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Introduction Growing evidence shows a hypercoagulable state in obstructive sleep apnea (OSA) that could be a risk factor for thromboembolic disease. Objectives We aimed to elucidate mechanisms involved in the procoagulant profile observed in patients with OSA and to investigate the potential utility of global tests in its characterization. Methods Thirty-eight patients with severe OSA without previous history of thrombosis and nineteen healthy age- and sex-matched controls were included. Kinetic of clot formation was determined using rotational thromboelastometry. Haemostatic capacity of plasma and microparticles was determined by Calibrated Automated Thrombinography. Platelet surface receptors, activation markers and formation of platelet/leukocytes aggregates were analyzed by flow cytometry. Results Thromboelastometry showed a procoagulant state in patients with OSA that did not seem to be related to a basal activation of platelets but by the increased existence of platelet/leukocyte aggregates. Patients with OSA presented many signs of endothelial damage such as increased plasma levels of E-selectin and cfDNA and enhanced thrombin generation due to the presence of microparticles rich in tissue-factor, which is related to OSA severity. Conclusions OSA induces an enhancement in the dynamics of clot formation which appears to be caused by at least two pathological mechanisms. First, a greater formation of platelet-leukocyte aggregates; secondly, endothelial damage which provokes a greater procoagulant potential due to the increase in tissue factor-rich microparticles. Moreover, this study has identified thromboelastometry and thrombin generation assay as useful tools to evaluate the prothrombotic state in these patients.

Introduction: Current guidelines recommend prophylactic treatment of hemophilia B with the missing coagulation factor IX, either with standard half-life or extended half-life products. Extended half-life products have half-lives three to six times longer than the former, allowing a reduction in the number of weekly injections and therefore, potentially impacting on treatment adherence and quality of life. Albutrepenonacog alfa is an extended half-life fusion protein of coagulation factor IX with recombinant human albumin, indicated for both on-demand and prophylactic treatment for bleeding in patients with hemophilia B of all ages.Areas covered: The authors review the clinical and pharmacokinetic characteristics of albutrepenonacog alfa, as well as the available information regarding trough levels and real-world evidence. Given the availability of other factor IX products in the market, indirect comparisons of clinical and pharmacokinetic characteristics are presented.Expert opinion: The authors exhibit their expert opinion on which patient profiles are candidates for prophylactic treatment with albutrepenonacog alfa, and on the management of patients in terms of dosing, regimens of administration and protocols for switching the treatment.

Thrombocytopenia has been identified as a common complication of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in the general population. In an attempt to determine the impact of coronavirus disease 2019 (COVID-19) in patients with immune thrombocytopenia (ITP), a retrospective single-centre study was performed. Thrombocytosis was observed in patients with chronic ITP after SARS-CoV-2 infection, frequently needing treatment adjustment or even discontinuation of therapy. Relapses and newly diagnosed cases showed a fast response after initial treatment compared to ITP. Reduced immune activity due to lymphopenia during COVID-19 could explain this paradoxical effect, although further studies are needed.

INTRODUCTION: We present the first registry of patients with congenital bleeding disorders and COVID-19. The study has been carried out in the Community of Madrid, which has the highest number of cases in Spain. The objective is to understand the incidence of COVID-19, the course of the disease if it occurs and the psychosocial and occupational impact on this population. METHODS: We included 345 patients (246 of haemophilia, 69 of von Willebrand Disease, two rare bleeding disorders and 28 carriers of haemophilia). A telephone survey was used to collect the data. RESULTS: Forty-two patients presented symptoms suggestive of infection by COVID-19, and in six cases, the disease was confirmed by RT-PCR. The cumulative incidence of our series was 1.73%. It is worth noting the complexity of the management of COVID-19 in two patients on prophylaxis with non-factor replacement therapy. Adherence to the prescribed treatment was maintained by 95.5% of patients. Although 94% were independent for daily living activities, 42.4% had a recognized disability and 58% required assistance, provided by the Madrid Haemophilia Association (Ashemadrid) in 75% of cases. Only 4.4% of consultations were held in person. CONCLUSIONS: Patients with congenital bleeding disorders infected with SARS-CoV-2 presented a mild course of the disease that did not require admission. Their identification and treatment by a specialist team from a Haemophilia Treatment Center are essential to make a correct assessment of the risk of haemorrhage/thrombosis. COVID-19 had a major impact on the psychosocial aspects of these patients which must be remedied with recovery plans.

The pharmacokinetic (PK) response of severe hemophilia A (HA) patients to infused factor VIII (FVIII) shows substantial variability. Several environmental and genetic factors are associated with changes in FVIII plasma levels and infused FVIII PK. Based on the hypothesis that factors influencing endogenous FVIII can affect FVIII PK, the contribution of single-nucleotide variants (SNVs) in candidate genes was investigated in 51 severe HA patients. The effects of blood group, F8 variant type, von Willebrand factor antigen and activity levels, age, and weight were also explored. The myPKFiT device was used to estimate individual PK parameters, and SNVs and clinically reportable F8 variants were simultaneously analyzed in an Illumina MiSeq instrument, using the microfluidics-based Fluidigm Access Array system. The contribution of SNVs to FVIII half-life and clearance was addressed by robust regression modeling, taking into account other modulators. In line with previous studies, we provide robust evidence that age, body weight, and blood group, as well as SNVs in ABO and CLEC4M, participate in the variability of FVIII PK in HA patients. Main results: each copy of the rs7853989 (ABO) allele increases FVIII half-life by 1.4 hours (p = 0.0131) and decreases clearance by 0.5 mL/h/kg (p = 5.57E-03), whereas each additional rs868875 (CLEC4M) allele reduces FVIII half-life by 1.1 hours (p = 2.90E-05) and increases clearance by 0.3 mL/h/kg (p = 1.01E-03). These results contribute to advancing efforts to improve FVIII replacement therapies by adjusting to each patient's PK profile based on pharmacogenomic data. This personalized medicine will decrease the burden of treatment and maximize the benefits obtained.

In hemophilic patients methods are needed to better diagnose joint damage early, so that treatments can be adjusted to slow the progression of hemophilic arthropathy. The aim of this study is to investigate the relationship between the Hemophilia Joint Health Score version 2.1 (HJHS 2.1) and hemophilia early arthropathy detection with ultrasound (HEAD-US) scales, as well as each of their individual items, to better understand the value each provides on the joint condition of patients with hemophilia. The study included data from patients with hemophilia older than 16 years of age, who attended a routine check-up. HJHS 2.1 and HEAD-US assessments were performed on the elbows, knees and ankles. We studied the correlations and agreements between the two scales and analyzed the relationship between the various items of the HJHS 2.1 (inflammation, duration, atrophy, crepitation, flexion deficit, extension deficit, pain, strength, gait) and HEAD-US (synovitis, cartilage and bone). The study included 203 joints from 66 patients with hemophilia (mean age, 34 years). We found a good correlation between the two scales (r = 0.717). However, HJHS 2.1 revealed only 54% of the cases with synovitis and 75% of the cases with osteochondral damage. HEAD-US detected several relevant physical and functional aspects in less than 53% of the cases. HJHS 2.1 and HEAD-US provide complementary data on joint disease in adults with hemophilia; both assessments should therefore, be made available. HEAD-US presented the added value of detecting early joint changes (synovitis and osteochondral damage), while HJHS 2.1 showed the added value of detecting relevant physical and functional changes.

Objectives This study estimated the cost of prophylaxis with activated prothrombin complex concentrate (aPCC) and recombinant activated factor VIIa (rFVIIa) in surgical patients with haemophilia A and inhibitors in Spain. Methods A decision‐analytic model was developed to estimate the cost to the Spanish National Health System of providing haemostatic coverage in this haemophilia population, with age distribution and average weight derived from the literature, and the annual number of surgeries (0.33 per patient) from local data. Drug costs were calculated from official ex‐factory prices with a 7.5% mandatory deduction and recommended dosing regimens. Results The estimated average costs per patient were €10 100.73 (aPCC) and €14 265.89 (rFVIIa) for dental extraction, €24 043.88 (aPCC) and €62 301.08 (rFVIIa) for minor surgery and €126 595.81 (aPCC) and €347 731.09 (rFVIIa) for major surgery. Assuming an estimated 23 annual surgeries in this population (N = 69), distributed as 19% dental extraction, 50% minor surgery and 31% major surgery, the total annual cost of prophylaxis was €1 209 682.35 with aPCC and €3 221 929.28 with rFVIIa. Conclusions aPCC costs were 62.5% lower than rFVIIa. Assuming potential clinical equivalence, aPCC is a potentially cost‐saving option for surgical patients with haemophilia A and inhibitors.

Introduction Haemophilia A is a rare bleeding disorder caused by defects in coagulation factor VIII (FVIII). Damoctocog alfa pegol (BAY 94–9027, Jivi, Bayer, Germany) is a site-specifically PEGylated, extended-half-life, recombinant FVIII, approved for use in previously treated patients (PTPs) aged ≥12 years with haemophilia A. However, a real-world evidence regarding routine clinical use of damoctocog alfa pegol is limited. Methods and analysis HEM-POWR is a multinational, multicentre, non-interventional, prospective, postmarketing cohort study evaluating the effectiveness and safety of real-world treatment with damoctocog alfa pegol. Estimated enrolment is ≥200 PTPs with haemophilia A, receiving damoctocog alfa pegol (on-demand, prophylaxis or intermittent prophylaxis (as per local label)), observed for 36 months. Primary outcomes are total bleeding events and annualised bleeding rate; secondary outcomes include long-term safety, joint health, pharmacokinetics, patient-reported outcomes (PROs) from validated questionnaires and perioperative haemostasis. Where applicable, reasons for switching to damoctocog alfa pegol, choice of treatment regimen and dose will also be captured. Exploratory and descriptive statistical analyses will be performed, and will be stratified by parameters including, but not limited to, prophylaxis regimen and haemophilia severity. Patients can record bleeds and consumption in electronic (e) Diaries, ePROs, and can access non-promotional study information (videos explaining study procedures) via an online patient portal. Optionally, patients can enrol in the LIFE-ACTIVE substudy designed to investigate the relationship between activity (measured by the ActiGraph CP Insight watch) and effectiveness parameters collected from HEM-POWR. Ethics and dissemination Study approval was obtained by local independent ethics committees and authorities in participating study centres across Europe, the Americas and Asia. Informed consent from patients or their legal representative is a requirement for participation. The study results will be submitted for publication in a peer-reviewed scientific journal and presented at scientific conferences. Trial registration numbers NCT03932201, EUPAS26416. Protocol version and date V.1.2, 27 September 2019.

