Quizartinib versus salvage chemotherapy in relapsed or refractory FLT3-ITD acute myeloid leukaemia (QuANTUM-R): a multicentre, randomised, controlled, open-label, phase 3 trial.

BACKGROUND: Patients with relapsed or refractory FLT3 internal tandem duplication (FLT3-ITD)-positive acute myeloid leukaemia have a poor prognosis, including high frequency of relapse, poorer response to salvage therapy, and shorter overall survival than those with FLT3 wild-type disease. We aimed to assess whether single-agent quizartinib, an oral, highly potent and selective type II FLT3 inhibitor, improves overall survival versus salvage chemotherapy. METHODS: QuANTUM-R is a randomised, controlled, phase 3 trial done at 152 hospitals and cancer centres in 19 countries. Eligible patients aged 18 years or older with ECOG performance status 0-2 with relapsed or refractory (duration of first composite complete remission ≤6 months) FLT3-ITD acute myeloid leukaemia after standard therapy with or without allogeneic haemopoietic stem-cell transplantation were randomly assigned (2:1; permuted block size of 6; stratified by response to previous therapy and choice of chemotherapy via a phone-based and web-based interactive response system) to quizartinib (60 mg [30 mg lead-in] orally once daily) or investigator's choice of preselected chemotherapy: subcutaneous low-dose cytarabine (subcutaneous injection of cytarabine 20 mg twice daily on days 1-10 of 28-day cycles); intravenous infusions of mitoxantrone (8 mg/m2 per day), etoposide (100 mg/m2 per day), and cytarabine (1000 mg/m2 per day on days 1-5 of up to two 28-day cycles); or intravenous granulocyte colony-stimulating factor (300 µg/m2 per day or 5 µg/kg per day subcutaneously on days 1-5), fludarabine (intravenous infusion 30 mg/m2 per day on days 2-6), cytarabine (intravenous infusion 2000 mg/m2 per day on days 2-6), and idarubicin (intravenous infusion 10 mg/m2 per day on days 2-4 in up to two 28-day cycles). Patients proceeding to haemopoietic stem-cell transplantation after quizartinib could resume quizartinib after haemopoietic stem-cell transplantation. The primary endpoint was overall survival in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT02039726, and follow-up is ongoing. FINDINGS: Between May 7, 2014, and Sept 13, 2017, 367 patients were enrolled, of whom 245 were randomly allocated to quizartinib and 122 to chemotherapy. Four patients in the quizartinib group and 28 in the chemotherapy group were not treated. Median follow-up was 23·5 months (IQR 15·4-32·3). Overall survival was longer for quizartinib than for chemotherapy (hazard ratio 0·76 [95% CI 0·58-0·98; p=0·02]). Median overall survival was 6·2 months (5·3-7·2) in the quizartinib group and 4·7 months (4·0-5·5) in the chemotherapy group. The most common non-haematological grade 3-5 treatment-emergent adverse events (within ≤30 days of last dose or >30 days if suspected to be a treatment-related event) for quizartinib (241 patients) and chemotherapy (94 patients) were sepsis or septic shock (46 patients [19%] for quizartinib vs 18 [19%] for chemotherapy), pneumonia (29 [12%] vs eight [9%]), and hypokalaemia (28 [12%] vs eight [9%]). The most frequent treatment-related serious adverse events were febrile neutropenia (18 patients [7%]), sepsis or septic shock (11 [5%]), QT prolongation (five [2%]), and nausea (five [2%]) in the quizartinib group, and febrile neutropenia (five [5%]), sepsis or septic shock (four [4%]), pneumonia (two [2%]), and pyrexia (two [2%]) in the chemotherapy group. Grade 3 QT prolongation in the quizartinib group was uncommon (eight [3%] by central reading, ten [4%] by investigator report); no grade 4 events occurred. There were 80 (33%) treatment-emergent deaths in the quizartinib group (31 [13%] of which were due to adverse events) and 16 (17%) in the chemotherapy group (nine [10%] of which were due to adverse events). INTERPRETATION: Treatment with quizartinib had a survival benefit versus salvage chemotherapy and had a manageable safety profile in patients with rapidly proliferative disease and very poor prognosis. Quizartinib could be considered a new standard of care. Given that there are only a few available treatment options, this study highlights the value of targeting the FLT3-ITD driver mutation with a highly potent and selective FLT3 inhibitor. FUNDING: Daiichi Sankyo.

Improving Revised International Prognostic Scoring System Pre-Allogeneic Stem Cell Transplantation Does Not Translate Into Better Post-Transplantation Outcomes for Patients with Myelodysplastic Syndromes: A Single-Center Experience.

