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Standard pharmacokinetic (PK) assessments are demanding for persons with hemophilia A, requiring a 72-hour washout and 5 to 11 timed blood samples. A no-washout, single-clinic visit, sparse sampling population PK (PPK) protocol is an attractive alternative. Here, we compared PK parameters obtained with a traditional washout, 6-sampling time point PPK protocol with a no-washout, single-clinic visit, reverse 2-sampling time point PPK protocol in persons with severe hemophilia A (SHA) receiving ADVATE. A total of 39 inhibitor-negative males with SHA (factor VIII activity [FVIII:C]

Preventing factor VIII (FVIII) inhibitors following replacement therapies with FVIII products in patients with hemophilia A remains an unmet medical need. Better understanding of the early events of evolving FVIII inhibitors is essential for risk identification and the design of novel strategies to prevent inhibitor development. The Hemophilia Inhibitor Previously Untreated Patients (PUPs) Study (HIPS; www.clinicaltrials.gov #NCT01652027) is the first prospective cohort study to evaluate comprehensive changes in the immune system during the first 50 exposure days (EDs) to FVIII in patients with severe hemophilia A. HIPS participants were enrolled prior to their first exposure to FVIII or blood products (“true PUPs”) and were evaluated for different immunological and clinical parameters at specified time points during their first 50 EDs to a single source of recombinant FVIII. Longitudinal antibody data resulting from this study indicate that there are 4 subgroups of patients expressing distinct signatures of FVIII-binding antibodies. Subgroup 1 did not develop any detectable FVIII-binding immunoglobulin G (IgG) antibodies. Subgroup 2 developed nonneutralizing, FVIII-binding IgG1 antibodies, but other FVIII-binding IgG subclasses were not observed. Subgroup 3 developed transient FVIII inhibitors associated with FVIII-binding IgG1 antibodies, similar to subgroup 2. Subgroup 4 developed persistent FVIII inhibitors associated with an initial development of high-affinity, FVIII-binding IgG1 antibodies, followed by IgG3 and IgG4 antibodies. Appearance of FVIII-binding IgG3 was always associated with persistent FVIII inhibitors and the subsequent development of FVIII-binding IgG4. Some of the antibody signatures identified in HIPS could serve as candidates for early biomarkers of FVIII inhibitor development.

The FVIII binding site on von Willebrand factor (VWF) is located in the D’ (766-864) and D3 (1054-1060) regions of the VWF gene. The cysteine residues in the D’ domain form disulfide bridges within the D’ trypsin-inhibitor-like (TIL’) and E’ regions,and these are of critically importance for the binding between TIL’E’ and FVIII. We analyzed the molecular etiology and laboratory phenotype of von Willebrand disease (VWD) 2N patients reported in the literature and added personal experiences from three European VWF VWD Research Centers.

International audience; Introduction - Antihaemophilic factor (recombinant) (rAHF; ADVATE ) is approved for prophylaxis and treatment of bleeding in children and adults with haemophilia A. Reconstitution in 2 mL sterile water for injection instead of 5 mL allows for a 60% reduction in infusion volume and administration time, but could increase the likelihood of hypersensitivity and infusion-related reactions, especially in children. Aim - To assess local tolerability, safety and effectiveness of rAHF 2 mL during routine clinical practice factor VIII (FVIII) replacement (on-demand and prophylaxis) in children with severe (FVIII

The objective of this scoping review is to summarize the current use of pharmacokinetics for tailoring prophylaxis in hemophilia patients switching between clotting factor products. Patients with hemophilia may require switching of clotting factor concentrates due to a variety of factors, but there have been perceived risks associated with switching, such as inhibitor development or suboptimal protection due to inadequate dosing while titrating treatment. Studies that look at patients switching from one clotting factor concentrate to another are categorized in terms of their primary and/or secondary objectives, notably biosimilarity and comparative pharmacokinetic studies and inhibitor development studies. Research on how best to switch concentrates with respect to dosing regimen are lacking, and currently a trial-and-error approach is used for dosing the new factor concentrate. In the future, studies looking at the predictability of pharmacokinetics (PK) of a new factor concentrate based on individual PK knowledge of the original factor concentrate may offer clinical benefit by providing a safer switching approach and protocol.

Diamond-Blackfan anemia (DBA) is a rare congenital erythroid aplasia, underlied by haploinsufficient mutations in genes coding for ribosomal proteins (RP) in approximately 70% of cases. DBA is frequently associated with somatic malformations, endocrine dysfunction and with an increased predisposition to cancer. Here we present clinical and genetic characteristics of 62 patients from 52 families enrolled in the Czech and Slovak DBA Registry. Whole exome sequencing (WES) and array comparative genomic hybridization (aCGH) were employed to identify causative mutations in newly diagnosed patients and in cases with previously unrecognized molecular pathology. RP mutation detection rate was 81% (50/62 patients). This included 8 novel point mutations and 4 large deletions encompassing some of the RP genes. Malignant or predisposing condition developed in 8/62 patients (13%): myelodysplastic syndrome in 3 patients; breast cancer in 2 patients; colorectal cancer plus ocular tumor, diffuse large B-cell lymphoma and multiple myeloma each in one case. These patients exclusively harbored RPL5, RPL11 or RPS19 mutations. Array CGH is beneficial for detection of novel mutations in DBA due to its capacity to detect larger chromosomal aberrations. Despite the importance of genotype-phenotype correlation in DBA, phenotypic differences among family members harboring an identical mutation were observed.

Objectives\ud \ud In a separate document, we have provided specific guidance on performing individual pharmacokinetic (PK) studies using limited samples in persons with hemophilia with the goal to optimize prophylaxis with clotting factor concentrates. This paper, intended for clinicians, aims to describe how to interpret and apply PK properties obtained in persons with hemophilia. \ud \ud \ud Methods\ud \ud The members of the Working Party on population PK (PopPK) of the ISTH SSC Subcommittee on Factor VIII and IX and rare bleeding disorders, together with additional hemophilia and PK experts, completed a survey and ranking exercise whereby key areas of interest in the field were identified. The group had regular web conferences to refine the manuscript’s scope and structure, taking into account comments from the external feedback to the earlier document. \ud \ud \ud Results\ud \ud Many clinical decisions in hemophilia are based on some form of explicit or implicit PK assessment. Individual patient PK profiles can be analyzed through traditional or PopPK methods, with the latter providing the advantage of fewer samples needing to be collected on any prophylaxis regimen, and without the need the for a washout period. The most useful presentation of PK results for clinical decision making are a curve of the factor activity level over time, the time to achieve a certain activity level, or related parameters like half‐life or exposure (AUC). Software platforms have been developed to deliver this information to clinicians at the point of care. Key characteristics of studies measuring average PK parameters were reviewed, outlining what makes a credible head‐to‐head comparison among different concentrates. Large data collections of PK and treatment outcomes currently ongoing will advance care in the future. \ud \ud \ud Conclusions\ud \ud Traditionally used to compare different concentrates, PK can support tailoring of hemophilia treatment by individual profiling, which is greatly simplified by adopting a PopPK/Bayesian method and limited sampling protocol.