Introducción: La hemofilia es una enfermedad rara, por lo que su abordaje en Urgencias puede suponer un reto para los pediatras. Objetivos: Describir la frecuencia y motivos de consulta de los niños hemofílicos en Urgencias. Material y métodos: Estudio retrospectivo longitudinal realizado en Urgencias Pediátricas de un hospital de tercer nivel. Se incluyeron hemofílicos A y B, desde el nacimiento hasta los 16 años, que consultaron por cualquier motivo durante 6 años (2011-2016). Se analizaron: edad, tipo y gravedad de hemofilia, motivo de consulta, profilaxis domiciliaria frente a sangrados, pruebas complementarias, diagnóstico establecido, tratamiento y número de visitas a Urgencias. Resultados: Se analizaron 116 varones con un total de 604 visitas. La media de edad fue de 5,5 años y la mediana de 5,3. De ellos, 101 pacientes eran hemofílicos A (38 leves, 4 moderados, 59 graves) y 15 hemofílicos B (9 leves, 3 moderados, 3 graves). Los principales motivos de consulta (clasificados en triaje) fueron: problema musculoesquelético/traumático o sangrado (66,7%), causas no relacionadas con hemofilia (29%), sospecha de infección de catéter central (2,8%) y administración rutinaria de factor (1,5%). Se realizaron pruebas complementarias en 335 visitas (55,5%). Del total, 317 consultas (52,5%) requirieron factor; 103 episodios (17,1%) precisaron ingreso, cuyos principales motivos fueron: traumatismo craneoencefálico (35,9%), infección de catéter venoso central (13,6%), hemartrosis (8,7%), hematoma muscular (6,8%) y hematuria (5,8%). Conclusión: Los pacientes consultaron por causas habituales de la edad pediátrica, pero también lo hicieron por motivos específicos de su enfermedad; lo más frecuente fue el problema musculoesquelético/traumático o sangrado. El Servicio de Urgencias es un componente indispensable en su atención, Introduction: Haemophilia is a rare disease and its management can pose a challenge to Emergency Department paediatricians. Aim: To describe the frequency and reasons for consultation by haemophilic children in the ED. Materials and methods: Longitudinal retrospective study was conducted in a paediatric Emergency Department of a tertiary care hospital. The study included haemophiliacs A and B, ages 0 to 16 years old, and who had consulted the Emergency Department for whatever reason over a span of 6 years (2011-2016). The data analysed include: age, type and severity of haemophilia, reason for query, prophylactic status, complementary examinations, established diagnosis, treatment, and number of visits to the Emergency Department. Results: The analysis included 116 males with a total of 604 Emergency Department visits. The mean age was 5.5 years, and the median age was 5.3 years. A total of 101 patients were categorised as haemophiliac A (38 mild, 4 moderate, 59 severe), and 15 as haemophiliac B (9 mild, 3 moderate, 3 severe). The main reasons for initial Emergency Department visits (ranked by triage) were: musculoskeletal problems/injury or bleeding (66.7%), causes unrelated to haemophilia (29%), suspected central venous catheter related infection (2.8%), and routine clotting factor infusion (1.5%). Additional tests were conducted during 335 visits (55.5%). Factor replacement was undertaken in 317 visits (52.5%). A total of 103 episodes (17.1%) required hospital admission, due to: head trauma (35.9%), central venous catheter -related infection (13.6%), haemarthrosis (8.7%), muscle haematoma (6.8%), and haematuria (5.8%). Conclusion: Haemophilic patients went to the Emergency Department for common paediatric causes, but also requested consultation on specific problems related to haemophilia, with musculoskeletal problems/injury or bleeding being the main issues. The paediatric Emergency Department is an indispensable component of haemophilia care

Very few data exist on when a particular thrombopoietin-receptor agonist (TPO-RA) is favored in clinical practice for the treatment of patients with immune thrombocytopenia (ITP), about novel risk factors for vascular events (VE) with these drugs, nor about predictive factors for therapy free responses (TFR). We conducted an observational, retrospective, long-term follow-up multicenter study from November 2016 to January 2018 of 121 adult ITP patients initiating TPO-RA between January 2012 to December 2014. Data reflected that a platelet count ≤25 × 109/l at the time when the TPO-RA was initiated was associated with a 2.8 higher probability of receiving romiplostim vs. eltrombopag (P = 0.010). VE on TPO-RA was related to previous neoplasia in patients over 65 years (50% vs. 2.2%, P vs. 33%, P = 0.001). Receiving romiplostim as first TPO-RA with no subsequent TPO-RA switching was associated with a 50% likelihood of TFR after 2.9 years of therapy (3.3 years in chronic ITP patients). These real-world data help deciphering some areas of uncertainty, and offer insight into some of the most relevant challenges of ITP which may help clinicians make appropriate treatment decisions in the management of adult ITP patients with TPO-RA.

Arthrocentesis of an acute hemarthrosis in hemophilia remains a controversial issue. The purpose of this study is to define the role that joint aspiration can play in the recovery from acute hemarthrosis in patients with hemophilia. The study sample included 33 hemophilic patients (55 joints) with acute elbow, knee, and ankle hemarthrosis as confirmed by ultrasonography. Patients were distributed into a treatment group and a control group. Patients in the first group were subjected to joint aspiration, whereas patients in the second were not. Arthrocentesis was carried out immediately after diagnosis of acute hemarthrosis in liquid phase. Patients were infused with the deficient coagulation factor and were instructed to observe relative rest until resolution of hemarthrosis. The following parameters were analyzed: time to full resolution of hemarthrosis (determined by ultrasonography), duration of treatment with the deficient coagulation factor, time to pain relief, time to recovery of prebleed range of motion, and time to resumption of school/work (all of these measured in days). The joints treated with joint aspiration exhibited a significantly faster resolution of bleeding (fewer days). In addition, this group required fewer days of pharmacological treatment, with faster achievement of functional recovery and resumption of school/work activities. No complications were observed. This study shows that joint aspiration under hemostatic cover and in strictly aseptic conditions is a well-tolerated technique that makes the recovery of acute hemarthrosis of hemophilic patients faster.

The treatment goal for patients with immune thrombocytopaenia (ITP) is to raise platelet counts to levels that minimize or stop bleeding. Thrombopoietin receptor agonists (TPO-RAs) have been successfully and extensively employed as second-line therapy for ITP. However, TPO-RAs have a small but significant increase in the risk of thrombosis. The aim of this study was to elucidate the mechanisms involved in the pro-coagulant effect of TPO-RAs to take them into account when considering their use in ITP patients with concomitant diseases/conditions that might increase risk of suffering thrombotic events. Eighty-two patients with chronic primary ITP (40 untreated and 42 undergoing TPO-RA therapy) and 112 healthy individuals were recruited. The patients with ITP undergoing TPO-RA therapy presented a pro-coagulant profile due to the formation of a more fibrinolysis-resistant clot because of increased plasminogen activator inhibitor-1 (PAI-1) levels. Increase in platelet content of PAI-1 might be the result of the effect of TPO-RA during megakaryopoiesis, as suggested by experiments performed in MEG-01 cells. Moreover, patients under TPO-RA treatment presented an enhanced pro-coagulant activity associated with microparticles and an increased platelet apoptosis that causes a higher exposure of phosphatidylserine and, consequently, a larger surface for the binding of the prothrombinase complex.

Loss of sialic acid from the carbohydrate side chains of platelet glycoproteins can affect platelet clearance, a proposed mechanism involved in the etiopathogenesis of immune thrombocy-topaenia (ITP). We aimed to assess whether changes in platelet glycosylation in patients with ITP affected platelet counts, function, and apoptosis. This observational, prospective, and transversal study included 82 patients with chronic primary ITP and 115 healthy controls. We measured platelet activation markers and assayed platelet glycosylation and caspase activity, analysing samples using flow cytometry. Platelets from patients with ITP with a platelet count, This research was funded by FIS-Fondos FEDER PI19/00631, FIS-Fondos FEDER PI19/00772 and Platelet Disorder Support Association

Background and Objectives: The aim of this study was to determine the impact of the COVID-19 pandemic on the lives of patients with immune thrombocytopaenia (ITP) treated at our hospital. Materials and Methods: The study was conducted in the Community of Madrid, which has the highest number of COVID-19 cases in Spain. We included 143 adult patients with ITP (130 with chronic ITP, 8 with persistent ITP, and 5 with newly diagnosed ITP). We conducted a telephone survey to collect the data and created a registry. Materials and Methods: Overall, 24 patients presented symptoms suggestive of COVID-19, which was confirmed by RT-PCR in 8 cases. The cumulative incidence of confirmed SARS-CoV-2 infection was higher in the patients with ITP than in the Madrid population. There were no differences in the disease incidence or clinical course of infection in the patients treated with immunosuppressants. Almost all of the patients reported adherence to the prescribed treatment, although 49.2% of the hospital visits were either cancelled or postponed, 17.2% because of the patients’ fear of coming to the centre. Nearly half of the cohort was considered vulnerable, and 17% had been granted a dependency or disability benefit. Conclusions: COVID-19 had a major impact on the psychosocial, occupational, and quality of care of patients with ITP., This study was supported by FIS-Fondos FEDER PI19/00631 and PI19/00772 and by the Platelet Disorder Support Association

Acquired haemophilia A (AHA) is a rare severe bleeding disorder resulting from the production of autoantibodies directed against coagulation factor VIII. At presentation, bleeding events can be severe, and an early diagnosis and treatment are of major importance. The current study aims to analyse the treated patients who have been diagnosed with AHA for a better understanding of our population and treatment outcome. We conducted a retrospective study with 26 patients who had been diagnosed with AHA and who were treated in our hospital between January 2006 and January 2021. The patients ranged in age from 30 to 85 years old: 46.10% were men, 46.10% had no known underlying condition, 27% had an underlying malignancy, 7.60% presented with other diseases: psoriatic arthritis and Paget’s disease, and 19.30% presented with AHA during puerperium. All of the patients had bleeding events and were treated with bypass agents for this as well as with immunosuppressive therapy to eradicate the inhibitor. A total of 53.80% of the patients had major bleeding. Sixty-nine percent of the patients achieved complete remission, but 26.90% died during the follow-up, although bleeding was not the cause of death in any of these cases. Our observations underline the importance of clinical suspicion and early referral to centres with experience and laboratory facilities for managing AHA.