The natural history of patients with myelodysplastic syndromes (MDS) is variable. The Revised International Prognostic Score (IPSS-R) is commonly used in practice to predict outcomes in patients with MDS at both diagnosis and before hematopoietic stem cell transplantation (HSCT). However, the effect of change in the IPSS-R before allogeneic HSCT with chemotherapy or hypomethylating agents on post-transplantation outcomes is currently unknown. We assessed whether improvement in IPSS-R prognostic score pre-HSCT would result in improvement in clinical outcomes post-HSCT. Secondary goals included studying the effect of prognostic factors on post-transplantation survival. All patients with MDS who underwent allogeneic HSCT at the Leukemia/BMT Program of British Columbia between February 1997 and April 2013 were included. Pertinent information was reviewed from the program database. IPSS-R was calculated based on data from the time of MDS diagnosis and before HSCT. Outcomes of patients who had improved IPSS-R pre-HSCT were compared with those with stable or worse IPSS-R. Overall survival (OS) and event-free survival (EFS) were estimated using the Kaplan-Meier method, with P values determined using the log-rank test. Hazard ratios were calculated using multivariable Cox proportional hazards regression models to study the effects of the prognostic variables on OS and EFS. A total of 138 consecutive patients were included. IPSS-R improved in 62 of these patients (45%), worsened in 23 (17%), remained stable in 41 (30%), and was unknown in 12 (9%). OS was not statistically different across the improved, worsened, and stable groups (30% versus 22% versus 40%, respectively; P = .63). The cumulative incidences of relapse and nonrelapse mortality at 5 years were 28.4% (95% confidence interval [CI], 21.1 to 36.1) and 31.6% (95% CI, 23.8 to 39.7), respectively. The rate of relapse was 23% in patients with <5% blasts at the time of HSCT, 69% in those with 5% to 20% blasts, and 66% in those with >20% blasts (P = .0004). In the entire cohort OS was 34% and EFS was 33%. There was no significant difference in outcomes between patients who received myeloablative conditioning and those who received nonmyeloablative conditioning before HSCT (OS, 34% and 39%, respectively; P = .63 and EFS, 34% and 32%, respectively; P = .86). OS was not statistically different among patients with improved, worsened, or stable IPSS-R. On multivariate analysis, only 3 factors were associated with OS: cytogenetic risk group at diagnosis, blast count at transplantation, and the presence or absence of chronic graft-versus-host disease. Improving IPSS-R before HSCT does not translate into better survival outcomes. Blast count pretransplantation was highly predictive of post-transplantation outcomes.

Excellent real-world outcomes of adults with Burkitt lymphoma treated with CODOX-M/IVAC plus or minus rituximab.

Treatment of Burkitt lymphoma (BL) with intensive, multi-agent chemotherapy with aggressive central nervous system (CNS) prophylaxis results in high cure rates, although no regimen is standard of care. We examined population-based survival outcomes of adults with BL treated with a modified combination of cyclophosphamide, vincristine, doxorubicin, prednisone and systemic high-dose methotrexate (MTX) (CODOX-M) with IVAC (ifosfamide, mesna, etoposide, cytarabine and intrathecal MTX) (CODOX-M/IVAC) ± rituximab over a 15-year period in British Columbia. For the 81 patients identified (including 8 with CNS involvement and 18 with human immunodeficiency virus-associated BL), 5-year progression-free survival (PFS) and overall survival (OS) were 75% [95% confidence interval (CI): 63-83%] and 77% (95% CI: 66-85%), respectively, with no treatment-related deaths. Those who completed the regimen per protocol (n = 38) had significantly improved 5-year PFS 86% (P = 0·04) and OS 92% (P = 0·008), as did those under 60 years with 5-year PFS 82% (P = 0·005) and OS 86% (P = 0·002), which remained significant in multivariate analysis [PFS: hazard ratio (HR) 3·36, P = 0·018; OS HR 4·03, P = 0·012]. Incorporation of high-dose systemic methotrexate also significantly affected multivariate survival outcomes (OS HR 0·28, P = 0·025). Stem cell transplant in first remission had no effect on OS or PFS. This large, real-world analysis of BL patients treated with CODOX-M/IVAC ± rituximab demonstrates excellent survival outcomes comparable to clinical trials. These results help to serve as a benchmark when comparing curative therapies for BL patients as novel regimens are incorporated into clinical practice.

Economic impact of genomic diagnostics for intermediate-risk acute myeloid leukaemia.

