Lateral and vertical pressures in two different full-scale grain bins during loading Presiones laterales y verticales durante el llenado de diferentes silos para granos

Lateral and vertical floor pressures were measured in two different corrugated-walled steel grain bins using load cells mounted on the floor and walls of the bin. Bin one was 12.8 m in diameter and 17.1 m tall and bin two was 11.0 m in diameter and 14.0 m tall. Tests were conducted with corn. In the 12.8 m diameter bin the largest average lateral wall pressure was 28.2 kPa at a grain depth of 15.2 m, while in the 11.0 m diameter bin the largest average lateral pressure was 26.9 kPa at a grain depth of 11.9 m. Design standard EP433 produced only slightly more conservative lateral wall pressure values at larger grain heights than design standard DIN1055. In both the 12.8 m and 11.0 m diameter bins a significant decrease in vertical floor pressures was measured near the wall of the bins (> 0.85 r), while at the other load cell locations the vertical floor pressure values were very similar in magnitude. In design, both EP433 and DIN1055 underestimated the vertical floor pressures which were measured in these bins. Based on these results some thought should be given to designing metal bins for both 'initial' conditions in which grain slides along 'virgin' materials and have a high coefficient of friction, and for 'worn' conditions in which oils and waxes have been deposited on the bin walls and thus produce a low coefficient of friction.

A prospective multicenter study of paroxysmal nocturnal hemoglobinuria cells in patients with bone marrow failure

Background

Paroxysmal nocturnal hemoglobinuria (PNH), a rare clonal hematopoietic stem cell disorder, is characterized by chronic, uncontrolled complement activation leading to intravascular hemolysis and an inflammatory prothrombotic state. The EXPLORE study aimed to determine the prevalence of undiagnosed PNH in patients with aplastic anemia (AA), myelodysplastic syndrome (MDS), and/or other bone marrow failure (BMF) syndromes and the effect of PNH clone size on hemolysis.

Methods

Patients, selected from medical office chart reviews, had blood samples collected for hematologic panel testing and for flow cytometry detection of PNH clones.

Results

Granulocyte PNH clones ≥ 1% were detected in 199 of all 5,398 patients (3.7%), 93 of 503 AA patients (18.5%), 50 of 4,401 MDS patients (1.1%), and 3 of 130 other BMF patients (2.3%). Higher-sensitivity analyses detected PNH clones ≥ 0.01% in 167 of 1,746 patients from all groups (9.6%) and in 22 of 1,225 MDS patients (1.8%), 116 of 294 AA patients (39.5%), and four of 54 other BMF patients (7.8%). Among patients with PNH clones ≥ 1%, median clone size was smaller in patients with AA (5.1%) than in those with MDS (17.6%) or other BMF (24.4%), and the percentage of patients with lactate dehydrogenase levels (a marker for intravascular hemolysis) ≥ 1.5 × upper limit of normal was smaller in patients with AA (18.3%) than in those with MDS (42.0%).

Conclusions

These results confirm the presence of PNH clones in high-risk patient groups and suggest that screening of such patients may facilitate patient management and care.

A Prospective Multicenter Study of Paroxysmal Nocturnal Hemoglobinuria Cells in Patients with Bone Marrow Failure

Background: Paroxysmal nocturnal hemoglobinuria (PNH), a rare clonal hematopoietic stem cell disorder, is characterized by chronic, uncontrolled complement activation leading to intravascular hemolysis and an inflammatory prothrombotic state. The EXPLORE study aimed to determine the prevalence of undiagnosed PNH in patients with aplastic anemia (AA), myelodysplastic syndrome (MDS), and/or other bone marrow failure (BMF) syndromes and the effect of PNH clone size on hemolysis. Methods: Patients, selected from medical office chart reviews, had blood samples collected for hematologic panel testing and for flow cytometry detection of PNH clones. Results: Granulocyte PNH clones ≥ 1% were detected in 199 of all 5398 patients (3.7%), 93 of 503 AA patients (18.5%), 50 of 4401 MDS patients (1.1%), and 3 of 130 other BMF patients (2.3%). Higher-sensitivity analyses detected PNH clones ≥ 0.01% in 167 of 1746 patients from all groups (9.6%) and in 22 of 1225 MDS patients (1.8%), 116 of 294 AA patients (39.5%), and 4 of 54 other BMF patients (7.8%). Among patients with PNH clones ≥ 1%, median clone size was smaller in patients with AA (5.1%) than in those with MDS (17.6%) or other BMF (24.4%), and the percentage of patients with lactate dehydrogenase levels (a marker for intravascular hemolysis) ≥ 1.5 × upper limit of normal was smaller in patients with AA (18.3%) than in those with MDS (42.0%). Conclusions: These results confirm the presence of PNH clones in high-risk patient groups and suggest that screening of such patients may facilitate patient management and care. © 2013 Clinical Cytometry Society.

Abstract 2989: Loss of methylation in a regulatory region of BCL2 in MDS/AML

Background:

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematopoietic disorders characterized by ineffective hematopoiesis and increased risk of progression to acute myeloid leukemia (AML). A hallmark of MDS is increased apoptosis, while AML undergoes decreased apoptosis and increased proliferation. BCL2, an anti-apoptotic protein, is overexpressed in high grade MDS and AML and may confer poor prognosis and increased chemotherapy resistance. In this study we examined the DNA methylation status of BCL2 in MDS and AML.

Methods:

We conducted DNA methylation profiling on genomic DNA extracted from bone marrows of 22 refractory anemia with ringed sideroblasts (RARS), 8 refractory anemia with excess blasts (RAEB), 21 de novo AML, 21 therapy related AML, and 7 normal volunteers. We used both Illumina 27K BeadChip and 450K BeadChip methylation arrays to assess CpG methylation. Standard student T-test was used to screen differentially methylated MDS and AML CpG sites compared to normal samples. We validated the microarray data by combined bisulfite restriction analysis (COBRA) and bisulfite sequencing.

Results:

We identified a region in the BCL2 gene body that was among the most differentially methylated in MDS and AML versus normal bone marrow. Within that amplicon, BCL2 in both RARS, a low grade MDS, and RAEB, a high grade MDS, were hypermethylated compared to normal bone marrow (43% vs 18%, 48% vs 18%, respectively, p<0.05). BCL2 in de novo AML and therapy related AML were hypomethylated compared to normal bone marrow (12% vs 35%, 13% vs 35%, respectively, p<0.05). We validated these results by COBRA and bisulfite sequencing. This region coincided with H3K27ac and H3K4m1 enhancer type marks in ENCODE data in normal cells.

Conclusions:

Our study identifies a region of BCL2 that is hypermethylated in both low and high risk MDS while hypomethylated in AML compared to normal bone marrows. We hypothesize aberrant epigenetic modification of BCL2 plays a key role in apoptosis and transformation from MDS to AML, and our data support the idea of combining demethylating drugs with BCL2 antagonists. We are currently investigating whether BCL2 protein expression correlates with methylation, and plan to map the histone marks with CHIP-seq to correlate chromatin accessibility and DNA methylation in BCL2.

Citation Format: Sangmin Lee, Naomi Galili, Stephen Nimer, Mark D. Minden, Vundavalli V. Murty, Suresh Jhanwar, Azra Raza, Benjamin Tycko. Loss of methylation in a regulatory region of BCL2 in MDS/AML. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2989. doi:10.1158/1538-7445.AM2013-2989

The genetic basis of phenotypic heterogeneity in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are malignant clonal disorders of haematopoietic stem cells and their microenvironment, affecting older individuals (median age ∼70 years). Unique features that are associated with MDS - but which are not necessarily present in every patient with MDS - include excessive apoptosis in maturing clonal cells, a pro-inflammatory bone marrow microenvironment, specific chromosomal abnormalities, abnormal ribosomal protein biogenesis, the presence of uniparental disomy, and mutations affecting genes involved in proliferation, methylation and epigenetic modifications. Although emerging insights establish an association between molecular abnormalities and the phenotypic heterogeneity of MDS, their origin and progression remain enigmatic.

