Bleeding In Hemophilia Patients Research Articles

Evaluating the Effectiveness of Recombinant Factor VIIa in Nonhemophilic Pediatric Cancer Patients with Acute Severe Bleeding

Abstract Context: Despite recombinant factor VIIa (rFVIIa) being approved for treating bleeding in hemophilia patients, there has been limited research on its efficacy in nonhemophilic cases, particularly, in pediatric cancer patients who are vulnerable to bleeding. Aim: Our objective is to assess rFVIIa’s effectiveness in managing severe bleeding in pediatric nonhemophilic cancer patients. Settings and Design: We conducted a retrospective study at a comprehensive cancer center. Materials and Methods: It involves reviewing cases of nonhemophilic pediatric cancer patients treated with rFVIIa for acute severe bleeding during hospitalization between 2013 and 2022 using the pharmacy electronic system. Patients without a cancer diagnosis were excluded. The primary outcome assessed was the cessation of bleeding within 48 h post the last administered rFVIIa dose. Statistical Analysis Used: Descriptive statistics were used to report the outcomes. Results: The results revealed that our analysis encompassed 22 nonhemophilic pediatric cancer patients experiencing acute severe bleeding. The mean age was 7 ± 16.9 (SD) years, with 18 (81.8%) being male. Among them, 7 (31.8%) had leukemia and 5 (22.7%) had neuroblastoma. Thrombocytopenia was prevalent in 21 (95.5%) patients, and 7 (31.8%) underwent bone marrow transplantation. On average, patients received 85 ± 10 (SD) µg/kg of rFVIIa for one to two doses per bleeding episode. Bleeding cessation was achieved in 13 (59%) patients. Conclusion: Our findings suggest that rFVIIa could serve as a viable therapeutic option for managing acute severe bleeding in nonhemophilic pediatric cancer patients.

Deletion of tissue factor pathway inhibitor isoform beta or gamma, but not alpha, improves clotting in hemophilic mice

BackgroundTissue factor pathway inhibitor (TFPI) regulates tissue factor–triggered coagulation. Humans and mice express transcripts encoding for multidistributed (endothelial, platelet, and plasma) 3-Kunitz domain TFPIα and endothelial membrane–anchored 2-Kunitz TFPIβ. Mice express a third transcript, γ, that encodes plasma lipoprotein–associated 2-Kunitz TFPI. In humans, proteolysis of α and/or β produces plasma lipoprotein–associated 2-Kunitz TFPI at lower levels. In clinical trials, monoclonal antibodies that target all TFPI isoforms extend coagulation and correct bleeding in hemophilic patients but with some thrombosis risks. ObjectivesTo determine the impact of TFPI isoform-specific deletions on promoting clotting in hemophilic mice. MethodsEngineered TFPI isoform–specific, hemophilic (factor VIII-null) mice were evaluated for clotting. ResultsMice expressing any single TFPI isoform were healthy. Thrombin generation assays identified TFPIγ as the dominant anticoagulation isoform in mouse plasma. Hemostasis was assessed by serial bleeding times from a tail vein laceration. Repeatedly, after a clot forms, it was manually disrupted; the number of clots/disruptions occurring over a 15-minute period were reported. C57BL/6 and hemophilic mice clot on average 25.6 vs 5.4 times, respectively. On a hemophilia background, TFPIβ or TFPIγ-specific deletion improved clotting to 14.6 and 15.2 times, respectively (P < .0001). TFPIα-specific deletion was without impact, clotting 5.1 times. Heterozygous deletion of TFPIβ was effective, clotting 11.8 times (P < .0001). Heterozygous deletion of TFPIα or TFPIγ alone was ineffective, clotting 3.0 and 6.1 times, respectively, but heterozygous TFPIαγ deletion improved clotting to 11.2 times (P < .001). ConclusionIn hemophilic mice, endothelial TFPIβ and plasma γ-derived 2-Kunitz TFPI individually contribute more to bleeding than total TFPIα.

