scholarly journals Association of Hematological Nadirs and Survival in a Non-Human Primate Model of Hematopoietic Syndrome of Acute Radiation Syndrome

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4354-4354
Author(s):  
Zoya Gluzman Poltorak ◽  
Vainstein Vladimir ◽  
Lena A. Basile
Keyword(s):  
Bone Marrow ◽  
Blood Cell ◽  
Acute Radiation ◽  
Severe Neutropenia ◽  
Severe Thrombocytopenia ◽  
Operating Characteristics ◽  
Employment Equity ◽  
Cutoff Value ◽  
Equity Ownership ◽  
Bone Marrow Regeneration

Abstract Recombinant human interleukin-12 (rHuIL-12, HemaMaxTM) is being developed for mitigation of HSARS under the FDA Animal Rule using a NHP model of HSARS for proof of efficacy and clinical studies in healthy human subjects to demonstrate safety. We have shown previously that a single injection of rHuIL-12 administered 24-25 hours after lethal total body irradiaton (TBI), in the absence of antibiotics, fluids or blood products, resulted in improved survival while filgrastim (G-CSF) did not provide any survival benefit in our NHP HSARS model (Basile et al 2012, Gluzman-Poltorak et al 2014, Gluzman-Poltorak et al 2014). The mechanism by which IL-12 mitigates HSARS following TBI appears to involve multiple effects of IL-12 on hematopoieses. In our previous studies, animals treated with rHuIL-12 showed statistically significant reductions in the occurrence of severe neutropenia and severe thrombocytopenia, as well as attenuated nadirs for lymphocytes, neutrophils, platelets, and reticulocytes. To characterize further relationship between survival and hematological nadirs (lymphocytes, neutrophils, platelets, RBCs and reticulocytes) in the rhesus model of HSARS and to better understand the effects of rHuIL-12 versus G-CSF on blood cell nadirs, we undertook a meta-analysis analysis across three studies in irradiated rhesus monkeys. Animals used in this analysis were irradiated (700 cGy) and treated with a single subcutaneous injection of vehicle (n=64) or rHuIL-12 50-500ng/kg (n=108) 24-25 hours after irradiation, or daily subcutaneous injections of G-CSF at 10μg/kg/d for 18 days starting 24-25 hours after irradiation (n=26). Males and females were equal in each group. Lymphocytes, neutrophils and platelets were significantly lower in decedents versus monkeys that survived to day 60 overall and this was true in each treatment group (p<0.001, Wilcoxon rank-sum test). The mean RBC nadir was significantly higher in survivors compared to non-survivors in the rHuIL-12 group (p = 0.008), but not in the control group or the G-CSF group. Lymphocytes nadir appears to be the strongest and most consistent predictor of death followed by neutrophils and platelets (Spearman’s rank correlation). RBCs and reticulocytes are less informative in terms of predicting survival status. In addition, the receiver operating characteristic (ROC) curve area under the curve (AUC) by nadir value was assessed. The operating characteristics for lymphocytes, neutrophils and platelets allow for relatively large positive predictive values (PPV) of death with relatively high sensitivity. A cutoff value for lymphocytes nadir of 0.08x109/L (values less than or equal predicting death and higher values predicting life) allows for largest PPVs (97.2% and 92.5%) with 76.1% and 62.7% sensitivities for control and rHuIL-12 treatments, respectively. A cutoff value for neutrophils nadir of 0.03x109/L permits for 84% and 71.1% PPVs with sensitivities of 91.3% and 91.5 % for control and rHuIL-12 treatments, respectively. A cutoff value for platelets nadir of 9x109/L permits for 84.1% and 76.8% PPVs with sensitivities of 80.4% and 72.9 % for control and rHuIL-12 treatments, respectively. RBCs and reticulocytes were found less informative. To conclude, in the rhesus model of HSARS we have observed that an augmented hematological nadirs generally predicts an increased potential for survival as this effect reflects early bone marrow regeneration. The nadir for lymphocytes appears to be the strongest and most consistent predictor of death. Decrease of lymphocyte counts has been established as a best marker of bone marrow damage in a large database of human victims of acute radiation (METREPOL, Fliedner et al 2001). Thus, the correlation of our results with the human data supports the validity of our animal model as an accurate representation of human HSARS and its ability to predict effectiveness in humans exposed to lethal radiation. These data also suggest that the significant increase in early bone marrow regeneration seen in our studies, resulting in increases in nadir values for all major blood cell types, may be the main mechanism of action by which rHuIL-12 mitigates the lethality of HSARS. This project has been entirely funded with Federal funds from BARDA/ASPR/DHHS under Contract No. HHSO100201100037C. Disclosures Gluzman Poltorak: Neumedicines Inc.: Employment, Equity Ownership. Vladimir:Neumedicines Inc.: Consultancy, Employment, Equity Ownership. Basile:Neumedicines Inc.: Employment, Equity Ownership, Neumedicines Inc. Patents & Royalties.

A Multi-Lineage Oral Hemokine™ HQK-1002 Enhances Neutrophil Recovery in Sub-Lethally Irradiated Mice and in Baboons.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2509-2509
Author(s):  
Susan Perrine ◽  
Michael Boosalis ◽  
Stanley Kosanke ◽  
Gary White ◽  
Serguei A. Castaneda ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Research Funding ◽  
Acute Radiation ◽  
Severe Neutropenia ◽  
Employment Equity ◽  
Once Daily ◽  
Neutrophil Recovery ◽  
Equity Ownership ◽  
Orally Bioavailable