Validation of a prognostic model and the impact of mutations in patients with lower-risk myelodysplastic syndromes

PURPOSE

A subset of patients with myelodysplastic syndromes (MDS) who are predicted to have lower-risk disease as defined by the International Prognostic Scoring System (IPSS) demonstrate more aggressive disease and shorter overall survival than expected. The identification of patients with greater-than-predicted prognostic risk could influence the selection of therapy and improve the care of patients with lower-risk MDS.

PATIENTS AND METHODS

We performed an independent validation of the MD Anderson Lower-Risk Prognostic Scoring System (LR-PSS) in a cohort of 288 patients with low- or intermediate-1 IPSS risk MDS and examined bone marrow samples from these patients for mutations in 22 genes, including SF3B1, SRSF2, U2AF1, and DNMT3A.

RESULTS

The LR-PSS successfully stratified patients with lower-risk MDS into three risk categories with significant differences in overall survival (20% in category 1 with median of 5.19 years [95% CI, 3.01 to 10.34 years], 56% in category 2 with median of 2.65 years [95% CI, 2.18 to 3.30 years], and 25% in category 3 with median of 1.11 years [95% CI, 0.82 to 1.51 years]), thus validating this prognostic model. Mutations were identified in 71% of all samples, and mutations associated with a poor prognosis were enriched in the highest-risk LR-PSS category. Mutations of EZH2, RUNX1, TP53, and ASXL1 were associated with shorter overall survival independent of the LR-PSS. Only EZH2 mutations retained prognostic significance in a multivariable model that included LR-PSS and other mutations (hazard ratio, 2.90; 95% CI, 1.85 to 4.52).

CONCLUSION

Combining the LR-PSS and EZH2 mutation status identifies 29% of patients with lower-risk MDS with a worse-than-expected prognosis. These patients may benefit from earlier initiation of disease-modifying therapy.

Prediction of response to therapy with ezatiostat in lower risk myelodysplastic syndrome

Background

Approximately 70% of all patients with myelodysplastic syndrome (MDS) present with lower-risk disease. Some of these patients will initially respond to treatment with growth factors to improve anemia but will eventually cease to respond, while others will be resistant to growth factor therapy. Eventually, all lower-risk MDS patients require multiple transfusions and long-term therapy. While some patients may respond briefly to hypomethylating agents or lenalidomide, the majority will not, and new therapeutic options are needed for these lower-risk patients. Our previous clinical trials with ezatiostat (ezatiostat hydrochloride, Telentra®, TLK199), a glutathione S-transferase P1-1 inhibitor in clinical development for the treatment of low- to intermediate-risk MDS, have shown significant clinical activity, including multilineage responses as well as durable red-blood-cell transfusion independence. It would be of significant clinical benefit to be able to identify patients most likely to respond to ezatiostat before therapy is initiated. We have previously shown that by using gene expression profiling and grouping by response, it is possible to construct a predictive score that indicates the likelihood that patients without deletion 5q will respond to lenalidomide. The success of that study was based in part on the fact that the profile for response was linked to the biology of the disease.

Methods

RNA was available on 30 patients enrolled in the trial and analyzed for gene expression on the Illumina HT12v4 whole genome array according to the manufacturer’s protocol. Gene marker analysis was performed. The selection of genes associated with the responders (R) vs. non-responders (NR) phenotype was obtained using a normalized and rescaled mutual information score (NMI).

Conclusions

We have shown that an ezatiostat response profile contains two miRNAs that regulate expression of genes known to be implicated in MDS disease pathology. Remarkably, pathway analysis of the response profile revealed that the genes comprising the jun-N-terminal kinase/c-Jun molecular pathway, which is known to be activated by ezatiostat, are under-expressed in patients who respond and over-expressed in patients who were non-responders to the drug, suggesting that both the biology of the disease and the molecular mechanism of action of the drug are positively correlated.

Phase 1 dose-ranging study of ezatiostat hydrochloride in combination with lenalidomide in patients with non-deletion (5q) low to intermediate-1 risk myelodysplastic syndrome (MDS)

Background

Ezatiostat, a glutathione S-transferase P1-1 inhibitor, promotes the maturation of hematopoietic progenitors and induces apoptosis in cancer cells.

Results

Ezatiostat was administered to 19 patients with non-deletion(5q) myelodysplastic syndrome (MDS) at one of two doses (2000 mg or 2500 mg/day) in combination with 10 mg of lenalidomide on days 1–21 of a 28-day cycle. No unexpected toxicities occurred and the incidence and severity of adverse events (AEs) were consistent with that expected for each drug alone. The most common non-hematologic AEs related to ezatiostat in combination with lenalidomide were mostly grade 1 and 2 fatigue, anorexia, nausea, diarrhea, and vomiting; hematologic AEs due to lenalidomide were thrombocytopenia, neutropenia, and anemia. One of 4 evaluable patients (25%) in the 2500/10 mg dose group experienced an erythroid hematologic improvement (HI-E) response by 2006 MDS International Working Group (IWG) criteria. Four of 10 evaluable patients (40%) in the 2000 mg/10 mg dose group experienced an HI-E response. Three of 7 (43%) red blood cell (RBC) transfusion-dependent patients became RBC transfusion independent, including one patient for whom prior lenalidomide monotherapy was ineffective. Three of 5 (60%) thrombocytopenic patients had an HI-platelet (HI-P) response. Bilineage HI-E and HI-P responses occurred in 3 of 5 (60%), 1 of 3 with HI-E and HI-N (33%), and 1 of 3 with HI-N and HI-P (33%). One of 3 patients (33%) with pancytopenia experienced a complete trilineage response. All multilineage responses were observed in the 2000/10 mg doses recommended for future studies.

Conclusions

The tolerability and activity profile of ezatiostat co-administered with lenalidomide supports the further development of ezatiostat in combination with lenalidomide in MDS and also encourages studies of this combination in other hematologic malignancies where lenalidomide is active.

Trial registration

Clinicaltrials.gov: NCT01062152

Clinical effect of point mutations in myelodysplastic syndromes

BACKGROUND

Myelodysplastic syndromes are clinically heterogeneous disorders characterized by clonal hematopoiesis, impaired differentiation, peripheral-blood cytopenias, and a risk of progression to acute myeloid leukemia. Somatic mutations may influence the clinical phenotype but are not included in current prognostic scoring systems.

METHODS

We used a combination of genomic approaches, including next-generation sequencing and mass spectrometry-based genotyping, to identify mutations in samples of bone marrow aspirate from 439 patients with myelodysplastic syndromes. We then examined whether the mutation status for each gene was associated with clinical variables, including specific cytopenias, the proportion of blasts, and overall survival.

RESULTS

We identified somatic mutations in 18 genes, including two, ETV6 and GNAS, that have not been reported to be mutated in patients with myelodysplastic syndromes. A total of 51% of all patients had at least one point mutation, including 52% of the patients with normal cytogenetics. Mutations in RUNX1, TP53, and NRAS were most strongly associated with severe thrombocytopenia (P<0.001 for all comparisons) and an increased proportion of bone marrow blasts (P<0.006 for all comparisons). In a multivariable Cox regression model, the presence of mutations in five genes retained independent prognostic significance: TP53 (hazard ratio for death from any cause, 2.48; 95% confidence interval [CI], 1.60 to 3.84), EZH2 (hazard ratio, 2.13; 95% CI, 1.36 to 3.33), ETV6 (hazard ratio, 2.04; 95% CI, 1.08 to 3.86), RUNX1 (hazard ratio, 1.47; 95% CI, 1.01 to 2.15), and ASXL1 (hazard ratio, 1.38; 95% CI, 1.00 to 1.89).

