as potential therapeutic targets. In this study, we summarized the role of lncRNAs in the expression and function of white blood cells and oncogenic transformation into four main types of leukemia.     

Real-World Outcomes of Adult B-Cell Acute Lymphocytic Leukemia Patients Treated With Inotuzumab Ozogamicin

BackgroundInotuzumab ozogamicin (InO) is an anti-CD22 monoclonal antibody–drug (calicheamicin) conjugate that has shown superior efficacy compared to conventional chemotherapy in relapsed/refractory (RR) B-cell acute lymphocytic leukemia (ALL) patients. We sought to find the safety and efficacy of InO in a real-world setting.Patients and MethodsA multicenter cohort analysis on 84 RR ALL patients who received InO outside of clinical trials was conducted to evaluate response and toxicity.ResultsThe median (range) age of patients at InO initiation was 50 (20-87) years. Forty patients (48%) had ≥ 3 therapies and 23 patients (27%) underwent allogeneic hematopoietic stem-cell transplantation (allo-HCT) before InO. The median (range) number of cycles of InO provided was 2 (1-6), and cumulative dose was 3.3 (1.8-9.3) mg/m². Overall response rate (complete remission/complete remission with incomplete count recovery) was 63%; 44% had complete remission with minimal residual disease negativity. Twenty-three patients (27%) with response received allo-HCT. The median duration of response was 11.5 months and when censored at allo-HCT was not reached (51% in remission at 2 years). The median overall survival after InO was 11.6 months and when censored at time of allo-HCT was 13.6 months. The most common grade 3 or higher adverse events observed were transaminitis (16%), hyperbilirubinemia (5%), bleeding (4%), veno-occlusive disease (2%), and hyperglycemia (2%). In multivariate analysis, allo-HCT after InO did not retain favorable significance for duration of response (hazard ratio = 1.27; 95% confidence interval, 0.89-1.61; P = .2) or overall survival (hazard ratio = 1.10; 95% confidence interval, 0.37-3.25; P = .85).ConclusionInO was well tolerated and had significant efficacy in RR B-cell ALL patients.     

Survival Rates of Adults With Acute Lymphoblastic Leukemia in a Low-Income Population: A Decade of Experience at a Single Institution in Mexico

BackgroundThe therapeutic progress for adults with acute lymphoblastic leukemia (ALL) has been slow, with a 5-year survival of 30% to 45% in developed countries. Scarce information is available regarding the treatment and survival rates from nonindustrialized populations. In the present study, the characteristics of adults with ALL at a single institution were documented.Patients and MethodsThe clinical files of patients aged ≥ 18 years who had been diagnosed with ALL from 2005 to 2015 at a reference center in Mexico were scrutinized. Overall survival (OS) and event-free survival (EFS) were determined using the Kaplan-Meier method. The hazard ratios for death and relapse were estimated using Cox regression analysis.ResultsA total of 94 adults were included. Their median age was 33 years; 69 (73.4%) had high-risk and 25 (26.6%) had standard-risk ALL. Of the 94 patients, 67 (71.3%) achieved complete remission (CR), 20 (21.3%) experienced disease resistance, and 7 (7.4%) died early during induction to remission, mainly of sepsis. The 5-year EFS and OS was 23.4% and 31.1% for the whole group and 24.9% and 38.9% for patients who achieved CR, respectively. Of the 94 patients, 50 (43.9%) died of sepsis or disease progression. Relapse developed in 43 patients (45.7%). The median survival after relapse was 6.93 months. Bone marrow was the most frequent site of relapse (21 patients [48.8%]) and conferred a significantly lower 5-year OS of 16.4%.ConclusionAdults with ALL in Mexico had high-risk characteristics and an increased relapse rate; however, the OS after CR was similar to the greatest achieved in developed countries, suggesting that a threshold for curing adult ALL with current therapeutic strategies has been reached.     

Pre-B-Cell Acute Lymphoblastic Leukemia in Childhood

The pre-B-cell (clgM) phenotype of childhood ALL comprises about one-fifth of newly diagnosed cases. It has a high frequency of chromosomal translocation, and is closely associated with the t(l;19)(q23;p13). The poor treatment outcome and high-risk features previously ascribed to this phenotype appear to be primarily due to the subset of cases with the t(l;19). Early results of at least one study suggest that aggressive treatment may even nullify the adverse prognostic implication of the t(l;19). Finally, molecular analyses of these cases have yielded exciting new information regarding the pathogenesis of pre-B-cell ALL with the t(l;19), and recombinant DNA technology (polymerase chain reaction) is likely to make molecular diagnosis and detection of minimal residual disease possible in the near future.     

Acute Lymphoblastic Leukaemia in the Elderly

Acute lymphoblastic leukaemia (ALL) is rare in adults over the age of 60 years, with an incidence of 1 per 100,000 per year. We review the current (sparse) literature and our Regional experience of 62 consecutive cases of ALL in this age group collected over a ten year period.

The patterns of cytogenetic abnormalities and immunophenotypes differs from those seen in ALL in childhood and young adults, but are similar to those reported in previous studies. B-ALL was found at twice the rate observed in younger adults (9/51 versus 6/99) and T-ALL was rare (2/51). In our patients we had few cytogenetic results but in the literature up to 50% of patients have been found to be Philadelphia positive, supporting the hypothesis that ALL in this group is often a stem cell disorder. In our patients treatment results were disappointing, with only 30% of those given 'curative' treatment achieving a complete remission, and a relapse rate of 92%, mirroring other published series. The overall four year survival was 4%. We conclude that ALL in the elderly is a rare condition with an extremely poor prognosis. Aggressive treatment may prolong life but it seldom cures.