ALBERT

Description: Background: The patients with severe aortic-valve stenosis (AS) are often complicated with bleeding episodes. The association between AS and gastrointestinal bleeding due to angiodysplasia is reported as Heyde's syndrome, which is categorized as one of the acquired von Willebrand disease (AVWD) in cardiovascular disorders. An international survey has shown that Type 2A is the common subtype of AVWD in the patients with AS. AVWD Type 2A is characterized by impaired platelet-dependent VWF function caused by marked decrease or absence of the most hemostatically active HMW-VWFM. In the patients with AS, a significant correlation between the increased high shear stress and loss of HMW-VWFM in vivo. Further, the absence of HMW-VWFM and bleeding tendency are normalized after valve replacement. These results suggest that enhanced proteolysis of von Willebrand factor (VWF) as it passes through the stenotic valve may induce the loss of HMW-VWFM because high shear stress can induce structure changes in VWF, which is sensitive form to the VWF cleaving protease, termed ADAMTS13. Here, we performed investigation of plasma levels of VWF antigen (VWF:Ag), ADAMTS13 activity (ADAMTS13:AC), and platelet thrombus formation in the patients with AS by valve replacement to confirm the pathophysiological mechanism of this rare disease. Patients and Methods: Ten consecutive patients who underwent aortic valve replacement for AS in Nara Medical University Hospital were enrolled in this study. The severity of AS was judged by the American Heart Association guideline. All patients had no bleeding history and received bovine tissue valves replacement followed by administration of warfarin and/or anti-platelet agents for prevention of thrombosis a week after surgery. We collected a series of blood samples from these patients before and day1, 8, 15, 22 after valve replacement. Excluding one patient who developed critical cardiac failure just after valve replacement, 9 patients were eventually evaluated by analyses of VWF:Ag, VWF multimers, ADAMTS13:AC, and mural thrombus formation using flow chamber system. VWF:Ag was measured by sandwich ELISA using a rabbit anti-human VWF polyclonal antiserum. Analysis of VWF multimers was performed according to the method of Ruggeri and Zimmerman. ADAMTS13:AC was measured by a chromogenic ADAMTS13-act-ELISA. Platelet thrombus formation was evaluated by thrombus generation under a high shear stress in a parallel plate flow chamber system. Briefly, whole blood anti-coagulated with argatroban was incubated with the fluorescent dye DiOC6 (1uM), and these samples containing DiOC6 -labeled platelets were perfused for 7 min over a type I collagen-coated glass surface under a high shear rate (1500 s-1). The DiOC6 fluorescence corresponding to the platelets was examined at an excitation wavelength of 488 nm with a barrier filter at 500 nm. The percentage of the area covered by adhering platelets (surface coverage) and each thrombus volume were evaluated. Results: Plasma levels of VWF:Ag before surgery were 78.1 % (median) and those on day 1, 8, 15, 22 after surgery were 130, 224, 155, and 134 %, respectively (Fig 1). Conversely, these levels of ADAMTS13:AC were 50.5, 35.5, 25.5, 25.1, and 30.3 %, respectively (Fig 2). The ratio of VWF:Ag/ADAMTS13:AC at before and day 1, 8, 15, 22 after surgery were 1.6, 4.5, 8.1, 6.1, and 4.1, respectively. In VWF multimer analysis, we found the obvious defect of HMW-VWFM in 7 of 9 patients before surgery, who were diagnosed with severe AS. The remaining two patients had moderate AS with the slight defect of HMW-VWFM. These defects were improved within 14 days after surgery. In platelet thrombus formation, the amount of thrombus volumes significantly increased at day 8, 15, and 22 after compared with before surgery (Fig 3). Conclusion: The dramatic recovery of platelet thrombus formation was observed in the patients with AS by valve replacement. The rapid increment of VWF and normalization of VWFM pattern, together with reduction of ADAMTS13 after valve replacement suggested heightened proteolysis of VWF by ADAMTS13 under high shear stress would be a major cause of this unique bleeding complication. The highest ratio of VWF:Ag/ADAMTS13:AC at day 8 after surgery might imply the necessity of blockade of heightened VWF function with anti-platelet agents. Figure 1 Figure 1. Disclosures Matsumoto: Alfresa Pharma Corporation: Patents & Royalties. Fujimura:Alfresa Pharma Corporation: Patents & Royalties.