CONCLUSIONS

Somatic point mutations are common in myelodysplastic syndromes and are associated with specific clinical features. Mutations in TP53, EZH2, ETV6, RUNX1, and ASXL1 are predictors of poor overall survival in patients with myelodysplastic syndromes, independently of established risk factors. (Funded by the National Institutes of Health and others.).

Cigarette smoking shortens the survival of patients with low-risk myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of hematological malignancies with poor survival. Although previous studies have identified the prognostic role of multiple demographic and clinical characteristics, the potential role of lifestyle factors has not been evaluated. In this study, we conducted an extensive assessment of the predictors of MDS survival, with a special focus on lifestyle factors. A total of 616 patients (median survival = 4.1 years) were included in the analysis, and multivariate Cox proportional hazard models were utilized to estimate hazard ratios. Compared with non-smokers, MDS patients who smoked at the initial clinical encounter had a significantly increased risk of death [hazard ratio (HR) = 1.46, 95% confidence intervals (CI): 1.07-2.00]. The elevated risk was restricted to men (HR = 1.76, 95% CI: 1.21-2.56) and not observed among women (HR = 0.98, 95% CI: 0.51-1.85). When patients were stratified by the IPSS categorization, a near three fold increased risk of death was associated with smoking among patients with low-risk MDS (HR = 2.83, 95% CI: 1.48-5.39), whereas smoking did not appear to influence the survival of patients with intermediate- or high-risk MDS. This study was the first to identify smoking as a significant and independent predictor of MDS survival, particularly among low-risk patients.

Pattern of hypomethylating agents use among elderly patients with myelodysplastic syndromes

Little is known about how hypomethylating agents (HMAs) have been adopted into the treatment of myelodysplastic syndromes (MDS). We conducted a population-based study to assess the use of HMAs among 4416 MDS patients (age≥66 years) who were diagnosed during 2001-2005 and followed up through the end of 2007. Multivariate logistic regression models were utilized to evaluate the role of various patient characteristics. 475 (10.8%) patients had received HMAs by 2007, with the proportion increasing over time. Patients who were white (odds ratio (OR)=0.66, 95% confidence interval (CI): 0.46-0.95), male (OR=1.47, 95% CI: 1.19-1.82), young (Ptrend<0.01), more recently diagnosed (OR=1.90, 95% CI: 1.54-2.34), had fewer comorbidities (Ptrend<0.01), or had a history of other cancer (OR=1.28, 95% CI: 1.00-1.63) were more likely to receive HMAs. Compared with patients with refractory anemia, those diagnosed with refractory anemia with excess blasts or refractory cytopenia with multilineage dysplasia had a higher chance to be treated with HMAs (OR=3.52 and 2.32, respectively). Relatively few MDS patients were treated with HMAs during the introduction period of these agents, and multiple patient characteristics such as sex, comorbidities, and MDS subtype influence the likelihood a patient receives HMAs.

Pharmacotherapy of myelodysplastic syndromes

IMPORTANCE OF THE FIELD

Despite the remarkable progress in the treatment of patients with myelodysplastic syndromes (MDS) in the past decade, response to the hypomethylating agents azacitidine and decitabine in non-del(5q) MDS patients remains at approximately 50%, leaving half of patients needing treatment with essentially no options. As biologic insight into the molecular pathways that account for disease evolution and clinical heterogeneity is expanded, the arsenal of potential drugs that may elicit significant response is also increasing. One of the greatest challenges for the treating physician is to decide when to initiate therapy and which therapy (approved drug or newer agents still in clinical trial) is likely to be the most beneficial. While there is no single answer to these issues, there are several approaches that may be considered, and these are addressed in this review.

AREAS COVERED IN THIS REVIEW

This review examines the clinical outcomes of the FDA-approved drugs as well as of the promising new therapies that are in current clinical trials.

WHAT THE READER WILL GAIN

The clinician now has multiple treatment options for patients with MDS. It is important to consider multiple factors before initiating therapy with disease-modifying drugs. This review presents some of the decision-making approaches that are in practice at present.

TAKE HOME MESSAGE

For the first time, various treatment options are available for patients with MDS. In light of the intense efforts now in progress, the next decade promises to be one of hope and excitement for both MDS patients and treating clinicians.

The biology of myelodysplastic syndromes: unity despite heterogeneity

Myelodysplastic syndromes (MDS) traditionally have been grouped together as a disease entity based on clinical phenomena seen in association. Despite the similarities, there is great heterogeneity among the syndromes. Recent insights have shown, however, that there exists a biologically cohesive theme that unifies and thereby validates the conceptual interconnectedness. The first suggestion that such a relationship existed where biology could directly explain the observed cytopenias was the finding of excessive premature apoptosis of hematopoietic cells in MDS marrows. This apoptosis was mediated by paracrine as well as autocrine factors implicating both the seed and the soil in the pathology of the disease. Pro-inflammatory cytokines in the marrow microenvironment were mainly the paracrine mediators of apoptosis, but how the clonal cells committed suicide because of autocrine stimulation had remained a mystery for more than a decade. It has been shown now that deregulation of ribosome biogenesis can initiate a stress response in the cell through the p53 signaling pathway. Congenital anemias had been associated with mutations in ribosomal protein genes. The surprise came with the investigation of 5q- syndrome patients where haplo-insufficiency of the ribosomal protein gene RPS14 was found to be the cause of this MDS subtype. Similar ribosomal deregulation was shown to be present in all varieties of MDS patients, serving as another unifying characteristic. In addition to these findings, there are other DNA-related abnormalities such as uniparental disomy, mutations in the TET2 gene, and epigenetic phenomena that are associated with and occur across all types of MDS. This paper summarizes the themes unifying this heterogeneous group of diseases.

Oral Ezatiostat HCl (TLK199) and Myelodysplastic syndrome: a case report of sustained hematologic response following an abbreviated exposure

Treatment options for patients with lower risk non-del(5q) myelodysplastic syndromes (MDS) who fail erythroid stimulating agents are restricted to one of the hypomethylating drugs with an expected response rate of ~50%. Ezatiostat HCl, an agent with the potential for producing multi-lineage responses in this population is currently in clinical investigation phase. This case report describes a 77 year old male who received less than two cycles of therapy with ezatiostat HCl which had to be aborted due to intolerable side effects, but which produced a sustained normalization of all three blood counts. This trilineage response has now lasted for more than a year. Interestingly, the patient began with a del(5q) abnormality and responded briefly to lenalidomide. Upon relapse of the anemia, a bone marrow showed the disappearance of the del(5q) but the appearance of a new clonal abnormality t(2;3). Given that the patient had a complete cytogenetic response to a truncated exposure to lenalidomide followed by a trilineage response to an even briefer course of ezatiostat HCl suggests a potential role for ezatiostat HCl in del(5q) patients who relapse following lenalidomide.

