Paediatric chronic myeloid leukaemia presenting in de novo or secondary blast phase - a comparison of clinical and genetic characteristics.

Additional data on blast phase (BP) chronic myeloid leukaemia (CML) in children and adolescents is essential for improving diagnostic and therapeutic approaches of this rare but serious condition. Here, we describe distinct clinical and genetic characteristics of 18 paediatric patients with de novo (n = 10) and secondary (n = 8) BP CML enrolled in the CML-PAED-II trial and registry. Our findings suggest that paediatric patients exhibit a diverse cytogenetic profile compared to adults with BP CML. In addition, patients with de novo BP CML in this cohort presented at a younger age, whereas patients with secondary BP CML more often harboured complex karyotypes.

Early peripheral blast cell clearance predicts minimal residual disease status and refines disease prognosis in acute myeloid leukemia.

Minimal residual disease (MRD) assessment in acute myeloid leukemia (AML) is increasingly used in risk stratification. However, several issues around this use are unresolved, including, among others, the most suitable time-point(s) for its application. Overall, late assessments appear more effective at distinguishing outcome but, in some studies, the early evaluations were already highly informative, anticipating the value of later ones. Our work integrated MRD with peripheral blast clearance (PBC), a treatment-related biomarker previously demonstrated to be a powerful predictor of response. From 2007 to 2014, we have studied 120 patients treated according to the NILG 02-06 trial and who achieved CR after induction. Patients in PBC-defined categories (separated by a 1.5-log threshold) showed significantly different probabilities of attaining MRD negativity, after either induction (MRD1) or consolidation (MRD2). Peripheral blast clearance combined with MRD1 largely anticipated MRD2-related information: when both biomarkers predicted chemosensitive disease (PBChigh /MRD1neg ), the rate of MRD2-negativity was 90%, and DFS and OS estimates were 68% and 76% at 3 years, respectively. When both markers were unfavorable (PBClow /MRD1pos ), rates of MRD2 negativity, DFS, and OS were 20%, 34%, and 24%, respectively, at 3 years. In fact, MRD2 added prognostic value only in cases with discordant PBC/MRD1 data. Our data support a reasoned timing for MRD-based therapeutic decisions, modulated on individual chemosensitivity, an approach we have implemented in a forthcoming prospective multi-center trial by Gruppo Italiano Malattie EMatologiche dell'Adulto (GIMEMA).

Performance of the Sysmex White Precursor Channel to discover circulating leukemic blast cells.

INTRODUCTION: Circulating immature precursor cells indicate malignant diseases like acute myeloid or lymphoid leukemia, and blast cells are key finds for disease management. Automatized cell counters are an essential contemporary appliance for blast detection, but false-positive samples remain challenging in terms of time and resources. To reduce this issue, the White Precursor Channel (WPC) was introduced to Sysmex XN series; however, sensitivity may reduce when accommodating low specificity. Therefore, our aim was to evaluate WPC blast alarm flag performance with regard to detecting blast cells. METHODS: At two major Danish hospitals, random blood samples were collected from the routine setting   in a four-week period and analyzed on WPC XN20 (Sysmex, Japan). Results were compared with manual differential white blood cell count (Manual WBCC) assisted by CellaVisionDM96. RESULTS: In 117 samples, we found 0.2 to 34.4% blasts, WPC blast flag specificity = 82% and a low sensitivity = 40%. However, other XN alarm flags forwarded samples to Manual WBCC, so blast cells were detected despite missing a specific blast flag: With all alarm flags, combined sensitivity increased to 88%. Overall, the WPC application stopped 18% of the 117 samples going to Manual WBCC (three false negatives). Q values are arbitrary probability measurements for the blast flag, and in five samples (0.5 to 47.3% blasts) imprecision ranged from 5.3 to 122 CV%. CONCLUSIONS: WPC blast alarm flags are imprecise and inaccurate, especially when blast counts are low. However, the XN20 will alarm samples with other flags so that most samples containing blast cells will be manually reviewed after all. Hence, the presented flag types should not bias the decisions of manual reviewers.

Phase I/II study of dasatinib in combination with decitabine in patients with accelerated or blast phase chronic myeloid leukemia.

Treatment of advanced-phase chronic myeloid leukemia (CML) remains unsatisfactory. Single-agent tyrosine kinase inhibitors have modest and short-lived activity in this setting. We conducted a phase I/II study to determine safety and efficacy of the combination of dasatinib and decitabine in patients with advanced CML. Two different dose schedules were investigated with a starting decitabine dose of either 10 mg/m2 or 20 mg/m2 daily for 10 days plus dasatinib 100 mg daily. The target dose level was decitabine 10 mg/m2 or 20 mg/m2 daily for 10 days plus dasatinib 140 mg daily. Thirty patients were enrolled, including seven with accelerated-phase CML, 19 with blast-phase CML, and four with Philadelphia-chromosome positive acute myeloid leukemia. No dose-limiting toxicity was observed at the starting dose level with either schedule. Grade ≥3 treatment emergent hematological adverse events were reported in 28 patients. Thirteen patients (48%) achieved a major hematologic response and six (22%) achieved a minor hematologic response, with 44% of these patients achieving a major cytogenetic response and 33% achieving a major molecular response. Median overall survival (OS) was 13.8 months, with significantly higher OS among patients who achieved a hematologic response compared to non-responders (not reached vs 4.65 months; P < .001). Decitabine plus dasatinib is a safe and active regimen in advanced CML. Further studies using this combination are warranted.