Acute Myeloid Leukaemia (AML) is a rare but serious group of diseases that require critical decision-making for curative treatment. Over the past decade, scientific discovery has revealed dozens of prognostic gene mutations for AML while sequencing costs have plummeted. In this study, we compared the cost-effectiveness of multigene integrative analysis (genomic analysis) with the standard molecular testing currently used for diagnosis of intermediate-risk AML. We used a decision analytic model with data for costs and outcomes from British Columbia, Canada, to assess the long-term (10-year) economic impacts. Our results suggest that genomic analysis would result in a 26% increase in the use of first-remission allogeneic stem cell transplantation. The resulting treatment decisions and downstream effects would come at an additional cost of $12 556 [2013 Canadian dollars (CAD)] per person and the incremental cost-effectiveness ratio would be $49 493 per quality-adjusted life-year gained. Cost-effectiveness was dependent on quality of life during the long-term (5-10) years of survival, relapse rates following first-remission chemotherapy and the upfront cost of transplantation. Non-relapse mortality rates, short-term quality of life and the cost of genomic sequencing had only minor impacts. Further research on post-remission outcomes can lead to improvements in the cost-effectiveness of curative treatments for AML.

Dielectrophoretic Microfluidic Chip Enables Single-Cell Measurements for Multidrug Resistance in Heterogeneous Acute Myeloid Leukemia Patient Samples.

The front-line treatment for adult acute myeloid leukemia (AML) is anthracycline-based combination chemotherapy. However, treatment outcomes remain suboptimal with relapses frequently observed. Among the mechanisms of treatment failure is multidrug resistance (MDR) mediated by the ABCB1, ABCC1, and ABCG2 drug-efflux transporters. Although genetic and phenotypic heterogeneity between leukemic blast cells is a well-recognized phenomenon, there remains minimal data on differences in MDR activity at the individual cell level. Specifically, functional assays that can distinguish the variability in MDR activity between individual leukemic blasts are lacking. Here, we outline a new dielectrophoretic (DEP) chip-based assay. This assay permits measurement of drug accumulation in single cells, termed same-single-cell analysis in the accumulation mode (SASCA-A). Initially, the assay was optimized in pretherapy samples from 20 adults with AML whose leukemic blasts had MDR activity against the anthracyline daunorubicin (DNR) tested using multiple MDR inhibitors. Parameters tested were initial drug accumulation, time to achieve signal saturation, fold-increase of DNR accumulation with MDR inhibition, ease of cell trapping, and ease of maintaining the trapped cells stationary. This enabled categorization into leukemic blast cells with MDR activity (MDR(+)) and leukemic blast cells without MDR activity (MDR(-ve)). Leukemic blasts could also be distinguished from benign white blood cells (notably these also lacked MDR activity). MDR(-ve) blasts were observed to be enriched in samples taken from patients who went on to enter complete remission (CR), whereas MDR(+) blasts were frequently observed in patients who failed to achieve CR following front-line chemotherapy. However, pronounced variability in functional MDR activity between leukemic blasts was observed, with MDR(+) cells not infrequently seen in some patients that went on to achieve CR. Next, we tested MDR activity in two paired AML patient samples. Pretherapy samples taken from patients that achieved CR to front-line chemotherapy were compared with samples taken at time of subsequent relapse. MDR(+) cells were frequently observed in leukemic blast cells in both pretherapy and relapsed samples, consistent with MDR as a mechanism of relapse in these patients. We demonstrate the ability of a new DEP microfluidic chip-based assay to identify heterogeneity in MDR activity in leukemic blasts. The test provides a platform for future studies to characterize the mechanistic basis for heterogeneity in MDR activity at the individual cell level.

Deep profiling of multitube flow cytometry data.

MOTIVATION: Deep profiling the phenotypic landscape of tissues using high-throughput flow cytometry (FCM) can provide important new insights into the interplay of cells in both healthy and diseased tissue. But often, especially in clinical settings, the cytometer cannot measure all the desired markers in a single aliquot. In these cases, tissue is separated into independently analysed samples, leaving a need to electronically recombine these to increase dimensionality. Nearest-neighbour (NN) based imputation fulfils this need but can produce artificial subpopulations. Clustering-based NNs can reduce these, but requires prior domain knowledge to be able to parameterize the clustering, so is unsuited to discovery settings. RESULTS: We present flowBin, a parameterization-free method for combining multitube FCM data into a higher-dimensional form suitable for deep profiling and discovery. FlowBin allocates cells to bins defined by the common markers across tubes in a multitube experiment, then computes aggregate expression for each bin within each tube, to create a matrix of expression of all markers assayed in each tube. We show, using simulated multitube data, that flowType analysis of flowBin output reproduces the results of that same analysis on the original data for cell types of >10% abundance. We used flowBin in conjunction with classifiers to distinguish normal from cancerous cells. We used flowBin together with flowType and RchyOptimyx to profile the immunophenotypic landscape of NPM1-mutated acute myeloid leukemia, and present a series of novel cell types associated with that mutation.

Phase 2 trial of CPX-351, a fixed 5:1 molar ratio of cytarabine/daunorubicin, vs cytarabine/daunorubicin in older adults with untreated AML.