Trisomy 11 in myelodysplastic syndromes defines a unique group of disease with aggressive clinicopathologic features

Trisomy 11 in myelodysplastic syndromes (MDS) is rare, with undefined clinical significance and is currently assigned to the International Prognostic Scoring System (IPSS) intermediate-risk group. Over a 15-year period, we identified 17 MDS patients with trisomy 11 either as a sole abnormality (n=10) or associated with one or two additional alterations (n=7), comprising 0.3% of all MDS cases reviewed. Of 16 patients with Bone Marrow material available for review, 14 (88%) patients presented with excess blasts, 69% patients evolved to acute myeloid leukemia (AML) in a 5-month median interval and the median survival was 14 months. For comparison, we studied 19 AML patients with trisomy 11 in a noncomplex karyotype, of which, a substantial subset of patients had morphologic dysplasia, and/or preexisting cytopenia(s)/MDS. Genomic DNA PCR showed MLL partial tandem duplication in 5 of 10 MDS and 7 of 11 AML patients. A review of literature identified 17 additional cases of MDS with trisomy 11, showing similar clinicopathologic features to our patients. Compared with our historical data comprising 1165 MDS patients, MDS patients with trisomy 11 had a significantly inferior survival to patients in the IPSS intermediate-risk cytogenetic group (P=0.0002), but comparable to the poor-risk group (P=0.97). We conclude that trisomy 11 in MDS correlates with clinical aggressiveness, may suggest an early/evolving AML with myelodysplasia-related changes and is best considered a high-risk cytogenetic abnormality in MDS prognostication.

Complete remissions observed in acute myeloid leukemia following prolonged exposure to lintuzumab: a phase 1 trial

A multi-institutional, phase 1 dose-escalation trial of lintuzumab (humanized anti-CD33 antibody; SGN-33, HuM195) was performed in patients with CD33-positive myeloid malignancies. In this study, higher doses than previously tested and prolonged duration of treatment for responding patients were evaluated. Over the dose range of 1.5-8 mg/kg/week, lintuzumab was well tolerated, and a maximum tolerated dose was not defined. The most common adverse event was transient chills with the initial lintuzumab infusion (39%). Responses were observed in 7 of 17 patients with acute myeloid leukemia: morphologic complete remission (n = 4), partial remission (n = 2), and morphologic leukemia-free state (n = 1). Of 14 patients with myelodysplastic syndrome or myeloproliferative diseases, 1 patient had major hematologic improvement and 9 patients had stable disease. In contrast to aggressive conventional chemotherapy, lintuzumab was administered in an ambulatory clinic setting with acceptable toxicity.

Remicade as TNF Suppressor in Patients with Myelodysplastic Syndromes

Remicade, a chimeric human-murine monoclonal antibody capable of neutralizing tumor necrosis factor alpha was given to 37 low-risk myelodysplastic syndromes (MDS) patients in two cohorts; 5 and 10 mg/kg intravenously every 4 weeks for 4 cycles. Median age was 68 years, 33 had primary MDS, 14 had refractory anemia (RA), 14 RA with ringed sideroblasts, 9 RA with excess blasts. Nine patients stopped therapy prior to completing 4 cycles, 3 from cohort 1 and 6 from cohort 2 and response was evaluated using the International Working Group criteria in 28 patients who completed the 4 cycles. Six patients showed disease progression, 14 had stable disease and 8 showed hematologic responses, 3/15 (20%) in cohort 1 and 5/13 (38%) in cohort 2. Two patients had multi-lineage responses, 2 had > 100% increase in absolute neutrophils, 1 had > 1 gm/dl increase in hemoglobin, 1 had reduction in blasts from 7% to 1%, and 2 had minor cytogenetic responses (> 50% reduction in + 8 and 20q-metaphases respectively). We conclude that Remicade may have a variety of activities in low risk MDS patients, is well tolerated with a high patient compliance, and may be considered for combination therapy in the future.

Phase II study of topotecan and thalidomide in patients with high-risk myelodysplastic syndromes

This phase II trial investigated the safety and preliminary efficacy of a topotecan/thalidomide combination therapy in patients with myelodysplastic syndrome who had refractory anemia with excess blasts (RAEB), RAEB with transformation, or chronic myelomonocytic anemia. Patients received three 21-day cycles of topotecan 1.25 mg/m(2) on days 1-5, which was repeated for two additional cycles in patients whose bone marrow blast percentages did not decrease. Oral thalidomide was then started at 100 mg/day (with the dose escalated up to 300 mg/day if well tolerated) for up to 1 year. Patients were monitored throughout the trial for hematologic and clinical adverse events, and efficacy was assessed using International Working Group (IWG) criteria. Forty-five patients, mostly elderly (median age 68 years; range 52-79 years), were enrolled. Therapy was generally well tolerated compared to high-dose chemotherapy. Three patients died from disease progression/infections during topotecan therapy, and four patients discontinued topotecan because of high-grade neutropenia (two patients), syncope (one patient), or hip surgery (one patient). Of 24 patients who received thalidomide, three discontinued because of treatment-related toxicity. Thirty-eight patients were evaluable for response: nine (24%) had hematologic improvement and 13 (34%) had stable disease. Responses occurred in patients with all disease subtypes. Six patients achieved transfusion independence, and one patient had a trilineage response. Approximately one-third of the patients had decreases in bone marrow blasts of 50%. Therefore, a topotecan and thalidomide combination therapy is promising, although further studies are needed to determine the optimum doses and schedule.

A safety and schedule seeking trial of Bcl-2 inhibitor obatoclax in previously untreated older patients with acute myeloid leukemia (AML)

3579

Background: Obatoclax (Ob) is a small-molecule inhibitor of all Bcl-2 prosurvival proteins. In a previous study a 70 year old patient with untreated AML had a cytogenetic CR 8 days after receiving 20 mg/m2 of Ob over 24 hrs. This study evaluated the single-agent response rate in older patients with previously untreated AML. Methods: A Safety phase to evaluate escalating doses of Ob given by 3-hr infusion was performed. Based on previous results, the dose of 60 mg over 24 hrs was used for the 24-hr infusion arm of the Schedule Seeking phase, in which Ob was administered as either a 3-hr or 24-hr infusion for 3 consecutive days every 2 wks. The endpoint of the Schedule Seeking phase was CR after C2 in 16 randomized patients. Eligibility criteria included age ≥ 70, untreated AML (1 prior Rx allowed in Safety phase), ECOG PS ≤2, adequate renal and hepatic function. PK samples were collected during C1. Results: 18 patients (8 male; median age 82) were enrolled. 2/3 patients enrolled into the 1st cohort (30 mg x 3 days) of the Safety phase had DLT events (ataxia and somnolence). 3 patients enrolled into a 20 mg x 3 days cohort had no DLTs; this dose was used for Schedule Seeking patients receiving 3-hr infusions. In the Schedule Seeking phase, 7 patients were randomized to receive 20 mg by 3-hr infusion and 5 were randomized to receive 60 mg by 24-hr infusion. The most common (>25%) AEs were euphoric mood (50%), ataxia (38%), & somnolence (38%). Efficacy data after C2 show that 3 patients in the 20 mg 3-hr infusion cohort in the Safety phase and 1 at the same dose & schedule in the Schedule Seeking phase had ≥50% decrease in BM blasts after C2, which was not seen in the 60 mg 24-hr infusion cohort. There were no CRs. There was a single death by D28 (24-hr infusion). There were significant differences in PK by infusion schedule. Conclusions: MTD for Ob as a 3-hr infusion administered in older patients with AML on 3 consecutive days is 20 mg/day, and both this regimen and 60 mg as a 24-hr infusion x 3 days were well tolerated. Evidence of biological activity was seen with the 3-hr infusion schedule but not with the 24-hr infusion schedule, suggesting that efficacy may be improved with the 3-hr infusion schedule and may be related to PK differences.