Recently, analyses on inhibitor development according to concentrate in previously untreated patients (PUPs) from two national cohort studies have been published. A similar analysis has been performed on the first 4 years of data collection of the European Haemophilia Safety Surveillance System (EUHASS) project. Together with the initial report from the RODIN study published in 2013 [4], these publications provide data on a very considerable number of patients, almost exclusively originating from Europe. Reporting to multiple registries is common, and a rare disease such as haemophilia is no exception. Although the FranceCoag study, the UKHCDO study and the EUHASS study excluded patients overlapping with the RODIN study from their analyses, the additional overlap between the EUHASS, the FranceCoag and UKHCDO studies has not been previously reported. The analysis of non-overlapping data from the EUHASS study has the potential to contribute to the ongoing discussion about the perceived increased inhibitor risk associated with the use of specific recombinant Factor VIII concentrates. Thus, we hereby provide additional analyses of the data from the EUHASS study., peer-reviewed

A complete set of rapid activity and classical von Willebrand factor (VWF) assays for Willebrand disease (VWD) diagnosis was used in the present study to characterize VWD type 1, 2A, 2B and 2M patients due to mutations in the A1, A2 and A3 domains. The VWF:RCo/VWF:Ag, VWF:GPIbM/VWF:Ag and VWF:GPIbR/VWF:Ag ratios at cuttt off value of 0.7 separated VWD type 1 and LowVWF from VWD type 2. The results from the Brno cohort of VWD 2A patients with the G1579R mutation in the A2 domain in sixteen affected member from five families and in one case with the G1609R in the A2 domain revealed that the VWF:GPIbM/VWF:Ag and VWF:GPIbR/VWF: Ag ratios are marked decreased (range 0.03-0.27) to a similar degree as compared to VWF:RCo/VWF:Ag and VWF:CB/VWF:Ag ratios (range 0.03-0.27) due to the proteolytic loss of large and intermediate VWF multimers. The results in VWD 2B patients due to gain of ristocetin induced platelet agglutination (RIPA) function mutations R1306W, R1308C and R1341 in the A1 domain demonstrated that the ratios for VWF:GPIbM/VWF:Ag and VWF:GPIbR/VWF:Ag as compared to VWF:RCo/VWF:Ag ratio were markedly decreased in VWD 2B, whereas the VWF:GPIbM/VWF:Ag ratio was somewhat higher (range 0.32 to 0.36) in VWD 2M. VWD 2M patients due to loss of RIPA function mutation R1359K in the A1 domain are featured by decreased VWF ratios for WVF:RCo/Ag and VWF:GPIbR/Ag, but less decreased for the VWF:GPIbM/Ag ratio and normal VWF ratio for VWF:CB/Ag ratio the need to retain the VWF:CB assay to make a correct diagnosis of VWD 2M for its differentiation from VWD type 1. The G1415D mutation in the A1 domain is featured by decreased RIPA and decreased VWF:RCo/VWF:Ag ratio (VWD 2M) but normal values for VWF:CB/VWF:Ag, VWF:GPIbM/VWF:Ag and VWFGPIbR/VWF:Ag ratios consistent with VWD 2M. Double heterozygous P1266L/V1278I mutation in two patients and heterozygous E1292D/WT mutation in three patients in the A1 domain were diagnosed as VWD 2M or 1M associated with a secretion defect (SD). The Platelet Function Analyzer Closure Times (PFA-CT) are strongly prolonged in VWD 2A, 2B and 2M. and moderately prolonged between the upper limit of normal to 300 seconds in heterozygous mutated VWD type 1 patients.

Thirty-two consecutive children aged 0–18 years with VTE treated with LMWH administered as a continuous infusion (CI) were identified at the Children's University Hospital Brno. The treatment led to at least partial resolution of the thrombus within two weeks in 85% of patients. There were no adverse events or increased bleeding reported in any patients. No recurrences were observed during a followup period of 6 months. Although continuous infusion should not replace subcutaneous (SC) administration of LMWH, CI appeared to be safe and efficient and may provide an alternate method of administering LMWH in a subset of the paediatric population where SC administration may not be feasible. Further prospective studies are needed to support the promising findings of our pilot clinical observation.

Legionella was detected in aeration ponds (biological treatment plant) at Borregaard Ind. Ltd., Norway, and in air samples harvested directly above these ponds. Since 2005, three outbreaks of legionellosis occurred within a 10 km radius from this plant. This work addresses the dispersion patterns of Legionella-containing particles by characterizing the aerosol plume emitted from these ponds (outbreak source) less than 500 meters using wind-tunnel measurements, CFD simulations, and real-life measurements. The most abundant particles directly over the ponds were less than 6 and more than 15 microm. The results showed that the aerosol plume remained narrow; 180 meters wide at 350 meters downwind of the ponds, and that 2 and 18 microm aerosols were mainly deposited in the vicinity of the ponds ( 150 - 200 meters). Furthermore, the maximum aerosol concentration level appeared 5-10 meters above ground level and the maximum concentration 500 meters downwind was approximately 2 per cent of the concentration level directly above the ponds. Our study demonstrates the strength of combining modeling with real-life aerosol analyses increasing the understanding of dispersion of airborne (pathogenic) microorganisms.