CPX-351 is a liposomal formulation of cytarabine:daunorubicin designed to deliver synergistic drug ratios to leukemia cells. In this phase 2 study, newly diagnosed older acute myeloid leukemia (AML) patients were randomized 2:1 to first-line CPX-351 or 7+3 treatment. The goal was to determine efficacy and identify patient subgroups that may benefit from CPX-351 treatment. Response rate (complete remission + incomplete remission) was the primary end point, with event-free survival (EFS) and overall survival (OS) as secondary end points. The 126 patients entered were balanced for disease and patient-specific risk factors. Overall, CPX-351 produced higher response rates (66.7% vs 51.2%, P = .07), meeting predefined criteria for success (P < .1). Differences in EFS and OS were not statistically significant. A planned analysis of the secondary AML subgroup demonstrated an improved response rate (57.6% vs 31.6%, P = .06), and prolongation of EFS (hazard ratio [HR] = 0.59, P = .08) and OS (HR = 0.46, P = .01). Recovery from cytopenias was slower after CPX-351 (median days to absolute neutrophil count ≥1000: 36 vs 32; platelets >100 000: 37 vs 28) with more grade 3-4 infections but without increase in infection-related deaths (3.5% vs 7.3%) or 60-day mortality (4.7% vs 14.6%), indicating acceptable safety. These results suggest a clinical benefit with CPX-351, particularly among patients with secondary AML, and provide the rationale for a phase 3 trial currently underway in newly diagnosed secondary AML patients. This study is registered at Clinicaltrials.gov as #NCT00788892.

Vosaroxin plus cytarabine versus placebo plus cytarabine in patients with first relapsed or refractory acute myeloid leukaemia (VALOR): a randomised, controlled, double-blind, multinational, phase 3 study.

BACKGROUND: Safe and effective treatments are urgently needed for patients with relapsed or refractory acute myeloid leukaemia. We investigated the efficacy and safety of vosaroxin, a first-in-class anticancer quinolone derivative, plus cytarabine in patients with relapsed or refractory acute myeloid leukaemia. METHODS: This phase 3, double-blind, placebo-controlled trial was undertaken at 101 international sites. Eligible patients with acute myeloid leukaemia were aged 18 years of age or older and had refractory disease or were in first relapse after one or two cycles of previous induction chemotherapy, including at least one cycle of anthracycline (or anthracenedione) plus cytarabine. Patients were randomly assigned 1:1 to vosaroxin (90 mg/m(2) intravenously on days 1 and 4 in a first cycle; 70 mg/m(2) in subsequent cycles) plus cytarabine (1 g/m(2) intravenously on days 1-5) or placebo plus cytarabine through a central interactive voice system with a permuted block procedure stratified by disease status, age, and geographical location. All participants were masked to treatment assignment. The primary efficacy endpoint was overall survival and the primary safety endpoint was 30-day and 60-day all-cause mortality. Efficacy analyses were done by intention to treat; safety analyses included all treated patients. This study is registered with ClinicalTrials.gov, number NCT01191801. FINDINGS: Between Dec 17, 2010, and Sept 25, 2013, 711 patients were randomly assigned to vosaroxin plus cytarabine (n=356) or placebo plus cytarabine (n=355). At the final analysis, median overall survival was 7·5 months (95% CI 6·4-8·5) in the vosaroxin plus cytarabine group and 6·1 months (5·2-7·1) in the placebo plus cytarabine group (hazard ratio 0·87, 95% CI 0·73-1·02; unstratified log-rank p=0·061; stratified p=0·024). A higher proportion of patients achieved complete remission in the vosaroxin plus cytarabine group than in the placebo plus cytarabine group (107 [30%] of 356 patients vs 58 [16%] of 355 patients, p<0·0001). Early mortality was similar between treatment groups (30-day: 28 [8%] of 355 patients in the vosaroxin plus cytarabine group vs 23 [7%] of 350 in the placebo plus cytarabine group; 60-day: 70 [20%] vs 68 [19%]). Treatment-related deaths occurred at any time in 20 (6%) of 355 patients given vosaroxin plus cytarabine and in eight (2%) of 350 patients given placebo plus cytarabine. Treatment-related serious adverse events occurred in 116 (33%) and 58 (17%) patients in each group, respectively. Grade 3 or worse adverse events that were more frequent in the vosaroxin plus cytarabine group than in the placebo plus cytarabine group included febrile neutropenia (167 [47%] vs 117 [33%]), neutropenia (66 [19%] vs 49 [14%]), stomatitis (54 [15%] vs 10 [3%]), hypokalaemia (52 [15%] vs 21 [6%]), bacteraemia (43 [12%] vs 16 [5%]), sepsis (42 [12%] vs 18 [5%]), and pneumonia (39 [11%] vs 26 [7%]). INTERPRETATION: Although there was no significant difference in the primary endpoint between groups, the prespecified secondary analysis stratified by randomisation factors suggests that the addition of vosaroxin to cytarabine might be of clinical benefit to some patients with relapsed or refractory acute myeloid leukaemia. FUNDING: Sunesis Pharmaceuticals.