[Table: see text]

Prevalence of paroxysmal nocturnal hemoglobinuria (PNH) cells in patients with myelodysplastic syndromes (MDS), aplastic anemia (AA), or other bone marrow failure (BMF) syndromes: Interim results from the EXPLORE trial

7082

Background: In patients with PNH, lack of the glycophosphatidylinositol (GPI)-anchored terminal complement inhibitor CD59 on hematopoietic stem cells results in chronic intravascular hemolysis, kidney and pulmonary disorders, thrombosis, and shortened life span. Presence of even minor populations of PNH cells in AA or MDS patients is medically important as it may indicate a higher likelihood of response to immunosuppressive therapy. We conducted the first large multicenter, point-prevalence study (EXamination of PNH, by Level Of CD59 on REd and white blood cells [EXPLORE]) of PNH cells in patients with AA, MDS, or other BMF syndromes. Here we report an interim analysis. Methods: A central laboratory conducted high-sensitivity flow cytometry utilizing a combination of GPI-linked antibodies (CD59, CD24, and CD14) and fluorescent aerolysin (FLAER) to identify GPI anchor-deficient PNH cells in RBC and WBC resulting in 0.01% sensitivity. The primary endpoint was percentage of patients who had a PNH WBC clone ≥1%. Results: Among 5,212 patients screened, 4,500 (86.3%) were MDS patients, 413 (7.9%) were AA patients, and 356 (6.8%) had other BMF syndromes. Approximately 1/4 (24.5%) of patients with AA, 1.2% with MDS, and 4.6% with other BMF were newly found to have a significant PNH clone ≥ 1%. Many of the newly identified clones were of clinical significance as the median PNH clone size was 11.1% in AA patients, 16.3% in MDS patients, and 32.6% in patients with other BMF. Presence of PNH cells (≥ 0.01%) was common in all examined BMF types: 70% of AA patients, 55% of MDS patients and 55% of patients with other BMF. PNH cells were identified in all MDS subtypes represented in the trial. Conclusions: Interim analysis from this first large multicenter study demonstrates that PNH cells are present in a majority of patients with AA, MDS, and other BMF. A spectrum of PNH clone sizes was noted in patients with each form of BMF. Screening patients with BMF with high-sensitivity flow cytometry for PNH cells may guide treatment options for the underlying BMF and/or PNH. The EXPLORE trial continues to enroll patients with AA. (EXPLORE Clinical Study Abstract 1/6/2009)

[Table: see text]

Phase 1-2a multicenter dose-escalation study of ezatiostat hydrochloride liposomes for injection (Telintra, TLK199), a novel glutathione analog prodrug in patients with myelodysplastic syndrome

BACKGROUND

Ezatiostat hydrochloride liposomes for injection, a glutathione S-transferase P1-1 inhibitor, was evaluated in myelodysplastic syndrome (MDS). The objectives were to determine the safety, pharmacokinetics, and hematologic improvement (HI) rate. Phase 1-2a testing of ezatiostat for the treatment of MDS was conducted in a multidose-escalation, multicenter study. Phase 1 patients received ezatiostat at 5 dose levels (50, 100, 200, 400 and 600 mg/m2) intravenously (IV) on days 1 to 5 of a 14-day cycle until MDS progression or unacceptable toxicity. In phase 2, ezatiostat was administered on 2 dose schedules: 600 mg/m2 IV on days 1 to 5 or days 1 to 3 of a 21-day treatment cycle.

RESULTS

54 patients with histologically confirmed MDS were enrolled. The most common adverse events were grade 1 or 2, respectively, chills (11%, 9%), back pain (15%, 2%), flushing (19%, 0%), nausea (15%, 0%), bone pain (6%, 6%), fatigue (0%, 13%), extremity pain (7%, 4%), dyspnea (9%, 4%), and diarrhea (7%, 4%) related to acute infusional hypersensitivity reactions. The concentration of the primary active metabolites increased proportionate to ezatiostat dosage. Trilineage responses were observed in 4 of 16 patients (25%) with trilineage cytopenia. Hematologic Improvement-Erythroid (HI-E) was observed in 9 of 38 patients (24%), HI-Neutrophil in 11 of 26 patients (42%) and HI-Platelet in 12 of 24 patients (50%). These responses were accompanied by improvement in clinical symptoms and reductions in transfusion requirements. Improvement in bone marrow maturation and cellularity was also observed.

CONCLUSION

Phase 2 studies of ezatiostat hydrochloride liposomes for injection in MDS are supported by the tolerability and HI responses observed. An oral formulation of ezatiostat hydrochloride tablets is also in phase 2 clinical development.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT00035867.

Combination of 5-azacytidine and thalidomide for the treatment of myelodysplastic syndromes and acute myeloid leukemia

BACKGROUND

The treatment of myelodysplastic syndromes (MDS) remains a challenge to the clinician despite recent advances. Many patients will either not respond or will have only limited and/or brief responses to single-agent therapy. Eventually, 30% of patients with MDS will progress and develop acute myeloid leukemia (AML). New strategies are needed for these patients.

METHODS

5-Azacytidine (AZA) and thalidomide were administered to 40 patients with MDS or AML. AZA was given at a dose of 75 mg/m2 subcutaneously for 5 of 28 days together with thalidomide starting at a dose of 50 mg per day and increasing to 100 mg per. Six patients had refractory anemia (RA), 2 patients had RA with ringed sideroblasts, 10 patients had RA with excess blasts (RAEB), 1 patient had RAEB in transformation, 4 patients had chronic myelomonocytic leukemia, 1 patient had chronic idiopathic myelofibrosis, and 16 patients had AML. Thirty-six patients were evaluable for outcome.

RESULTS

A hematologic improvement (HI) was observed in 15 of 36 patients (42%), stable disease was observed in 5 of 36 patients (14%), and 10 of 36 patients (28%) had disease progression. Six patients experienced complete remission (CR), 2 patients experienced an erythroid HI (HI-E), 1 patient experience an absolute neutrophil count HI (HI-ANC), 5 patients experienced a platelet HI (HI-P), and 7 patients had bilineage HI (HI-P and HI-ANC or an HI-E and HI-ANC). It was noteworthy that 9 of 14 patients with AML had a history of prior MDS, 2 of 9 patients achieved a CR, 4 of 9 patients had HI (HI-E and bilineage HI), and 1 patient had stable disease and was continuing treatment. DNA microarray analysis of 8 responders and 4 nonresponders revealed that the genes associated with cellular proliferation had higher expression levels in nonresponders.

CONCLUSIONS

The current findings indicated that a combination of low-dose AZA and thalidomide was well tolerated and was effective therapy for the treatment of patients with MDS and AML arising from prior MDS.

Isolation of specific and biologically active peptides that bind cells from patients with acute myeloid leukemia (AML)

Purpose

In a departure from conventional strategies to improve treatment outcome for myeloid malignancies, we report the isolation of leukemia-specific peptides using a phage display library screened with freshly obtained human myeloid leukemia cells.

Results

A phage display library was screened by 5 rounds of biopanning with freshly isolated human AML cells. Individual colonies were randomly picked and after purification, biologic activity (growth and differentiation) on fresh AML cells was profiled. Ten peptides were synthesized for further biological studies. Multiple peptides were found to selectively bind to acute myeloid leukemia (AML) cells. The peptides bound to leukemia cells, were internalized and could induce proliferation and/or differentiation in the target patient cells. Two of the peptides, HP-A2 and HP-G7, appeared to have a novel mechanism of inducing differentiation since they did not cause G1 arrest in cycling cells even as the expression of the differentiation marker CD11b increased.

Conclusion

Peptide induced differentiation of leukemia cells offers a novel treatment strategy for myeloid malignancies, whereas their ability to induce proliferation could be harnessed to make cells more sensitive to chemotherapy. Conceptually, these leukemia specific peptides can also be used to refine diagnosis, document minimal residual disease, and selectively deliver toxins to malignant cells.