Introduction Clearance of infused factor VIII (FVIII) varies approximately 2-fold between persons with severe hemophilia A. This results in significant interpatient differences in factor levels following an infusion of FVIII and contributes to potentially significant differences in protection against spontaneous musculoskeletal bleeding in patients on fixed dose prophylaxis regimens. Aim The aim of this study is to compare two PK protocols: 1) a 6-point PK protocol with a 72 hour washout; and 2) a 2-point, one clinic visit PK protocol with no washout using the following pharmacokinetic (PK) parameters: clearance (Cl) and time to FVIII:C of 1% above baseline (tt1%) in persons with severe hemophilia A. Methods Inhibitor negative males with severe hemophilia A (FVIII Results 28 males (median age: 12 years, range: 2-69 years) participated. The frequency distribution of clearance and the median half-life (t1/2) generated using myPKFiT is presented in Figure 1. There was a substantial to almost perfect agreement observed when comparing the PK parameters derived from the 6-point PK protocol with washout using the two PK programs (Table 1). There was a moderate to almost perfect agreement observed when comparing the PK parameters derived from the 6-point PK protocol with washout to the 2-point PK protocol with no washout using the myPKFiT program (Table 2). Conclusion The 2-point, one clinic visit, PK protocol (24 and 3 hrs) with no washout offers a convenient and practical approach to generating clinically relevant PK parameters in persons with severe hemophilia A. It can provide information relevant to selection of personalized prophylaxis regimens that aim to reduce to a minimum/eliminate spontaneous joint bleeding. Disclosures Blanchette: Shire: Other: Investigator-initiated research funding; Novo Nordisk: Other: Speaker's fees; Shire: Other: Speaker's fees; Bayer: Other: speaker's fees; Bioverativ: Other: Investigator-initiated research funding; Pfizer: Other: Speaker's fees. Jackson:Pfizer: Honoraria; Roche: Honoraria; Bayer: Honoraria; Novo Nordisk: Honoraria; Shire: Honoraria; Bioverativ: Other: Investigator initiated grant funding. Carcao:Octapharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; LFB: Honoraria, Membership on an entity's Board of Directors or advisory committees; CSL-Behring: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biotest: Honoraria, Membership on an entity's Board of Directors or advisory committees; Grifols: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bioverativ/Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Khoo:Shire: Research Funding; Biogen Idec: Research Funding. Blatny:Shire, Pfizer, Roche: Consultancy, Speakers Bureau.

Background and objectives FVIII inhibitors remain the major complication of replacement therapy in hemophilia A. Why some patients develop inhibitors whereas others do not is poorly understood. The Hemophilia Inhibitor PUP Study (HIPS, clinicaltrials.gov NCT01652027), a prospective multicenter observational study, aim to identify early immune biomarkers which predict inhibitor development in previously untreated patients (PUPs) with severe hemophilia A. Such biomarkers would facilitate early risk identification and the initiation of potential immune intervention strategies. Previously we reported time-resolved antibody data for the first 15 patients who completed antibody analysis (Gangadharan 2017). Here we present data from all 25 patients enrolled in HIPS, identifying four distinct patient subgroups based on their unique antibody signatures. We also summarize data for F8 mutations and longitudinal data of circulating immune cells such as FoxP3+ T cells (Tregs), Th17 cells, and granulysin+ cells. Methods FVIII inhibitor testing (Nijmegen method, performed in the central laboratory Medical University of Vienna) and antibody analytics were assessed prior to first exposure, 7-9 days after exposure day (ED) 1 and 5-7 days after EDs 5, 10, 20, 30, 40, and 50. FVIII-specific advanced antibody analytics were performed using methodology described by Whelan 2013 and Hofbauer 2015. FVIII mutational analysis was performed at Bloodworks Northwest, Seattle. Longitudinal epigenetic cell counting in whole blood using quantitative PCR-based methylation assays (www.epiontis.com) was done to monitor changes in peripheral FoxP3+ T cells (Tregs), pro-inflammatory Th17 cells, and granulysin+ cells. Results Our data reveal 4 different subgroups of patients associated with distinct signatures of FVIII-specific antibodies. The first subgroup includes 7 subjects who developed FVIII inhibitors by study criteria (B.U. > 0.6 B.U. x 2 measurements from consecutive study days in central laboratory). All 7 subjects had high-risk F8 gene mutations including large deletions (2), intron 22 inversions (4) and duplications (1). Inhibitors in these patients were associated with the development of high-affinity class-switched FVIII-specific antibodies which were detected prior to the first detection of inhibitors. High-affinity IgG1 was generally observed first, followed by high affinity IgG3 and subsequently high-affinity IgG4. Other isotypes and IgG subclasses of anti-FVIII antibodies were only seen occasionally. The second subgroup includes 2 subjects with low titer inhibitors. One subject, who expressed an intron 22 inversion, had a transient low titer FVIII inhibitor (1.4 BU/ml) which was associated with a high-affinity IgG1 antibody only. The other subject, who expressed a frame shift mutation, developed high affinity IgG1 by ED1. This patient had a low titer inhibitor detected (0.8 BU/ml) at ED20 which remained low (0.5 BU/ml) at study end, ED50. No other IgG subclasses were observed in either patient. The third subgroup includes 7 subjects with non-neutralizing antibodies. These subjects expressed intron 22 inversions (3), missense mutations (3) or an intron 1 inversion (1). Six of these patients developed low-affinity IgG1 antibodies which were observed until study end without the appearance of high-affinity antibodies or any other IgG-subclass. No FVIII inhibitors were detected at any time. The remaining subject initially developed low-affinity IgG1 antibodies and subsequently high-affinity IgG1 which remained until study end. No other IgG subclasses and no FVIII inhibitor were detected. The fourth subgroup includes 7 subject who never developed any FVIII-specific antibodies or FVIII inhibitors. These patients expressed missense mutations (3), an intron 22 inversion (1), a duplication (1), a frameshift mutation (1) or a nonsense mutation (1). Relative proportions of circulating FoxP3+ T cells (Tregs), Th17 cells or granulysin+ cells did not correlate with the development of FVIII inhibitors or FVIII-specific antibodies in individual PUPs. Conclusions Data obtained from the HIPS study identify four distinct patient subgroups based on their specific antibody signatures. Most importantly, high affinity class-switched antibodies preceded clinical inhibitor detection, substantiating their potential role as suitable predictive biomarkers for inhibitor development. Disclosures Gangadharan: Shire: Employment. Reipert:Shire: Employment, Equity Ownership. Berg:Research Institute for Applied Bioanalytics and Drug Development, IMC Fachhochschule Krems /: Research Funding. Scheiflinger:Shire: Employment, Equity Ownership. Blatny:Shire, Pfizer, Roche: Consultancy, Speakers Bureau. Fijnvandraat:CSL Behring, Bayer, Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding. Gruppo:Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees. Male:CSL Behring: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Biotest: Speakers Bureau; Novo Nordisk: Speakers Bureau; Octapharma: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Speakers Bureau; SOBI: Speakers Bureau. McGuinn:Shire: Research Funding; BioMarin: Consultancy; CSL Behring: Consultancy; Pfizer: Research Funding; Spark: Consultancy, Research Funding; Bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy. Meeks:HEMA Biologics: Other: Advisory Board; Genentech: Other: Advisory Board; Catalyst Biosciences: Other: Advisory Board; CSL Behring: Other: Advisory Board; Bayer: Other: Advisory Board; Bioverativ: Other: Advisory Board; Shire: Other: Advisory Board; Pfizer: Research Funding. Ragni:MOGAM: Membership on an entity's Board of Directors or advisory committees; Shire: Research Funding; Sangamo: Research Funding; SPARK: Consultancy, Research Funding; Novo Nordisk: Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring: Research Funding; Alnylam: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioverativ: Consultancy, Research Funding. Recht:Shire: Research Funding; Biogen: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kedrion: Membership on an entity's Board of Directors or advisory committees. Santagostino:Bayer, Shire, CSL Behring, Pfizer, Novo Nordisk, Grifols, Kedrion, Sobi, Bioverativ, Octapharma, Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Shapiro:Bayer Healthcare: Other: International Network of Pediatric Hemophilia; Octapharma: Research Funding; Prometic Life Sciences: Consultancy, Research Funding; Daiichi Sankyo: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genetech: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bio Products Laboratory: Consultancy; Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sangamo Biosciences: Consultancy; Kedrion Biopharma: Consultancy, Research Funding; Bioverativ, a Sanofi Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; OPKO: Research Funding; BioMarin: Research Funding. Staber:NovoNordisk: Consultancy; Bayer: Honoraria; uniQure: Honoraria. Brown:Shire: Research Funding.