We describe the case of a patient with severe hemophilia A who underwent major orthopedic surgery managed postoperatively by telemedicine (TM). The case is a splendid example of the implementation of TM and good collaboration between a Comprehensive Hemophilia Treatment Center (CHTC) and a local hospital.

We aimed to identify the key players in the prothrombotic profile of patients with systemic lupus erythematosus (SLE) not mediated by antiphospholipid antibodies, as well as the potential utility of global coagulation tests to characterize hemostasis in these patients. Patients with SLE without antiphospholipid antibodies and without signs of thrombosis were included. The kinetics of clot formation were determined by ROTEM&reg, Platelet activation markers were determined by flow cytometry. Thrombin generation associated with Neutrophil Extracellular Traps (NETs) and microparticles (MPs) was measured by calibrated automated thrombogram (CAT). The plasma levels of PAI-1 were also determined. ROTEM&reg, showed a procoagulant profile in SLE patients. SLE patients had activated platelets and more leukocyte/platelet aggregates at basal conditions. The plasma PAI-1 and platelet aggregates correlated with several ROTEM&reg, parameters. The thrombin generation associated withthe tissue factor (TF) content of MPs and with NETs was increased. Our results suggest the utility of global tests for studying hemostasis in SLE patients because they detect their procoagulant profile, despite having had neither antiphospholipid antibodies nor any previous thrombotic event. A global appraisal of hemostasis should, if possible, be incorporated into clinical practice to detect the risk of a thrombotic event in patients with SLE and to consequently act to prevent its occurrence.

[Background]: Ten years after their availability, thrombopoietin receptor agonists (TPO-RA) have heralded a paradigm shift in the treatment of immune thrombocytopenia (ITP). This study was aimed to analyze the implementation of current recommendations in the standard practice of adult ITP patients, and how age may influence those changes., [Methods]: We included 121 adult patients (> 65 years, n = 54; younger individuals, n = 67) who initiated treatment with TPO-RA between January 2012 and December 2014., [Results]: Patients older than 65 years treated with TPO-RA presented at diagnosis with significantly higher platelet counts, less bleeding, and a more prothrombotic profile than younger ones. The high efficacy rates of TPO-RA, preferentially used during the last decade in non-chronic phases, precluded from further therapies in the majority of ITP patients. Their administration was associated with a sharp decline in the last decade in the use of splenectomy and intravenous immunoglobulin, especially in younger ITP individuals., [Conclusion]: These results confirm (1) that there is a preferential use of TPO-RAs in elderly ITP patients with fewer bleeding complications but more unfavorable prothrombotic conditions than in younger individuals, and (2) that early use of these agents has been established as an effective therapeutic alternative to other second line therapies., This work was supported by Amgen S.A. Spain.

In times of crisis, continuous adaptation is necessary. Communication between all members of a research team is key to adapting the development of clinical trials to the context of the epidemiological crisis of coronavirus. We are accustomed to performing day‐to‐day tasks to fulfil protocol requirements with precision. To this end, we typically have had protocol‐guided face‐to‐face visits and we have followed a detailed sequenced procedure during each visit.

Given the current SARS‐CoV‐2 pandemic, many patients with haemophilia will have close contact with a confirmed case or suffer from coronavirus 2019 respiratory disease (COVID‐19) and will need medical attention. Considering that this situation is exceptional, it is necessary to carry out integrated assistance for patients with haemophilia patients and their relatives, focusing such assistance on all the dimensions of life. In this regard, the WFH's recommendations to optimise haematological prophylaxis and its adherence should be emphasised to minimise the risk of bleeding and thus reduce the need to visit health care facilities [1].

La hemofilia A (HA) supone una importante carga economica para el sistema sanitario, especialmente relevante en pacientes hemofilicos que desarrollan inhibidor. De cara al establecimiento de politicas sanitarias resulta importante disponer de informacion sobre el coste anual que supone el manejo de este grupo de pacientes. El presente estudio tiene como objetivo estimar el coste farmacologico medio anual de un paciente con HA e inhibidores, desde la perspectiva del Sistema Nacional de Salud. Se realizo un modelo economico para estimar el coste farmacologico anual asociado a terapia con agentes bypass (factor vii activado recombinante (rFVIIa) y concentrado de complejo protrombinico activado (aPCC)) en pacientes con HA e inhibidor. La poblacion se estratifico segun la edad: pacientes pediatricos (

Etiopathogenesis of myelodysplastic syndrome (MDS) might cause per se an anomalous haemostasis that can be even more deteriorated by thrombocytopaenia. So, evaluation of haemostasis in patients with MDS rises as a necessity.This work aimed to characterize haemostasis in non-bleeder MDS patients with a platelet count similar to healthy controls to establish differences between the two groups not related to thrombocytopaenia.Thromboelastometry in samples from MDS patients suggested the existence of at least two antagonistic processes: one of them giving a hypocoagulable pattern (prolonged clotting time and lower α angle) and another conferring a procoagulant profile (decreased fibrinolysis). Hypocoagulable state might be due to a decreased ability of platelets to be stimulated and to the presence in plasma of a factor/s that prolonged the time to initiate thrombin generation. This factor/s might be antibodies as this effect was observed in samples from MDS patients with an associated autoimmune-inflammatory condition.Otherwise, hypercoagulable state seemed to rely on an increased presence of red cell- and monocyte-derived microparticles and to the increased exposure of phosphatidylserine that served as scaffold for binding of coagulation factors.We concluded that haemostasis in MDS patients is a complex process influenced by more factors than platelet count.

Introduction: Platelet glycoproteins are key contributors to platelet function but their glycans structure is unclear. Alterations in glycan composition have been reported to impact platelet clearance under physiological conditions and in the disease mechanism of immune thrombocytopenia (ITP). Therefore, this study sought to characterize glycan structures in human platelets from healthy control individuals and ITP patients using mass spectrometry (MS)-based glycomics approach, andto compare their glycomic profiles to facilitate understanding of glycan alterations in ITP. Methods: Glycan residues on platelet surface were determined by flow cytometry. Platelet lysates (1×10 8 platelets) from 4 healthy controls and from 4 ITP patients with a clear anomalous glycosylation pattern were characterized by MALDI-MS based glycomic approaches. N-linked glycans were released from platelet glycoproteins by PNGase F digestion and subsequently purified with a Sep-Pak C18 reverse phase cartridge. O-linked glycans were released by reductive elimination. Both pools of glycans were permethylated prior to MALDI-TOF MS to obtain an initial carbohydrate profile. Selected glycan molecular ion species were analyzed by MALDI-TOF-TOF MS/MS before and after digesting with exoglycosidases. Results: Glycans present in platelets from healthy controls and from ITP patients were largely consistent. The MS spectra for N-glycans showed a mixture of high mannose glycans (m/z 1579.8, 1783.9, 1988.0, 2192.1 and 2396.2); complex glycans (m/z 2966.5, 3776.9 and 4587.4); and bisected or truncated glycans (m/z 3211.6 and 4022.1). The spectra showed the presence of bi-, tri- and tetra-antennary complex glycans, which varied in their level of sialylation.Figure 1 shows the relative abundance ratio within eight families of core glycan structures. Platelets from ITP patients showed a consistent increase in desialylated structures such as Hex 5HexNAc 4Fuc 1. In addition to different amounts of attached sialic acid, varying levels of fucosylation were observed; ranging from the addition of a single core Fuc (m/z 2244.1), to the addition of up to three Fuc residues (m/z 3402.7). Collision-activated decomposition (CAD) MALDI-TOF/TOF analysis was performed to generate fragment ions from molecular ions detected in MALDI-TOF profiling for detailed sequencing of platelet N-glycans. This analysis suggested the presence of three isoforms: (i) sialylated tetra-antennary structure with core fucosylation and one Lewis x/a antenna; (ii) sialylated tetra-antennary structure with one Lewis y/b antenna; (ii) sialylated, core-fucosylated tri-antennary structure with one LacNAc extension and one Lewis x/a antenna. Sialidase S digestion was used to highlight the extent of desialylation in the presence of sialidase. Noteworthy, the ratio of non-sialylated bi-and tri-antennary N-glycans in ITP patients were higher than that in controls. This enzymatic digestion confirms the presence of α2,3-linked Neu5Ac on platelet glycans. Remaining sialylated structures may possess α2,6-linked Neu5Ac. O-glycan profiles obtained showed the predominance of core 1 and core 2 structures (Figure 2). The two most dominant glycan structures in core 1 were sialyl T antigen (GalNAc 1Gal 1NeuAc 1; m/z 895.5) and disialyl T antigen (GalNAc 1Gal 1NeuAc 2; m/z 1256.7), being the latter less abundant in ITP patients. The core 2 structure was modified by the addition of fucose and/or sialic acid residues (m/z 1157.7, 1344.8, 1518.9 and 1706.0). Conclusion: N- and O-glycan structures in human platelets were characterized by MALDI-TOF MS profiling to reveal interesting structural features including the presence of sialylLewis x/a epitope, Lewis x/a epitope, Lewis y/b epitope and LacNAc extensions in complex type N-glycans. Presence of terminal sialic acid and sialylLewis x/a on platelet N-glycan antenna also suggest their potentialfunction as ligands for siglecs that are associated with cell signaling functions. Siglec-1 and -2 have been suggested to have potential roles in ethiopathogenesis of autoimmune diseases. Desialylation observed in glycans of platelets from ITP patients, might trigger immune system activation in these patients. This research was funded by ISCIII-Fondos FEDER PI19/00772 and Platelet Disorder Support Association Figure 1 Figure 1. Disclosures Butta: Roche: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; CSL-Behring: Research Funding; Novo-Nordisk: Speakers Bureau. Canales: F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; iQone: Honoraria; Sandoz: Honoraria, Speakers Bureau; Incyte: Consultancy; Janssen: Consultancy, Honoraria, Speakers Bureau; Gilead/Kite: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Sanofi: Consultancy; Eusa Pharma: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria. Jiménez-Yuste: Pfizer: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; BioMarin: Consultancy; Sobi: Consultancy, Honoraria, Research Funding; NovoNordisk: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria, Research Funding. Alvarez Román: Octapharma: Consultancy, Honoraria, Research Funding; Biomarin: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; CSL-Behring: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria, Research Funding; Novo-Nordisk: Consultancy, Honoraria, Research Funding; Sobi: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding.