Abstract Abstract 2509 Poster Board II-486 Acute radiation syndrome and therapeutic radiation are associated with cytopenias, notably severe neutropenia, particularly when large regions of bone marrow are exposed. An orally-active neutrophil stimulant which reduces the duration or magnitude of neutropenia would offer therapeutic benefit in radiation therapy and would be useful for acute radiation exposure. Orally-bioavailable short-chain fatty acid derivatives (SCFAD, HemokinesTM HQK-1002 and its S-enantiomer HQK-1002S), which stimulate proliferation of growth factor-dependent hematopoietic cell lines and CFU-GM cultures, were evaluated for in vivo activity in irradiated and 5-FU-treated mice and in normal baboons. In sub-lethal irradiation studies, mice were irradiated (6 Gy single dose) and then treated with saline or HQK-1002 once daily, 5 days/week for 2 weeks, beginning on day 1 after irradiation, and absolute neutrophil counts (ANC) were determined. The mean nadir of absolute neutrophil counts (ANC) <500/mm3 was 6 days in sub-lethally-irradiated mice treated with HQK-1002, and 18 days in the saline treated controls. In HQK-1002 treated mice, ANC did not decline below 200/mm3, while saline-treated animals experienced 10 days of severe neutropenia with ANC <200/mm3. In lethally-irradiated (LD90) mice, either saline or the (S) enantiomer of HQK-1002 was administered daily. ANC and marrow pathology were compared between saline and HQK-1002S-treated animals. The duration of peripheral neutropenia was similar in controls and HQK-1002S-treated animals, but bone marrow pathology demonstrated profound ablation of all mature myeloid series (10-20% cellularity) in the saline controls, while HQK-1002S-treated animals had normal bone marrow cellularity (55–75%) with complete neutrophil maturation within 2 weeks following radiation. In 5FU-treated mice, neutrophil recovery was compared between HQK-1002, saline, or G-CSF treatment for 3 weeks. Recovery from profound neutropenia (nadir at Day 9) occurred by Day 13 in G-CSF- and HQK-1002 treated animals, 5 days before recovery was observed in saline controls. HQK-1002 and HQK-1002S were also administered to non-irradiated, normal juvenile baboons, once daily for 5 days, and CBCs and neutrophil counts were assayed. HQK-1002 or HQK-1002S treatment in 3 unchallenged baboons resulted in a two-fold to three-fold rises in ANC within 7 days. Collectively, these studies strongly suggest that HQK-1002 and HQK-1002S, orally-bioavailable SCFADs, stimulate myelopoiesis in vivo in normal animals and during sub-lethal radiation-induced bone marrow suppression, and merit further evaluation in neutropenia associated with marrow suppression. Disclosures: Perrine: HemaQuest Pharmaceuticals: Employment, Equity Ownership, Patents & Royalties, Research Funding. Boosalis:HemaQuest Pharmaceuticals: Equity Ownership. Thomson:HemaQuest Pharmaceuticals: Employment, Equity Ownership. Berenson:hemaQuest Pharmaceuticals: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Faller:HemaQuest Pharmaceuticals: Consultancy, Equity Ownership, Patents & Royalties, Research Funding.

scholarly journals Astarabine, a Novel Leukemia-Targeted Cytarabine Composition Allows, for the First Time, the Delivery of High Cytarabine Doses for Older or Unfit Patients with Acute Leukemia. Results of an Ongoing Phase I/IIa Study

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1650-1650
Author(s):  
Tsila Zuckerman ◽  
Stela Gengrinovitch ◽  
Ruth Ben-Yakar ◽  
Ron Hoffman ◽  
Israel Henig ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Leukemia ◽  
De Novo ◽  
Intensive Therapy ◽  
High Dose ◽  
Newly Diagnosed ◽  
Employment Equity ◽  
Unfit Patients ◽  
Equity Ownership ◽  
High Doses

Abstract Introduction: Therapy of acute myeloid leukemia (AML) has not changed significantly during several decades. High-dose cytarabine, although used as the first-line treatment for AML since 1970s and as a second-line treatment for acute lymphoblastic leukemia (ALL), is associated with severe side effects, such as cerebellar toxicity and bone marrow suppression. Hence, while the incidence of AML increases with age, doses of cytarabine are significantly attenuated or the drug is entirely excluded from the regimen used in older adults due to its potential toxicities, particularly in individuals with hepatic or renal dysfunction. Astarabine is a new composition of cytarabine covalently bound to asparagine. It is designed to target cytarabine to leukemic blasts, thus avoiding extramedullary toxicity. Leukemic cells, which are dependent on an external source of amino acids in general and asparagine in particular, due to their high metabolic rate, have a relatively increased uptake of Astarabine. Inside the blasts, Astarabine is cleaved to cytarabine, enabling targeted killing and relative sparing of normal hematopoiesis. As such, Astarabine may serve as an ideal therapy for leukemia, particularly for delivering high doses of cytarabine to medically unfit or older adults who otherwise can be given supportive therapy only. The aim of this study was to evaluate the safety and optimal dose of Astarabine in refractory/relapsed or medically unfit patients with acute leukemia. Methods: This Phase I/IIa prospective open label study enrolled patients aged ≥18 years with relapsed/refractory or newly-diagnosed acute leukemia unfit for intensive therapy, as judged by the treating physician. The study was approved by the Rambam IRB (approval #0384-11). Patients were enrolled into 6 Astarabine escalating-dose cohorts, each composed of 3-6 patients. Treatment was administered as a 1-hour single daily infusion for 6 days. For cohorts 1-4, Astarabine doses for each infusion were 0.5g/m2, 1.5g/m2, 3g/m2 and 4.5g/m2. The doses were reduced by 50% for patients >50 years. Since dose limiting toxicity (DLT) was not reached in cohorts 1-4, the study was extended to include cohorts 5 and 6 with daily Astarabine doses of 4.5g/m2 and 6g/m2, respectively, with no dose reduction for patients >50 years old. Results: The outcome of 15 patients is reported herein. Six patients with a median age of 64 years (range 27-81) had refractory/relapsed AML, 9 patients with a median age of 80 years (range 70-90) were newly diagnosed (secondary AML - 6, de-novo AML - 2, de-novo ALL - 1) and unfit for intensive therapy. Astarabine treatment was well-tolerated. Two patients died (one from pneumonia and one from sudden death 2 weeks from end of treatment) before completing 30 days post-treatment and hence were excluded from the outcome analysis. Response to the treatment was observed in the bone marrow of 6 of the 7 newly-diagnosed patients for whom bone marrow analysis was available, 3 of whom had a continuous complete remission (CR) for 4 (ongoing), 8, and 10 months post-treatment, and 3 had a continuous partial remission (PR) for 3,7, and 7 (ongoing) months. The median overall survival (OS) of the patients with CR/PR is 7 months to date (table 1). No significant response was observed in the relapsed/refractory patients, with a median OS of 2.5 months. Twelve patients died from disease progression. Conclusions: Astarabine, a new composition of leukemia-targeted cytarabine, is safe and very well tolerated, even in patients over 80 years of age, resulting in response in 6 of 7 newly diagnosed patients with acute leukemia. To the best of our knowledge, this is the first report permitting high-dose of cytarabine, considered a cornerstone of leukemia therapy, to be given to a population of patients that heretofore did not have this option. Further dose escalation studies are currently ongoing at a cytarabine-equivalent dose of 4.5 and 6 g/m2/day. A phase II study is planned to confirm these encouraging results and define the use of Astarabine for patients otherwise unable to receive high doses of cytarabine. Disclosures Zuckerman: BioSight Ltd: Consultancy, Research Funding. Gengrinovitch:BioSight Ltd: Employment, Equity Ownership, Patents & Royalties: Inventor all of the patents. Ben-Yakar:BioSight Ltd: Consultancy, Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: Inventor of all patents.

