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The study of long noncoding RNAs (lncRNAs) is an emerging area of cancer research, in part due to their ability to serve as disease biomarkers. However, few studies have investigated lncRNAs in chronic lymphocytic leukemia (CLL). We have identified one particular lncRNA, treRNA, which is overexpressed in CLL B-cells. We measured transcript expression in 144 CLL patient samples and separated samples into high or low expression of treRNA relative to the overall median. We found that high expression of treRNA is significantly associated with shorter time to treatment. High treRNA also correlates with poor prognostic indicators such as unmutated IGHV and high ZAP70 protein expression. We validated these initial findings in samples collected in a clinical trial comparing the nucleoside analog fludarabine alone or in combination with the alkylating agent cyclophosphamide in untreated CLL samples collected prior to starting therapy (E2997). High expression of treRNA was independently prognostic for shorter progression free survival in patients receiving fludarabine plus cyclophosphamide. Given these results, in order to study the role of treRNA in DNA damage response we generated a model cell line system where treRNA was over-expressed in the human B-CLL cell line OSU-CLL. Relative to the vector control line, there was less cell death in OSU-CLL over-expressing treRNA after exposure to fludarabine and mafosfamide, due in part to a reduction in DNA damage. Therefore, we suggest that treRNA is a novel biomarker in CLL associated with aggressive disease and poor response to chemotherapy through enhanced protection against cytotoxic mediated DNA damage.

Early phase studies of alvocidib showed activity in relapsed CLL including patients with high risk genomic features and those refractory to fludarabine. A multi-center, international, phase II study of alvocidib in fludarabine refractory CLL was undertaken to validate these early results. Patients with fludarabine refractory CLL or prolymphocytic leukemia arising from CLL were treated with single agent alvocidib. The primary outcome measure was overall response rate, with secondary outcomes including survival, toxicity, and response duration. One hundred and sixty five patients were enrolled and 159 patients were treated. The median age was 61 years, the median number of prior therapies was 4, and 96% of patients were fludarabine refractory. The investigator-assessed overall response rate was 25%; the majority of responses were partial. Response rates were lower among patients with del(17p) (14%), but equivalent in patients with del(11q) or bulky lymphadenopathy. Median progression free and overall survival were 7.6 and 14.6 months, respectively. Tumor lysis occurred in 39 patients (25%), and 13 received hemodialysis. Diarrhea, fatigue, and hematologic toxicities were common. Alvocidib has clinical activity in patients with advanced, fludarabine refractory CLL. Future studies should focus on discovery of biomarkers of clinical response and tumor lysis, and enhanced supportive care measures.

Fludarabine (F) and cyclophosphamide (C) remain backbones of up-front chemotherapy regimens for chronic lymphocytic leukemia (CLL). We report long-term follow-up of a randomized F vs. FC trial in untreated CLL#. With median follow-up of 88 months, estimated median progression-free survival (PFS) was 19.3 vs. 48.1 months for F (n= 109) and FC (n= 118), respectively (p< 0.0001), and median overall survival (OS) was 88.0 vs. 79.1 months (p= 0.96). In multivariable analyses, variables associated with inferior PFS and OS respectively were age (p= 0.002,p< 0.001), Rai stage (p= 0.006,p= 0.02) and sex (p = 0.03, PFS only). Del(17)(p13.1) predicted shorter PFS and OS (p < 0.0001 for each), as did del(11q)(22.3) (p< 0.0001,p= 0.005, respectively), trisomy 12 with mutatedNotch1(p= 0.003,p= 0.03, respectively) and unmutatedIGHV(p= 0.009,p= 0.002, respectively), all relative to patients without these features. These data confirm results from shorter follow-up and further justify targeted therapies for CLL. [ABSTRACT FROM AUTHOR]