Background: Primary immune thrombocytopenia (ITP) is a megakaryocytic (MK)/platelet-specific autoimmune disorder characterized by platelet count It is widely accepted the involvement of platelet autoantibodies on deterioration of platelets from patients with ITP. Moreover, an enhanced activity of neuraminidase may also reduce sialic acid from glycoside residues on platelet surface, especially from the highly glycosylated von Willebrand factor (vWF) receptor. Because controversial results regarding the functionality of platelets from ITP patients can be found in literature, we aimed to determine platelet ability to be stimulated by agonists. Moreover, we aimed to determine the way anti-platelet auto- antibodies (abs) and neuraminidase activity may affect the function of platelets derived from MKs of healthy controls. Methods: This observational, prospective and transversal study included 42 patients with chronic primary ITP and 55 healthy controls. Platelet fibrinogen and vWF receptors and activation markers (PAC1 binding to activated fibrinogen receptor and exposure of P-selectin after agonists treatment), were evaluated by flow cytometry. Presence of Antibodies (abs) against platelet's glycoproteins in ITP serum was analysed with a Luminex based assay (LifecodesPak Lx). Neuraminidase (NEU) activity in serum was determined with the substrate 20-(4-methylumbelliferyl)-a-D-N-(MUNANA). Human CD34 + cell-enriched population was obtained with CliniMACS (MiltenyiBiotec) from G-CSF mobilized peripheral blood of a healthy donor. For MK differentiation, CD34 + cells were cultured 12 days in StemSpan™ Serum-Free Expansion Medium II (SFEM II) with 50ng/ml of recombinant human thrompoietin. Then, 10% of serum from healthy controls (4) or ITP patients (4) were added to the culture of mature MKs and incubated for 3 days. Phenotypic analysis of MKs and culture derived-platelets was carried out using abs against CD34, CD41, CD42a and CD42b.Platelet-like particles were considered as CD41-positive events with a size (FSC) and granularity (SSC) scatter properties similar to blood platelets. Culture-derived platelets were stimulated with 100 µM TRAP and 10 µM ADP and activation markers were analyzed by flow cytometry. Results: Expression of fibrinogen receptor on platelets from ITP patients were similar to those from healthy controls but showed a reduced capacity to be activated. Impairment in platelet degranulation measured as exposition of P-selectin after agonist's stimulation was also observed in platelets from these patients (Figure 1). Of note, surface content of CD42b subunit of vWF receptor was reduced (Figure 1). To determine whether diminished platelet function might be due to a plasma component, we induced platelet production from MK of healthy controls as referred in Methods. Abs against platelets and neuraminidase activity were determined in serum samples. Serum from 4 healthy controls or from 4 ITP patients (1 with anti-CD42b, 1 with anti-GPIa-IIa and 2 with undetectable abs) were added to MKs culture. No differences existed in MK differentiation and platelet production between MKs incubated with serum from healthy controls or from ITP patients, but similarly as observed in platelets from ITP patients, MK-derived platelets had an impaired ability to be activated (Table 1). Platelets derived from MKs incubated with ITP serum with anti-platelet abs had also a diminished exposure of CD42b (73±8% of controls). Moreover, neuraminidase content of these samples was slightly higher than that from ITP samples without abs (130 vs 100 % of controls). Conclusion: Platelets from ITP patients had a diminished ability to be stimulated. In vitro study showed that megakaryopoiesis was normal in presence of ITP serum, but released platelets had a lower ability to be activated. Involvement of abs in this effect cannot be ruled out despite we detected abs only in 2 of the tested sera because efficiency of method to detect these abs is ~ 50%. On the other hand, reduced levels of CD42b might be due to the increased activity of neuraminidase. Reduction of sialic acid from CD42b might initiate its metalloproteinase-mediated cleavage or change affinity of the ab used for its detection. Research funded by ISCIII-Fondos FEDER PI19/00772 and Platelet Disorder Support Association Figure 1 Figure 1. Disclosures Alvarez Román: Pfizer: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; Sobi: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria, Research Funding; Biomarin: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; CSL-Behring: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Novo-Nordisk: Consultancy, Honoraria, Research Funding. García Barcenilla: Roche: Speakers Bureau; Takeda: Speakers Bureau; Bayer: Speakers Bureau; SOBI: Speakers Bureau. Canales: Janssen: Consultancy, Honoraria, Speakers Bureau; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Gilead/Kite: Consultancy, Honoraria; Eusa Pharma: Consultancy, Honoraria; Incyte: Consultancy; Karyopharm: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Sanofi: Consultancy; iQone: Honoraria; Sandoz: Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau. Jiménez-Yuste: Grifols: Consultancy, Honoraria, Research Funding; NovoNordisk: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; BioMarin: Consultancy; Sobi: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding. Butta: Novo-Nordisk: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; Roche: Speakers Bureau; CSL-Behring: Research Funding.

Introduction: Hemophilia A (HA) patients under emicizumab prophylaxis treatment may require the concomitant use of procoagulant factors for breakthrough bleedings or immune tolerance induction. Thromboembolic events have been described with the concomitant use of emicizumab and activated prothrombin complex concentrate (aPCC), but not with recombinant activated factor VII (rFVIIa). Previous studies showed that the in vitro combination of emicizumab and plasma-derived Factor VIII/Von Willebrand Factor (pdFVIII/VWF) had a non-additive effect on thrombin generation (TG)(Bravo M-I, et al J Thromb Haemost. 2020;18:1934-39). The aim of this study was to evaluate the TG resulting from ex vivo combination of plasma samples from HA patients treated with emicizumab, with a pdFVIII/VWF concentrate (Fanhdi ®, Grifols). Methods: Twelve adult patients with severe HA without inhibitors on prophylaxis with emicizumab and nine healthy controls were included in the study. Blood samples were drawn in citrate plus corn trypsin inhibitor tubes. Then, platelet poor plasma (PPP) was collected for the TG assay, which measures the whole kinetics of TG. Thrombin peak (TP) and endogenous thrombin potential (ETP) were calculated using calibrated automated thrombogram (Thrombinoscope ™ software, Stago) after in vitro activation of coagulation by trigger solution, PPP Reagent LOW TM (4 μM phospholipids/1 pM tissue factor), fluorogenic substrate and CaCl 2 (FLUKAkit TM) reagents (Diagnostica Stago). Fluorescence was read in a Fluoroskan Ascent reader (Thermo) equipped with a 390/460 filter set. Samples were spiked with increasing concentrations of pdFVIII/VWF (10 to 400 IU/dL), rFVIIa (0.9 µg/mL) or aPCC (0.5 U/mL). Results: TG from healthy control samples was measured to establish TP and ETP normal ranges. TP and ETP results obtained from HA plasma with emicizumab were lower than in healthy controls. The addition of pdFVIII/VWF as of 25 IU/kg (prophylaxis dose in HA w/o inhibitors) to samples from HA patients concomitantly treated with emicizumab restored TP and ETP levels within healthy controls normal range (Table 1). Increasing ex vivo concentrations of pdFVIII/VWF maintained TP and ETP similar to healthy controls. The highest concentration of concomitant treatment with pdFVIII/VWF (200 IU/kg) and emicizumab did not result in excessive TP and, importantly, ETP levels were always within the normal range. The combination with the bypassing agent rFVIIa moderately increased TP and ETP values up to normal range. However, when HA plasma was spiked with aPCC in the presence of emicizumab, TP and ETP dramatically increased above normal range resulting in a synergistic procoagulant profile. Conclusions: The concomitant use of pdFVIII/VWF in patients with prophylaxis with emicizumab did not trigger a multiplying effect on TG. These results were aligned with previous in vitro data and suggested the low risk of overdose and thrombotic events of concomitant treatment emicizumab with the pdFVIII/VWF concentrate in HA patients. Figure 1 Figure 1. Disclosures Bravo: Grifols: Current Employment, Other: Grifols is a manufacturer of the pdFVIII/VWF concentrate, Fanhdi®. Raventós: Grifols: Current Employment, Other: Grifols is a manufacturer of the pdFVIII/VWF concentrate, Fanhdi®. Pérez: Grifols: Current Employment, Other: Grifols is a manufacturer of the pdFVIII/VWF concentrate, Fanhdi®. Alvarez Román: Grifols: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Novo-Nordisk: Consultancy, Honoraria, Research Funding; Sobi: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; CSL-Behring: Consultancy, Honoraria, Research Funding; Biomarin: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding. Butta: CSL-Behring: Research Funding; Roche: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; Novo-Nordisk: Speakers Bureau. Jiménez-Yuste: Bayer: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding; BioMarin: Consultancy; Sobi: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; NovoNordisk: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria, Research Funding. Costa: Grifols: Current Employment, Other: Grifols is a manufacturer of the pdFVIII/VWF concentrate, Fanhdi®. Willis: Grifols: Current Employment, Other: Grifols is a manufacturer of the pdFVIII/VWF concentrate, Fanhdi®.