Numerous recent reports have described the use of recombinant factor VIIa (rFVIIa) in non-hemophilia bleeding Situations for achievement of hemostasis. However, its use in clinical situations other than hemophilia patients with inhibitors has been complicated by some reports of thrombotic events. rFVIIa has been used successfully to treat coagulopathic and/or bleeding neonates. The prevalence of thrombotic events in these neonates is completely unknown. This study was initiated to determine the risk of thrombotic events associated with rFVIIa use in neonates. Procedure. All published literature in non-hemophilic, non-congenital factor VII deficient neonates receiving rFVIIa was reviewed. In addition, all data submitted to the SeveN Bleep Registry, a web-based registry of rFVIIa uses in non-hemophilic children was analyzed.

X-linked neutropenia (XLN, OMIM #300299) is a rare form of severe congenital neutropenia. It was originally described in a three-generation family with five affected members that had an L270P mutation in the GTP-ase binding domain (GBD) of the Wiskott-Aldrich syndrome protein (WASP) [Devriendt et al (2001) Nature Genetics, Vol. 27, 313-317]. Here, we report and describe a large three-generation family with XLN, with 10 affected males and eight female carriers. A c.882T>C mutation was identified in the WAS gene, resulting in an I294T mutation. The infectious course is variable and mild in view of the profound neutropenia. In addition to the original description, low-normal IgA levels, low to low-normal platelet counts and reduced natural killer (NK)-cell counts also appear as consistent XLN features. However, inverted CD4/CD8 ratios were not found in this family, nor were cases identified with myelodysplastic syndrome or acute myeloid leukaemia. Female carriers exhibited a variable attenuated phenotype. Like L270P WASP, I294T WASP is constitutively active towards actin polymerization. In conclusion, this largest XLN kindred identified to date provides new independent genetic evidence that mutations disrupting the auto-inhibitory GBD of WASP are the cause of XLN. Reduced NK cells, low to low normal platelet counts and low to low-normal IgA levels are also features of XLN.

Our objective was to assess the incidence of inhibitors development in Czech Republic since the introduction of recombinant factor VIII (rFVIII) and to look for the factors potentially influencing this parameter. It is to be expected that inhibitors risk may be increased after the introduction of recombinant products. Data of Czech National Haemophilia Programme registry entered from 2003 till 2013 were analysed. Both annual and absolute incidences of newly developed inhibitors in previously untreated patients (PUPs) were calculated. Bleeding and treatment data were also extracted, and association to the treatment regimen and development of inhibitors were analysed. Within the given period, we commenced 45 PUPs with haemophilia A on rFVIII and treated them for 137 treatment-years. Twenty-two of the PUPs had severe haemophilia A, being treated for 88 treatment-years. Treatment strategy for them was prophylaxis. Other PUPs were treated on demand. Median annual bleeding rate was 5 for boys with severe haemophilia, 3 for moderate haemophilia and 1 for mild form of the disease. No inhibitors developed in PUPs with moderate/mild haemophilia A. Annual inhibitor incidence rate in PUPs with severe haemophilia A treated with rFVIII was 56.8 per 1000 treatment-years. Absolute incidence was 22.7% (5/22). All inhibitors appeared within the first 50 exposure days. Comparing rFVIII-treated group with the control group treated under same/similar conditions with plasma-derived FVIII during the same follow-up period, we were not able to find significant difference in inhibitor development between these two groups. Our results support the finding that use of rFVIII is not a proven risk factor for inhibitor development in patients with haemophilia A.

Background: Evidence about inhibitor formation in non-severe haemophilia and the potential role for clotting factor concentrate type is scant., Aim: To report inhibitor development in non-severe haemophilia patients enrolled in the European Haemophilia Safety Surveillance (EUHASS) study., Methods: Inhibitors are reported quarterly and total treated patients annually. Incidence rates and 95% Confidence Intervals (95% CI) were calculated according to diagnosis and concentrate used., Results: Between 1-10-2008 and 31-12-2012, 68 centres reported on 7969 patients with non-severe haemophilia A and 1863 patients with non-severe haemophilia B. For haemophilia A, 37 inhibitors occurred in 8622 treatment years, resulting in an inhibitor rate of 0.43/100 treatment years (95% CI 0.30-0.59). Inhibitors occurred at a median age of 35 years, after a median of 38 exposure days (EDs; P25-P75: 20-80); with 72% occurring within the first 50 EDs. In haemophilia B, one inhibitor was detected in 2149 treatment years, resulting in an inhibitor rate of 0.05/100 years (CI 0.001-0.26). This inhibitor developed at age 6 years, after 6 EDs. The rate of inhibitors appeared similar across recombinant and plasma derived FVIII concentrates. Rates for individual concentrates could not be calculated at this stage due to low number of events., Conclusion: Inhibitors in non-severe haemophilia occur three times more frequently than in previously treated patients with severe haemophilia at a rate of 0.43/100 patient years (haemophilia A) and 0.05/100 years (haemophilia B). Although the majority of Inhibitors developed in the first 50 EDs, inhibitor development continued with increasing exposure to FVIII., peer-reviewed