Hairy cell leukemia (HCL) was once considered an untreatable form of chronic lymphoid malignancy. Based upon the recognition of the importance of adenosine deaminase to the normal B cell survival and proliferation, a hypothesis was developed that temporary inhibition of this enzyme might be therapeutically successful in treating chronic B cell leukemias. Pentostatin was initially explored in patients with refractory chronic lymphocytic leukemia (CLL). Both pentostatin and cladribine, purine nucleoside analogs, have been utilized to successfully treat HCL. The high degree of complete and durable remission observed with either agent resulted in many believing that the treatment of this rare disease had been fully optimized. However, a considerable number of patients will relapse. While tremendous progress has been made in initial management, the issues related to optimal therapy, timing of initiation of treatment, and discovery of novel agents that may be effective in those who have relapsed are important. Investigational agents currently being explored in chronic lymphocytic leukemia may also have benefit for those patients who have relapsed or are resistant to therapy of hairy cell leukemia. Many important questions remain (e.g. importance of minimal residual disease) and will require international collaboration to fully address these unanswered questions. The Hairy Cell Leukemia Consortium was established to address these unanswered questions. [ABSTRACT FROM AUTHOR]

Background: Flavopiridol is a cyclin-dependent kinase inhibitor in phase II clinical development for treatment of various forms of cancer. When administered with a pharmacokinetically (PK)-directed dosing schedule, flavopiridol exhibited striking activity in patients with refractory chronic lymphocytic leukemia. This study aimed to evaluate pharmacogenetic factors associated with inter-individual variability in pharmacokinetics and outcomes associated with flavopiridol therapy. Methodology/Principal Findings: Thirty-five patients who received single-agent flavopiridol via the PK-directed schedule were genotyped for 189 polymorphisms in genes encoding 56 drug metabolizing enzymes and transporters. Genotypes were evaluated in univariate and multivariate analyses as covariates in a population PK model. Transport of flavopiridol and its glucuronide metabolite was evaluated in uptake assays in HEK-293 and MDCK-II cells transiently transfected with SLCO1B1. Polymorphisms in ABCC2, ABCG2, UGT1A1, UGT1A9, and SLCO1B1 were found to significantly correlate with flavopiridol PK in univariate analysis. Transport assay results indicated both flavopiridol and flavopiridol-glucuronide are substrates of the SLCO1B1/OATP1B1 transporter. Covariates incorporated into the final population PK model included bilirubin, SLCO1B1 rs11045819 and ABCC2 rs8187710. Associations were also observed between genotype and response. To validate these findings, a second set of data with 51 patients was evaluated, and overall trends for associations between PK and PGx were found to be consistent. Conclusions/Significance: Polymorphisms in transport genes were found to be associated with flavopiridol disposition and outcomes. Observed clinical associations with SLCO1B1 were functionally validated indicating for the first time its relevance as a transporter of flavopiridol and its glucuronide metabolite. A second 51-patient dataset indicated similar trends between genotype in the SLCO1B1 and other candidate genes, thus providing support for these findings. Further study in larger patient populations will be necessary to fully characterize and validate the clinical impact of polymorphisms in SLCO1B1 and other transporter and metabolizing enzyme genes on outcomes from flavopiridol therapy. [ABSTRACT FROM AUTHOR]

Targeting aberrant DNA hypermethylation in chronic lymphocytic leukaemia (CLL) and non-Hodgkin lymphoma (NHL) with decitabine may reverse epigenetic silencing in B-cell malignancies. Twenty patients were enrolled in two phase I trials to determine the minimum effective pharmacological dose of decitabine in patients with relapsed/refractory CLL ( n = 16) and NHL ( n = 4). Patients received 1–3 cycles of decitabine. Dose-limiting toxicity (DLT) was observed in 2 of 4 CLL and 2 of 2 NHL patients receiving decitabine at 15 mg/m2 per d days 1–10, consisting of grade 3–4 thrombocytopenia and hyperbilirubinaemia. Six patients with CLL received decitabine at 10 mg/m2 per d days 1–10 without DLT; however, re-expression of methylated genes or changes in global DNA methylation were not observed. Therefore, a 5-day decitabine schedule was examined. With 15 mg/m2 per d decitabine days 1–5, DLT occurred in 2 of 6 CLL and 2 of 2 NHL patients, consisting of grade 3–4 neutropenia, thrombocytopenia, and febrile neutropenia. Eight patients had stable disease. In 17 patients, there were no significant changes in genome-wide methylation or in target gene re-expression. In conclusion, dose-limiting myelosuppression and infectious complications prevented dose escalation of decitabine to levels associated with changes in global methylation or gene re-expression in CLL and NHL. [ABSTRACT FROM AUTHOR]