Introduction: The management of Factor (F) VII deficiency is complex due to the lack of a clear correlation between FVII levels and the bleeding manifestations of the patients, with a variety of responses to the treatments. Additionally,the presence of FVII inhibitors may also occur. Thus, it is essential to be able to monitoring the hemostatic profile and the effect of the different therapies in each patient individually. Our aim was to perform a personalized analysis of the coagulation status of patients with FVII deficiency and to evaluate their response to new potential therapies using five different coagulation tests. Methods: Six patients were included (clinical data in Table-1):4 with bleeding symptoms on prophylaxis with recombinant activated FVII (rFVIIa), one of them with FVII inhibitors; and 2 untreated patients without bleeding episodes. Blood samples obtained from patients on prophylaxis were collected predose. Prothrombine time (PT) and activated partial thromboplastin time (aPTT)were tested using HemosIL ® RecombiPlasTin 2G, and SynthASil respectively. Rotational Thromboelastometry (ROTEM ®) was performed for monitoring the clot formation using blood with corn trypsin inhibitor (CTI) to inhibit contact activation and a low amount of Tissue Factor (TF) as trigger (dilution 1:50,000 of EXTEM reagent). The thrombin generation (TG) was tested with the Calibrated Automated Thrombogram (CAT) system using platelet poor plasma (PPP) obtained from blood with CTI and activated with only 1 pM TF plus phospholipids (PPP-Low ®, Stago). The plasmin generation (PG) was measured in citrated PPP using a comercial kit (Synapse). The total thrombus-formation analysis system (T-TAS ®, Zacros) was conducted by loading CTI blood samples in AR-chips coated with collagen and thromboplastin for assessing thrombus formation mediated by the activation of the coagulation under flow conditions (High shear). The Area under the flow pressure curve (AUC) was calculated over 30 min after starting. Effects of ex vivo spiking doses of factor replacement (rFVIIa) or non-factor replacement treatments (anti-TFPI, clone mAb2021, Creative Biolabs) were tested. Results: aPTT values remained normal in all patients. FVII deficiency significantly affected PT and patients with more severe bleeding phenotype (patient #1, 2, 3, and 4) showed much longer PT values. Similarly, ROTEM and T-TAS assays showed that FVII deficiency only caused an important delayed clotting time (CT) and very anomalous thrombus formation (AUC) in patients with severe bleeding symptoms.More prolonged lag time (LT) and an important decrease in the peak of thrombin and plasmin generation was also observed in the same patients (#1, 2, 3, and 4). Patient #1 with FVII inhibitors presented a more affected hemostatic profile according to all the coagulation parameters obtained with the five different assays. In contrast, the patients #4 and #5 with absence of bleeding complications showed most of these values within the normal reference range obtained from healthy controls. Concentrations of 1µg/ml (equivalent to 90 μg/kg) of the factor-replacement treatment rFVIIa, showed the normalization of the PT, the clotting time (CT), and the restoration of the thrombin and plasmin generation, and the regularization of the coagulation-dependent thrombus formation in all the patients. In vitro spiking with anti-TFPI (400-800 ng/ml), an alternative non-factor replacement treatment,corrected the thrombus formation (AUC) defects under high shear flow observed in the patients, and produced a significant reduction of CT and LT, and increments of thrombin generation although less effectively than the factor replacement therapy. Conclusions: All the global tests, performed with the described conditions in this study, were sensitive enough to show an abnormal hemostatic profile in the FVII-deficient patients with worst clinical symptoms, validating their use to monitor the risk of bleeding events and the responses to different treatments in this deficiency. These assays may allow to monitoring more personalized treatments to these patients. The results also pointed to the possibility that inhibition of TFPI might be useful for treatment of patients with FVII deficiency, opening the idea of its usage especially as an alternative therapy for patients with inhibitors. Research funded by ISCIII-Fondos FEDER PI19/00772 and PI19/00631 Figure 1 Figure 1. Disclosures Alvarez Román: Pfizer: Consultancy, Honoraria, Research Funding; Sobi: Consultancy, Honoraria, Research Funding; Biomarin: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Novo-Nordisk: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria, Research Funding; CSL-Behring: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding. García Barcenilla: Roche: Speakers Bureau; Takeda: Speakers Bureau; SOBI: Speakers Bureau; Bayer: Speakers Bureau. Canales: Takeda: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Incyte: Consultancy; Sanofi: Consultancy; Novartis: Consultancy, Honoraria; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; iQone: Honoraria; Sandoz: Honoraria, Speakers Bureau; Eusa Pharma: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; Gilead/Kite: Consultancy, Honoraria. Butta: CSL-Behring: Research Funding; Roche: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; Novo-Nordisk: Speakers Bureau. Jiménez-Yuste: Octapharma: Consultancy, Honoraria, Research Funding; Sobi: Consultancy, Honoraria, Research Funding; BioMarin: Consultancy; Pfizer: Consultancy, Honoraria, Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; NovoNordisk: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding.

Introduction: Hematologists frequently face a percentage of patients with a mild bleeding tendency due to a haemostatic abnormality that cannot be identified with conventional laboratory techniques. Such patients are termed as having an unclassified bleeding disorder (UBD). A good diagnosis is important in order to prevent bleedings during invasive processes and/or childbirth by choosing the optimal therapeutic treatment. We aimed to investigate hemostatic parameters that may be altered in patients with UBD in order to determine the cause of their bleeding symptoms. In particular, possible defects in the tissue factor (TF)-mediated regulation of coagulation or in the plasmin generation during the fibrinolysis, as well as the possible beneficial effects of treatment with antibodies blockers of TFPI. Methods: This is a single-centre, case-control, non-interventionist, prospective study. During an 8 months-period, 40 patients with bleeding symptoms (evaluated with ISTH-BAT score) were studied. Routine coagulation tests (aPTT and PT) and platelet function testing [aggregometry, PFA-100, flow cytometry and Total Thrombus-formation Analysis System (T-TAS; Zarcos, Japan)] were performed. In 17 patients, no abnormalities were detected in platelet function and/or in coagulation tests; so the following procedures were performed: Thrombin generation test by Calibrated automated thrombography (CAT) in samples of platelet poor plasma with corn trypsin inhibitor (CTI), an inhibitor of contact activation phase, using a low amount of TF (1 pM TF and 4 µM phospholipids) as a trigger to allow the evaluation of the TF-dependent pathway. Plasmin generation (PG) test with a kit from Synapse Research Institute (Maastricht, The Netherlands), using Thrombinoscope software. TFPI activity in plasma, measured with ACTICHROME® TFPI kit (Biomedica Diagnostics, USA). The effects of rFVIIa (Novoseven, NovoNordisk; 90 µg/kg) and of a human Anti-TFPI recombinant Ab (clon mAb2021, Creative Biolabs; 400 ng/ml) were tested in CAT, PG and TFPI activity tests. Results: Those patients with aPTT, PT and a platelet function within normal range were further studied performing thrombin generation, plasmin generation and TFPI activity tests. Table 1 shows the results obtained. Samples from patients 1, 2, 4, 7, 8, 9 and 10 had a diminished generation of thrombin, and in vitro treatment with anti-TFPI and rFVIIa only ameliorated thrombin generation in samples from patients 4, 7, 8 and 9. Plasma from patients 8 and 10 had increased activity of TFPI. Generation of thrombin in samples from patients 3, 5, 6 and 11 was within normal range. Plasmin generation was increased and not modified by in vitro treatment with anti-TFPI and rFVIIa in samples 3 and 11; whereas samples 5 (with normal plasmin generation) and 6 (with no data of plasmin generation due to lack of enough sample) had a high TFPI activity in plasma that was inhibited by anti-TFPI. Normal values in all these parameters evaluated were found in six patients, indicating the involvement of different mechanisms that are still unknown. Conclusions: UBD have a diverse pathological basis for the bleeding. So, a single laboratory test to make a correct diagnosis of this pathology cannot be recommended. In accordance with this fact, a personalized treatment should be applied for each patient. Non-conventional laboratory tests need to be standardized and included for studying possible defects in the regulation of TF and/or plasmin pathways that can be involved in very rare mild bleeding phenotypes. TFPI inhibition might emerge as a good therapy for some of these patients. Failure to detect the bleeding cause in some of these patients, suggests the need to perform further studies in this field. This work was supported by Novo Nordisk Pharma S.A. Table 1- Thrombin and plasmin generation and TFPI activity in samples of patients with UBD. Results out of normal range are shown in red. LT: lagtime; ETP: endogenous thrombin potential; EPP: endogenous plasmin potential; TFPI: Tissue factor pathway inhibitor. Figure 1 Figure 1. Disclosures Alvarez Román: Grifols: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; CSL-Behring: Consultancy, Honoraria, Research Funding; Biomarin: Consultancy, Honoraria, Research Funding; Novo-Nordisk: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; Sobi: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding. Martín: Novo Nordisk: Speakers Bureau; Pfizer: Speakers Bureau. Jiménez-Yuste: F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Research Funding; BioMarin: Consultancy; Takeda: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; Sobi: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; NovoNordisk: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria, Research Funding. Canales: Eusa Pharma: Consultancy, Honoraria; Sandoz: Honoraria, Speakers Bureau; Sanofi: Consultancy; Karyopharm: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Incyte: Consultancy; Gilead/Kite: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; iQone: Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria. Butta: Novo-Nordisk: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; Roche: Speakers Bureau; CSL-Behring: Research Funding.