scholarly journals EZH2 Mutations and Impact on Clinical Outcome Analyzed in 1604 Patients with Acute Myeloid Leukemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1528-1528
Author(s):  
Sebastian Stasik ◽  
Jan Moritz Middeke ◽  
Michael Kramer ◽  
Christoph Rollig ◽  
Alwin Krämer ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Board Of Directors ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Employment Equity ◽  
Advisory Committees ◽  
Mutational Status ◽  
Equity Ownership ◽  
Acute Myeloid

Abstract Purpose: The enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase and key epigenetic regulator involved in transcriptional repression and embryonic development. Loss of EZH2 activity by inactivating mutations is associated with poor prognosis in myeloid malignancies such as MDS. More recently, EZH2 inactivation was shown to induce chemoresistance in acute myeloid leukemia (AML) (Göllner et al., 2017). Data on the frequency and prognostic role of EZH2-mutations in AML are rare and mostly confined to smaller cohorts. To investigate the prevalence and prognostic impact of this alteration in more detail, we analyzed a large cohort of AML patients (n = 1604) for EZH2 mutations. Patients and Methods: All patients analyzed had newly diagnosed AML, were registered in clinical protocols of the Study Alliance Leukemia (SAL) (AML96, AML2003 or AML60+, SORAML) and had available material at diagnosis. Screening for EZH2 mutations and associated alterations was done using Next-Generation Sequencing (NGS) (TruSight Myeloid Sequencing Panel, Illumina) on an Illumina MiSeq-system using bone marrow or peripheral blood. Detection was conducted with a defined cut-off of 5% variant allele frequency (VAF). All samples below the predefined threshold were classified as EZH2 wild type (wt). Patient clinical characteristics and co-mutations were analyzed according to the mutational status. Furthermore, multivariate analysis was used to identify the impact of EZH2 mutations on outcome. Results: EZH2-mutations were found in 63 of 1604 (4%) patients, with a median VAF of 44% (range 6-97%; median coverage 3077x). Mutations were detected within several exons (2-6; 8-12; 14-20) with highest frequencies in exons 17 and 18 (29%). The majority of detected mutations (71% missense and 29% nonsense/frameshift) were single nucleotide variants (SNVs) (87%), followed by small indel mutations. Descriptive statistics of clinical parameters and associated co-mutations revealed significant differences between EZH2-mut and -wt patients. At diagnosis, patients with EZH2 mutations were significantly older (median age 59 yrs) than EZH2-wt patients (median 56 yrs; p=0.044). In addition, significantly fewer EZH2-mut patients (71%) were diagnosed with de novo AML compared to EZH2-wt patients (84%; p=0.036). Accordingly, EZH2-mut patients had a higher rate of secondary acute myeloid leukemia (sAML) (21%), evolving from prior MDS or after prior chemotherapy (tAML) (8%; p=0.036). Also, bone marrow (and blood) blast counts differed between the two groups (EZH2-mut patients had significantly lower BM and PB blast counts; p=0.013). In contrast, no differences were observed for WBC counts, karyotype, ECOG performance status and ELN-2017 risk category compared to EZH2-wt patients. Based on cytogenetics according to the 2017 ELN criteria, 35% of EZH2-mut patients were categorized with favorable risk, 28% had intermediate and 37% adverse risk. No association was seen with -7/7q-. In the group of EZH2-mut AML patients, significantly higher rates of co-mutations were detected in RUNX1 (25%), ASXL1 (22%) and NRAS (25%) compared to EZH2-wt patients (with 10%; 8% and 15%, respectively). Vice versa, concomitant mutations in NPM1 were (non-significantly) more common in EZH2-wt patients (33%) vs EZH2-mut patients (21%). For other frequently mutated genes in AML there was no major difference between EZH2-mut and -wt patients, e.g. FLT3ITD (13%), FLT3TKD (10%) and CEBPA (24%), as well as genes encoding epigenetic modifiers, namely, DNMT3A (21%), IDH1/2 (11/14%), and TET2 (21%). The correlation of EZH2 mutational status with clinical outcomes showed no effect of EZH2 mutations on the rate of complete remission (CR), relapse free survival (RFS) and overall survival (OS) (with a median OS of 18.4 and 17.1 months for EZH2-mut and -wt patients, respectively) in the univariate analyses. Likewise, the multivariate analysis with clinical variable such as age, cytogenetics and WBC using Cox proportional hazard regression, revealed that EZH2 mutations were not an independent risk factor for OS or RFS. Conclusion EZH mutations are recurrent alterations in patients with AML. The association with certain clinical factors and typical mutations such as RUNX1 and ASXL1 points to the fact that these mutations are associated with secondary AML. Our data do not indicate that EZH2 mutations represent an independent prognostic factor. Disclosures Middeke: Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Rollig:Bayer: Research Funding; Janssen: Research Funding. Scholl:Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Abbivie: Other: Travel support; Alexion: Other: Travel support; MDS: Other: Travel support; Novartis: Other: Travel support; Deutsche Krebshilfe: Research Funding; Carreras Foundation: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees. Hochhaus:Pfizer: Research Funding; Incyte: Research Funding; Novartis: Research Funding; Bristol-Myers Squibb: Research Funding; Takeda: Research Funding. Brümmendorf:Janssen: Consultancy; Takeda: Consultancy; Novartis: Consultancy, Research Funding; Merck: Consultancy; Pfizer: Consultancy, Research Funding. Burchert:AOP Orphan: Honoraria, Research Funding; Bayer: Research Funding; Pfizer: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; Novartis: Research Funding. Krause:Novartis: Research Funding. Hänel:Amgen: Honoraria; Roche: Honoraria; Takeda: Honoraria; Novartis: Honoraria. Platzbecker:Celgene: Research Funding. Mayer:Eisai: Research Funding; Novartis: Research Funding; Roche: Research Funding; Johnson & Johnson: Research Funding; Affimed: Research Funding. Serve:Bayer: Research Funding. Ehninger:Cellex Gesellschaft fuer Zellgewinnung mbH: Employment, Equity Ownership; Bayer: Research Funding; GEMoaB Monoclonals GmbH: Employment, Equity Ownership. Thiede:AgenDix: Other: Ownership; Novartis: Honoraria, Research Funding.