The ISTH SSC on Factor VIII/IX has previously issued guidelines for studies assessing the pharmacokinetics (PK) of factor concentrates [1,2]. They suggested drawing 10 or 11 blood samples over a period of 32-48h or 50-72h, after infusing 25-50 or 50-75 IU/kg, respectively for factor VIII (FVIII) or factor IX (FIX), in cohorts of 12-15 patients with a crossover design. Such PK studies are not ideal for tailoring the treatment of individual patients, mostly for the requirement of several blood samples. Due to broad inter-individual variation, the individual disposition of FVIII and FIX cannot be predicted from morphometric characteristics and average PK parameters, but requires empirical assessment in each individual [3–6]. Previous guidance of this ISTH SSC described the PK methodology for the prediction of individual trough levels of FVIII [7]. The present communication, building on recent advancements in the population PK (PopPK) of FVIII and FIX [8], adds to the former documents.

Diamond-Blackfan anemia is a rare inherited bone marrow failure syndrome diagnosed in early infancy that is characterized by a (a) macrocytic anemia with no other significant cytopenia, (b) reticulocytopenia, and (c) normal bone marrow cellularity with a paucity of erythroid precursors. Physical anomalies are often present. Mutations in several ribosomal proteins have been associated with the disease. Here we present a detailed description of 39 patients from 34 families enrolled in the Czech National Diamond-Blackfan Anemia Registry. Erythrocyte adenosine deaminase activity and serum erythropoietin levels were measured and bone marrow analysis and clonogenic assays were carried out. Twenty-two different ribosomal proteins were sequenced. We identified mutations in five different ribosomal proteins in 28/39 patients (71.8%) from 23/34 families (67.6%). Several new mutations are described. The most interesting data relate to genotype–phenotype correlations. All patients with ribosomal protein L5 or ribosomal protein L11 mutations have a thumb defect usually with one or more other anomalies. Most of these patients were born small for gestational age and currently have short stature. We also described five patients with a ribosomal protein S26 mutation. All of the latter are transfusion-dependent and they exhibit skeletal abnormalities rather than thumb or craniofacial deformities. Patients with ribosomal protein S19 seem to bear mildest associated anomalies, usually in a craniofacial region.

The blueberry muffin baby syndrome can be caused by a variety of entities, both neoplastic and nonneoplastic. We present a rare cause of this syndrome: congenital extraosseal Ewing sarcoma. The patient was a blueberry muffin baby with a retroperitoneal tumor, whose cells were negative for neuronal markers and CD-99 immunohistochemically but were positive for a breakpoint in EWSR1 gene. This tumor could be one of the most primitive/undifferentiated examples in the Ewing/peripheral primitive neuroectodermal tumor family.

Numerous recent reports have described the use of recombinant factor VIIa (rFVIIa) in non-hemophilia bleeding situations for achievement of hemostasis. However, its use in clinical situations other than hemophilia patients with inhibitors has been complicated by some reports of thrombotic events. rFVIIa has been used successfully to treat coagulopathic and/or bleeding neonates. The prevalence of thrombotic events in these neonates is completely unknown. This study was initiated to determine the risk of thrombotic events associated with rFVIIa use in neonates.All published literature in non-hemophilic, non-congenital factor VII deficient neonates receiving rFVIIa was reviewed. In addition, all data submitted to the SeveN Bleep Registry, a web-based registry of rFVIIa uses in non-hemophilic children was analyzed. As the baseline risk of thrombotic events in bleeding and/or coagulopathic neonates is not known, we also reviewed the records of 100 consecutive neonates from a single institution who received fresh frozen plasma (FFP) alone to treat their coagulopathy and/or bleeding episode.A total of 134 neonates received rFVIIa. Of these, 10 (7.5%) had a thrombotic event. The baseline risk of thrombotic events in neonates receiving FFP was 7%.Overall the prevalence of thrombotic events in bleeding and/or coagulopathic neonates appears to be around 7%, whether or not they receive rFVIIa.

A 15-month-old dachshund was presented for examination because of a cough. Thoracic radiographs revealed the presence of a mass in the upper mediastinum. A diagnosis of gammadelta T-cell lymphoma was made by biopsy and flow cytometry analysis. The dog was treated with chemotherapy and remains asymptomatic after 24 months.

Classical galactosaemia is relatively common in Ireland due to a high carrier rate of the Q188R GALT mutation. It is screened for using a bacterial inhibition assay (BIA) for free galactose. A Beutler assay on day one of life is performed only in high risk cases (infants of the Traveller community and relatives of known cases). A 16-month-old Irish-born boy of Nigerian origin was referred for investigation of developmental delay, and failure to thrive. He had oral aversion to solids and his diet consisted of cow’s milk and milk-based cereal mixes. He was found to have microcephaly, weight

Many patients with haemophilia develop inhibitors to factor VIII and require bypassing agents to provide haemostatic cover for limb- or life-threatening bleeding episodes. Due to the reduced risk of blood-borne pathogen transmission with recombinant products, on-demand recombinant factor VIIa (rFVIIa; NovoSeven is the treatment of choice for children with inhibitors. In haemophiliac patients without inhibitors, primary prophylaxis has been clinical practice for several years. This paper summarises 13 case histories of rFVIIa secondary prophylaxis for haemophilia patients with inhibitors. This was a retrospective survey of adult and paediatric severe haemophilia patients with inhibitors treated with rFVIIa from ten European Haemophilia Centres. There was a wide variation in administered rFVIIa dose, from 200-250 microg kg(-1) per week to 220 microg kg(-1) daily. In many cases, this was lower than the recommended on-demand dose of rFVIIa. In 12/13 cases, prophylaxis with rFVIIa considerably reduced the number of bleeding episodes compared with previous treatment. Eight/nine patients were satisfied or very satisfied with rFVIIa treatment, and in cases reporting subjective quality of life (QoL), all were improved, much improved, or significantly improved. In haemophilia patients with inhibitors, prophylaxis with rFVIIa is highly effective in reducing the number of bleeding episodes and results in good patient compliance and improved QoL. Randomised controlled trials are needed to confirm these findings. Results of a recently completed clinical trial on secondary prophylaxis with rFVIIa in frequently bleeding haemophilia patients with inhibitors are expected in late 2006.