Background Damoctocog alfa pegol (BAY 94-9027, Jivi®) is an approved factor (F)VIII treatment indicated for use in previously treated patients with hemophilia A aged ≥12 years, based on its safety and efficacy profile as demonstrated in the PROTECT VIII trial (NCT01580293).Here, we report preliminary results of a post-marketing interventional study of damoctocog alfa pegol prophylaxis in previously FVIII-treated patients with severe hemophilia A aged ≥18 years. Methods This is an ongoing, multicenter, single group, uncontrolled, open-label, post-marketing, interventional, phase IV trial (NCT04085458) of damoctocog alfa pegol in previously FVIII-treated patients with severe hemophilia A, aged ≥18 years (Figure 1). Eligible patients receive prophylaxis with damoctocog alfa pegol for 100 exposure days (EDs), starting with 45 IU/kg every 5 days (E5D) (recommended dose) or 40 IU/kg twice-weekly (2×W) until their next planned visit (Visit 3 after 10-15 EDs). At Visit 3, patients can either continue with the same regimen, increase their dose, or switch regimen to 2×W, E5D, or every 7 days (E7D), based on their needs as judged by the investigator. Patients who switched prophylaxis regimen after their third visit were assigned to a variable frequency (VAR) group. Patients with ≥1 infusion of damoctocog alfa pegol and bleeding data for ≥3 months were eligible for inclusion in the modified intent-to-treat cohort and are included in this interim analysis. Primary endpoint is FVIII inhibitor development (titer ≥0.6 Bethesda units). Secondary endpoints include treatment emergent adverse events (TEAE), anti-PEG (polyethylene glycol) antibody development and annualized bleeding rate (ABR). Bleeds and study drug consumption were recorded using an electronic patient diary. All analyses are exploratory. Results By June 1, 2021, 32 patients have been enrolled. Of these, 30 patients have had ≥1 infusion of damoctocog alfa pegol and bleeding data for ≥3 months, and are thus included in this analysis (2×W, n = 7; E5D, n = 8; E7D, n = 9; VAR, n = 6). Median (range) age at start of FVIII treatment was 5.0 (0-15.0) years, with the majority (n = 24; 80.0%) starting with an on-demand regimen. Median (range) age for starting prophylaxis was 32.0 (0-64) years. At data cutoff, median (range) total time in study was 422 (112-554) days and 87 (30-114) EDs. Safety data are presented in Table 1. No patients developed FVIII inhibitors, PEG antibodies or anti-drug antibodies. Sixteen (53.3%) patients developed TEAE, with the majority being mild in severity (n = 12, 40.0%). Three (10.0%) patients experienced mild or moderate TEAEs, which were considered study drug-related by the investigator. At data cutoff, median (quartile, [Q]1; Q3) total and joint ABRs were 1.82 (0.7; 5.5) and 0.37 (0.0; 2.6), respectively. Of 20 patients who were treated for ≥12 months, 30% (n = 6) had zero total bleeds and 60% (n = 12) had zero joint bleeds in their last year of treatment. Conclusions Preliminary results from 30 patients observed for up to 80 weeks show that individualized prophylaxis regimens of damoctocog alfa pegol were well tolerated in this post-marketing study. No immunogenicity concerns were observed, with no patients developing FVIII inhibitors, anti-PEG or anti-drug antibodies. Despite many patients starting prophylaxis late, ABRs were low and a large proportion achieved zero bleeds. These data support the favorable safety and efficacy profile of damoctocog alfa pegol prophylaxis in routine clinical use. Figure 1 Figure 1. Disclosures Holme: Bayer, Octapharma, Pfizer and Shire: Research Funding; Bayer, Novo Nordisk, Octapharma, Pfizer, Shire and Sobi: Consultancy. Hvitfeldt Poulsen: Pfizer: Research Funding; Bayer, Novo Nordisk, Sobi, Pfizer, Octapharma: Other: Congress Support. Tueckmantel: Bayer: Current Employment. Alvarez Roman: Amgen, Bayer, CSL Behring, Novartis, Novo Nordisk, Shire/Takeda, Sobi, Roche: Speakers Bureau; Shire/Takeda: Research Funding. De Cristofaro: Shire/Takeda: Research Funding; Bayer, Takeda: Consultancy; Bayer: Other: Congress Support; Sobi: Consultancy.

Factor X deficiency is a rare coagulation disorder that can be hereditary or acquired. The typology and severity of the associated bleeding symptoms are highly heterogeneous, adding to the difficulties of diagnosis and management. Evidence-based guidelines and reviews on factor X deficiency are generally limited to publications covering a range of rare bleeding disorders. Here we provide a comprehensive review of the literature on factor X deficiency, focusing on the hereditary form, and discuss the evolution in disease management and the evidence associated with available treatment options. Current recommendations advise clinicians to use single-factor replacement therapy for hereditary disease rather than multifactor therapies such as fresh frozen plasma, cryoprecipitate, and prothrombin complex concentrates. Consensus in treatment guidelines is still urgently needed to ensure optimal management of patients with factor X deficiency across the spectrum of disease severity.

Introduction: Trauma-induced coagulopathy (TIC) is a multifactorial condition secondary to severe trauma. In TIC, early fibrinogen (FI) replacement and low dose of recombinant activated factor VII (rFVIIa) may positively impact outcome. Factor XIII (FXIII), on the other hand, may stimulate in vitro clot formation and clot stability. We hypothesized that combination of FI, rFVIIa and FXIII might normalize clot formation more effectively than the isolated use of each concentrate in a model of TIC. Aim: Evaluation of the procoagulant effect of isolated or combined use of FI, rFVIIa and FXIII in a model of TIC. Methods: TIC in vitro model was obtained by dilution of whole blood from seven healthy controls with isotonic saline (NaCl 0.9%) (2:3 whole blood:saline ratio). FI, rFVIIa and FXIII were spiked in combination or alone until obtaining final levels of 2 g/L, 1 μg/mL and 100 IU/dL respectively. Procoagulant effects of the different concentrates or their mixtures were evaluated by Rotational Thromboelastometry (ROTEM®, Werfen) triggered using starTEM® (calcium chloride 0,2 M) and exTEM® reagent (source of tissue factor) diluted with saline up to 1:100.000 (final dilution) for a better evaluation of both the extrinsic and intrinsic pathways of coagulation. The values of clotting time (CT: time until 2 mm of amplitude, in seconds), amplitude (parameter proportional to the clot strength) at 5 minutes (A5, in mm) and clot formation time (CFT: time from CT to 20 mm of amplitude, in seconds) were evaluated. Statistical analysis of differences was performed by One-Way ANOVA test assuming no paring of data and using the Holm-Sidak's correction for multiple comparisons with a family-wise significance and confidence level of 0.01. Statistical significance was set at p< 0.05. Results/Discussion: Data are summarized in Table I and Figure 1. CT needed the combination of two of more concentrates to reach the normal range suggesting that the administration of FI alone in TIC may not be enough to restore the patients' hemostatic potential. In regard to the clot strength evaluated by A5, the addition of FXIII or rFVIIa alone or in combination did not improve the value of A5 that was only normalized by the addition of FI. This effect of FI was increased in the presence of FXIII or rFVIIa which indicated that normal levels of FI might be required for rFVIIa or FXIII to be effective emphasising the possible benefit of the combinatory therapy. Like observed in A5, the velocity of clot formation evaluated by the CFT was normalised only by the addition of FI. However, the combination of FI plus FXIII + rFVIIa had a stronger effect on CFT compared with the combination of FI + FXIII or FI + rFVIIa, indicating that the improvement of thrombin generation due to rFVIIa plus an increment of fibrin formation and net stabilization through the contribution of higher levels of FI and FXIII respectively, might provide a beneficial synergistic procoagulant effect in TIC. Conclusion: The use of FI in TIC may contribute to increase the patient's hemostatic potential but might not be enough. Combinatory therapies based on the administration of FI, rFVIIa and FXIII might be of better benefit in this setting. Ex-vivo studies using blood of patients with stablished TIC might bring new insights on the possible advantages of this combinatory therapy to design more effective protocols to treat this frequent and life-threatening acquired condition. Disclosures Canales: Sandoz: Honoraria; iQone: Honoraria; Janssen: Speakers Bureau; Janssen: Honoraria; Roche: Speakers Bureau; Karyopharm: Honoraria; Sandoz: Speakers Bureau; Novartis: Honoraria; Takeda: Speakers Bureau; Roche: Honoraria; Sandoz: Honoraria; Janssen: Speakers Bureau; Roche: Speakers Bureau; Sandoz: Speakers Bureau; Takeda: Speakers Bureau; Janssen: Honoraria; Karyopharm: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Roche: Honoraria; Gilead: Honoraria. Butta:NovoNordisk: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; SOBI: Speakers Bureau; Pfizer: Speakers Bureau; ROCHE: Research Funding, Speakers Bureau; Novartis: Speakers Bureau; Grifols: Research Funding. Alvarez Román:NovoNordisk,: Research Funding, Speakers Bureau; Takeda: Research Funding, Speakers Bureau; SOBI,: Consultancy, Research Funding, Speakers Bureau; Pfizer,: Research Funding, Speakers Bureau; Roche: Speakers Bureau; Novartis: Speakers Bureau; Bayer: Consultancy; Grifols: Research Funding. Jiménez-Yuste:F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer: Consultancy; Grifols, Novo Nordisk, Takeda, Sobi, Pfizer: Research Funding; F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer, Grifols, Octapharma, CSL Behring, Bayer: Honoraria.