Inhibitory hemophilia: contemporary treatment with emicizumab. Considerations for pediatric practice

Introduction. This article provides an overview of current knowledge and global experience regarding the use of emicizumab, with a focus on its specific considerations in pediatric practice. Emicizumab, a monoclonal antibody, operates uniquely compared to other therapies. It has been approved in Moldova since 2019 for preventing bleeding in hemophilia patients. Significant data from clinical studies and accumulated clinical practice provide answers to most questions physicians have when prescribing emicizumab. The article presents recommendations based on current information and global experience to aid decision-making in emicizumab usage. The purpose of this article is to provide information on management tactics for pediatric patients with hemophilia A receiving emicizumab. Materials and methods. Over 40 publications were reviewed, consisting of recommendations, study results, and observations related to emicizumab use in pediatric patients with Hemophilia A. Results. In 2017, emicizumab became the first registered non-factorial therapy for Hemophilia A. It was approved for use in treating the inhibitory form of the condition. In 2018, indications for emicizumab were expanded to include patients with the inhibitory form of hemophilia A and severe hemophilia A without inhibitors. Emicizumab is used to prevent bleeding and is not intended to stop an already occurring bleeding. If bleeding has occurred, the patient will need to be prescribed FVIII or bypassing agents. Emicizumab is administered as a loading dose of 3 mg/kg once a week for the first 4 weeks, followed by a maintenance dose of 1.5 mg/kg once a week, 3 mg/kg once every two weeks, or 6 mg/kg once every four weeks. The dose is based on the patient’s body weight, which needs regular monitoring. If a dose is missed, it should be administered as soon as possible before the next scheduled dose, and the injection schedule should not be altered. Emicizumab can be used in children under one year to prevent bleeding. Conclusions. Hemophilia, caused by a deficiency in coagulation factors VIII or IX, is a bleeding disorder. The main treatment-related complication in hemophilia patients is the development of inhibitors – alloantibodies that neutralize the procoagulant activity of infused FVIII or factor IX. The reasons why only 20%-30% of Hemophilia A patients develop inhibitors remain a challenge. Emicizumab, a bispecific monoclonal antibody, bridges the gap between activated factor IX and factor X to replace the missing activated factor VIII, thereby restoring hemostasis.

Aberrant methylation and expression of TNXB promote chondrocyte apoptosis and extracullar matrix degradation in hemophilic arthropathy via AKT signaling.

Recurrent joint bleeding in hemophilia patients frequently causes hemophilic arthropathy (HA). Drastic degradation of cartilage is a major characteristic of HA, but its pathological mechanisms has not yet been clarified. In HA cartilages, we found server matrix degradation and increased expression of DNA methyltransferase proteins. We thus performed genome-wide DNA methylation analysis on human HA (N=5) and osteoarthritis (OA) (N=5) articular cartilages, and identified 1228 differentially methylated regions (DMRs) associated with HA. Functional enrichment analyses revealed the association between DMR genes (DMGs) and extracellular matrix (ECM) organization. Among these DMGs, Tenascin XB (TNXB) expression was down-regulated in human and mouse HA cartilages. The loss of Tnxb in F8-/- mouse cartilage provided a disease-promoting role in HA by augmenting cartilage degeneration and subchondral bone loss. Tnxb knockdown also promoted chondrocyte apoptosis and inhibited phosphorylation of AKT. Importantly, AKT agonist showed chondroprotective effects following Tnxb knockdown. Together, our findings indicate that exposure of cartilage to blood leads to alterations in DNA methylation, which is functionally related to ECM homeostasis, and further demonstrate a critical role of TNXB in HA cartilage degeneration by activating AKT signaling. These mechanistic insights allow development of potentially new strategies for HA cartilage protection.

Unresolved hemostasis issues in haemophilia.