Background: While deacetylase (DAC) inhibitors show promise for the treatment of B-cell malignancies, those introduced to date are weak inhibitors of class I and II DACs or potent inhibitors of class I DAC only, and have shown suboptimal activity or unacceptable toxicities. We therefore investigated the novel DAC inhibitor AR-42 to determine its efficacy in B-cell malignancies. Principal Findings: In mantle cell lymphoma (JeKo-1), Burkitt's lymphoma (Raji), and acute lymphoblastic leukemia (697) cell lines, the 48-hr IC50 (50% growth inhibitory concentration) of AR-42 is 0.61 μM or less. In chronic lymphocytic leukemia (CLL) patient cells, the 48-hr LC50 (concentration lethal to 50%) of AR-42 is 0.76 μM. AR-42 produces dose- and time-dependent acetylation both of histones and tubulin, and induces caspase-dependent apoptosis that is not reduced in the presence of stromal cells. AR-42 also sensitizes CLL cells to TNF-Related Apoptosis Inducing Ligand (TRAIL), potentially through reduction of c-FLIP. AR-42 significantly reduced leukocyte counts and/or prolonged survival in three separate mouse models of B-cell malignancy without evidence of toxicity. Conclusions/Significance: Together, these data demonstrate that AR-42 has in vitro and in vivo efficacy at tolerable doses. These results strongly support upcoming phase I testing of AR-42 in B-cell malignancies. [ABSTRACT FROM AUTHOR]

The article presents a study which evaluates the use of the combination of pentostatin (P), cyclophosphamide (C), and rituximab (R) in the treatment patients with untreated B-cell chronic lymphocyte leukemia (CCL). The study involves conducting a P and R phase 2 trial without C, using a higher dosage of P on 33 patients. The results reveal that the overall response rate was 76%, which determine that increasing P dosage does not eliminate the need of C in the CCL chemoimmunotherapy.

Apolizumab (Hu1D10), a humanized monoclonal anti- Human leukocyte antigen -DR β-chain antibody, mediates apoptosis of chronic lymphocytic leukemia (CLL) cells in vitro. We conducted a phase I/II dose-escalation study of thrice-weekly apolizumab (1.5, 3.0, 5.0 mg/kg/dose) for 4 weeks in relapsed CLL. Two of six patients at 5.0 mg/kg/dose developed treatment-related dose-limiting toxicity (aseptic meningitis, hemolytic uremia). Other toxicities included infusion toxicity, urticaria, and headache. Eleven patients were enrolled in a phase I/II expansion to evaluate the maximum tolerated dose (MTD) of 3.0 mg/kg/dose. In total, 23 patients were enrolled (22 CLL, 1 ALL). Nineteen patients with CLL were treated at or above the MTD. One partial response was observed, and three patients had stable disease exceeding 6 months. Pharmacokinetic analysis demonstrated a dose-dependent Cmax increase and serum antibody accumulation after week 1 of therapy. Given the toxicity and lack of efficacy in this and other trials in lymphoma and solid tumors, further development of apolizumab was discontinued. [ABSTRACT FROM AUTHOR]