Description: Background/aims: Deficiency of plasma ADAMTS13 activity (:act) accumulates unusually large von Willebrand factor multimer (UL-VWFM) in circulation that might induce platelet thrombi formation. We demonstrated that hepatic stellate cells are major ADAMTS13-producing cells in human liver using in situ hybridization and immunohistochemistry (Blood, 2005, 106:922), and a decreased plasma ADAMTS13:act in patients with cirrhotic biliary atresia can be fully restored after living-related liver transplantation (Blood2000, 96:636a). Taken these findings together, ADAMTS13 may play a role on the regulation of sinusoidal microcirculation in the liver. We, therefore, investigated the relationship of ADAMTS13 and its substrate (UL-VWFM) to clinical features in patients with chronic liver diseases. Methods: Plasma levels of ADAMTS13:act, ADAMTS13 antigen (:ag) and VWF antigen (VWF:ag) were determined in 33 patients with chronic hepatitis (CH) and 109 liver cirrhosis (LC). ADAMTS13:act was measured by both the classic VWFM assay and the novel monoclonal antibody-based ELISA (Transfusion2006, 46:1444). The ADAMTS13:ag was quantified by a sandwich ELISA using two anti-ADAMTS13 murine monoclonal Abs (A10 and C7), and the UL-VWFM was analyzed by a SDS−0.9% agarose gel electrophoresis. Results: ADAMTS13:act in LC progressively decreased from the highest in Child A (mean 79%), to Child B (63%), to the lowest in Child C (30%), compared with CH (87%) and normal healthy subjects (N, 102%). The activity measured by VWFM assay highly correlated with that assayed by ELISA (r=0.75, p

Description: Background: Thrombotic microangiopathy (TMA) and sinusoidal obstruction syndrome (SOS) as well as acute GVHD are major complications after allogeneic hematopoietic stem cell transplantation (alloHSCT) to overcome to achieve better overall survival. These complications are closely relevant to inflammation and coagulation involving endothelium, which are named as transplantation-associated coagulopathy (TAC). Recombinant thrombomodulin (rTM) is a new drug for treating DIC approved by Japanese Ministry of Health, Labour and Welfare in 2008. Membranous TM has many aspects to inhibit inflammation via activated Protein C (APC), lectin-like domain, and activated thrombin-activatable fibrinolysis inhibitor as well as to inhibit coagulation by binding factor IXa and Xa through APC. Biomarkers such as inflammatory cytokines and endothelial molecules are expected to be clue in elucidating TAC. We established SIGHT study group to explore above complications following alloHSCT. In the present study, we investigated the effects of rTM on levels of the biomarkers and whether we could prevent TAC using rTM among registered patients in the SIGHT study group. Patients and methods: SIGHT study group covered nationwide institutes more than 70 in Japan. Patients whoever were eligible for alloHSCT to treat hematopoietic disorders by physicians decision were permitted and written informed consent was requested to register in the study. Blood samples were collected from the patients before and after transplantation through day 28. Levels of cytokines (IL-6, TNF-α, HMGB1, MCP-1, RANTES) and soluble molecules (VCAM-1, E-selectin, PAI-1, PDMP) were measured by ELISA. rTM was administered as a prophylactic therapy for TAC in day 4-14 after alloHSCT. Control group was received heparin or no anti-coagulation therapy as prophylaxis during same schedule as rTM group. Patients were not randomized to these three arms but allowed to select one by their physicians decision. The primary endpoint was a comparison of fluctuation of these biomarkers in three arms. Secondary endopoint was a comparison of the rate of developing TAC. Results: The subjects were 293 patients who underwent alloHSCT in SIGHT study group between June 2010 and February 2014. 