Despite rapid technological advancement in factor and nonfactor products in the prevention and treatment of bleeding in haemophilia patients, it is imperative that we acknowledge gaps in our understanding of how hemostasis is achieved. The authors will briefly review three unresolved issues in persons with haemophilia (PwH) focusing on the forgotten function that red blood cells play in hemostasis, the critical role of extravascular (outside circulation) FIX in hemostasis in the context of unmodified and extended half-life FIX products and finally on the role that skeletal muscle myosin plays in prothrombinase assembly and subsequent thrombin generation that could mitigate breakthrough muscle hematomas.

Earliest Possible Detection and Intervention for Synovitis in Hemophilia- Results from a Single Center Retrospective Cohort Study

Introduction There is scientific evidence to suggest that the most serious health problems for hemophilic patients arise from joint damage, which in turn results from joint bleeding, which is overlooked and therefore not treated. The ankle joint was affected the earliest in most hemophilic patients. Strategies for detecting and treating bleeding in hemophilic patients need to be further developed and made more widely known by clinicians. Aim of our study The aim of our retrospective, single-center cohort study was to compare the effects of reactive versus preventive joint ultrasound as guidance for adjustments of treatment regimens for patients with severe hemophilia at our Hemophilia Comprehensive Care Center (HCCC) in Duisburg, Germany. Methods Before 2020, we used ultrasound according to the German hemophilia-synovitis guidelines in 2018. This meant that we sonographed the ankle joints and knees of most of our patients when they reported discomfort in the joint or when a joint bleeding had occurred. In these cases, prophylactic hemophilia treatment was immediately adjusted to a level at which the bleeding and/or discomfort stopped. If the factor treatment was not sufficient to accomplish this goal, the joints were treated with radiosynoviorthesis (RSO). In 2020, we changed our diagnostic strategy from reactive to preventive measures. Thus, we used ultrasound on every ankle and knee joint of our severely hemophilic patients at least once a year. If we found so called “silent symptoms,” which means touch-sensitive joints, the joints were sonographed once every three months. In cases of signs of joint degradation, we adjusted the prophylactic factor treatment accordingly. Results From 2020 to 2022, we examined a total of 1193 joints of 688 patients with hemophilia A or B, as well as with vWD disease type 2 or 3 and other severe coagulation disorders (factor VII deficiency, factor XIII deficiency, afibrinogenemia, and Glanzman disease). Of these, 103 had severe hemophilia A or B. In this study, we examined 656 joints sonographically. Of these, we examined 281 ankle joints in 80 patients and 175 knees in 64 patients, and adjusted the therapy regimens accordingly in these patients if necessary. Seven RSOs of the ankle joints and three RSOs of the knees were performed in the cohort up to 2020. After 2020, only two RSOs of the ankle joints were performed in the cohort. Conclusions At least for patients at our HCCC in Duisburg, Germany, we were able to show for the period 2020-2022 that closer ultrasound monitoring of ankle joints and knees in patients with severe hemophilia A or B and appropriate adjustment of prophylactic factor therapy was associated with less severe and less frequent joint degradation.

Tissue Factor Pathway Inhibitor (TFPI) Beta and Gamma Isoforms Contribute to Bleeding in Hemophilia Mice