Randomized Phase II Study Evaluating the Efficacy and Safety of Romiplostim Treatment of Patients with Low or Intermediate Risk Myelodysplastic Syndrome (MDS) Receiving Lenalidomide.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1770-1770 ◽  
Author(s):  
Roger M Lyons ◽  
Richard A. Larson ◽  
Michael A. Kosmo ◽  
Sunil Gandhi ◽  
Delong Liu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Research Funding ◽  
Intermediate Risk ◽  
Employment Equity ◽  
Treatment Groups ◽  
Platelet Counts ◽  
Equity Ownership ◽  
Clinically Significant ◽  
Dose Reductions ◽  
Platelet Transfusions

Abstract Abstract 1770 Poster Board I-796 Introduction Romiplostim is a peptibody protein designed to increase platelet production by binding to and activating the thrombopoietin receptor. Low platelet counts in patients with myelodysplastic syndromes (MDS) may be due to the underlying disease or to treatment with disease-modifying agents, and platelet transfusions are often the only treatment for clinically significant thrombocytopenia (CST) or bleeding. This was a phase 2 multi-center, randomized, double-blind, placebo-controlled, dose-finding study that evaluated the effect of romiplostim on the incidence of clinically significant thrombocytopenic events (grade 3 or 4 thrombocytopenia and/or receipt of platelet transfusions) and the safety of romiplostim in patients with low or intermediate risk MDS receiving lenalidomide. Patients and Methods Patients who were ≥18 years old, had MDS by bone marrow exam and WHO criteria, had low or Intermediate-1 risk category MDS using the IPSS, and were planning to receive lenalidomide were eligible. Patients were randomized 1:1:1 into treatment groups receiving placebo, 500 μg romiplostim, or 750 μg romiplostim by weekly subcutaneous injections in combination with lenalidomide (one 10 mg capsule by mouth daily for each 28-day cycle). Treatments continued for a total of four cycles. Results The median age of the 39 randomized patients was 74 years (range, 39 to 90); 15 (39%) had platelet counts <50 × 109/L, and 7 (18%) had del(5q). We report trends due to baseline imbalances between treatment groups, likely due to the limited sample size. The overall incidence rates of CST appeared to be greater in the placebo group than either romiplostim group (Table). In contrast to the placebo patients, median platelet counts remained above 50 × 109/L in both the 500 μg and 750 μg romiplostim groups for the treatment period. The incidence of platelet transfusions appeared to be lower in the 500 μg romiplostim group, and the incidence of adverse events was comparable between all of the groups. No deaths were reported during the treatment period. Twelve patients (31%) discontinued the study. Disease progression to AML was reported in 1 patient in the romiplostim 500 μg group. The patient withdrew consent and discontinued the study. No bone marrow was available to confirm AML by protocol-defined criteria. Fewer lenalidomide dose reductions and delays due to thrombocytopenia were seen in both of the romiplostim treated groups. The proportion of patients who achieved an MDS treatment response was 8%, 36% and 15% for the placebo, 500 μg romiplostim, and 750 μg romiplostim groups, respectively. MDS response rates appeared higher in the romiplostim group, regardless of baseline del(5q) status. Baseline imbalance between groups due to the small sample size limited our interpretation of the data. Conclusions Romiplostim appeared to be well-tolerated in low and intermediate risk MDS patients receiving lenalidomide. This preliminary information suggests that romiplostim may reduce the rate of clinically significant thrombocytopenic events in these patients while increasing platelet counts and decreasing the incidence of lenalidomide dose reductions and delays due to thrombocytopenia Disclosures Lyons: GlaxoSmithKline: Consultancy, Speakers Bureau; Johnson&Johnson: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy; Amgen Inc.: Consultancy, Honoraria, Research Funding, Speakers Bureau. Off Label Use: Use of romiplostim to treat Thrombocytopenia in MDS. Larson:Amgen Inc.: Equity Ownership, Research Funding. Liu:Amgen Inc.: Honoraria, Research Funding. Hu:Amgen Inc.: Employment, Equity Ownership. Franklin:Amgen Inc.: Employment, Equity Ownership. Berger:Amgen Inc.: Employment, Equity Ownership.

Use of a New Rotary Powered Device for Bone Marrow Aspiration and Biopsy Yields Excellent Specimens Quickly and Efficiently.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4544-4544
Author(s):  
Ronan T. Swords ◽  
Kevin R. Kelly ◽  
Devalingam Mahalingam ◽  
Stephen C. Cohen ◽  
Larry J. Miller ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Biopsy ◽  
Clinical Evaluation ◽  
Research Funding ◽  
Bone Marrow Aspiration ◽  
Swine Model ◽  
Employment Equity ◽  
Equity Ownership ◽  
Specimen Quality ◽  
The Mean