Identification of RPS14 as a 5q- syndrome gene by RNA interference screen

Somatic chromosomal deletions in cancer are thought to indicate the location of tumor suppressor genes, whereby complete loss of gene function occurs through biallelic deletion, point mutation, or epigenetic silencing, thus fulfilling Knudson's two-hit hypothesis.¹ In many recurrent deletions, however, such biallelic inactivation has not been found. One prominent example is the 5q- syndrome, a subtype of myelodysplastic syndrome (MDS) characterized by a defect in erythroid differentiation.² Here, we describe an RNA interference (RNAi)-based approach to discovery of the 5q- disease gene. We find that partial loss of function of the ribosomal protein RPS14 phenocopies the disease in normal hematopoietic progenitor cells, and moreover that forced expression of RPS14 rescues the disease phenotype in patient-derived bone marrow cells. In addition, we identified a block in the processing of pre-rRNA in RPS14 deficient cells that is highly analogous to the functional defect in Diamond Blackfan Anemia, linking the molecular pathophysiology of the 5q- syndrome to a congenital bone marrow failure syndrome. These results indicate that the 5q- syndrome is caused by a defect in ribosomal protein function, and suggests that RNAi screening is an effective strategy for identifying causal haploinsufficiency disease genes.

An erythroid differentiation signature predicts response to lenalidomide in myelodysplastic syndrome

BACKGROUND

Lenalidomide is an effective new agent for the treatment of patients with myelodysplastic syndrome (MDS), an acquired hematopoietic disorder characterized by ineffective blood cell production and a predisposition to the development of leukemia. Patients with an interstitial deletion of Chromosome 5q have a high rate of response to lenalidomide, but most MDS patients lack this deletion. Approximately 25% of patients without 5q deletions also benefit from lenalidomide therapy, but response in these patients cannot be predicted by any currently available diagnostic assays. The aim of this study was to develop a method to predict lenalidomide response in order to avoid unnecessary toxicity in patients unlikely to benefit from treatment.

METHODS AND FINDINGS

Using gene expression profiling, we identified a molecular signature that predicts lenalidomide response. The signature was defined in a set of 16 pretreatment bone marrow aspirates from MDS patients without 5q deletions, and validated in an independent set of 26 samples. The response signature consisted of a cohesive set of erythroid-specific genes with decreased expression in responders, suggesting that a defect in erythroid differentiation underlies lenalidomide response. Consistent with this observation, treatment with lenalidomide promoted erythroid differentiation of primary hematopoietic progenitor cells grown in vitro.

CONCLUSIONS

These studies indicate that lenalidomide-responsive patients have a defect in erythroid differentiation, and suggest a strategy for a clinical test to predict patients most likely to respond to the drug. The experiments further suggest that the efficacy of lenalidomide, whose mechanism of action in MDS is unknown, may be due to its ability to induce erythroid differentiation.

Prognosis in myelodysplastic syndromes: are the new classifications useful?

Increased understanding of the biologic and clinical parameters that define subgroups of myelodysplastic syndromes has led to continuing refinement of classification strategies for diagnostic and prognostic use. The French-American-British classification, based primarily on morphology, was modified by the World Health Organization system to include the negative impact of multilineage dysplasias and higher blast counts. In addition, this system identifies a distinct clinical subgroup characterized by an isolated chromosome 5 deletion. The International Prognostic Scoring System was created to calculate prognosis, risk of transformation to acute myeloid leukemia, and median survival times. However, therapeutic decisions cannot be solely guided by these systems, and the clinician must decide whether the intent is curative or palliative. Clinical symptoms and degree of transfusion dependency will dictate the degree of therapeutic intervention.

Hypocellularity in myelodysplastic syndrome is an independent factor which predicts a favorable outcome

Hypocellular myelodysplastic syndrome (MDS) represents only a small portion of MDS, of which, the clinical significance has not been well-defined. By using currently accepted age-adjusted criteria to define hypocellularity as <30% in patients <70 years old, and <20% in >70 years old, we identified 163 (15.5%) hypocelluar MDS from 1049 consecutive adult MDS patients over an 11-year period (1995-2006). Compared to normal/hypercellular MDS, hypocellular MDS patients were younger (p<0.01), less anemic (p=0.02), but more neutropenic (p<0.001) and thrombocytopenic (p=0.05), and had a comparable cytogenetic risk group distribution (p=0.09) and international prognostic scores (IPSS, p=0.13). With a median follow-up of 52 months, hypocellular MDS showed a favorable overall survival (56 months versus 28 months, log-rank p<0.0001) over normal/hypocellular MDS, and this survival preference was also demonstrated in all IPSS groups and cytogenetic risk groups, and was independent of all other risk factors (Cox regression test, p=0.01). In conclusion, our study demonstrated that hypocellular MDS has characteristic clinicopathologic features, and bone marrow hypocellularity in MDS is an independent factor which predicts a favorable outcome.

Prognostic value of low platelets in MDS patients with del(5q)

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The most common (10–15%) chromosomal abnormality found in myelodysplastic syndromes (MDS) is an interstitial deletion of the long arm of chromosome 5 (del(5q)). The recent finding that lenalidomide is efficacious for MDS patients with del(5q) as either the sole abnormality or as part of a complex karyotype has focused renewed interest in the prognostic characteristics of these patients. We analyzed 189 patients with del(5q), 70 having isolated and 119 having additional chromosomal abnormalities. The median survival for the isolated del(5q) patient was 2.45 years and for those with complex abnormalities was 0.63 years (p=0.001). Each of these groups was then divided by IPSS category; median survival for Low/Int1 (n=56) was 2.46 years and 0.49 years for Int2/High (n=10, p=0.019).Thus our median survival times match previously published results and we have a representative dataset. Since 5q- syndrome patients with normal to high platelets have the best survival, platelet count may be of prognostic significance. We determined the median platelet count for our dataset to be 115,000 and analyzed median survival for patients with greater (n=89) or less (n=88) than the median value. Survival for those with higher platelet counts was 2.6 years, but dropped to 0.54 years with lower counts (p=0.0001). We then analyzed each of these two groups independently for survival based on IPSS, blast % and karyotype. Median survival for patients with >115,000 platelets and either Low/Int1-risk (n=62), <5% blasts (n=46) or an isolated del(5q) (n=46) was 2.95–3.0 years. The survival of these patients dramatically decreased (0.63 years) if they had Int2/High IPSS (n=19) or >10% blasts (=11). The presence of additional chromosomal abnormalities decreased survival to 1.85 years (n=28). A different range of survival times occurred with patients that had <115,000 platelets. Their median survival based on Low/Int1 IPSS (n=20), <5% blasts (n=18) or isolated del(5q)(n=20) was only 0.68–0.84 years. Int2/High IPSS (n=64), >5% blasts (n=50) or additional chromosomal abnormalities (n=68) lowered survival to 0.44–0.49 years. Thus lower platelet counts in del(5q) MDS patients with favorable IPSS (median survival 0.84 years), <5% blasts (median survival 0.68 years) or isolated del(5q) (median survival 0.74 years) appear to have poor prognosis.

No significant financial relationships to disclose.