271 patients out of them were analyzed to measure level of these biomarkers. There was no significant difference in all characteristics but GVHD prophylaxis between two groups. rTM group received more cyclosporine than control group (p=0.05). MCP-1 and IL-6 exhibited more significant elevations on day 7 after alloHSCT, while HMGB-1 did on the day of alloHSCT. In contrast, the levels of TNF-α, E-selectin, VCAM-1, PAI-1 and PDMP exhibited increment since around day 7 after alloHSCT. Significant improvements in TNF-α, E-selectin, VCAM-1, HMGB-1, PAI-1 and PDMP was shown after rTM-treatment, but not shown in control group. Regarding complications following alloHSCT, the rate of developing acute GVHD and SOS was significantly lower in rTM group than without it (36.5% vs 62.2%, p=0.000; 12.5% vs 24.5%, p=0.032, respectively), while TMA did not differ (8.4% vs 10.2%, p=0.961). Stepwise multivariate logistic regression analyses revealed that anti-coagulation therapy without rTM and the level of PAI-1 on day 28 after HSCT were independent risk factor for acute GVHD (p=0.000, odds ratio=3.006; p=0.000, odds ratio=1.068, respectively). Also anti-coagulation therapy without rTM and the level of HMGB-1 on day 28 after HSCT were significantly predictive for risk of SOS (p=0.015, odds ratio=2.650; p=0.001, odds ratio=1.433, respectively). Tacrolimus was significantly good risk of SOS (p=0.022, odds ratio=0.404). The level of VCAM-1 on day 28 after HSCT was significantly associated with risk of TMA (p=0.040, odds ratio=1.001). Conclusions: We identified predictive biomarkers for TAC following alloHSCT, which were PAI-1 for acute GVHD, HMGB-1 for SOS, and VCAM-1 for TMA, respectively in this study. The present findings suggest that rTM has the possibility to play a therapeutic role for acute GVHD and SOS induced by suppression on these biomarkers. Endothelial and pro-coagulant biomarkers were released delayed compared with inflammatory biomarkers. TMA is reported to develop around day 44 in median after alloHSCT. Further studies are needed whether rTM should administer later or longer to improve TMA than the present duration after alloHSCT. Disclosures No relevant conflicts of interest to declare.

Description: Background Levels of cytokines, chemokines and soluble molecules fluctuate after allogeneic hematopoietic stem cell transplantation (HSCT). These biomarkers are possible to be a diagnostic and prognostic value for transplantation-associated coagulopathy (TAC). In the present study, we investigated the effects of recombinant thrombomodulin (rTM) on levels of the cytokines, chemokines, and soluble factors registered in the ‘SIGHT’ research. SIGHT comprises the capital letters of five complications after HSCT, namely sinusoidal obstruction syndrome (SOS same as VOD), infection, GVHD, hemophagocytic syndrome and thrombotic microangiopathy. Methods The subjects were 159 patients who underwent allogeneic HSCT (bone marrow = 83, peripheral blood stem cells = 31, cord blood = 45). Blood samples were collected before and after transplantation. Levels of cytokines (interleukin-6, tumor necrosis factor-α, high-mobility group box (HMGB) 1), chemokines (monocyte chemotactic protein (MCP)-1, RANTES), and soluble molecules (soluble vascular cell adhesion molecule (VCAM)-1, soluble E-selectin, plasminogen activator inhibitor-1, platelet-derived microparticles (PDMP)) were measured by enzyme-linked immunosorbent assay. The rTM was administered as a therapy for transplantation-associated coagulopathy (TAC). This protocol was completed in day 4-14 after HSCT and consisted of day doses of 380 unit/kg with every days. Control group was also used heparin or no anti-coagulation therapy. Results MCP-1, IL-6, and TNF-a exhibited more significant elevations on days 7–14 after HSCT. In contrast, the levels of HMGB1, sE-selectin, sVCAM-1, PAI-1 and PDMP exhibited significant changes on days 14–28. There were significant improvements in TNF-a, sE-selectin, sVCAM-1, HMGB1, PAI-1 and PDMP after rTM-treatment (n=73), but not after rTM-untreatment patients (n=86). Conclusion We believe one of causes for TAC is pro-inflammatory cytokine including HMGB1. For this reason, it is thought that the direct anti-inflammatory effect of rTM’s lectin domein plays an important role in therapeutic mechanism for TAC. The present findings suggest the possibility that rTM can play a therapeutic role for TAC after allogeneic HSCT. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction: Daily plasma exchange (PE) has become a definitive first-line treatment for acquired thrombotic thrombocytopenic purpura (TTP). However, it remains to be controversial whether platelet transfusion is harmful or not for patients with acquired TTP during initial treatment. Some articles showed that platelet transfusion was considered as hazardous because platelet transfusion might generate widespread fresh platelet aggregates in circulation, but others reported that the mortality rate was not different between patients with and without platelet transfusion. Herein, we conducted a retrospective analysis of a large cohort of patients with acquired idiopathic TTP (ai-TTP) in Japan evaluating whether platelet transfusion was associated with unfavorable outcomes. Patients and Methods: Our laboratory has been functioning as a nationwide referral center for thrombotic microangiopathies (TMAs) in Japan. We collected a large dataset of medical information on 1211 patients with TMA from March 2000 to December 2013. Among them, 263 were ai-TTP patients with severe deficiency (

Description: Background: Although molecular complete remission (mCR) in multiple myeloma (MM) can be assessed by allele-specific oligonucleotide (ASO)-PCR, this technique requires preparation of clonotype-specific primers for each individual, which is laborious and time-consuming. We utilized the LymphoSIGHTTM platform, which employs consensus primers and next-generation sequencing (NGS) to amplify and sequence all rearranged immunoglobulin gene segments present in a myeloma clone, to assess mCR. This technique has been shown to have 1-2 logs greater sensitivity compared to ASO-PCR and flow cytometry, respectively (Faham et al, Blood 2012). Usage of the sequencing method for minimal residual disease (MRD) detection in MM may provide increased sensitivity and specificity, while overcoming the challenges associated with ASO-PCR. We compared the LymphoSIGHTTM method with ASO-qPCR for MRD detection in autografts and bone marrow (BM) in the autologous peripheral blood stem cell (PBSC) transplantation (ASCT) setting. Methods: One hundred and nine Japanese patients with newly diagnosed MM who received various induction regimens prior to ASCT were retrospectively analyzed. All patients had achieved a partial response (PR) or better after ASCT. BM slides from 84 MM patients and fresh/frozen BM cells from 25 MM patients at diagnosis, as well as autografts/post-ASCT BM cells from each patient, were obtained for DNA extraction. IGH-based ASO-qPCR was performed as described previously (Methods Mol Biol 2009). Using universal primer sets, we amplified IGH variable (V), diversity (D), and joining (J) gene segments, IGH-DJ, and IGK from genomic DNA. Amplified products were subjected to deep sequencing using NGS. Reads were analyzed using standardized algorithms for clonotype determination. Myeloma-specific clonotypes were identified for each patient based on their high frequency in BM samples. Results : Myeloma clonotypes could be identified in autografts/post-ASCT BM cells in 98 of 109 patients (90%) and by ASO-qPCR in 63 of 101 patients (62%). MRD by NGS was assessed in autografts of 89 patients. 