Abstract Abstract 4544 Background The importance of bone marrow aspiration and biopsy in the evaluation of hematopoietic and non-hematopoietic disorders is well established. Recently, a new FDA-cleared battery powered bone marrow biopsy system was developed to allow operators access to the bone marrow space quickly and efficiently. Aims The first aim of this study was to evaluate the quality of core specimens using the new powered device compared to specimens obtained using the traditional manual technique in a swine model. The second aim was to evaluate the safety and efficacy of the device in patients presenting for outpatient hematology clinic visits. Materials and Methods For the pre-clinical evaluation of the device, three anesthetized pigs were used for the study. The powered device (OnControl, Vidacare Corporation, San Antonio, TX, USA) was comprised of a battery powered driver and needle set. The manual device used was a T-Handle Jamshidi bone marrow biopsy needle (Cardinal Health, Dublin, OH, USA). Core biopsy samples obtained were assessed for length and sample quality and then submitted for analysis to a pathologist blinded to the device used. The clinical evaluation of the device was conducted in accordance with practice guidelines and directions for use. Data collection included insertion success, time from insertion to removal, specimen quality, operator satisfaction with control/function of the device and overall operator satisfaction based on a scoring system (0-5; 0=totally unacceptable, 5=outstanding). Results Twenty six samples were collected from the swine model (19 samples using the powered device and 9 using the manual technique). No cellular artifact or thermal damage was reported in any of the samples obtained. The mean lengths for samples obtained using the powered and manual techniques were respectively 19.4mm±1.6mm and 18.6mm±5.3mm. For the clinical evaluation of the device, 16 patients were recruited from 2 centers. Mean insertion time was 11.25±3.39 seconds and mean time from needle contact with skin to needle removal was 38.5±13.94 seconds. No complications were reported. Five operators rated the overall use of the device as outstanding in 75% of cases. Conclusions In this study, the manual and powered samples were equivalent in specimen quality. The powered device however, captured longer biopsies when compared to the manual technique. In the patients evaluated, the device was easy to use as well as being safe and effective. The mean procedural time was significantly faster than previously reported with a manual technique. A randomized study of the powered device compared to the manual technique is underway. Disclosures: Swords: Vidacare Corporation: Research Funding. Kelly:Vidacare Corporation: Research Funding. Mahalingam:Vidacare Corporation: Research Funding. Cohen:Vidacare Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Miller:Vidacare Corporation: Employment, Equity Ownership. Philbeck:Vidacare Corporation: Employment, Equity Ownership. Brenner:Vidacare Corporation: Consultancy, Research Funding. Giles:Vidacare Corporation: Research Funding.

Single Cell Network Profiling (SCNP) Functionally Characterizes FLT3 Pathway Deregulation in Non-M3 Acute Myeloid Leukemia (AML) and Provides Prognostic Value Independent From Mutational Status

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2512-2512
Author(s):  
Alessandra Cesano ◽  
Santosh Putta ◽  
Kavita Mathi ◽  
David B. Rosen ◽  
Urte Gayko ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Single Cell ◽  
Induction Therapy ◽  
Mutational Load ◽  
Receptor Signaling ◽  
Employment Equity ◽  
Cell Network ◽  
Mutational Status ◽  
Equity Ownership

Abstract Abstract 2512 Background: FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) mutations (FLT3 ITD+) result in constitutive activation of this receptor and have been shown to increase the risk of relapse in patients (pts) with AML; however, substantial heterogeneity in clinical outcomes still exists within both the FLT3 ITD+ and FLT3 ITD- AML subgroups, suggesting alternative mechanisms of disease relapse not accounted for by FLT3 mutational status. Single Cell Network Profiling (SCNP) is a multiparametric flow cytometry-based assay that simultaneously measures, in a quantitative fashion and at the single cell level, both extracellular surface marker levels and changes in intracellular signaling proteins in response to extracellular modulators (Kornblau et al. Clin Cancer Res 2010). Previously, we reported the use of this assay to functionally characterize FLT3 receptor signaling in healthy bone marrow and AML samples (Rosen et al. PLoS One 2010). By applying it to a separate cohort of samples collected from elderly non-M3 AML pts at diagnosis, a subclassification of AML samples beyond their “static” molecular FLT3 ITD status was generated (Rosen et al. ASH 2010 Abstr 2739). Specifically, FLT3 ITD- AML samples displayed a wide range of induced signaling, with a fraction having signaling profiles comparable to FLT3 ITD+ AML samples. Conversely, FLT3 ITD+ AML samples displayed more homogeneous induced signaling, with the exception of those with low mutational load, which had profiles more analogous to FLT3 ITD- AML samples. Due to the small numbers of pts in that exploratory study (n=44 [38 FLT3 ITD- and 6 FLT3 ITD+ pts]), an independent study was undertaken to confirm the observations, as well as to evaluate their clinical relevance (i.e., association with disease free survival (DFS) following anthracycline/cytarabine-based induction therapy). Methods: SCNP was performed as previously described on cryopreserved bone marrow or peripheral blood samples collected prior to anthracycline/cytarabine-based induction therapy from 104 elderly (>60y) non-M3 AML pts enrolled on ECOG trial 3999 or 3993 for whom ITD mutational status (including % mutational load), response and DFS data were available. Samples included 85 FLT3 ITD- and 19 FLT3 ITD+ AML, 30 and 8 of which, respectively, were collected from patients who achieved complete remission (CR). Objectives: The primary study objective was to confirm that levels of FLT3 ligand (FLT3L)-induced signaling (as measured by changes in intracellular phospho-S6 level) are more homogeneous in FLT3 ITD+ than in FLT3 ITD- myeloblasts. Four FLT3 ITD+ groups were pre-defined based on % mutation load (>0, 30%, 40%, or 50%). In addition, FLT3 ITD mutational status and signaling data from the SCNP assay (FLT3L and stem cell factor-induced phospho-S6 signaling and cytarabine/daunorubicin-induced apoptosis [cleaved PARP]) were combined to mathematically model their association with DFS among pts who achieved CR. DFS was defined as time from date of confirmed CR to date of relapse or death. Results: As shown in Figure 1a, our previous observations that variance in FLT3L-induced signaling is higher in FLT3 ITD- AML samples than in FLT3 ITD+ ones and that variance is decreased with increasing mutational load were verified in this study (Levene Test for FLT3 ITD- vs FLT3 ITD+ 50 p value=0.023). Further, when the association of DFS with FLT3 ITD mutational status and signaling data from the SCNP assay was measured using a Cox Proportional-Hazards model, the SCNP data were shown to provide independent information from FLT3 ITD mutational status (p =0.0115 for FLT3L-induced phospho-S6 signaling, Figure 1b). Conclusions: These data add to the growing body of evidence that, even within currently accepted risk stratification groups, AML is a heterogeneous disease. Functional characterization of FLT3 receptor signaling deregulation using SCNP provides prognostic information independent from FLT3 ITD mutational status and allows for more accurate pt stratification by functionally defining DFS risk sub-groups. Characterization of FLT3 signaling deregulation by SCNP could ultimately aid in the improved clinical management of AML pts and help identify candidates for FLT3 receptor inhibitor studies. Disclosures: Cesano: Nodality: Employment, Equity Ownership. Putta:Nodality Inc.: Employment, Equity Ownership. Mathi:Nodality: Employment. Rosen:Nodality Inc.: Employment, Equity Ownership. Gayko:Nodality Inc.: Employment, Equity Ownership. Hawtin:Nodality: Employment, Equity Ownership.