Hemorrhage in acute promyelocytic leukemia: Can it be predicted and prevented?

Hemorrhagic death is the leading cause of treatment failure in acute promyelocytic leukemia (APL). Our ability to identify patients at greatest risk of hemorrhage, and to actively prevent hemorrhage, remains limited. Nevertheless, some data is available to guide contemporary clinical practice and future investigation. Circulating disease burden, best represented by the peripheral WBC / blast count, is the most consistent predictor of major and fatal bleeding risk. In contrast, laboratory markers of disseminated intravascular coagulation (DIC) appear to be poor predictors. A number of interventions have been posited to reduce bleeding risk. Prompt initiation of all-trans retinoic acid (ATRA), avoidance of invasive procedures, transfusion support, and cytoreduction all have theoretical merit. Though they lack strong evidence to support their benefit with respect to bleeding, they are associated with limited risks, and are therefore advisable. Low-dose therapeutic heparin and antifibrinolytics have not shown the ability to positively modify bleeding risk, and heparin has been associated with harm. Thrombomodulin has shown promise in limited retrospective studies however further prospective data are needed. rFVIIa may have a role in cases of life-threatening bleeding however evidence is largely anecdotal. Additional studies evaluating the above interventions, and investigating other potential interventions are needed.

Identification of CD318 (CDCP1) as novel prognostic marker in AML.

Genetic and morphological markers are well-established prognostic factors in acute myeloid leukemia (AML). However, further reliable markers are urgently needed to improve risk stratification in AML. CD318 (CDCP1) is a transmembrane protein which in solid tumors promotes formation of metastasis and correlates with poor survival. Despite its broad expression on hematological precursor cells, its prognostic significance in hematological malignancies so far remains unclear. Here, we evaluated the role of CD318 as novel prognostic marker in AML by immunophenotyping of leukemic blasts. Flow cytometric evaluation of CD318 on leukemic cells in 70 AML patients revealed a substantial expression in 40/70 (57%) of all cases. CD318 surface levels were significantly correlated with overall survival in patients receiving anthracycline-based induction therapy or best available alternative therapy. Using receiver-operating characteristics, we established a cut-off value to define CD318lo and CD318hi expression in both cohorts. Notably, high CD318 expression correlated inversely as prognostic marker in both treatment cohorts: as poor prognostic marker in patients receiving intense therapy, whereas upon palliative care it correlated with better outcome. In conclusion, FACS-based determination of CD318 expression may serve as novel prognostic factor depending on implemented therapy in AML patients.

More acute lymphoid leukemia than acute myeloid leukemia blasts are killed by rabbit antithymocyte globulin.

Rabbit antithymocyte globulin (ATG, thymoglobulin), a polyclonal antibody, is used to prevent graft-versus-host disease (GVHD) and graft failure in the setting of allogeneic hematopoietic cell transplantation (HCT). Recent in vitro studies suggest that ATG also has anti-leukemic activity. Whether acute lymphoid leukemia (ALL) or acute myeloid leukemia (AML) is more sensitive to ATG is not known. We used primary cells from 12 B-ALL and 38 AML patients and measured ATG-induced complement-dependent cytotoxicity (CDC) and complement-independent cytotoxicity (CIC) at clinically relevant ATG concentrations (10 and 50 mg/L). At 50 mg/L, ALL blasts were killed to a greater degree than AML blasts by CDC (median 96% vs 50% dead cells, P = 0.001) as well as CIC (median 23% vs 11% apoptotic cells, P = 0.049). At 10 mg/L, the difference was significant for CDC but not CIC. In conclusion, the anti-leukemic activity of ATG, particularly CDC, is more potent for ALL than AML in vitro. If this applies in vivo, ATG-based GVHD prophylaxis may be particularly advantageous for ALL.

Prognosis of patients with chronic myeloid leukemia presenting in advanced phase is defined mainly by blast count, but also by age, chromosomal aberrations and hemoglobin.