Bleeding is probably the major complication of anticoagulant treatment with vitamin K antagonists represented nowadays mostly by warfarin in the Czech Republic. The main risk factors in hemorrhagic complications of warfarinisation are the intensity and instability of the anticoagulant treatment, individual patient characteristics, warfarin interactions with other drugs and the length of the anticoagulant therapy. Severe bleeding in warfarin patients is most effectively brought about by a fast and complete undoing of the anticoagulation effect of the drug employing the prothrombin complex concentrate and slow i.v. vitamin K1 infusion regardless of the reason for the anticoagulation. This approach can secure the minimalisation of the bleeding's negative consequences. A less severe bleeding or asymptomatic increase in the international normalized ratio can be treated effectively by skipping or decreasing of the warfarin dosage and/or oral administration of vitamin K1 (i.v. administration only in selected higher risk cases) that does result only in a partial consolidation of coagulopathy but of such type that the risk of thrombotic event requires. The article's goal is to contribute to the treatment standardization in patients with warfarin overdose and/or with hemorrhagic complications due to warfarin treatment and it is available at www.thrombosis.cz. The guidelines include a ready-reference chart whose objective is immediate and quick crash course in the clinical practice.

Invasive fungal infection continues to pose a significant threat to immunocompromised patients, with cerebral aspergillosis being among the most feared ones. The authors describe an adolescent girl with acute lymphoblastic leukemia (ALL) with subsequent acute liver failure, who developed an aspergillus brain abscess. The patient was treated with combined antifungal therapy using amphotericin B local instillation, prolonged systemic amphotericin B colloidal dispersion along with vinca alkaloids-containing chemotherapy, followed by neurosurgical debridement and oral voriconazole in the setting of ongoing antileukemic maintenance chemotherapy. Her ALL remains now in complete remission 30 months from diagnosis, with no evidence of fungal infection.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder of unknown frequency. In its classic form, PNH is characterized by hemolysis accompanied by nocturnal hemoglobinuria. The clinical course is unpredictable and may vary from severe hemolysis and recurrent venous thrombosis to latent periods with milder symptoms. We report a 15-year-old girl with hemolytic episodes, abdominal pain, and passage of dark urine. Hemoglobinuria was demonstrated by a "blood"-positive dipstick test in the absence of red blood cells in the urinary sediment. The diagnosis of PNH was confirmed by flow cytometry.

Congenital afibrinogenemia is very rare inherited bleeding disorder, caused by absence of fibrinogen in plasma. Serious spontaneous bleeding including intracranial haemorrhage may occur at any age. We present a case report of a boy with afibrinogenemia caused by novel mutation – homozygous deletion Aα 6477A. Diagnosis was set after bleeding post cleft lip and palate plastic surgery. Spontaneous intracranial haematoma in occipital region occurred when the boy was 11 month old. Replacement therapy with plasma derived fibrinogen concentrate successfully covered neurosurgical evacuation of hematoma. The patient was then commenced on regular prophylaxis with fibrinogen concentrate two times a week. No further bleeding episodes occurred until present time. Spontaneous intracranial bleeding in patients with inherited bleeding disorders is often life threatening. Immediate replacement therapy is crucial, together with diagnostics and surgery, when necessary. Prophylactic substitution therapy after a severe bleeding episode is recommended. Disclosures No relevant conflicts of interest to declare.

Background Inhibitor development is a complex, multifactorial immune response involving both patient-specific and treatment-related factors. Of the known risk factors, intensive treatment at an early age has been shown to be significant, and clinical observations have suggested that early prophylaxis (i.e. first exposure to FVIII in the absence of a bleed in the first year of age) may protect patients from inhibitor development by inducing FVIII tolerance. Aim This study aimed to assess prospectively if a once-weekly, low-dose prophylactic regimen started before 1 year of age and before the onset of a severe bleeding phenotype (i.e. joint bleed), together with the minimization of immunological danger signals, could reduce the incidence of inhibitor formation in PUPs with severe and moderately severe hemophilia A to 15% or less. Methods The EPIC study was a Phase 3b, prospective, single arm, historically-controlled, international multicenter study to assess the incidence rate of inhibitor formation in PUPs with severe and moderately severe hemophilia A during the first 50 exposure days (EDs) of treatment with ADVATE starting with a once-weekly, low-dose (ADVATE 25 IU/kg once weekly), prophylactic regimen. If clinically indicated, it was permissible to increase the frequency of dosing to 2 or 3 times per week. In addition, infusions during the first 20 EDs had to be given 3 to 4 days before or after any vaccinations, which had to be given subcutaneously, not intramuscularly; infusions had to be avoided if the subject had high fever (above 38°C [100°F]). Main enrolment criteria were: severe and moderately severe hemophilia A (FVIII ≤2%), age Results A total of 22 subjects were enrolled in the study. Of 20 subjects who met all entry criteria, 19 received treatment; of these, all had severe hemophilia A (FVIII0.6 BU in PUPs were 27%. A total of 67 major protocol deviations (PD) were reported in 15 patients: 44 PDs of these were reported in 10 subjects and were related to the treatment regimen and therefore have contrasted with the protocol intention, which was to minimize immunological danger signals and low dose prophylactic regimen. As a result of the observed inhibitor incidence the study was terminated based on futility analysis, i.e. the probability to achieve the primary end-point of inhibitor rate reduction to ≤15%. Details on inhibitor patients will be presented. Discussion The EPIC study showed no safety issue as confirmed by the Data Safety Monitoring Board. To align treatment decisions in the presence of danger signals (which are not completely avoidable in children around 1 year of age) with a demanding study protocol was found to be challenging. Thus the hypothesis that an early low dose prophylaxis in the absence of immunological danger signals might reduce inhibitor incidence in PUPs with hemophilia A could neither be verified nor disproved within this study. Disclosures: Auerswald: Novo Nordisk: Consultancy, Research Funding; Biotest: Consultancy, Research Funding; CSL-Behring: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; Baxter: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Kurnik:Baxter: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; Biotest: Consultancy, Research Funding; CSL-Behring: Consultancy, Research Funding; Novo Nordisk: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Blatny:Baxter: speaker fee Other. Reininger:Baxter Innovations GmbH: Employment.