Allogeneic Hematopoietic Stem Cell Transplantation Is an Effective Salvage Therapy for Patients with Chronic Myeloid Leukemia Presenting with Advanced Disease or Failing Treatment with Tyrosine Kinase Inhibitors.

Allogeneic hematopoietic stem cell transplantation (HSCT) remains the only known curative therapy for chronic myeloid leukemia (CML); however, it is rarely utilized given the excellent long-term results with tyrosine kinase inhibitor (TKI) treatment. The purpose of this study is to examine HSCT outcomes for patients with CML who failed TKI therapy or presented in advanced phase and to identify predictors of survival, relapse, and nonrelapse mortality (NRM). Fifty-one patients with CML underwent HSCT for advanced disease at diagnosis (n = 15), TKI resistance as defined by the European LeukemiaNet guidelines (n = 30), TKI intolerance (n = 2), or physician preference (n = 4). At a median follow-up of 71.9 months, the 8-year overall survival (OS), event-free survival (EFS), relapse, and NRM were 68%, 46%, 41%, and 23%, respectively. In univariate analysis, predictors of OS included first chronic phase (CP1) disease status at HSCT (P = .0005), European Society for Blood and Marrow Transplantation score 1 to 4 (P = .04), and complete molecular response (CMR) to HSCT (P < .0001). Donor (female) to patient (male) gender combination (P = .02) and CMR to HSCT (P < .0001) predicted lower relapse. In multivariate analysis, CMR to HSCT remained an independent predictor of OS (odds ratio [OR], 43), EFS (OR, 56) and relapse (OR, 29). This report indicates that the outlook is excellent for those patients who remain in CP1 at the time of HSCT and achieve a CMR after HSCT. However, only approximately 50% of those in advanced phase at HSCT are long-term survivors. This highlights the ongoing need to try to identify patients earlier, before disease progression, who are destined to fail this treatment to optimize transplantation outcomes.

Phase II, multicenter, randomized trial of CPX-351 (cytarabine:daunorubicin) liposome injection versus intensive salvage therapy in adults with first relapse AML.

BACKGROUND: CPX-351 is a liposome-encapsulated fixed-molar-ratio formulation of cytarabine and daunorubicin that exploits molar ratio-dependent drug-drug synergy to enhance antileukemic efficacy. METHODS: This phase II study randomized 125 patients 2:1 to CPX-351 or investigators' choice of first salvage chemotherapy. Patients with acute myeloid leukemia (AML) in first relapse after initial Complete Remission (CR) lasting ≥1 month were stratified per the European Prognostic Index (EPI) into favorable, intermediate, and poor-risk groups based on duration of first CR, cytogenetics, age, and transplant history. Control salvage treatment was usually based on cytarabine and anthracycline, often with 1 or more additional agents. Survival at 1 year was the primary efficacy end point. RESULTS: Patient characteristics were well balanced between the 2 study arms. Improvements in efficacy outcomes were observed following CPX-351, but did not meet prospectively defined statistical criteria for 1-year survival improvement in the overall population. Subset analyses of the EPI-defined poor-risk strata demonstrated higher response rates (39.3% vs 27.6%) and improvements in event-free survival (HR, 0.63; P = .08) and overall survival (HR, 0.55; P = .02). Also, 60-day mortality was lower in the CPX-351 study arm for poor-risk patients (16.1% vs 24.1%). CONCLUSIONS: Taken together, the data suggest possible improved outcomes in CPX-351-treated first relapse AML patients with EPI-defined poor-risk disease.

Phase II study of targeted therapy with temozolomide in acute myeloid leukaemia and high-risk myelodysplastic syndrome patients pre-screened for low O(6) -methylguanine DNA methyltransferase expression.

Resistance to temozolomide is largely mediated by the DNA repair enzyme O(6) -methylguanine DNA methyltransferase (MGMT). We conducted a prospective multicentre study of patients with previously untreated acute myeloid leukaemia (AML) or high-risk myelodysplastic syndrome (MDS) who were not candidates for intensive therapy. Patient selection was based on MGMT expression by Western blot. Patients with MGMT:ACTB (ß-actin) ratio <0·2 were eligible to receive temozolomide 200 mg/m(2) /d ×7 d. Patients achieving a complete response (CR) could receive up to 12 monthly cycles of temozolomide ×5/28 d. Of 166 patients screened, 81 (49%) demonstrated low MGMT expression; 45 of these were treated with temozolomide. The overall response rate was 53%; 36% achieved complete clearance of blasts, with 27% achieving a CR/CR with incomplete platelet recovery (CRp). Factors associated with a trend toward a higher response rate included MDS, methylated MGMT promoter and standard cytogenetic risk group. Induction and post-remission cycles were well-tolerated and most patients were treated on an outpatient basis. Patient who achieved CR/CRp had a superior overall survival compared to partial or non-responders. In conclusion, targeted therapy based on pre-selection for low MGMT expression was associated with a higher response rate to temozolomide compared to previous reports of unselected patients.