Serum levels of pro-[vascular endothelial growth factor (VEGF)] and anti-[thrombospondin-1 (TSP)] angiogenic cytokines were prospectively measured in a phase II trial of chemoimmunotherapy (CIT) for chronic lymphocytic leukaemia (CLL) patients ( n = 56). Pretreatment VEGF levels were lower among patients who achieved complete remission (CR) or nodular partial remission (nPR) relative to those with partial remission (PR) or stable/progressive disease (median 122·0 pg/ml vs. 246·8 pg/ml; P = 0·03). VEGF:TSP ratio was lower (anti-angiogenic phenotype) among patients who achieved CR/nPR. The pretreatment VEGF:TSP ratio also correlated with overall survival ( P = 0·008). A pro-angiogenic profile appears associated with diminished response and inferior survival in CLL patients receiving CIT. [ABSTRACT FROM AUTHOR]

Treatment options for chronic lymphocytic leukaemia (CLL) are limited and eventually fail because of the development of toxicities or drug resistance. Thus, identification of new therapeutic strategies and targets is a high priority. The semisynthetic geldanamycin derivative 17-allylamino-17-demethoxygeldanamycin (17-AAG) inhibits heat shock protein 90 (Hsp90) binding to client proteins, thereby leading to their degradation. We demonstrate that at biologically active and clinically attainable levels (1 μmol/l), 17-AAG treatment of CLL B cells in vitro causes modest apoptosis as well as decreased AKT protein levels. Given the potential activation of AKT following antibody therapy in CLL, we evaluated the combination of 17-AAG and rituximab. These agents produced synergistic cytotoxicity of CLL cells in vitro. However, rituximab-mediated antibody-dependent cellular cytotoxicity was modestly reduced with 17-AAG, and complement-dependent cytotoxicity was not altered. We conclude that the combination of Hsp90 inhibitors with therapeutic antibodies, such as rituximab may represent a novel strategy to enhance therapeutic response in CLL. Furthermore, our data indicates that AKT and Hsp70 protein levels are relevant pharmacodynamic endpoints to monitor the in vivo effect of 17-AAG therapy. [ABSTRACT FROM AUTHOR]

Chronic lymphocytic leukemia (CLL) is a common leukemia with a highly variable natural history. A subset of patients with high-risk CLL rapidly progress to develop symptomatic disease requiring treatment. Over-represented in this group are those who have a deletion of 17p13.1, the chromosomal location of the tumor suppressor gene P53. Of all prognostic factors examined in CLL, del(17p13.1) has a superior predictive value for poor response to conventional therapy. In this article we review the current published data on prognostic factors relevant to treatment in CLL. We next provide therapeutic recommendations for patients with del(17p13.1) that are available to oncologists in general practice. Chemoimmunotherapy, alemtuzumab, or high-dose corticosteroids are all effective as initial therapy for these patients, but progression is generally rapid. If allogeneic immune therapy is to be considered, it should be approached as part of initial or first salvage therapy. The investigational agent flavopiridol has also demonstrated clinical activity in this subset of patients. Identification of small molecules and new treatment approaches for patients with del(17p13.1) is a major focus of several investigators. Selection of therapy based on high-risk genomic features represents an appropriate treatment approach supported by currently available published data. [Copyright &y& Elsevier]

The article discusses a study on the safety and efficacy of pentostatin, cyclophosphamide and rituximab (PCR) as first-line treatment for patients with chronic lymphocytic leukemia. The study also examined how age, creatinine clearance (CrCl), Β-2 microglobulin (B2M), and performance status (PS) relate to the efficacy and tolerability of this pentostatin-based chemoimmunotherapy regimen.