Key Points: Expression of any single TFPI isoform (α, β, or γ) is sufficient for mouse survival.Two-Kunitz domain TFPI isoforms, anchored β and circulating γ, each contribute to hemophilia bleeding.In vivo, TFPIβ is a more potent anticoagulant than TFPIα. Upon injury, tissue factor (TF) triggers coagulation by complexing with factor (F)VIIa to activate FIX and FX, leading to thrombin generation and a fibrin clot. Tissue factor pathway inhibitor limits TF-triggered coagulation. Humans and mice express transcripts encoding for 3-Kunitz domain TFPIα and membrane-anchored 2-Kunitz TFPIβ. Mice also express transcripts encoding untethered, 2-Kunitz TFPIγ. In humans, proteolysis of TFPIα and/or β produces “γ-like” 2-Kunitz TFPI. Hemophilia A and B, caused by deficiency in factors VIII and IX, respectively, are congenital X-linked recessive bleeding disorders that affect an estimated 1.1 million males worldwide. Hemophilia can cause excessive bleeding spontaneously or in response to trauma that can be life-threatening or significantly decrease the quality of life. Approved treatments for hemophilia include factor replacement, bypassing agents, the bispecific antibody Emicizumab, and recently approved gene therapies. Also in development are agents that reduce endogenous anticoagulant activity to counter the procoagulant deficiency of hemophiliacs, including monoclonal antibodies (Mab) to TFPI. These Mab target all TFPI isoforms to improve coagulation and correct bleeding in hemophilia patients, but with some demonstrated thrombosis risk. We investigated if TFPI-isoform-specific inhibition could provide equivalent efficacy which might reduce thrombotic risk. We generated TFPI-isoform-specific exon deletions in mice bred into hemophilia (FVIII-null) background. We find mice expressing any single TFPI isoform (α, β, or γ) appear healthy and reproduce. Our in vivo tail-vein re-bleeding assay is based on serial clot disruptions over 15 minutes, which we have shown is sensitive to anticoagulant and antiplatelet treatment, as well as factor replacement therapy. In this assay, we find C57Bl/6 WT mice clot 25.6 + 0.8 times (mean + SEM), whereas FVIII-null hemophilia mice clot 5.3 +0.4 times. In hemophilia mice, TFPIα-specific deletion is without impact, forming clots 5.1 + 0.8 times, whereas TFPIβ-specific or TFPIγ-specific deletion improves clot formation to 16.8 + 2.0 and 15.2 + 1.5 times, respectively (p&amp;lt;0001). Even hemophilia mice with heterozygotic deletion of the β exon form clots 11.8 + 0.8 times (p&amp;lt;0001). Thus, in vivo 2-Kunitz TFPI isoforms, anchored β and untethered γ each provides greater anticoagulant activity and impact on bleeding than 3-Kunitz TFPIα. Ex vivo plasma-based thrombin generation assays show that TFPIγ provides more anticoagulant activity than TFPIα. As shown in the figure, the deletion of TFPIγ increases thrombin generation to a greater extent than the deletion of TFPIα. The addition of an anti-TFPI antibody that effectively blocks TFPI activity shows a significant increase in endogenous thrombin potential in the plasma of TFPIαβ-deleted (γ-only) mice (370 nM.min), versus TFPIβγ-deleted (α-only) plasma (70 nM.min) and TFPIαγ-deleted (β-only) mice plasma (22 nM.min), (p&amp;lt;0.001). As expected, membrane-anchored TFPIβ is not detected in plasma. It is well established that 3-Kunitz TFPIα is a potent anticoagulant in plasma-based clotting time assays, while truncated 2-Kunitz TFPI, like mouse TFPIγ, appears inactive. Based on such assays, it was unexpected that TFPIγ-only expressing mice thrive, and in vivo, TFPIα is not the dominant endogenous anticoagulant. If mouse models are to be useful in providing insights into human hemostasis and TF-associated diseases, then it is critical to understand the similarities and differences between mice and humans. As humans do not express TFPIγ, the observed impact of depleting circulating 2-Kunitz TFPI on bleeding and thrombin generation in hemophilic mice is unlikely to translate to man. By contrast, our results demonstrating that, in vivo, TFPIβ is a more potent anticoagulant than TFPIα in mice has potential therapeutic implications in humans.

18 F-FDG PET/CT imaging for haemophilic arthropathy compared with clinical, radiological and power Doppler sonographic characteristics of 20 haemophilia patients.