Background:Joint damage is the most frequent and most debilitating comorbidity of haemophilia and can be prevented by adequate prophylactic treatment. Nevertheless, many causes and not only plasma levels of the factor affect joint damage in severe haemophilia (SH) patients. One to be considered is variability on fibrin polymerization capacity since it might influence the bleeding tendency and, consequently, would affect the joint condition in SH patients. To our knowledge, there are not enough studies about that. Aim:This work aimed to evaluate if there exists a relationship between fibrin capacity of polymerization and joint condition in SH patients. Methods:This is a prospective and transversal study that was approved by Ethics Committee from Hospital Universitario La Paz. Twenty eight SH patients (25 with SHA, 5 of them with inhibitors; 3 with SHB, 2 of them with inhibitor), median age [p25-p75]=41 [29.8-51.3] years old) were recruited. Joint condition was evaluated using the HEAD-US score. Plasma level of fibrinogen (Fib) was determined by Clauss method. Rotational thromboelastometry (ROTEM) was performed with fibTEM, an extrinsically activated test with tissue factor and the platelet inhibitor cytochalasin D. fibTEM results correlate well in many cases with the Clauss Fib assay, but is additionally influenced by fibrin polymerization ability which cannot reliably be detected with clotting tests. Fibrinogen capacity to increase the clot strength was evaluated by the ratio R= Fib/fibTEM maximum clot firmness (MCFfibTEM) which means the plasma concentration of Fib needed to increase maximum clot firmness in 1 mm. Data were analysed with GraphPrism Pad 6.0. Results:Median value of Fib was 306 [263-341] mg/dl, MCFfibTEM = 12 [10-15] mm and R= 25.0 [20.5-29.5] mg/dl/mm. Patients were classified taking into account the value of the 25th percentile of each variable (Fib, MCFfibTEM and R). Subjects with Fib ≤ 263 mg/dl were considered patients with low fibrinogen level, those with MCFfibTEM ≤ 10 mm were considered patients with low platelet independent maximum clot strength and subjects with a R < 20.5 mg/dl/mm were considered good responders to fibrinogen. Based on this analysis, neither Fib nor MCFfibTEM influenced the joint condition. However, patients with poor response to fibrinogen (R ≥ 20.6 mg/dl/mm) had a significantly greater joint damage than the good responders to fibrinogen (R < 20.6 mg/dl/mm) (Table 1). Poor responders to fibrinogen had frequently joint damage in ankles followed by elbows and knees being cartilage the most commonly affected joint compartment. Good responders to fibrinogen only presented milder joint alterations in elbows and ankles. Conclusions: Our results suggested that polymerization capacity of fibrin may be variable between patients with SH and might influence joint condition. More patients need to be recruited to confirm this finding. This work was supported by grants from FIS-FONDOS FEDER (PI19/00631 and PI19/00772). EMM holds a predoctoral fellowship from Fundación Española de Trombosis y Hemostasia (FETH-SETH). Disclosures Fernandez-Bello: Pfizer:Speakers Bureau;Novartis:Speakers Bureau;Stago:Speakers Bureau;Roche:Speakers Bureau;NovoNordisk:Current Employment, Research Funding, Speakers Bureau;Takeda:Research Funding, Speakers Bureau;SOBI,:Research Funding.de la Corte:Pfizer:Research Funding, Speakers Bureau;NovoNordisk:Research Funding, Speakers Bureau;Takeda:Speakers Bureau;Roche:Research Funding, Speakers Bureau;Sobi:Research Funding, Speakers Bureau;Bayer:Speakers Bureau.Alvarez Román:Novartis:Speakers Bureau;Bayer:Consultancy;Grifols:Research Funding;Pfizer,:Research Funding, Speakers Bureau;Roche:Speakers Bureau;NovoNordisk,:Research Funding, Speakers Bureau;Takeda:Research Funding, Speakers Bureau;SOBI,:Consultancy, Research Funding, Speakers Bureau.Martín:SOBI:Research Funding;NovoNordisk:Speakers Bureau;Novartis:Speakers Bureau;Roche:Speakers Bureau;Pfizer:Research Funding, Speakers Bureau.Rivas Pollmar:Pfizer:Speakers Bureau;Roche:Speakers Bureau;Novartis:Speakers Bureau.García Barcenilla:Novartis:Speakers Bureau;Bayer:Speakers Bureau;Roche:Speakers Bureau;Pfizer,:Speakers Bureau;Takeda:Research Funding, Speakers Bureau;NovoNordisk:Research Funding, Speakers Bureau.Canales:Janssen:Honoraria;Sandoz:Speakers Bureau;Takeda:Speakers Bureau;Karyopharm:Honoraria;Novartis:Honoraria;Celgene:Honoraria;Roche:Honoraria;Gilead:Honoraria;Sandoz:Honoraria;iQone:Honoraria;Janssen:Speakers Bureau;Janssen:Honoraria;Roche:Speakers Bureau;Karyopharm:Honoraria;Sandoz:Speakers Bureau;Novartis:Honoraria;Takeda:Speakers Bureau;Roche:Honoraria;Sandoz:Honoraria;Janssen:Speakers Bureau;Roche:Speakers Bureau.Butta:Takeda:Research Funding, Speakers Bureau;SOBI:Speakers Bureau;Pfizer:Speakers Bureau;ROCHE:Research Funding, Speakers Bureau;Novartis:Speakers Bureau;Grifols:Research Funding;NovoNordisk:Speakers Bureau.Jimenez-Yuste:F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer:Consultancy;Grifols, Novo Nordisk, Takeda, Sobi, Pfizer:Research Funding;F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer, Grifols, Octapharma, CSL Behring, Bayer:Honoraria.

Introduction: Emicizumab is a humanized, monoclonal, bispecific antibody that binds factor (F) FX and FIXa allowing thrombin generation in the absence of FVIII, which is used for routine treatment of patients with Hemophilia A (HA) with and without inhibitors. Plasma level of FIX will be an important limiting factor for the formation of the FX-FIXa-emicizumab ternary complex in the absence of FVIII, suggesting the potential use of FIX concentrates to regulate the procoagulant function of emicizumab and therefore, to use it as an alternative treatment in certain circumstances to stop or prevent bleedings in patients on prophylaxis with emicizumab. At the present time there are several recombinant FIX concentrates with differences in their content of activated FIX (FIXa) and in their half-life (standard or extended) that may differ in their procoagulant effects when combined with emicizumab. Aim: The aim of this study was to evaluate if there were differences in thein vitroprocoagulant effects of two recombinant FIX concentrates, one with standard half-life (rFIX Nonacog Alfa, BeneFIX®, Pfizer) and the other with extended half-life (rFIX fused to rAlbumin, Albutrepenonacog Alfa, Idelvion®, CLS Behring) in samples from patients on prophylaxis with Emicizumab. Methods: This is a prospective and transversal pilot study that was approved by the Ethics Committee from La Paz University Hospital. Two patients with haemophilia A (HA) with inhibitors in prophylaxis with emicizumab were recruited and one haemophilia B (HB) patient was included as a control for the effects of FIX. Blood samples were collected in tubes with corn trypsin inhibitor (CTI, Haematologic Technologies, USA), to block thecontact phase and to only evaluate coagulation mediated by the extrinsic pathway. Levels of FIXa in concentrates of FIX were quantified using the Spectrozyme® FIXa chromogenic substrate (LOXO) and measuring the increase in OD at 405 nm. Rotational thromboelastometry (ROTEM) was performed using whole blood activated by a low concentration of tissue factor solution (final dilution 1:50,000 of EXTEM reagent) plus recalcification. Parameters evaluated in ROTEM were CT (cloting time), defined as time until detection of a clot firmness of 2 mm; and CFT (clot formation time), defined as time between detection of a clot firmness from 2 to 20 mm. Calibrated automated thrombogram (CAT)was performed using platelet free plasma (PFP) activated by low concentration of tissue factor plus phospholipids (PPP-Reagent LOW®, Stago). Parameters evaluated in CAT were: Peak, defined as maximum thrombin concentration reached, in nM; and ETP, defined as the total amount of thrombin generated over time, in nMxmin. Results: The presence of FIXa activity assayed by a chromogenic substrate was not detectable with 20 IU of Idelvion while BeneFIX® showed a specific concentration-dependent FIX activity that was blocked with the serine protease inhibitor EGR-chloromethylketone (Figure 1). ROTEM (Figure 2) and CAT (Figure 3) results showed that the addition of increased concentrations of both concentrates of rFIX produces an enhanced procoagulant effect of Emicizumab similar to the effect produced by the addition of the bypassing agent rFVIIa (NovoSeven®, NovoNordisk). These results also showed that it is necessary three-four times higher concentration (U/dl) of Idelvion® to get similar procoagulant effects that those obtained with BeneFIX®. The higher procoagulant effects of BeneFIX® were also observed in samples of a patient with severe HB. Conclusion: Global coagulation assays suggest that increasing endogenous FIX levels with two rFIX concentrates that have different FIXa content and half-life, produce an enhanced procoagulant effect of Emicizumab opening the idea of the use of these concentrates as an alternative treatment for bleedings in patients with inhibitors on prophylaxis with Emicizumab. Further studies need to be performed to evaluate the procoagulant activity of the concomitant use of different rFIX concentrates and Emicizumab, and to assess security of this therapeutic approach. This work was supported by grants from FIS-FONDOS FEDER (PI19/00631 and P19/00772). EMM holds a predoctoral fellowship from Fundación Española de Trombosis y Hemostasia (FETH-SETH). Disclosures Fernandez-Bello: Novartis:Speakers Bureau;Stago:Speakers Bureau;Takeda:Research Funding, Speakers Bureau;NovoNordisk:Current Employment, Research Funding, Speakers Bureau;Roche:Speakers Bureau;SOBI,:Research Funding;Pfizer:Speakers Bureau.García Barcenilla:Pfizer,:Speakers Bureau;Takeda:Research Funding, Speakers Bureau;Roche:Speakers Bureau;Bayer:Speakers Bureau;Novartis:Speakers Bureau;NovoNordisk:Research Funding, Speakers Bureau.Alvarez Román:Roche:Speakers Bureau;Novartis:Speakers Bureau;Takeda:Research Funding, Speakers Bureau;Pfizer,:Research Funding, Speakers Bureau;Bayer:Consultancy;SOBI,:Consultancy, Research Funding, Speakers Bureau;Grifols:Research Funding;NovoNordisk,:Research Funding, Speakers Bureau.Martín:NovoNordisk:Speakers Bureau;SOBI:Research Funding;Pfizer:Research Funding, Speakers Bureau;Roche:Speakers Bureau;Novartis:Speakers Bureau.Rivas Pollmar:Novartis:Speakers Bureau;Roche:Speakers Bureau;Pfizer:Speakers Bureau.Canales:Roche:Honoraria;Celgene:Honoraria;Roche:Honoraria;Janssen:Honoraria;Novartis:Honoraria;Sandoz:Speakers Bureau;Sandoz:Honoraria;Janssen:Speakers Bureau;iQone:Honoraria;Sandoz:Honoraria;Gilead:Honoraria;Takeda:Speakers Bureau;Novartis:Honoraria;Karyopharm:Honoraria;Janssen:Honoraria;Takeda:Speakers Bureau;Janssen:Speakers Bureau;Roche:Speakers Bureau;Sandoz:Speakers Bureau;Roche:Speakers Bureau;Karyopharm:Honoraria.Butta:Grifols:Research Funding;Novartis:Speakers Bureau;ROCHE:Research Funding, Speakers Bureau;Pfizer:Speakers Bureau;SOBI:Speakers Bureau;Takeda:Research Funding, Speakers Bureau;NovoNordisk:Speakers Bureau.Jimenez-Yuste:F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer, Grifols, Octapharma, CSL Behring, Bayer:Honoraria;F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer:Consultancy;Grifols, Novo Nordisk, Takeda, Sobi, Pfizer:Research Funding.