Final Results from an International, Multi-Center, Single-Arm Study Evaluating the Safety and Efficacy of Romiplostim in Adults with Primary Immune Thrombocytopenia (ITP),

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3279-3279 ◽  
Author(s):  
Ann Janssens ◽  
Michael D. Tarantino ◽  
Robert Bird ◽  
Maria Gabriella Mazzucconi ◽  
Ralph Vincent V. Boccia ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Platelet Count ◽  
Board Of Directors ◽  
Research Funding ◽  
Platelet Response ◽  
Employment Equity ◽  
Advisory Committees ◽  
Platelet Production ◽  
Platelet Counts ◽  
Equity Ownership

Abstract Abstract 3279 Background: ITP is an autoimmune disorder characterized by increased platelet destruction and suboptimal platelet production. Romiplostim stimulates platelet production via the TPO-receptor, and is recommended for second- and third-line treatment of chronic ITP in adults. We report final data from a large prospective study of romiplostim in adults with ITP of varying duration and severity. Methods: Eligibility criteria were broad: patients ≥18 years of age, who had received prior ITP therapies (final protocol amendment: ≥1, previous amendments: ≥3), with low platelet counts (final amendment: ≤ 30 × 109/L, previous amendments: ≤ 10, ≤ 20 × 109/L) or experiencing uncontrolled bleeding. The only excluded comorbidities were: hematological malignancy, myeloproliferative neoplasms, MDS and bone marrow stem cell disorder. Romiplostim was initiated at 1 (final amendment) or 3 (previous amendments) μg/kg/week, with dose adjustments allowed to maintain platelet counts ≥50 × 109/L. Patients could continue on study until they had access to commercially available romiplostim. Rescue medications were allowed at any time; concurrent ITP therapies could be reduced when platelet counts were > 50 × 109/L. Primary endpoint was incidence of adverse events (AEs) and antibody formation. Secondary endpoint was platelet response, defined as either (1) doubling of baseline count and ≥ 50 × 109/L or (2) ≥20 × 109/L increase from baseline. Results: A total of 407 patients received romiplostim, 60% of whom were female. Median (Q1, Q3) time since ITP diagnosis was 4.25 (1.20, 11.40) years (maximum 57.1 years), with 51% of patients splenectomised and 39% receiving baseline concurrent ITP therapies. Seventy-one percent of patients completed the study, with requirement for alternative therapy and withdrawn consent the most common reasons for discontinuation (5% each). Median (Q1, Q3) on-study treatment duration was 44.29 (20.43, 65.86) weeks (maximum 201 weeks), with a total of 20,201 subject-weeks on study. Incidence and type of AEs were consistent with previous studies. The most common serious treatment-related AEs were cerebrovascular accident, headache, bone marrow reticulin fibrosis (with no evidence of positive trichrome staining for collagen and no evidence suggesting primary idiopathic myelofibrosis), nausea, deep vein thrombosis, hemorrhage and pulmonary embolism, with each reported in 2 of 407 (0.5%) patients. All other serious treatment-related AEs were each reported in one patient. Eighteen patients died; 3 deaths (hemolysis, intestinal ischaema, aplastic anemia) were considered treatment-related. No neutralizing antibodies to romiplostim or TPO were reported. Approximately 90% of patients achieved each of the platelet response definitions, regardless of splenectomy status. Overall, median (Q1, Q3) time to response was 2 (1, 4) weeks for response definition 1, and 1 (1, 3) week for response definition 2. Median (Q1, Q3) baseline platelet count was 14 (8, 21) × 109/L. After 1 week of treatment median (Q1, Q3) platelet count had increased to 42 (18, 101) × 109/L. From week 8 onwards, and excluding counts within 8 weeks of rescue medication use, median platelet counts were consistently above 100 × 109/L (range 101.0–269.5 × 109/L). Median (Q1, Q3) average weekly romiplostim dose was 3.62 (1.99, 6.08) μg/kg. Summary/conclusions: This is the largest prospective study in adult ITP reported to date. The data reported here are similar to those reported for previous romiplostim studies, with romiplostim able to safely induce a rapid platelet response in adult ITP patients with low platelet counts or bleeding symptoms. Romiplostim is an important, well-tolerated, treatment option for adult ITP patients, which significantly increases and maintains platelet counts. Adverse Event Subject Incidence Platelet Response Disclosures: Janssens: Amgen: Consultancy; Roche: Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees. Tarantino:Cangene corporation: Research Funding; Baxter: Research Funding; Talecris: Honoraria, Speakers Bureau; Up-to-date: Patents & Royalties; The Bleeding and Clotting Disorders Institute: Board Member. Bird:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees. Boccia:Amgen: Equity Ownership, Honoraria, Speakers Bureau. Lopez-Fernandez:Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Kozak:Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Steurer:Amgen: Honoraria. Dillingham:Amgen Limited: Employment, Equity Ownership. Lizambri:Amgen: Employment, Equity Ownership.

Novel Protein Agonist of Thrombopoiesis Acts Via a Physiocrine Pathway Distinct From That of Thrombopoietin

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2376-2376
Author(s):  
Minh-Ha T Do ◽  
Wei Zhang ◽  
Kyle Chiang ◽  
Chi-Fang Wu ◽  
Chulho Park ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Board Of Directors ◽  
Employment Equity ◽  
Advisory Committees ◽  
Platelet Production ◽  
Platelet Counts ◽  
Normal Platelet ◽  
Naturally Occurring ◽  
Equity Ownership