Repeated joint bleeding in haemophilia patients may lead to haemophilic arthropathy with marked inflammation and synovitis. This study investigated the potential of 18 F-fluorodeoxyglucose positron emission tomography-computed tomography (18 F-FDG PET/CT) as a novel diagnostic method for haemophilic arthropathy. We recruited 20 adult haemophilia patients who reported history of hemarthroses in the shoulder, elbow, hip, knee, or ankle joints. All joints were assessed by power Doppler ultrasonography and radiography, and graded by hyperaemia score and Pettersson score, respectively. Joint pain was evaluated by visual analogue score (VAS). Range of motion (ROM), Haemophilia Joint Health Score (HJHS) and annual joint bleeding rate (AJBR) were recorded. Finally, all participants had whole-body 18 F-FDG PET/CT, and maximum standardized uptake value (SUVmax) of the joints being studied was measured. Thirteen patients had severe haemophilia, and seven had moderate haemophilia. The mean age was 36 years. PET SUVmax showed significant correlations with VAS, ROM, Pettersson score, hyperaemia score, HJHS score and AJBR in all large joints except hip. Joints with pain, hyperaemia and radiographic changes were found to have higher SUVmax than those without these features. Using Youden's index, the optimal cut-off value for early radiographical arthropathy was found to be between 1.9 and 2.0. Our study indicates that 18 F-FDG PET/CT imaging correlated well with various conventional diagnostic techniques. It also demonstrated high sensitivity and specificity for early radiographic arthropathy. 18 F-FDG PET/CT imaging may quantitatively evaluate disease activity of most large joints in a single examination and help detect early haemophilic arthropathy.

POSC395 Pharmacoeconomic Analysis of rFVIIa Versus PCC in the Treatment of Minor-to-Moderate Bleeds in Hemophilia Patients with Inhibitors in China

In China, treatment options for bleeding episodes in hemophilia patients with inhibitors most often involve recombinant factor VIIa (rFⅦa) or prothrombin-complex concentrate (PCC).The aim of this study was to compare the cost and effectiveness of two most commonly used treatment regimens : rFⅦa followed by PCC (rFⅦa - PCC) and PCC followed by rFⅦa (PCC - rFⅦa) for the treatment of minor-to-moderate bleeds in hemophilia patients with inhibitors.

Different Approaches to Reduce Bleeding of a Hemophilia-A Patient during Cardiac Surgery

A 16-year-old hemophilia-A patient presented with symptomatic atrial septal defect (ASD). Managing bleeding during cardiovascular surgeries is a significant challenge, even for none-hemophilic patients, due to heparin administration, cardiopulmonary bypass (CPB) coagulopathy and surgical complications. This essay is an effort to discuss ASD, CPB effects on the coagulation system, and highlight some approaches to lower bleeding in hemophilic patients with congenital heart disease.

The Weight Assessment and its Relation to Hemophilia Joint Health Score in Hemophilic Patients

Background: Haemophilia is a group of hereditary disorders that impair the body's ability to control blood clotting or coagulation. Joint bleeding (hemarthrosis) results in synovial hypertrophy and damage of the cartilage, leading to joint destruction with recurrent bleeding episodes (hemophilic arthropathy). Objective: To assess weight of hemophilic children and correlate the weight to Hemophilia Joint Health Score. Methods: The sample size included was 66 patients with hemophilia in Zagazig city between October 2019 and March 2020. They were categorized according to presence of arthropathy or not [Two groups; one group with hemophilic arthropathy and the other group without hemophilic arthropathy]. All patients were subjected to full history taking including personal history, thorough clinical examination [assessment of vital signs and color, assessment of any bone deformity, pain or muscle weakness and Hemophilia Joint Health Score ] and weight assessment, Results: Our case control study showing male predominance in both groups. In hemophilic arthropathy, 100% (10.68 ± 4.28) and without hemophilic arthropathy 97% (7.17 ± 4.12) and more prevalence of hemophilia A [factor V111 deficiency] in both groups (with H.A.97% & without H.A.78.8%). In addition, our study reported that most common site of bleeding in hemophilic patients rather than big joints affection; gum [18.2%] then gum & teeth [12.1%]. Increased weight was found more in hemophilia with arthropathy than in hemophilia without arthropathy. Conclusion: Our case control study showing male predominance and more prevalence of hemophilia A than B in both hemophilic groups (with or without hemoarthropathy). Weight was significantly increased in hemophilia with arthropathy group than in hemophilia without arthropathy group.

Aquatic exercise in patients with haemophilia: Electromyographic and functional results from a prospective cohort study.