Distinct but phenotypically heterogeneous human cell populations produce rapid recovery of platelets and neutrophils after transplantation.

Delayed recovery of mature blood cells poses a serious, expensive, and often life-threatening problem for many stem cell transplantation recipients, particularly if heavily pretreated and serving as their own donor, or having a CB transplantation as the only therapeutic option. Importantly, the different cells required to ensure a rapid, as well as a permanent, hematopoietic recovery in these patients remain poorly defined. We now show that human CB and mobilized peripheral blood (mPB) collections contain cells that produce platelets and neutrophils within 3 weeks after being transplanted into sublethally irradiated NOD/scid-IL-2Rγc-null mice. The cells responsible for these 2 outputs are similarly distributed between the aldehyde dehydrogenase-positive and -negative subsets of lineage marker-negative CB and mPB cells, but their overall frequencies vary independently in individual samples. In addition, their total numbers can be seen to be much (> 30-fold) lower in a single "average" CB transplantation compared with a single "average" mPB transplantation (normalized for a similar weight of the recipient), consistent with the published differential performance in adult patients of these 2 transplantation products. Experimental testing confirmed the clinical relevance of the surrogate xenotransplantation assay for quantifying cells with rapid platelet regenerative activity, underscoring its potential for future applications.

Expression of integrin α2 receptor in human cord blood CD34+CD38-CD90+ stem cells engrafting long-term in NOD/SCID-IL2Rγ(c) null mice.

Human hematopoietic stem cells reside in the CD34+CD38-CD90+ population in cord blood and bone marrow. However, this cell fraction is heterogeneous, and the phenotype of the rare primitive stem cells remains poorly defined. We here report that primitive cord blood CD34+CD38-CD90+ stem cells, with the ability to reconstitute NOD/SCID-IL2Rγ(c) null (NSG) mice long-term, at 24 weeks after transplantation, can be prospectively isolated at an increased purity by using integrin α2 receptor as an additional stem cell marker. Using a limiting dilution transplantation assay, we found a highly significant enrichment of multilineage reconstituting stem cells in the CD34+CD38-CD90+ cell fraction expressing the integrin α2 receptor, with a frequency of 1/29 cells, as compared to a frequency of 1/157 in the corresponding integrin α2- cells. In line with this, long-term reconstituting stem cells within the cord blood CD34+CD38- cell population were significantly enriched in the integrin α2+ fraction, while stem cells and progenitors reconstituting short-term, at 8-12 weeks, were heterogeneous in integrin α2 expression. Global gene expression profiling revealed that the lineage-marker negative (Lin-) CD34+CD38-CD90+CD45RA- integrin α2+ cell population was molecularly distinct from the integrin α2- cell population and the more mature Lin-CD34+CD38-CD90-CD45RA- cell population. Our findings identify integrin α2 as a novel stem cell marker, which improves prospective isolation of the primitive human hematopoietic stem cells within the CD34+CD38-CD90+ cell population for experimental and therapeutic stem cell applications.

Oral ciclopirox olamine displays biological activity in a phase I study in patients with advanced hematologic malignancies.

The antimycotic ciclopirox olamine is an intracellular iron chelator that has anticancer activity in vitro and in vivo. We developed an oral formulation of ciclopirox olamine and conducted the first-in-human phase I study of this drug in patients with relapsed or refractory hematologic malignancies (Trial registration ID: NCT00990587). Patients were treated with 5-80 mg/m² oral ciclopirox olamine once daily for five days in 21-day treatment cycles. Pharmacokinetic and pharmacodynamic companion studies were performed in a subset of patients. Following definition of the half-life of ciclopirox olamine, an additional cohort was enrolled and treated with 80 mg/m² ciclopirox olamine four times daily. Adverse events and clinical response were monitored throughout the trial. Twenty-three patients received study treatment. Ciclopirox was rapidly absorbed and cleared with a short half-life. Plasma concentrations of an inactive ciclopirox glucuronide metabolite were greater than those of ciclopirox. Repression of survivin expression was observed in peripheral blood cells isolated from patients treated once daily with ciclopirox olamine at doses greater than 10 mg/m², demonstrating biological activity of the drug. Dose-limiting gastrointestinal toxicities were observed in patients receiving 80 mg/m² four times daily, and no dose limiting toxicity was observed at 40 mg/m² once daily. Hematologic improvement was observed in two patients. Once-daily dosing of oral ciclopirox olamine was well tolerated in patients with relapsed or refractory hematologic malignancies, and further optimization of dosing regimens is warranted in this patient population.