In an attempt to exploit bcl-2 overexpression and aberrant p53 function, two frequently encountered aberrations that predict marked treatment resistance and worse prognosis in patients with chronic lymphocytic leukemia (CLL) and non-Hodgkin’s lymphoma (NHL), we combined theophylline, pentostatin, and chlorambucil at two dose levels (cohort I: 30 mg/m2; cohort II: 20 mg/m2) on a 21-day cycle for up to six courses. We employed a phase I/II design to determine feasibility, define the maximum tolerated dose (MTD), and explore the impact of biologic modulation on response and time to progression (TTP) in 20 patients with relapsed or refractory CLL and NHL. Eight patients were enrolled in cohort I. They demonstrated a response rate (RR) of 28% and a 16.5-month TTP after receiving a median of two cycles. A 50% RR was observed in this cohort when patients with adverse histologies were excluded. Because of myelotoxicity, this dose level defined the MTD, and de-escalation occurred. All 12 patients in cohort II received 20 mg/m2 chlorambucil. A 50% RR and an 18-month TTP were observed after a median of 5.5 cycles. An RR of 47% and a complete remission (CR) of 5% were observed for the entire group, although responses and TTP varied greatly by histology. Significant activity was observed in patients with B-cell CLL and follicular lymphoma (FL). RR and TTP for fludarabine-sensitive/naïve and fludarabine-refractory (FR) B-cell CLL patients were 66 vs 25% and 20 vs 8.5 months, respectively. Both FL patients responded (one with partial remission and one with CR), with a 22.5-monthly median TTP. For responding patients, median TTP and overall survival (OS) was 21 and 69 months, respectively, compared to a median TTP of 2 months and an OS of 13.5 months for nonresponders. The combination of pentostatin, chlorambucil, and theophylline is the active regimen in patients with FL and B-cell CLL. [ABSTRACT FROM AUTHOR]

Investigates the induction of apoptosis in human B-cell chronic lymphocytic leukemia (CLL) cells by carboxyamido-triazole (CAI), a novel 'static' signal transduction inhibitor. Patient characteristics; Role of tumor reduction and disease stabilization in CLL; Detection of apoptosis in CLL cells.

Abstract: Alvocidib has demonstrated efficacy in high-risk chronic lymphocytic leukemia (CLL) patients. In this phase I study, we combined cyclophosphamide, alvocidib and rituximab (CAR) in a schema designed to mitigate tumor lysis syndrome (TLS) seen previously with alvocidib. Nine nucleoside analog-naïve, high-risk patients received escalating doses of CAR therapy. Dose limiting toxicity was not experienced. No instances of TLS were observed. Patient responses included three complete remissions and four partial remissions. CAR was tolerable and active in high-risk CLL patients without TLS toxicity. With continued monitoring of toxicities, a phase Ib/II study of this combination as frontline therapy is warranted. [Copyright &y& Elsevier]

Abstract: Flavopiridol has shown promising activities in hematologic and solid tumor models, as well as in clinical trials in chronic lymphocytic leukemia patients. Flavopiridol has relatively low solubility and high plasma protein-binding. To address these issues and to provide an alternative strategy to achieve clinical efficacy, we encapsulated flavopiridol into a liposomal carrier and characterized its physicochemical and pharmacokinetic properties. The liposomes, comprising hydrogenated soy phosphatidylcholine (HSPC), cholesterol and poly (ethylene glycol) 2000-distearoyl phosphatidylethanolamine (PEG-DSPE), were prepared by polycarbonate membrane extrusion and then loaded with flavopiridol by a pH-gradient driven remote loading procedure. The liposomes had a mean diameter of 120.7nm and a flavopiridol entrapment efficiency of 70.4%. Pharmacokinetic study in mice after i.v. bolus injection showed that the liposomal flavopiridol had an increased elimination phase half-life (T 1/2β, 339.7min vs. 57.0min), decreased clearance (CL, 0.012L/min vs. 0.036L/min), and increased area under the plasma concentration–time curve (AUC, 10.8minμmol/L vs. 3.4minμmol/L) compared to the free drug. This indicates a significant and potentially beneficial change in flavopiridol pharmacokinetics for the liposomal formulation. Further preclinical studies are warranted to define the toxicity and therapeutic efficacy of this novel formulation. [Copyright &y& Elsevier]