Introduction: Platelet surface glycoproteins (GPs) are highly glycosylated and are key elements for platelet function since most of them constitute receptors for adhesion ligands. However, exact role of their glycan composition is not clear. Under normal conditions, platelets contain sialic acid in the carbohydrate side chains of their GPs, and it has been described that alterations in the degree of their sialinization can affect the clearance of platelets. This mechanism has been proposed as involved in etiopathogenesis of immune thrombocytopaenia (ITP), mainly in those patients who do not respond to treatments. Thus, after the loss of sialic acid, there would be a greater exposure of galactose and of N-acetyl-glucosamine residues on the surface of circulating platelets to hepatic Ashwell-Morell receptors, which could induce their phagocytosis and platelet clearance. On the other hand, procoagulant platelets, defined as the platelet subpopulation that binds functional prothrombinase, exposed on their surface increased levels of P-selectin and GPIb, two glycan rich GPs. So, it is tempting to speculate that changes in glycan residues on platelet surface may induce changes in their function. Aim: We aimed to assess in ITP patients whether changes in platelet glycosylation, mainly the loss of sialic acid, may condition platelet function, apoptosis and binding of prothrombinase complex. Methods: This is an observational, prospective and transversal study approved by Ethics Committee from La Paz University Hospital. One hundred and eight patients with chronic primary ITP (68 with a platelet count ≥30x103 platelets/µL and 40 with a platelet count Platelet activation markers were determined in platelet rich plasma; whereas platelet glycosylation, binding of prothrombinase, annexin V and caspase's activities were assayed in washed platelets. Samples were analyzed by flow cytometry. Table 1 shows lectins tested and their sugar-binding specificity. Data were analyzed with GraphPad Prism 6.0 software. Results: Platelets from ITP patients with a platelet count These differences in glycosylation observed in ITP patients with a platelet count Conclusion: Changes in glycoside composition of GPs on platelet's surface impaired their functional capacity, increases their apoptosis and modifies conditions for the binding of coagulation proteins. These modifications in platelet's glycoside residues seem to be related to severity of ITP. This work was supported by grants from FIS-FONDOS FEDER (PI19/00772) and and Platelet Disorder Support Association. EMM holds a predoctoral fellowship from Fundación Española de Trombosis y Hemostasia (FETH-SETH). Disclosures Butta: Grifols: Research Funding; Novartis: Speakers Bureau; ROCHE: Research Funding, Speakers Bureau; Pfizer: Speakers Bureau; SOBI: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; NovoNordisk: Speakers Bureau. Alvarez Román:Grifols: Research Funding; Bayer: Consultancy; Novartis: Speakers Bureau; Roche: Speakers Bureau; Pfizer,: Research Funding, Speakers Bureau; SOBI,: Consultancy, Research Funding, Speakers Bureau; Takeda: Research Funding, Speakers Bureau; NovoNordisk,: Research Funding, Speakers Bureau. Martín:SOBI: Research Funding; Pfizer: Research Funding, Speakers Bureau; Roche: Speakers Bureau; Novartis: Speakers Bureau; NovoNordisk: Speakers Bureau. Rivas Pollmar:Novartis: Speakers Bureau; Roche: Speakers Bureau; Pfizer: Speakers Bureau. Justo Sanz:Takeda: Current Employment. García Barcenilla:NovoNordisk: Research Funding, Speakers Bureau; Takeda: Research Funding, Speakers Bureau; Pfizer,: Speakers Bureau; Roche: Speakers Bureau; Bayer: Speakers Bureau; Novartis: Speakers Bureau. Canales:Celgene: Honoraria; Janssen: Speakers Bureau; Novartis: Honoraria; Roche: Honoraria; Gilead: Honoraria; Sandoz: Honoraria; iQone: Honoraria; Takeda: Speakers Bureau; Sandoz: Speakers Bureau; Roche: Speakers Bureau; Janssen: Speakers Bureau; Sandoz: Honoraria; Roche: Honoraria; Takeda: Speakers Bureau; Novartis: Honoraria; Sandoz: Speakers Bureau; Karyopharm: Honoraria; Roche: Speakers Bureau; Janssen: Honoraria; Karyopharm: Honoraria; Janssen: Honoraria. Jimenez-Yuste:F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer, Grifols, Octapharma, CSL Behring, Bayer: Honoraria; F. Hoffman-La Roche Ltd, Novo Nordisk, Takeda, Sobi, Pfizer: Consultancy; Grifols, Novo Nordisk, Takeda, Sobi, Pfizer: Research Funding.

Multifactorial mechanisms leading to diminished platelet counts in immune thrombocytopaenia (ITP) might condition the ability of patients with ITP to respond to treatments. Examining their platelet and immune features, we aimed to detect singular characteristics of patients with ITP who do not respond to any treatment. We studied patients with chronic primary ITP who had been without treatment, or untreated (UT-ITP), for at least six months; included were responders to agonists of thrombopoietin receptors (TPO-RA), patients who showed no response to first- and second-line treatments (NR-ITP), and healthy controls. Platelets from NR-ITP patients exposed a reduced amount of sialic acid residues. Increased loss of platelet surface sialic acid residues was associated with increased platelet apoptosis. NR-ITP patients had an increased fraction of naive lymphocyte (L) B cells and a reduced LTreg (Lymphocyte T-regulator) subset. They also presented an anomalous monocyte and NK (Natural Killer) cells distribution. TPO-RA-treated patients seemed to recover an immune homeostasis similar to healthy controls. In conclusion, our results indicate a severe deregulation of the immune system of NR-ITP. The inverse correlation between loss of sialic acid and LTreg count suggests a potential relationship between glycan composition on the platelet surface and immune response, positing terminal sugar moieties of the glycan chains as aetiopathogenic agents in ITP.

Introduction: Haemophilia is a rare disease and its management can pose a challenge to Emergency Department paediatricians. Aim: To describe the frequency and reasons for consultation by haemophilic children in the ED. Materials and methods: Longitudinal retrospective study was conducted in a paediatric Emergency Department of a tertiary care hospital. The study included haemophiliacs A and B, ages 0 to 16 years old, and who had consulted the Emergency Department for whatever reason over a span of 6 years (2011–2016). The data analysed include: age, type and severity of haemophilia, reason for query, prophylactic status, complementary examinations, established diagnosis, treatment, and number of visits to the Emergency Department. Results: The analysis included 116 males with a total of 604 Emergency Department visits. The mean age was 5.5 years, and the median age was 5.3 years. A total of 101 patients were categorised as haemophiliac A (38 mild, 4 moderate, 59 severe), and 15 as haemophiliac B (9 mild, 3 moderate, 3 severe). The main reasons for initial Emergency Department visits (ranked by triage) were: musculoskeletal problems/injury or bleeding (66.7%), causes unrelated to haemophilia (29%), suspected central venous catheter related infection (2.8%), and routine clotting factor infusion (1.5%). Additional tests were conducted during 335 visits (55.5%). Factor replacement was undertaken in 317 visits (52.5%). A total of 103 episodes (17.1%) required hospital admission, due to: head trauma (35.9%), central venous catheter -related infection (13.6%), haemarthrosis (8.7%), muscle haematoma (6.8%), and haematuria (5.8%). Conclusion: Haemophilic patients went to the Emergency Department for common paediatric causes, but also requested consultation on specific problems related to haemophilia, with musculoskeletal problems/injury or bleeding being the main issues. The paediatric Emergency Department is an indispensable component of haemophilia care. Resumen: Introducción: La hemofilia es una enfermedad rara, por lo que su abordaje en Urgencias puede suponer un reto para los pediatras. Objetivos: Describir la frecuencia y motivos de consulta de los niños hemofílicos en Urgencias. Material y métodos: Estudio retrospectivo longitudinal realizado en Urgencias Pediátricas de un hospital de tercer nivel. Se incluyeron hemofílicos A y B, desde el nacimiento hasta los 16 años, que consultaron por cualquier motivo durante 6 años (2011-2016). Se analizaron: edad, tipo y gravedad de hemofilia, motivo de consulta, profilaxis domiciliaria frente a sangrados, pruebas complementarias, diagnóstico establecido, tratamiento y número de visitas a Urgencias. Resultados: Se analizaron 116 varones con un total de 604 visitas. La media de edad fue de 5,5 años y la mediana de 5,3. De ellos, 101 pacientes eran hemofílicos A (38 leves, 4 moderados, 59 graves) y 15 hemofílicos B (9 leves, 3 moderados, 3 graves). Los principales motivos de consulta (clasificados en triaje) fueron: problema musculoesquelético/traumático o sangrado (66,7%), causas no relacionadas con hemofilia (29%), sospecha de infección de catéter central (2,8%) y administración rutinaria de factor (1,5%). Se realizaron pruebas complementarias en 335 visitas (55,5%). Del total, 317 consultas (52,5%) requirieron factor; 103 episodios (17,1%) precisaron ingreso, cuyos principales motivos fueron: traumatismo craneoencefálico (35,9%), infección de catéter venoso central (13,6%), hemartrosis (8,7%), hematoma muscular (6,8%) y hematuria (5,8%). Conclusión: Los pacientes consultaron por causas habituales de la edad pediátrica, pero también lo hicieron por motivos específicos de su enfermedad; lo más frecuente fue el problema musculoesquelético/traumático o sangrado. El Servicio de Urgencias es un componente indispensable en su atención.

Introduction Patients with severe haemophilia and inhibitors against factor VIII who require surgery need a prophylactic approach to prevent bleeding complications. Scientific evidence to decide the best prophylactic treatment is very limited and mainly based on retrospective or case series. Aims To develop evidence- and expert opinion-based guidelines for prophylactic therapy for patients with haemophilia and inhibitors undergoing surgery. Methods A panel of nine Spanish haematologists undertook a systematic review of the literature and selected publications providing relevant information regarding the prophylactic management of patients with haemophilia and inhibitors undergoing dental extraction, minor surgery or major surgery. Results Although evidence is very limited, the panel considers that it seems advisable that prophylaxis should be given in most cases with a bypassing agent (aPCC or rFVIIa) and should start immediately before minor or major surgery. Patients should be closely monitored to enable dose/product modification as needed. Conclusion It is necessary to communicate clinical experience in a detailed way in order to ensure optimal schemes of prophylaxis for patients with haemophilia and inhibitors. Development of objective outcomes to evaluate efficacy is crucial.