Chronic myeloid leukemia (CML) is usually diagnosed in chronic phase, yet there is a small percentage of patients that is diagnosed in accelerated phase or blast crisis. Due to this rarity, little is known about the prognosis of these patients. Our aim was to identify prognostic factors for this cohort. We identified 283 patients in the EUTOS population-based and out-study registries that were diagnosed in advanced phase. Nearly all patients were treated with tyrosine kinase inhibitors. Median survival in this heterogeneous cohort was 8.2 years. When comparing patients with more than 30% blasts to those with 20-29% blasts, the hazard ratio (HR) was 1.32 (95%-confidence interval (CI): [0.7-2.6]). Patients with 20-29% blasts had a significantly higher risk than patients with less than 20% blasts (HR: 2.24, 95%-CI: [1.2-4.0], P = .008). We found that the blast count was the most important prognostic factor; however, age, hemoglobin, basophils and other chromosomal aberrations should be considered as well. The ELTS score was able to define two groups (high risk vs non-high risk) with an HR of 3.01 (95%-CI: [1.81-5.00], P < .001). Regarding the contrasting definitions of blast crisis, our data clearly supported the 20% cut-off over the 30% cut-off in this cohort. Based on our results, we conclude that a one-phase rather than a two-phase categorization of de novo advanced phase CML patients is appropriate.

Intracellular cytarabine triphosphate in circulating blasts post-treatment predicts remission status in patients with acute myeloid leukemia.

Cytarabine remains the backbone of therapy in acute myeloid leukemia (AML). The ability to assess intracellular cytarabine triphosphate (ara-CTP) levels in patients receiving cytarabine represents a major goal in the prediction of treatment response. This study, conducted within a clinical setting, aimed to assess ara-CTP levels in circulating peripheral blasts from non-M3 AML patients receiving cytarabine at one of three dosing levels, using a novel biosensor assay. Results from the initial 72 hours post-commencement were correlated with day 28 remission status, with feasibility parameters concurrently assessed. Intracellular ara-CTP was detectable in ex vivo blasts post-treatment for standard-dose (SD) and high-dose (HD) patients (p < 0.05), and quantification revealed a 27-fold increase in intracellular steady-state concentration between the two dosing levels. For low-dose cytarabine, high rates of patient discharge and low intracellular concentrations limited analysis; however, assessment of intracellular ara-CTP concentration was achievable in a dwindling population of blasts for SD and HD treatment cohorts, with 4 hours post-treatment commencement potentially being most predictive of clinical response (r = -0.912, p = 0.0113). Concurrent assessment of peripheral leukemia-associated immunophenotype (LAIP)-positive cells revealed a decline in burden (0-72 hours), which correlated with remission status (p < 0.05). Unexpectedly high rates of night sampling led to challenges associated with sampling rates, but did not have an impact on patient compliance. Additional training of night staff improved feasibility substantially. Multiple peripheral sampling during the initial 72 hours of treatment is feasible in newly diagnosed patients, and ara-CTP is detectable over the initial 24 hours, facilitating prediction of chemosensitivity of leukemic blasts to cytarabine.

Serum Vitamin D Levels in Patients with Myelodysplastic Syndromes: A Retrospective Single-Center Analysis.

BACKGROUND/AIMS: There is growing evidence supporting the role of innate immune deregulation and inflammation in the pathogenesis of myelodysplastic syndromes (MDS). Vitamin D (VD) is known to be involved in various immune and epigenetic processes. This analysis aimed to evaluate serum VD levels in patients with MDS and to analyze associations between serum VD levels and disease characteristics. METHODS: Serum levels of 25-hydroxyvitamin D3 (25(OH)-D3), the major form of VD in human serum, were measured by chemiluminescence immunoassay in 62 unselected patients with MDS. Associations between serum 25(OH)-D3 levels and disease characteristics were analyzed using Kendall's tau and two-sided p values. RESULTS: The median serum 25(OH)-D3 level was markedly reduced (17.5 ng/mL). Patients with lower-risk disease features had lower serum 25(OH)-D3 levels than patients with higher-risk disease features with regard to medullary blast counts (16 vs. 31 ng/mL, p < 0.001), the revised international prognostic scoring system (13 vs. 30.5 ng/mL, p = 0.001), and blood counts. CONCLUSIONS: We show that patients with lower-risk disease characteristics exhibit lower serum VD levels than patients with higher-risk disease characteristics. Whether these findings might reflect innate immune deregulation has to be investigated in further studies.

An effective modestly intensive re-induction regimen with bortezomib in relapsed or refractory paediatric acute lymphoblastic leukaemia.

This trial explored the efficacy of re-induction chemotherapy including bortezomib in paediatric relapsed/refractory acute lymphoblastic leukaemia. Patients were randomized 1:1 to bortezomib (1.3 mg/m2 /dose) administered early or late to a dexamethasone and vincristine backbone. Both groups did not differ regarding peripheral blast count on day 8, the primary endpoint. After cycle 1, 8 of 25 (32%) patients achieved complete remission with incomplete blood count recovery, 7 (28%) a partial remission and 10 had treatment failure. Most common grade 3-4 toxicities were febrile neutropenia (31%) and pain (17%). Bortezomib was safely combined with vincristine. Bortezomib rarely penetrated the cerebrospinal fluid.