Validation of IPSS criteria in more than 1,600 MDS patients

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Myelodysplastic syndromes (MDS) are a diverse group of clonal stem cell disorders characterized by bone marrow failure, dysmyelopoiesis and peripheral cytopenias and affecting predominantly an elderly population. The International Prognostic Scoring System (IPSS) incorporates the number of peripheral cytopenias, percentage of bone marrow blasts and chromosomal abnormalities and assigns a score to predict survival and risk of disease progression to AML. Using the extensive MDS database at the University of Massachusetts we analyzed survival time in relation to IPSS scoring and also its various individual components, i.e. blast percentage, number of cell lines involved and the number of karyotype abnormalities in 1,200+ patients. The overall median survival time in 1,424 MDS patients as a group was 2.9 years. IPSS low group had the longest median survival time of 7.5 years with IPSS Int-1 3.6 years. There was minimal difference in the median survival time between IPSS Int-2 and IPSS high risk group 1.2 and 1.1 years respectively. These results were significant for a P value of <0.0001. The median survival time for blasts <5% was 5.3 years and blast 5–10% was 1.7 years. Interestingly, there was minimal survival difference between median survival time for blasts 11–20% and blasts >20% showing 1.2 years and 1.3 years respectively. Again, these results were significant for a P value of <0.0001. The median survival time for the number of cytopenias involved was also calculated with 0, 1, 2 and 3 numbers of cytopenias showing 6.4 years, 4.4 years, 2.6 years and 1.8 years respectively, with P value of <0.0001. The median survival time for normal karyotype versus one or two karyotype abnormality was 4.9 years, 2.6 years and 2.4 years respectively. Three or more karyotype abnormalities showed a median survival time of 0.8 years. The P value was again significant (<0.0001). Our results not only validate the prognostic value of IPSS scoring system as a whole but also its various individual prognostic indicators.

No significant financial relationships to disclose.

Complete blood count may provide risk stratification for survival and AML transformation in CMML

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We performed a retrospective analysis of 120 patients with CMML (98 de novo CMML and 22 evolving from MDS) to examine clinical features that may influence survival and AML transformation. Univariate analysis showed low hemoglobin level; WBC > 13,000, platelet count < 50,000 and abnormal cytogenetics as poor prognostic features. Univariate analysis also determined that BM blasts >5% and Int2/High IPSS were associated with higher rates of AML but IPSS could not be used for survival assessment. Multivariate analysis showed hemoglobin < 12 g/dL, older age, abnormal cytogenetics as risk factors for shorter survival; older age, male sex, low platelet count, BM blasts > 5%, lymphocyte and monocyte counts were independent risk factors for AML transformation. Previous attempts to devise prognostic scoring systems for CMML have incorporated both peripheral blood and bone marrow features. We have used hemoglobin, lymphocyte count and platelet count to generate 3 prognostic scoring systems, which differed by severity of thrombocytopenia. Score 1 (>100, 50–100, <50) identified 3 different risk groups (low, intermediate, and high) with median OS: not reached (n/a), 18, and 9 months for all CMML patients (p<0.0001) as well as for the de novo CMML patients (p<0.0001). Score 2 (>50, <50) divided patients into 3 risk groups (low, intermediate, and high) with median OS: n/a, 19 and 10 months for all CMML (p=0.0002) versus n/a, 28 and 11 months for de novo CMML patients (p=0.0011). Score 3 (<100, >100) separated all CMML (p=0.0073) and de novo CMML patients (p=0.0054) into 2 risk groups (high, low) with median time to AML 53 months and n/a. In conclusion we suggest three new scoring systems for CMML patients that can be easily calculated after an initial CBC. Scores 1 and 2 help to assess survival while score 3 indicates risk for AML transformation. *Acknowledgements: This work has been partially supported by the AMA Foundation Seed Grant Research Program 2006.

No significant financial relationships to disclose.

Current Treatment Options: Impact of Cytogenetics on the Course of Myelodysplasia

The heterogeneity of myelodysplastic syndromes (MDS) has driven the search for unifying biologic and clinical features that would stratify patients into distinct prognostic and therapeutic subgroups. Cytogenetics has been shown to impact the course of myelodysplasia. Despite the presence of non-random cytogenetic abnormalities in approximately 50% of MDS patients, it is significant that only a proportion of metaphases may contain the abnormality. Clonality studies however show that the karyotypically normal metaphases are still part of the MDS clone. This would suggest that the chromosomal abnormality may not be the initiating lesion in MDS, and that the gross karyotypic changes represent clonal evolution in a genetically unstable population. Yet, as will be described below, specific cytogenetic abnormalities are associated with clinically and biologically distinct forms of the disease, most notable in the response of del(5q) patients to lenalidomide. One possible explanation for the appearance of non-random mutational events could relate to the interaction of MDS cells with their microenvironment. Whatever the initiating lesion in the MDS stem cell, the end result is a clonal expansion where the marrow becomes populated by the monoclonal progeny of this cell. Interaction of these cells with a microenvironment which has been shown to be rich in pro-apoptotic cytokines such as tumor necrosis factor alpha (TNFa), leads to increased genetic instability. Hypoxia mediated decrease in DNA repair enzymes could further accelerate mutational events culminating in accumulation of multiple chromosomal abnormalities. Some of these chromosomal changes are associated with increased sensitivity to specific drugs. Lenalidomide has shown a high degree of efficacy in MDS patients with del(5q), although the target for the drug is unknown since a small but significant subset of MDS patients without del(5q) abnormality also respond to the drug. In contrast, the molecular target for imatinib mesylate is known; mutations in tyrosine kinase receptor family of genes found in patients with t(5;12) and del(4q12) make these individuals sensitive to the drug. Patients with isolated trisomy 8 have an immune component to the disease phenotype which can be targeted by cyclosporine and or anti-thymocyte globulin (ATG), especially in the presence of a PNH (paroxysmal nocturnal hemoglobinurea) clone. In the absence of these specific cytogenetic abnormalities described above, the two FDA approved hypomethylating agents 5 azacytidine and decitabine should be considered as therapeutic alternatives.

Methylation-independent silencing of the tumor suppressor INK4b (p15) by CBFbeta-SMMHC in acute myelogenous leukemia with inv(16)

The tumor suppressor gene INK4b (p15) is silenced by CpG island hypermethylation in most acute myelogenous leukemias (AML), and this epigenetic phenomenon can be reversed by treatment with hypomethylating agents. Thus far, it was not investigated whether INK4b is hypermethylated in all cytogenetic subtypes of AML. A comparison of levels of INK4b methylation in AML with the three most common cytogenetic alterations, inv(16), t(8;21), and t(15;17), revealed a strikingly low level of methylation in all leukemias with inv(16) compared with the other types. Surprisingly, the expression level of INK4b in inv(16)+ AML samples was low and comparable with that of the other subtypes. An investigation into an alternative mechanism of INK4b silencing determined that the loss of INK4b expression was caused by inv(16)-encoded core binding factor beta-smooth muscle myosin heavy chain (CBFbeta-SMMHC). The silencing was manifested in an inability to activate the normal expression of INK4b RNA as shown in vitamin D3-treated U937 cells expressing CBFbeta-SMMHC. CBFbeta-SMMHC was shown to displace RUNX1 from a newly determined CBF site in the promoter of INK4b. Importantly, this study (a) establishes that the gene encoding the tumor suppressor p15(INK4b) is a target of CBFbeta-SMMHC, a finding relevant to the leukemogenesis process, and (b) indicates that, in patients with inv(16)-containing AML, reexpression from the INK4b locus in the leukemia would not be predicted to occur using hypomethylating drugs.

Chronic myelomonocytic leukemia evolving from preexisting myelodysplasia shares many features with de novo disease

The majority of chronic myelomonocytic leukemia (CMML) cases arise de novo; cases evolving from preexisting myelodysplasia (MDS) or myeloproliferative diseases have not been well-studied. We conducted the present study to determine the clinicopathologic features and to study possible underlying molecular and cytogenetic mechanisms involved in this evolution. Between April 1995 and November 2005, we identified 120 CMML cases, of which 20 (16.7%) had a previous diagnosis of MDS. Of the 20 patients with MDS, 6 had relative monocytosis at diagnosis. At the time of MDS to CMML evolution, mutations in JAK2 (V617F), FLT3 (ITD), K-ras-2, or N-ras were not acquired, and only 1 (6%) of 17 evaluable cases showed cytogenetic progression. The median time to evolution from MDS to CMML was 29 months, and the median survival following CMML development was 13 months. Three cases (17%) transformed to acute myeloid leukemia. These findings indicate that in some cases of otherwise typical MDS, the progenitor cells may have some capacity for monocytic proliferation at diagnosis and manifest rapid disease progression once a monocytic proliferation supervenes.