70 of 89 patients (79%) were positive by NGS; 28 of 62 patients (45%) were positive by ASO-qPCR. Although we observed a high correlation between NGS and PCR MRD results at MRD levels of 10-5 or higher, the sensitivity of ASO-PCR was 10-4-10-5, whereas that of NGS was 10-6 or lower when a sufficient amount of DNA was available for analysis. Eight cases where MRD was not detected in the autograft by NGS (MRDNGS(-)) and 38 MRDNGS(+) cases received post-ASCT therapy using novel agents such as bortezomib/lenalidomide/thalidomide, while 11 MRDNGS(-) cases and 32 MRDNGS(+) cases were followed without post-ASCT therapy. The MRDNGS(-) cases without post-ASCT therapy showed significantly better progression-free survival (PFS) than the MRDNGS(+) cases without post-ASCT therapy (P = 0.012) (Figure 1A) although overall survival rates were comparable between these groups. To investigate the value of sensitive detection by NGS, we compared PFS in 11 MRDNGS(-) cases (Group 1) with the 12 MRDNGS(+) cases where MRD was not detected by ASO-qPCR (MRDASO(-)) (Group 2). The patients in both groups did not receive any post-ASCT therapy. Group 1 showed significantly better PFS than Group 2 (P = 0.027) (Figure 1B). Furthermore, 9 MRDNGS(-) in post-ASCT BM cases tended to show a better PFS than 18 MRDNGS(+) in post-ASCT BM cases (P = 0.075) (Figure 1C). In a multivariate analysis, post-ASCT therapy using novel agents (P

Description: Idiopathic thrombocytopenic purpura (ITP) is one of the major causes of thrombocytopenia. Currently, the diagnosis of ITP is principally based on the exclusion of other possible concurrent causes of thrombocytopenia. In the guidelines proposed by the American Society of Hematology, the panel recommended that no specific laboratory tests are considered necessary for the diagnosis. However, availability of reliable laboratory assays should be helpful in supporting the diagnosis of ITP. Recently, 2 of us (MK and YI) reported that erythrocyte count, leukocyte count, anti-GPIIb/IIIa antibody-producing B cells, platelet-associated anti-GPIIb/IIIa antibodies, reticulated platelets and thrombopoietin measured at first visit were useful to predict a future diagnosis of chronic ITP (manuscript submitted). To confirm this, we conducted a multicenter prospective study involving 113 patients with thrombocytopenia and a normal peripheral blood film at first visit. Patients with clinically apparent associated conditions that can cause thrombocytopenia were excluded. Each patient underwent physical examination and routine laboratory tests, and was prospectively followed for 〉6 months. Anti-GPIIb/IIIa antibody-producing B cells, platelet-associated anti-GPIIb/IIIa antibodies, reticulated platelets and plasma thrombopoietin were also examined at first visit. Clinical diagnosis was made in a blinded fashion based on bone marrow findings and the clinical course. Eighty-nine patients were diagnosed as having chronic ITP, and 24 had a non-ITP disorder, including 11 with aplastic anemia (AA), 10 with myelodysplastic syndrome (MDS), and one each with Fanconi anemia, May-Hegglin anomaly and myelofibrosis. Six laboratory findings were identified as initial parameters that discriminated future diagnosis of chronic ITP from non-ITP. These included the absence of anemia, absence of leukopenia, increased anti-GPIIb/IIIa antibody-producing B cell frequency, increased platelet-associated anti-GPIIb/IIIa antibodies, elevated reticulated platelet percentage and normal or slight increase of thrombopoietin (all for P 〈 0.001). Stepwise multiple regression analysis revealed that anemia, anti-GPIIb/IIIa antibody-producing B cell frequency, reticulated platelet percentage and thrombopoietin were factors that independently contributed to the later diagnosis of chronic ITP. Three or more of 6 ITP-associated laboratory findings were present at presentation in 78 (93%) patients later diagnosed as chronic ITP, compared with 6 (25%) patients whose disorder was non-ITP (P 〈 10−5). All 6 “false-positive” patients were diagnosed as AA or MDS, but 4 of them probably had overlapping immune thrombocytopenia. In summary, this multicenter prospective study confirms usefulness of 6 laboratory tests for the diagnosis of chronic ITP. The identification of ITP-associated laboratory findings encourages the future development of reliable diagnostic criteria for chronic ITP.