Abstract 1342 Introduction. Aplastic anemia (AA) and myelodysplastic syndrome (MDS) are rare diseases in childhood. The most common subtype of MDS is refractory cytopenia (RC). Both diseases typically exhibit with overlapping features and in both disorders dysregulation of immune system variably contributes to the degree of bone marrow (BM) failure. In the diagnostic algorithm plays role also analysis of consecutive BM samples by morphology. Patients and methods. Patients diagnosed between 2005 – 2011 with at least two BM samples analyzed by flow cytometry (FC) before treatment has started and with centrally evaluated BM biopsy according to EWOG MDS criteria were included into the study. We compared first and the last available sample before treatment (immunosupression or stem cell transplantation). By FC we analyzed following parameters: cell subsets (granulocytes, monocytes, lymphoid cells, erythroid precursors), BM precursors (CD34pos, CD117pos), T cells (CD3pos, CD3pos4pos, CD3pos8pos, CD3posHLA DRpos out of all cells, HLA DRpos out of CD3pos/CD3pos4pos/CD3pos8pos cells); B cells (CD19pos, CD19pos10pos, CD19pos45dim to neg, CD19pos34posout of all cells, CD10pos and CD20pos10neg out of CD19pos). In total 22 patients with AA (12 girls, 10 boys, mean age 11 years; 1.1–18 years) and 20 patients with RC (11 girls, 9 boys, mean age 11 years; 3.7–18) were included into the study. Median of time interval between both samples was 139 (1–1343) days in RC and 15 (1–56) days in AA. WT1 expression on mRNA level was analyzed in the sample before treatment with the highest number of CD34pos precursors to avoid blood contamination. All patients were screened by FISH for changes on chromosome 7 and 8. We asked following questions: Are there differences in the parameters in both bone marrow samples between SAA and RC? Is there any different pattern between d0 and before therapy sample between AA and RC? Are there any differences in WT1 expression between AA and RC group? Results. RC and AA significantly differ in both time points. AA patients have significantly decreased precursors (CD34, CD117); the difference is more pronounced at the later time point. More lymphocytes (both B and T) and less granulocytes are present at later time point in AA patients (p Conclusion. By FC statistical differences can be identified in both samples (d0 and before treatment) between RC and AA. More pronounced differences are at later time point, which can be explained by further destruction of precursor and myeloid compartment more pronounced in AA patients compared to RC. WT1 expression is typically high in patients with RC and monosomy 7. Disclosures: No relevant conflicts of interest to declare.

Abstract 3651 Introduction: SeveN Bleep (Seven A in Nonhemophilia Bleeding in Pediatrics) is a web-based registry for collecting data on the use of rFVIIa in the treatment of severe and/or life threatening bleeding in children without hemophilia. The registry was endorsed by the Paediatric/Perinatal SSC subcommittee of ISTH. Methods: The registry was established in 2005. During the five years of its existence, 191 cases were recorded, of which 164 (86%) records fulfilled the validation criteria and were eligible for further analyses. For the purpose of analysis, the patients were stratified into two groups: neonates and infants 1 yr old. Statistical methods were used as appropriate. Results: Fifty nine (36%) valid records described the treatment with rFVIIa in neonates and infants, and 105 (64%) in older children. Of these, 27(16%) were for the prevention of severe bleeding. In the rest (84%) of cases, rFVIIa was used to treat severe bleeding. Those 137 cases (42 neonates+infants and 95 older children) were further analysed for the purpose of this report. The median weight in the In those older than 1 year, the median age was 10 years and median weight 30 kg. The reasons for administration of rFVIIa included trauma (45%), “non-trauma” surgery (14%) and bleeding related to malignancy and/or its treatment (11%). Survival rate in this group was 72%. 17% of deaths were related to the underlying hemorrhage treated. There were no thrombotic event or death related to rFVIIa treatment recorded in this group. There was a trend towards using a higher total dose (median 160ug/kg) in patients that died compared to a lower dose (median 120 ug/kg) in those who survived (p=0.078). In addition, those who survived needed lesser number of doses as compared to the deceased patients (median number of doses 1 and 2, respectively; p=0.052). Use of rFVIIa led to a significant decrease in the consumption of blood products in the 24 hour period after rFVIIa administration compared to the 24 hours prior to the use of rFVIIa - packed red cells (280 ml vs. 560 ml; p=0.001), FFP (250 ml vs. 500 ml; p=0.003). There were also significant changes in certain laboratory parameters related to rFVIIa administration also. Estimated blood loss decreased from 30 ml/kg prior to rFVIIa administration to 3 ml/kg after the use of rFVIIa (p=0.002). Conclusion: SevNBleep registry has proven to be a useful international tool for collection of relevant clinical data on the use of rFVIIa. rFVIIa appears to be beneficial in the management of bleeding in the pediatric population. The prevalence of adverse events related to use of rFVIIa was very low, though not absent. To minimize the potential bias related to reporting of SAEs, all major contributing centers has been contacted for further information with regards to consecutive reporting of patients treated with rFVIIa. Disclosures: Off Label Use: rFVIIa use in life threatening bleeding in children.