Abstract Abstract 2376 Thrombopoietin (TPO) is recognized as the main regulator of platelet production, yet its genetic ablation in mice does not completely obliterate thrombopoiesis, suggesting that alternate pathways could lead to platelet formation. We recently identified a naturally-occurring protein that acts as a potent agonist of platelet production by a mechanism distinct from that of TPO. This protein belongs to a novel class of human extracellular signaling proteins called physiocrines that are generated from tRNA synthetases by alternative splicing or proteolysis. Physiocrines interact with several classes of receptors through unique mechanisms to modulate cellular differentiation and tissue homeostasis in normal and pathological processes. The newly identified thrombopoietic physiocrine, termed ATYR0030, is an engineered version of a naturally-occurring physiocrine derived from the tyrosyl tRNA synthetase (YRS). In vivo, systemic administration of ATYR0030 or YRS physiocrine to rats led to an increase in platelets counts comparable to that seen with TPO treatment, but with a greater effect in animals with low baseline platelet levels. When injected into normal animals preselected for low platelet counts, ATYR0030 treatment resulted in an increase in platelets up to, but not beyond, normal levels (Figure 1), suggesting a role in platelet homeostasis and differentiating its effects from the known activity of TPO. Intravenous administration of ATYR0030 also accelerated recovery of platelet counts in carboplatin-treated rats, indicating a possible role in bone marrow reconstitution after chemical insult. Consistent with homeostatic properties, no toxicity was seen in a repeat-dose 28-day non-GLP safety study in rats dosed up to 100-fold above the efficacious range. Histopathology assessment revealed no tissue abnormalities, no increase in bone marrow reticulin and no hyperplasia of myeloid precursors. Clinical chemistry and hematology parameters were in the normal range with a modest increase in platelet counts, as anticipated in animals with normal platelet levels. Our in vitro data suggest that ATYR0030 may play a role in megakaryopoiesis by facilitating cell migration and adhesion to the vasculature. In contrast to TPO, ATYR0030 does not directly signal through the TPO receptor and does not activate the JAK/STAT pathway but rather appears to engage specific G-protein coupled receptors. In vitro, ATYR0030 does not stimulate proliferation of cultured M07e human megakaryoblasts or primary bone marrow cells isolated from AML patients (Figure 2). The parent synthetase is present in human platelets and is secreted in response to platelet activation, perhaps providing a feedback mechanism to stimulate the release of new platelets. In an effort to link the biological activity of ATYR0030 and the role that the parent synthetase plays in human physiology, we have begun to analyze samples from patients with abnormal platelets counts to determine circulating levels of the parent synthetase. The unique thrombopoietic activity of ATYR0030 may lead to an orthogonal approach to restoring normal platelet levels in thrombocytopenic patients who currently have limited treatment options. For example, in the myelodysplastic syndrome population, TPO-receptor agonists carry a risk of stimulating blast proliferation and accelerating disease progression to acute myeloid leukemia (AML). The distinct proliferation profile of ATYR0030 may translate into important safety benefits by reducing the risk of progression to AML. In addition, the potential role of ATYR0030 in regulating platelet homeostasis may provide a greater safety margin in the normalization of platelet levels, thereby also limiting the risk of thrombosis. Leveraging the therapeutic potential of this thrombopoietic physiocrine may lead to the development of a novel treatment option with a favorable safety profile. Disclosures: Do: aTyr Pharma: Employment, Equity Ownership, Patents & Royalties. Zhang:aTyr Pharma: Employment, Equity Ownership. Chiang:aTyr Pharma: Employment, Equity Ownership. Wu:aTyr Pharma: Employment, Equity Ownership, Patents & Royalties. Park:aTyr Pharma: Equity Ownership. Yang:aTyr Pharma: Consultancy, Equity Ownership, Patents & Royalties, Research Funding. Kunkel:aTyr Pharma: Consultancy, Stock Ownership. Ashlock:aTyr Pharma: Employment, Equity Ownership. Mendlein:aTyr Pharma: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Belani:Atyr Pahrma: Consultancy, Equity Ownership, Patents & Royalties. Vasserot:aTyr Pharma: Employment, Equity Ownership, Patents & Royalties. Watkins:aTyr Pharma: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

Results of the OPAL Study: A Phase II Study to Evaluate the Efficacy, Safety and Tolerability of Tosedostat (CHR-2797) in Elderly Subjects with Treatment Refractory or Relapsed Acute Myeloid Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 767-767
Author(s):  
Jorge E. Cortes ◽  
Eric J Feldman ◽  
Karen Yee ◽  
David A. Rizzieri ◽  
Anjali S. Advani ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Phase Ii ◽  
Research Funding ◽  
Phase Iii ◽  
Elderly Subjects ◽  
Primary Therapy ◽  
Primary Analysis ◽  
Employment Equity ◽  
Once Daily ◽  
Equity Ownership

Abstract Abstract 767 Background: Tosedostat is a novel oral inhibitor of the M1/17 family of aminopeptidases which induces an amino acid deprivation response that is selectively toxic for myeloid blasts (Leuk Res. 2011: 5:677-81) and has shown promising activity in elderly relapsed/refractory AML patients (J Clin Oncol 2010:28:4333-8). Aims: The OPAL study was undertaken to compare the activity of tosedostat at a once-daily dose of 120 mg for 24 weeks compared to 240 mg once daily for 8 weeks followed by 120 mg once daily for a further 16 weeks., as measured by bone marrow and hematology responses at 24 weeks. Methods: This was a phase II randomized (1:1) multi-center study. Patients were eligible if aged 60 years or older with previous CR lasting <12 months, or no CR after primary therapy, had a peripheral blast count <30,000/μl, PS<2 and adequate renal, hepatic and cardiac function. The primary analysis was performed at 24 weeks using IWG 2003 criteria. Results: Seventy-three patients were randomized and received tosedostat, 38 at 120 mg and 35 at 240 mg. Median age was 72 (range, 64 to 86), and 59% were male. Twenty-six patients (36%) had secondary or therapy-related AML, of which 19 (26%) had prior MDS. Median time since AML diagnosis was 211 days and 38% had received primary therapy with cytarabine/anthracyclines; 36% with a hypomethylating agent (HMA) and 23% with other cytarabine regimes. Fifty-two percent had been refractory to primary therapy, 19% had previously had a remission of up to 6 months and 29% a 6–12 month remission (mean 97 days including refractory). Twenty-three patients (32%) had no post-treatment bone marrow sample taken, predominantly due to early progression: 34% completed 12 weeks on study and 14% completed 24 weeks and were eligible to enter an extension study which is ongoing. The overall response rate was 22%; (CR/CRp/MLFS 12%; PR 10%) and an additional 29% had a best response of stable disease. The most common adverse events which occurred (total; grade 3 or worse) were diarrhea (58%; 4.1%), peripheral edema (55%; 0%), fatigue (49%; 21%), dyspnea (41%; 16%), nausea (38%; 0%), decreased appetite (37%; 3%), febrile neutropenia (36%; 29%) and hypotension (36%, 10%). Median overall survival (OS) (at 15 July 2011) was 126 days. Median OS in patients with CR/CRp/MLFS, PR and SD were 280, 195 and 162 days respectively, and 261.5 days for patients with a response of PR or better. Median OS for patients with progression of disease or who were unevaluable was 61 days. Similar responses were seen in the two dose groups. Additional non protocol-specified analyses showed that the following types of patient appeared to respond well: AML NOC vs other AML types 16% vs 29% response, median OS 75 vs 168 days; patients with poor risk cytogenetics compared to intermediate/better, median OS 159 vs 107 days; those who received prior HMA compared to others, 38% vs 13% response, median OS 171 vs 104 days; and absence of prior CR 29% vs 14% response and median OS 169 vs 103 days. Conclusions: These results provide further encouraging evidence of efficacy and a favorable toxicity profile in a difficult to treat patient population. A phase III program of pivotal studies with tosedostat in AML and MDS will start in the near future. Disclosures: Cortes: Chroma Therapeutics Ltd.: Consultancy, Research Funding. Feldman:Chroma Therapeutics Ltd.: Consultancy, Research Funding. Yee:Chroma Therapeutics Ltd.: Consultancy, Research Funding. Rizzieri:Chroma Therapeutics Ltd.: Consultancy, Research Funding. Advani:Chroma Therapeutics Ltd.: Consultancy, Research Funding. Charman:Chroma Therapeutics Ltd.: Employment, Equity Ownership. Toal:Chroma Therapeutics Ltd.: Employment, Equity Ownership. Kantarjian:Chroma Therapeutics Ltd.: Consultancy, Research Funding.