Description: Background: We recently reported that the International Prognostic Scoring System for Waldenström macroglobulinemia (ISSWM), which is widely used to predict the prognosis of WM patients, might not be applicable to Japanese patients, and evidence of pleural effusion might be a novel adverse prognostic factor for symptomatic WM in the rituximab era. Further studies with a large number of patients are deemed to be conducted. Methods: We retrospectively analyzed the clinical data of 498 patients with WM diagnosed between January 2001 and December 2015 from 44 institutes involved with the Japanese Society of Myeloma. The overall survival (OS) was analyzed using Kaplan-Meier methods and compared using log-rank test. Several clinical characteristics at the diagnosis were assessed by Cox regression for univariate and multivariate analyses of the OS. Results: We included 420 cases diagnosed with symptomatic (n=314) and asymptomatic WM (n=106) in accordance with the classification of the Second International Workshop on WM. The median age at the diagnosis was 69 (range, 32-91) years, with 75.5% male, and 16.0% had an Eastern Cooperative Oncology Group performance status (ECOG PS) of 2-4. Oral alkylating agents, purine analogs, cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) or CHOP-like regimens ± rituximab, rituximab monotherapy, or dexamethasone, rituximab and cyclophosphamide (DRC) were mainly administered as initial treatment. Rituximab-containing therapy was administered in 76.8% of all patients. The median follow-up was 45 months. The 5-year OS rate for all patients was 77.9%, while the rates for those with symptomatic and asymptomatic WM were 72.9% and 92.2%, respectively. Significant differences in the survival were seen between risk groups of ISSWM in symptomatic WM patients (5-year OS: high, 55.4%; intermediate, 81.2%; low, 90.2%; p65 years, platelet count ≤10×104/µL, serum β2-microglobulin (β2-MG) 〉3 mg/L, ECOG PS 2-4, abnormal karyotype, pleural involvement, WBC 1.5 mg/dL, CRP 〉2.0 mg/dL and sIL-2R 〉4000 U/mL were significant adverse prognostic factors for the OS. A multivariate analysis revealed that a platelet count ≤10×104/µL (hazard ratio [HR] 5.942; 95% confidence interval [CI] 2.265-14.761), serum β2-MG 〉3 mg/L (HR 2.748; 95% CI 1.091-7.655), ECOG PS 2-4 (HR 2.899; 95% CI 1.219-6.290), and pleural involvement (HR 11.066; 95% CI 3.672-29.829) were adverse independent risk factors for symptomatic WM. We constructed a prognostic model by combining these prognostic variables as follows: patients with good risk (n=219), no adverse factors or only serum β2-MG 〉3 mg/L or ECOG PS 2-4; patients with poor risk (n=81), ≥1 adverse factors with a platelet count ≤10×104/µL, pleural involvement, or both serum β2-MG 〉3 mg/L and ECOG PS 2-4. The 5-year OS rates were 82.3% for good risk and 44.4% for poor risk, and this prognostic model significantly stratified symptomatic WM patients separately by the survival (p

Description: von Willebrand factor (VWF) is a blood glycoprotein that plays an important role in platelet thrombus formation through interaction with its A1 domain and platelet glycoprotein 1b. Thus, VWF A1 domain was thought to be a good therapeutic target candidate for VWF mediated thrombosis. In this study, we analyzed the inhibitory effects of a novel DNA aptamer (TAGX-0004) on platelet aggregation compared with another VWF A1 domain binding aptamer (ARC1779) which had entered to Phase II clinical trial for acquired thrombotic thrombocytopenic purpura (TTP) in 2011. TAGX-0004 was generated by SELEX (systematic evolution of ligands by exponential enrichment) and consisted of artificial nucleic acid base, 7-(2-thienyl) imidazo [4,5-b] pyridine (Ds) as well as natural bases (Adenine, Thymine, Cytosine and Guanine). The dissociation constant (Kd) of the aptamers was analyzed by electrophoretic mobility shift assay (EMSA). 