Barnacle: detecting and characterizing tandem duplications and fusions in transcriptome assemblies.

BACKGROUND: Chimeric transcripts, including partial and internal tandem duplications (PTDs, ITDs) and gene fusions, are important in the detection, prognosis, and treatment of human cancers. RESULTS: We describe Barnacle, a production-grade analysis tool that detects such chimeras in de novo assemblies of RNA-seq data, and supports prioritizing them for review and validation by reporting the relative coverage of co-occurring chimeric and wild-type transcripts. We demonstrate applications in large-scale disease studies, by identifying PTDs in MLL, ITDs in FLT3, and reciprocal fusions between PML and RARA, in two deeply sequenced acute myeloid leukemia (AML) RNA-seq datasets. CONCLUSIONS: Our analyses of real and simulated data sets show that, with appropriate filter settings, Barnacle makes highly specific predictions for three types of chimeric transcripts that are important in a range of cancers: PTDs, ITDs, and fusions. High specificity makes manual review and validation efficient, which is necessary in large-scale disease studies. Characterizing an extended range of chimera types will help generate insights into progression, treatment, and outcomes for complex diseases.

Allogeneic haematopoietic stem cell transplantation for chronic lymphocytic leukaemia: outcome in a 20-year cohort.

The curative potential of allogeneic haematopoietic stem cell transplant (allo HSCT) in chronic lymphocytic leukaemia CLL is established, with a demonstrated role for graft-versus-leukaemia and less certainty for other factors in determining outcome. The first two decades of CLL patients proceeding to allo HSCT at the Leukaemia/Bone Marrow Transplant Program of British Columbia (n = 49 consecutive, 1991-2009) were studied to clarify factors predicting outcome. The donor was related in 29 (59%) and unrelated in 20 (41%). Conditioning was reduced-intensity in 27 (55%) and myeloablative in 22 (45%). Thirty-one of 49 patients survive with median follow-up of 5 years (0·2-15). Cumulative incidence of non-relapse mortality; complete remission (CR); clearance of fluorescence in situ hybridization (FISH) abnormality and progression at 10 years was 36%; 69%; 55% and 22%. Overall survival (OS) was 63% at 2 years; 55% at 5 years and beyond. Factors predicting OS (P value by log rank <0·05) were: comorbidity index <3, FISH rank (Dohner) and 17p deletion, alemtuzumab pre-HSCT, achievement of CR post-HSCT, donor chimerism >90%, clearance of FISH abnormality post-HSCT and absence of high-grade (3-4) graft-versus-host disease. Results from this province-wide, two-decade cohort demonstrated that a substantial proportion of patients with high-risk CLL become long term disease-free survivors.

Photodepletion differentially affects CD4+ Tregs versus CD4+ effector T cells from patients with chronic graft-versus-host disease.

Even the most potent immunosuppressive drugs often fail to control graft-versus-host disease (GVHD), the most frequent and deleterious posttransplantation complication. We previously reported that photodepletion using dibromorhodamine (TH9402) eliminates T cells from healthy donors activated against major histocompatibility complex-incompatible cells and spares resting T cells. In the present study, we identified photodepletion conditions selectively eradicating endogenous proliferating T cells from chronic GVHD patients, with the concomittant sparing and expansion of CD4(+)CD25(+) forkhead box protein 3-positive T cells. The regulatory T-cell (Treg) nature and function of these photodepletion-resistant cells was demonstrated in coculture and depletion/repletion experiments. The mechanism by which Tregs escape photodepletion involves active P-glycoprotein-mediated drug efflux. This Treg-inhibitory activity is attributable to interleukin-10 secretion, requires cell-cell contact, and implies binding with cytotoxic T-lymphocyte antigen 4 (CTLA-4). Preventing CTLA-4 ligation abrogated the in vitro generation of Tregs, thus identifying CTLA-4-mediated cell-cell contact as a crucial priming event for Treg function. Moreover, the frequency of circulating Tregs increased in chronic GVHD patients treated with TH9402 photodepleted cells. In conclusion, these results identify a novel approach to both preserve and expand Tregs while selectively eliminating CD4(+) effector T cells. They also uncover effector pathways that could be used advantageously for the treatment of patients with refractory GVHD.

Constitutional hypomorphic telomerase mutations in patients with acute myeloid leukemia.