Clinical response of myelodysplastic syndromes patients to treatment with coenzyme Q10

The myelodysplastic syndromes (MDS) are a collection of hematopoietic disorders with varying degrees of mono- to trilineage cytopenias and bone marrow dysplasia. In recent years much progress has been made in the treatment of MDS and there are now several therapeutic compounds used with varying levels of success. These compounds typically cause side effects that make them unattractive for treatment of patients in the early stages of MDS. Naturally occurring compounds that are not toxic may provide a means to treat patients in the initial stages of disease. We conducted a pilot study to test the efficacy of coenzyme Q10 (coQ10) in MDS patients with low to intermediate-2 risk disease. A variety of responses were observed in 7 of 29 patients including two trilineage and two cytogenetic responses. Sequencing mitochondrial DNA (mtDNA) from pretreatment bone marrows showed multiple mutations, some resulting in amino acid changes, in 3/5 nonresponders, 1/4 responders and in two control samples. We conclude that coQ10 may be of clinical benefit in a subset of MDS patients, but responders cannot be easily pre-selected on the basis of either the conventional clinical and pathologic characteristics or mtDNA mutations.

Immunomodulatory drugs in myelodysplastic syndromes

This review summarises the mechanism of action of immunomodulatory analogues of thalidomide and their use in myelodysplastic syndromes. Thalidomide was found to have a response rate of approximately 20% in these patients. Lenalidomide--which is more potent and less toxic than thalidomide--has been used in three clinical trials and produced the best responses (60 - > 90%) in low- and intermediate-1-risk transfusion-dependent patients with del(5q). The responses are purely erythroid in nature, and are associated with major cytogenetic responses in > 50% of the del(5q) patients. Non-del(5q) low- and intermediate-1-risk transfusion-dependent patients also had a approximately 25% incidence of transfusion independence following therapy with lenalidomide. Median time to response is approximately 4 weeks and 90% of patients respond within 12 weeks. The precise mechanism of action remains unknown but anticytokine, antiangiogenic and immunomodulatory properties are thought to play a role.

Low dose Vidaza and thalidomide is an effective combination for patients with myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML)

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Vidaza and thalidomide were administered to 29 patients with MDS or AML. Vidaza was given at a dose of 75mg/kg subq × 5 days q28 days and Thalidomide starting at 50mg/day and increasing to 100mg. Therapy was well tolerated. Median age was 70 years, and there were 16 males. Two patients had RA, 2 RARS, 9 RAEB, 4 CMMoL, 10 AML and 2 Unknowns. According to IPSS, 1 had low, 7 had Int-1, 5 had Int-2 and 4 had high risk disease, and 2 unclassified (10 had AML). Eleven patients had normal, 14 abnormal and 4 unknown for cytogenetics. Seven patients went off the study due to disease progression (5) or refused therapy (1), died within a week of treatment initiation (1) while 2 are on the first cycle and too early for evaluation. Twenty-five patients are evaluable for outcome. Ten patients received 5 or more cycles of Vidaza. HI was seen in 14/25 (56%), and stable disease in 6/25 (24%) while 5/25 (20%) had disease progression. Six patients experienced complete remission (CR) and are still receiving therapy (24%), 1 experienced HI-E, 2 HI-ANC, 3 HI-P, and 2 had a bilineage improvement (HI-P and ANC and HI-E and ANC). Of 10 AML patients, three went off study due to disease progression, 1 had stable disease, 6 responded with 4 complete remissions (CR), 1 HI-ANC and 1 HI-P. Interestingly, 6/10 AMLs had a history of prior MDS, 3/6 achieved CR, 2/6 had HI (ANC and platelets) and 1 has stable disease (continuing treatment). Among the 4 de novo AMLs, 1 had CR and 3 showed disease progression. We conclude that a combination of low dose Vidaza and thalidomide is well tolerated, and highly effective therapy for the treatment of patients with MDS as well as AML arising from a prior MDS. The ability to treat secondary MDS as out-patient and achieve such a high response rate represents a paradigm shift in AML therapy.

No significant financial relationships to disclose.

A humanized unconjugated antibody targeting CD33 (SGN-33; huM195) is active in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS)

16500

Background: CD33 is a sialoglycan protein expressed on normal myeloid and monocytic cells as well as the vast majority of myeloid malignancies. A humanized antibody has been developed that recognizes CD33 and induces antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. In prior clinical testing, this antibody led to significant reductions in blasts in patients with relapsed and refractory AML. Methods: A phase I single-arm dose escalation trial was initiated at multiple sites to assess the safety, immunogenicity, pharmacokinetics, and activity of SGN-33 at higher doses than previously tested. Cohorts of 3–6 patients with advanced MDS or AML will receive intravenous SGN-33 at weekly doses of 1.5 to 8 mg/kg over 5 weeks. Clinical response will be determined by bone marrow morphology and hematologic improvement. Responding patients will be eligible for 4 additional infusions. Results: Treatment of 6 patients at 1.5 mg/kg/wk has been well-tolerated, with no dose-limiting toxicity or related adverse events > grade 2. The median age is 79.5 years (range 52–88), and all patients were previously untreated. One patient discontinued treatment because of refractory thrombocytopenia, unrelated to SGN-33. CD33 saturation of the bone marrow blasts after 2 infusions ranged from 27% to 84% with an average of 55%. The mean change in bone marrow blasts by flow cytometry after 2 weeks was −9% (range −68% to +44%; N = 5), and the marrow monocytes changed by −39% (range −90% to +86%; N = 5). Two patients have completed re-staging after cycle 1. Blasts decreased from 29% to 12% in an 88 year-old woman with AML and from 11% to 9% in a 79 year-old man with RAEB. Conclusions: SGN-33 is well tolerated at 1.5 mg/kg/wk, and dose escalation is ongoing. Antitumor activity was seen in elderly patients with previously untreated AML and MDS. Incomplete saturation of the CD33 on bone marrow blasts suggests that higher doses may improve efficacy. SGN-33 holds promise for the treatment of patients with myeloid malignancy who are ineligible for aggressive therapy.

[Table: see text]

Targeted therapies in myelodysplastic syndromes: ASH 2003 review

The myelodysplastic syndromes (MDS) continue to pose conceptual and practical conundrums because of their heterogeneity and therapeutic challenges. They are not restricted to the presence of clonal cells that are prone to excessive proliferation and premature apoptosis. In MDS the bone marrow microenvironment also is abnormal and exhibits an excess of proinflammatory cytokines, especially tumor necrosis factor (TNF), neoangiogenesis, and poorly defined immune defects. Thalidomide, a drug with anti-TNF, antiangiogenic, and immunomodulatory activities, and other agents with anti-TNF effects, such as pentoxifylline, etanercept, and infliximab, have produced hematologic improvement in 20% to 40% of patients. These agents may provide effective therapy for a subset of lower-risk MDS patients, even if the drugs target the bone marrow microenvironment predominantly. However, in higher-risk MDS patients, especially those with more than 10% blasts, it is important to eliminate abnormal cell clones; drugs used for this purpose have included arsenic trioxide, topotecan, the farnesyl transferase inhibitor tipifarnib, and demethylating agents, such as 5-azacytidine and decitabine. To increase the therapeutic index, a combination strategy may be preferable for higher-risk MDS patients, in whom the seed (clone) and the soil (bone marrow microenvironment) must be targeted simultaneously. The challenge is to recognize the subset that is likely to respond to a given drug so that patients can be preselected for therapy.