RAP-536 Promotes Terminal Erythroid Differentiation and Reduces Anemia in a Murine Model of Myelodysplastic Syndromes

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3796-3796 ◽  
Author(s):  
Rajasekhar NVS Suragani ◽  
Robert Li ◽  
Dianne Sako ◽  
Asya Grinberg ◽  
R. Scott Pearsall ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Bone Marrow ◽  
Erythroid Differentiation ◽  
Severe Anemia ◽  
Ineffective Erythropoiesis ◽  
Employment Equity ◽  
Erythroid Hyperplasia ◽  
Erythroid Precursors ◽  
Equity Ownership ◽  
Terminal Erythroid Differentiation

Abstract Abstract 3796 Myelodysplastic syndromes (MDS) are a group of hematopoietic stem cell disorders characterized by peripheral blood cytopenias such as anemia, neutropenia or thrombocytopenia. Ineffective erythropoiesis due to increased proliferation and abortive maturation of precursors leads to severe anemia, the most common cytopenia observed in MDS syndromes. Despite elevated erythropoietin (EPO) and erythroid hyperplasia, MDS patients are often given recombinant EPO therapy to stimulate erythropoiesis. However, only a small proportion of patients respond to EPO therapy. Frequent blood transfusions as supportive care result in iron overloading and recently iron overloading is also linked to enhanced progression to AML. Therefore, alternative therapies are necessary to treat anemia in MDS patients. Signaling by members of the TGFβ superfamily are known regulators of erythropoiesis. We developed ACE-536, a ligand trap consisting of a modified activin receptor Type IIB extracellular domain linked to a human Fc domain. In vitro assays revealed that ACE-536 inhibits smad 2/3 ligands of the signaling pathway but not smad 1/5/8 ligands. Dose dependent studies using ACE-536 in mice, rats and monkeys revealed that ACE-536 treatment resulted in increased red blood parameters but did not affect other cell types. These data suggests that ACE-536 inhibits smad 2/3 phosphorylation modulating the expression of downstream genes involved in erythroid development pathway. BFU-E and CFU-E colony formation assays from bone marrow and spleen in mice following ACE-536 treatment revealed that ACE-536 did not affect the proliferation stages of erythropoiesis. In mice, terminal erythroid differentiation analysis by flow cytometry at 72hrs following RAP-536 (10mg/kg) treatment demonstrated decreased basophilic and increased ortho- and poly-chromatophilic erythroblasts and reticulocytes compared to VEH treatment. Cell cycle analysis of bone marrow and splenic erythroblasts counterstained with BrdU and 7-AAD after RAP-536 (10mg/kg, for 24 hours) or VEH treatment to EPO pre-treated (1500 units/kg, for 40 hours) mice (N=5/group) revealed that EPO+RAP-536 treatment resulted in significant decrease in S-phase and increase in G1/G2-phases of cell cycle compared to EPO+VEH treatment. In addition, EPO+RAP-536 treatment resulted in a greater increase in RBC parameters than either of the treatments alone. Together, these results demonstrate that ACE-536 increases red blood cell formation by promoting maturation of late stage erythroblasts. We then investigated the effect of ACE-536 on anemia in NUP98-HOXD13 (NHD13) transgenic murine model of MDS. NHD13 mice develop anemia, neutropenia and lymphopenia, with normal or hyper cellular bone marrow. A Majority of the mice die by 14 months due to severe pancytopenia or progression to acute myeloid leukemia. In this study, mice were divided into three groups based on age. Early (∼4 months old), mid (∼8 months old) and late stage (∼10 months) groups were randomized and dosed with either RAP-536 at 10 mg/kg or VEH twice per week for 6–8 weeks. NHD13 mice in each group had severe anemia characterized by reduced RBC, Hemoglobin and HCT and compared to wild-type littermates prior to treatment. Treatment of RAP-536 for 6–8 weeks significantly increased RBC parameters and reversed anemia at all stages. Peripheral blood smear analysis revealed no indication of increased leukemic progression due to RAP-536 treatment. Cell differential and flow cytometric evaluation of erythroid precursors from bone marrow demonstrated decreased erythroid precursors and hyperplasia after RAP-536 treatment compared to vehicle treated control. Our data demonstrate that RAP-536 can increase hematology parameters by enhancing maturation of terminally differentiated red blood cells. We have shown RAP-536 corrects ineffective erythropoiesis, decreases erythroid hyperplasia and normalizes myeloid: erythroid ratios without enhanced progression to AML in a murine MDS model. Therefore ACE-536 may represent a novel treatment for anemia associated with MDS, particularly in patients that are refractory to EPO therapy. ACE-536 has completed Phase I clinical trials in healthy human volunteers and Phase II study in MDS patients is planned. Disclosures: Suragani: Acceleron Pharma Inc: Employment, Equity Ownership. Li:Acceleron Pharma Inc: Employment, Equity Ownership. Sako:Acceleron Pharma Inc: Employment, Equity Ownership. Grinberg:Acceleron Pharma Inc: Employment, Equity Ownership. Pearsall:Acceleron Pharma Inc: Employment, Equity Ownership. Kumar:Acceleron Pharma Inc: Employment, Equity Ownership.

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