Loss-of-function mutations in telomerase complex genes can cause bone marrow failure, dyskeratosis congenita, and acquired aplastic anemia, both diseases that predispose to acute myeloid leukemia. Loss of telomerase function produces short telomeres, potentially resulting in chromosome recombination, end-to-end fusion, and recognition as damaged DNA. We investigated whether mutations in telomerase genes also occur in acute myeloid leukemia. We screened bone marrow samples from 133 consecutive patients with acute myeloid leukemia and 198 controls for variations in TERT and TERC genes. An additional 89 patients from a second cohort, selected based on cytogenetic status, and 528 controls were further examined for mutations. A third cohort of 372 patients and 384 controls were specifically tested for one TERT gene variant. In the first cohort, 11 patients carried missense TERT gene variants that were not present in controls (P < 0.0001); in the second cohort, TERT mutations were associated with trisomy 8 and inversion 16. Mutation germ-line origin was demonstrated in 5 patients from whom other tissues were available. Analysis of all 3 cohorts (n = 594) for the most common gene variant (A1062T) indicated a prevalence 3 times higher in patients than in controls (n = 1,110; P = 0.0009). Introduction of TERT mutants into telomerase-deficient cells resulted in loss of enzymatic activity by haploinsufficiency. Inherited mutations in TERT that reduce telomerase activity are risk factors for acute myeloid leukemia. We propose that short and dysfunctional telomeres limit normal stem cell proliferation and predispose for leukemia by selection of stem cells with defective DNA damage responses that are prone to genome instability.

Adult dual umbilical cord blood transplantation using myeloablative total body irradiation (1350 cGy) and fludarabine conditioning.

High treatment-related mortality (TRM) and high graft failure rate are serious concerns in HLA-mismatched umbilical cord blood (UCB) transplantation with myeloablative conditioning. We conducted a prospective trial of dual UCB transplantation using modified myeloablation consisting of total-body irradiation (TBI; 1350 cGy) and fludarabine (Flu) (160 mg/m(2)). Twenty-seven patients (median age, 33 years; range: 20-58 years) with hematologic malignancies were enrolled. The median combined cryopreserved total nucleated cell (TNC) dose was 4.3 × 10(7)/kg (range: 3.2-7.7 × 10(7)/kg). The cumulative incidences of neutrophil (≥500/µL) and platelet (≥50,000/µL) engraftment were 80% (95% confidence interval [CI], 58%-91%) and 68% (95% CI, 46%-83%), respectively. Among engrafted patients, a single cord blood unit was predominant by 100 days posttransplantation. A higher cryopreserved and infused TNC dose and infused CD3(+) cell dose were significant factors associated with the predominant UCB unit (P = .032, .020, and .042, respectively). TRM and relapse rates at 2 years were 28% (95% CI, 12%-47%) and 20% (95% CI, 7%-37%), respectively. Cumulative incidences of grades II-IV and grades III-IV acute graft-versus-host disease (aGVHD) were 37% (95% CI, 20%-55%) and 11% (95% CI, 3%-26%), respectively, and that of chronic GVHD was 31% (95% CI, 15%-49%). With a median follow-up of 23 months, overall survival and disease-free survival rates at 2 years were 58% (95% CI, 34%-75%) and 52% (95% CI, 29%-70%), respectively. This study supports the use of TBI 1350 cGy/Flu as an alternative to conventional myeloablative conditioning for dual UCB transplantation.

Cryopreserved mobilized autologous blood progenitors stored for more than 2 years successfully support blood count recovery after high-dose chemotherapy.

BACKGROUND AIMS: The ability of hematopoietic progenitor cells-apheresis (HPC-A) that have been stored for many years after cryopreservation to reconstitute hematopoiesis following high-dose chemo/radiotherapy has not been well-documented. METHODS: In this retrospective study, eight Canadian centers contributed data from 53 autologous stem cell transplants (ASCT) performed using HPC-A that had undergone long-term storage (>2 years, range 2-7 years) and 120 ASCT using HPC-A stored for <6 months (short-term storage). RESULTS: The doses of nucleated and CD34(+) cells per kilogram recipient weight were similar between the short- (mean ± SD, 4.7 ± 4.9 × 10(8) and 6.8 ± 4.3 × 10(6), respectively) and long- (4.0 ± 4.9 × 10(8) and 6.1 ± 3.4 × 10(6), respectively) term storage groups. The median days to neutrophils (absolute neutrophil count; ANC) >0.5 × 10(9)/L (median 11 days for both short- and long-term storage) and platelets >20 × 10(9)/L (median 12 and 11 for short- and long-term storage, respectively) post-ASCT were not significantly different between the two groups. When ASCT performed with <5 × 10(6)/kg CD34(+) cells was compared there was also no difference in ANC or platelet recovery (median 12 days for both after short-term storage, and 12 and 11 days, respectively, after long-term storage). Fourteen HPC-A products stored for >5 years also showed similar count recoveries as the entire long-term storage group (median 11 days for both ANC and platelets). CONCLUSIONS: Cryopreserved HPC-A can be stored for at least 5 years with no apparent loss in their ability to support hematopoietic reconstitution after high-dose chemotherapy.