Recurrent joint bleeds in haemophilia patients often cause musculoskeletal changes leading to functional capacity impairment. In this study, we assessed the effects of aquatic activities performed to improve functional capacity in these patients. The interventional protocol consisted of 24 hydrotherapy sessions during three months, in comparison with 24 swimming sessions. The pre- and post-intervention assessment consisted of Functional Independence Score, haemophilia joint health score (HJHS), Pediatric Haemophilia Activities List (PedHAL), surface electromyography (SEMG) of thigh muscles to assess muscle electric activity, and load cell on extensor and flexor thigh muscles to evaluate muscular strength. Forty-seven haemophilia patients were enrolled in this study, and 32 (23 severe haemophilia A, one moderate haemophilia A and 8 severe haemophilia B), median age 12y (6 to 40y), concluded the aquatic intervention. We observed a statistically significant increase with substantial improvement in functional capacity in the pre- and post-intervention evaluation of hydrotherapy in comparison with the swimming protocol, with HJHS (p=.006 and p=.001 respectively), PedHAL (Sum score) (p=.022 and p=.001) and score FISH (p=.021). The swimming group revealed significant improvements in muscular strength, in all muscles tested (p=.005 and p=.001). SEMG signal amplitude reached significantly higher levels in all muscles evaluated after both interventions except for the vastus medialis (right) in the hydrotherapy group. Our results concluded that both swimming and hydrotherapy were associated with physical improvement in haemophilia patients; however, only hydrotherapy lead to a more significant improvement in functional capacity.

Radiological aspects of musculoskeletal complications in three hemophilic patients with long-term follow-up

Objective: The objective of the study is to describe the radiological aspects of musculoskeletal complications of hemophilia found in three patients. Patients and Methods: It is a retrospective review of clinical and radiological records of three known and followed hemophilic patients, whose radiological examinations were carried out and archived on the Picture Archiving and Communication System of the University Hospital. Results: The three patients were male with severe hemophilia A, using recombinant factor VIII replacement therapy on demand, followed during 10 years. Joint bleeding was the most frequent complication. We found hemarthrosis at ultrasound in two patients (one after a minor trauma of the knee and one after repeated traumas of the ankle) and at magnetic resonance imaging (MRI) in the three patients (three in the knee and two in the ankle) and chronic arthropathy in two patients (two in the knee and one in ankle. The muscular lesions detected at ultrasound were hematomas of the left soleus muscle, right vastus medialis muscle, and right rectus abdominis muscle. Conclusion: Bleeding in hemophilic patients affects both muscles and joints, with long-term consequences for the joints. Medical imaging was very useful for the detection and follow-up of joint and muscle lesions in these three patients, based on ultrasound and MRI with T2* sequence.

Spinal Subdural Hematoma in a Young Adult with Hemophilia A: A Case Report

Hemophilia is a set of hereditary hemorrhagic disorders of coagulation-dysfunction that can cause repeated bleeding in various tissues and organs. And the patient can be disabled due to bleeding from bones, joints, and soft tissue, or die due to splenic rupture or intracranial bleeding. So it is crucial to detect the site of bleeding in hemophilia patients quickly. Spontaneous spinal canal hematoma is a rare complication of hemophilia, with less than 50 cases reported to date. It can be easily missed and cause serious harm to patients. Hematoma, if untreated, causes irreversible nerve damage by compression of the spinal cord. Early recognition and treatment are most useful to prevent spontaneous spinal canal hematoma. We describe the case of a 21-year-old man with severe lumbago for two days, who had hemophilia A for a decade. The patient was diagnosed with spinal subdural hematoma by magnetic resonance imaging (MRI) after ruling out other causes of lumbago and treated with drugs by a neurologist. The hematoma showed absorption by MRI after six months. In conclusion, spontaneous spinal canal hematoma is a severe complication of hemophilia, which is often missed. This successful case confirms the importance of early diagnosis and treatment of spontaneous spinal canal hematoma. We hope to increase the clinicians’ vigilance of this disease.