Abstract 3802 Poster Board III-738 Introduction Monosomy 7 or del(7q) are frequent cytogenetic abnormalities in children with myelodysplastic syndrome (MDS) and associates with poor prognosis. MDS globally affects all cellular subsets in bone marrow and in peripheral blood. We asked whether flow cytometry (FC) can separate individual subtypes of MDS from each other and from aplastic anemia (SAA) and whether in individual subtypes of childhood MDS can separate patients with and without monosomy 7. Patients/analyzed parameters In total we analyzed 94 children with centrally analyzed immunophenotype in the reference lab who were diagnosed and treated for MDS or SAA between 1998 and 2009. In total we analyzed 14 patients with refractory cytopenia, 37 patients with advanced forms of MDS (JMML 10, RAEB 25, CMML 2) and 43 patients with SAA. Monosomy 7/del(7q) was present in 17 patients (RC 6, JMML 3, RAEB 8). Analyzed parameters were as follows: B cells, CD10+CD19+, CD19+45dim/neg, CD19+34+, CD19/CD34 ratio, CD34+, CD117 cells, CD34+38dim/neg, CD3+, CD3+4+, CD3+8+, CD3+HLADR+. Statistics We analyzed all parameters using non parametric tests (Mann-Whitney, Kruskal Wallis) and principal component analysis (PCA). Results Principal component analysis of all analyzed patients together clearly separates advanced forms of MDS from RC and SAA, the most contributing factor being the number of CD34 and CD117+ cells. In non parametric statistics following factors significantly differ among MDS subtypes and SAA (Kruskal-Wallis): CD19, CD117, CD34, CD3, CD3+4+, CD8+ and CD3+HLADR+. RC and SAA patients are separated mainly by the number of B cells and the CD34:CD19 ratio. In addition, the following parameters differ between RC and SAA (Mann-Whitney): CD34, CD117 and CD3+HLADR+. Unlike the CD34:CD19 ratio, the number of CD19+34+ precursors does not differ between RC and SAA patients. Patients with monosomy 7 do not differ from the remaining patients when all MDS patients are analyzed together or separately in the respective subgroups (RC, non RC, JMML) by PCA or by non parametric statistics. Conclusion PCA separates advanced MDS forms from RC and SAA. Advanced forms of MDS are characterized by increased percentage of CD34+ and CD117+ cells compared to RC and SAA patients. The global reduction of B cell progenitor compartment is pronounced especially in non-JMML cases of MDS, whereas SAA patients typically present with isolated reduction of cells at early stages (CD19+34+) of B cell development. Patients with monosomy 7 cluster within the respective disease category, they do not form own cluster in PCA. Supported by MSMT VZ MSM0021620813, MZO 00064203 VZ FNM, MZO VFN2005, IGA NR/9531-3, NPV 2B06064. Disclosures: No relevant conflicts of interest to declare.

Abstract 4980 Background Myeloproliferative disorders (MPD) in general result from proliferation of a clone of myeloid cells derived from a neoplastic pluripotent precursor or from connective tissue elements in bone marrow. This leads to increased numbers in one or more blood cell lines in peripheral blood. Some MPDs can be associated with thrombocytosis (MPD-T): essential thrombocythaemia (ET), polycythaemia vera (PV) and early stages of chronic idiopathic myelofibrosis (CIMF). Usually in MPD-T the thrombocytosis is caused by increased platelet production from proliferating mature megakaryocytes, especially in ET. Elevated platelet counts in these patients are often associated with both thromboembolic events and bleeding. One of the goals of MPD treatment is the control of platelet count. Immature platelets mirror the platelet production in bone marrow. In certain automated blood count analyzers it is possible to measure Immature platelet fraction (IPF) from the routine CBC samples sent to haematology lab. Reference range for IPF parameter for method used in this study is 1,1-6,1%. Objective Measurement of IPF parameter by fully automated analyzer (XE-2100, Sysmex, Kobe, Japan) in optical channel and analyzing it ( software IPF Master) in patients treated for Ph-negative MPD. We enrolled 85 pts- 67 ET (79%), 10PV(12%) and 8 CIMF (9%) patients; 57 were women and 28 men; median age 56 years ranging from 20 up to 83 years. We analyzed and evaluated IPF in whole group as well as in subgroups depending on diagnosis, gender, age, JAK-2 mutation and platelet count. Results At the time of assessment the majority of our pts were already commenced on treatment for their MPD. Platelet counts (plt) in whole cohort ranged from 164 up to 2148 ×109/l, with median 374 ×109/l. Thirty eight pts (45%) had plt < 350 ×109/l. Plt Conclusions MPD-T patients in our cohort did not have marked elevation of IPF parameter, neither those with high platelet counts (so far untreated pts). Thus we can speculate, that increased number of Plts in peripheral blood is caused by increased number of mature megacaryocytes in bone marrow which produce adequate numbers of platelets without increase of immature fraction rather than increased number of immature platelets released from megacaryocytes appearing in normal numbers in bone marrow Thus it seems that negative feedback of increased Plt counts on releasing of Plts from megacaryocytes is maintained also in patients with MPD-T. Further assessment is needed and should further determine, what is the clinical relevance (if any) of measurement of IPF in patients treated for MPD-T. Disclosures Blatny: Sysmex, Czech Republic: Consultancy.

Background: In recent years, recombinant factor VIIa (rFVIIa) has been used in non-hemophilia bleeding situations (factor VII deficiency, trauma, liver disease, uremia, surgical bleeding, platelet disorders, and intracranial hemorrhage) for achievement of hemostasis. Although, the risk of thrombosis in hemophilia patients with inhibitors receiving rFVIIa is quite low, its use in other clinical situations has been complicated by some reports of thrombotic events. Recently, rFVIIa has been used to treat coagulopathic and/or bleeding neonates with good success. However, the prevalence of thrombotic events in these neonates is completely unknown. This study was initiated to determine the risk of thrombotic events associated with rFVIIa use in neonates. Methods: We reviewed all published literature in neonates receiving rFVIIa. In addition, we reviewed all data submitted to the SeveN Bleep Registry, a database developed by the scientific standardization subcommittee on pediatric and neonatal hemostasis of the International Society on Thrombosis and Haemostasis (ISTH) to record all uses of rFVIIa in pediatric non-hemophilic patients. As the baseline prevalence of thrombosis for bleeding and/or coagulopathic neonates is also unknown, we also reviewed the records of 100 consecutive neonates from a single institution who received fresh frozen plasma (FFP) alone to treat their coagulopathy and/or bleeding. Results: A total of 98 non-hemophilic neonates received rFVIIa. The majority of these neonates received rFVIIa only after failing to achieve hemostasis with standard care (FFP, cryoprecipitate, platelet transfusions). Of those receiving rFVIIa, 7 had a thrombotic event reported. In the control group that received FFP alone, 7 neonates also suffered a thrombotic event. Although the risk of thrombosis in these two groups is similar, neonates receiving rFVIIa tended to have indwelling line related thrombosis, while those receiving FFP tended to have strokes or myocardial insults. Overall the prevalence of thrombotic events in bleeding and/or coagulopathic neonates appears to be 7%, whether or not they received rFVIIa. Conclusions: In this study, the overall prevalence of thrombotic events was similar in the rFVIIa and FFP group. As data for this study was collected in a retrospective manor, and thereby subject to publication and submission bias, a more accurate determination of the prevalence of thrombosis in neonates will require a prospective study.