100 nM of each DNA aptamer was mixed with A1 domain of VWF protein (final concentration was 0 to 800 nM) in binding buffer (1x PBS, 0.005% NP-40) and incubated for 30 min at 37 °C. The samples were subjected to EMSA with 8% native PAGE, then stained by SYBR Gold. Kd value was determined with scatchard plot analysis. To characterize the binding sites of VWF A1 to these DNA aptamers, various mutants of VWF A1 domain were generated with an alanine substitution technique. Platelet aggregation was induced with ristocetin (RIPA), botrocetin (BIPA), collagen, epinephrine and adenosine diphosphate (ADP). The change of light transmission rate of platelet rich plasma (PRP) compared to platelet poor plasma (PPP) at 37 °C was recorded for 6 min, then the inhibition ratio of platelet aggregation was determined. Total thrombus-formation analysis system (T-TAS) (Fujimori Kogyo Co. Ltd., Tokyo, Japan), which is a novel micro-chip flow-chamber system, was employed to analyze thrombus formation visually and quantitatively in whole blood samples. The micro-chip coated with type 1 collagen was used for this analysis. Anti-VWF A1 inhibitory effects of these aptamers at high shear stress (initial rate of 2000 s-1) were calculated by continuous pressure levels within its narrow capillary. The course of thrombus formation was also optically recorded with a video-microscope located under the microchip. Biophysical interaction analysis using EMSA showed that TAGX-0004 had approximately 15-times higher binding activity to VWF A1 domain than ARC1779. Based on an alanine scan analysis, it was revealed that a couple of residues we tested were critical for binding of ARC1779 but not for TAGX-0004, which indicating that TAGX-0004 interacts with VWF A1 domain via different amino acid residue(s). Both aptamers did not inhibit the platelet aggregation induced by collagen, epinephrine or ADP. In RIPA, the 80% inhibition was observed by TAGX-0004 and ARC1779 at a final concentration of 10 nM and 750 nM, respectively. In BIPA, those were seen at those of 50 nM and 1000 nM, respectively. In T-TAS analysis, TAGX-0004 inhibited the thrombus formation completely at a final concentration of 100 nM, whereas ARC1779 exhibited partial inhibition of thrombosis formation even at 1000 nM. These results indicated that TAGX-0004 had stronger inhibitory effect on the platelet aggregation compared with ARC1779 under both static and high-shear conditions. In the present study, we showed the affinity to VWF-A1 domain of TAGX-0004 was stronger than that of ARC1779. In addition, TAGX-0004 was more effective in suppressing platelet aggregation under both static and high-shear stress condition than ARC1779. In the published results of clinical study of ARC1779, there were no hemorrhagic complications in the small clinical trial of patients (7 patients of ARC1779 group) despite the almost complete suppression of VWF function in severely thrombocytopenic patients. Therefore, TAGX-0004 could be developed as a promising therapeutic agent for VWF mediated thrombotic disorders, such as acute coronary syndrome and TTP. Disclosures No relevant conflicts of interest to declare.

Description: Background: Autologous stem cell transplantation (ASCT) in conjunction with therapeutic drugs such as bortezomib, thalidomide, and lenalidomide can dramatically improve response rates and the prognosis of patients with multiple myeloma (MM). However, most patients with MM are considered to be incurable, and relapse owing to minimal residual disease (MRD) is the main cause of death among these patients. Here we utilized a next-generation sequencing (NGS) approach for MRD assessment, which offers at least 1 to 2 logs greater sensitivity (10-6) compared to allele-specific oligonucleotide PCR (ASO-PCR) and flow cytometry, respectively (Faham et al Blood 2012). Previous studies have shown that NGS-based MRD assessment 90 days post-ASCT has prognostic value (Martinez-Lopez et al Blood 2014). In this study, we compared the prognostic value of MRD assessment in autografts and bone marrow (BM) samples from MM patients in the ASCT setting. Methods: One hundred and twenty-three Japanese patients with newly diagnosed MM who received various induction regimens prior to ASCT were retrospectively analyzed. All patients received ASCT and were followed between June 15, 2004 and April 25, 2015. All patients had achieved a partial response (PR) or better after ASCT. Analyzed samples included: (1) BM slides from 96 MM patients at diagnosis, (2) fresh/frozen BM cells from 27 MM patients at diagnosis, (3) autografts and/or (4) post-ASCT BM cells obtained at the time of best response based on serum and urine tests. IGH-based ASO-PCR was performed as described previously (Methods Mol Biol 2009). NGS-based MRD assessment was performed using the immunosequencing platform (Adaptive Biotechnologies, South San Francisco, CA) (Martinez-Lopez et al Blood 2014). Results: We compared MRD results in 51 samples assessed by ASO-PCR and NGS. We observed a high correlation between NGS and ASO-PCR results at MRD levels of 10-5 or higher (r=0.86, P