Abstract: TCL-1 expression is variable in CLL, and no study has examined its association with treatment response. We measured TCL-1 protein in CLL cells from 51 patients who then received pentostatin, cyclophosphamide, and rituximab. TCL-1 expression did not correlate with any pre-treatment characteristics. Lower TCL-1 levels were associated with higher probability of attaining flow cytometry-negative status post-treatment (52% versus 17%, p =0.046). Trends toward improved complete remission rate (49% versus 19%, p =0.064) and progression-free survival (medians: 33 versus 20 months, p =0.199) were noted with lower TCL-1 expression. These data suggest TCL-1 expression may help predict treatment outcome in CLL patients following chemoimmunotherapy, and examination in larger studies is warranted. [Copyright &y& Elsevier]

Summary: The heritability of B cell chronic lymphocytic leukemia (CLL) is relatively high; however, no predisposing mutation has been convincingly identified. We show that loss or reduced expression of death-associated protein kinase 1 (DAPK1) underlies cases of heritable predisposition to CLL and the majority of sporadic CLL. Epigenetic silencing of DAPK1 by promoter methylation occurs in almost all sporadic CLL cases. Furthermore, we defined a disease haplotype, which segregates with the CLL phenotype in a large family. DAPK1 expression of the CLL allele is downregulated by 75% in germline cells due to increased HOXB7 binding. In the blood cells from affected family members, promoter methylation results in additional loss of DAPK1 expression. Thus, reduced expression of DAPK1 can result from germline predisposition, as well as epigenetic or somatic events causing or contributing to the CLL phenotype. [Copyright &y& Elsevier]

Abstract: Introduction:: Studies with flavopiridol have demonstrated that this agent has in vitro activity in chronic lymphocytic leukemia (CLL) and promotes apoptosis independent of p53 function or prior fludarabine exposure. Based upon this pre-clinical data, a phase I/II study of 24h flavopiridol was performed. Patients and methods:: Patients with previously treated CLL patients were enrolled on two sequentially performed cohorts of 13 patients. Patients in the first cohort received flavopiridol (80mg/m2 as a 24-h continuous infusion [24h CI]) every 2 weeks. Patients in the second cohort received flavopiridol (80mg/m2 as a 24h CI) for week 1 and then were dose escalated by 20mg/m2 every 2 weeks to a maximal dose of 140mg/m2 in the absence of symptoms. Patients received up to 12 doses of therapy. Results:: Thirteen patients with fludarabine-refractory or intolerant CLL enrolled in each cohort. Patients received a median of five treatments in each cohort with only two patients completing all 12 courses of therapy. There were no partial or complete responses noted. Toxicity was manageable in most patients and included anemia, thrombocytopenia, infections, diarrhea, and fatigue. Conclusions:: Flavopiridol as a 24-h continuous infusion has no clinical activity in relapsed, fludarabine-refractory CLL. [Copyright &y& Elsevier]

Chemotherapy-related myeloid neoplasia (t-MN) is a significant late toxicity concern after cancer therapy. In the randomized intergroup phase 3 E2997 trial, initial therapy of chronic lymphocytic leukemia with fludarabine plus cyclophosphamide (FC) compared with fludarabine alone yielded higher complete and overall response rates and longer progression-free, but not overall, survival. Here, we report t-MN incidence in 278 patients enrolled in E2997 with a median 6.4-year follow-up. Thirteen cases (4.7%) of t-MN occurred at a median of 5 years from initial therapy for chronic lymphocytic leukemia, 9 after FC and 4 after fludarabine alone. By cumulative incidence methodology, rates of t-MN at 7 years were 8.2% after FC and 4.6% after fludarabine alone (P = .09). Seven of the 9 cases of t-MN after FC occurred without additional therapy. Abnormalities involving chromosomes 5 or 7 were found in 10 cases, which suggests alkylator involvement. These data suggest that FC may induce more t-MN than fludarabine alone. [ABSTRACT FROM AUTHOR]