Perioperative safety and haematostatic efficacy of a new bypassing agent pd-FVIIa/FX (Byclot) in haemophilia patients with high-responding type inhibitors.

: The novel agent pd-FVIIa/FX is a 1 : 10 protein weight mixture of activated factor VII (FVIIa) and factor X (FX) derived from donated blood plasma. A phase III clinical trial of pd-FVIIa/FX revealed high efficacy for bleeding episodes in haemophilia patients with inhibitors. However, up to now, only one case of this new agent being used for surgery had been reported. The objective of this study is to evaluate the perioperative haemostatic efficacy and safety of pd-FVIIa/FX in haemophilia patients with inhibitors. We retrospectively reviewed 25 operation charts from 14 haemophilia patients with high-responding inhibitors using pd-FVIIa/FX during the perioperative period. Efficacy was evaluated by attending physicians and results divided into four groups (excellent, good, fair, and poor). The operation chart was provided by nine Japanese medical institutes with expertise in haemophilia management. Out of the total of 25 surgical procedures, 44% (11/25) were classified as major surgery and the remainders were minor surgeries. In all of the surgeries but one, rFVIIa and/or APCC were administered in combination or sequential method. In all cases except one, the haemostatic efficiency rate was judged as excellent or good by treating physicians for an overall efficacy rate of 96%. No thrombotic adverse effects were reported. This study's results suggest that both combination and sequential therapy of pd-FVIIa/FX and other bypassing agents are well tolerated and effective for the control of perioperative bleeding in haemophilia patients with high-responding inhibitors.

Characterization of a Novel Human Factor VIIa Chimera with Increased Tissue Factor-Independent Activity for Emergency Hemostasis

While prophylactic treatment with emicizumab has shown remarkable efficacy in patients with hemophilia A, the treatment options for traumatic, perioperative, and breakthrough bleeding in hemophilia A or B patients with inhibitors remain extremely limited. Recombinant Factor VIIa (rFVIIa) is routinely used to promote hemostasis in hemophilia patients with inhibitors and is recommended as first line therapy for acute bleeding, especially for patients on emicizumab. In addition, rFVIIa has extensive off-label use for hemostasis in cardiovascular surgery, trauma, and intracranial hemorrhage. The hemostatic efficacy of rFVIIa depends on its ability to bind activated platelets and promote thrombin generation by activating Factor X (FX) in a tissue factor (TF)-independent manner. However, the use of rFVIIa requires frequent high doses at significant cost, and is limited by an inconsistent response. Therefore, there is a critical need for new strategies to treat acute bleeding in hemophilia patients with inhibitors and others requiring emergency hemostasis. We have previously shown that human platelets express endothelial cell protein C receptor which contributes to the platelet binding and activity of rFVIIa. Based on this work, we designed a novel FVIIa chimera (PC-FVIIa) with the potential for increased hemostatic efficacy and an enhanced safety profile compared to rFVIIa. The purpose of the current study was to characterize the in vitro activity of this chimera. A cDNA construct encoding the Gla and EGF1 domains of human Protein C along with the EGF2 and catalytic domains of human FVIIa was synthesized and cloned into HEK293 cells. Stable transfectants were selected and PC-FVIIa was purified from the media. Protein electrophoresis of eluates confirmed bands consistent with the expected molecular weight. Similar to rFVIIa, we found that autoactivation of PC-FVIIa readily occurs in the presence of calcium and phospholipid (15% PS/41% PC/44% PE). Autoactivation is rapidly accelerated by the addition of Factor Xa (FXa) and significantly impaired in the absence of either calcium or phospholipid. There was no significant difference between activated PC-FVIIa and rFVIIa in their ability to cleave a synthetic FVIIa substrate. As the Gla and EGF1 domains of rFVIIa are primarily responsible for binding TF, we hypothesized that PC-FVIIa would have little to no affinity for TF. Indeed, we found that the interaction between PC-FVIIa and TF is too weak to be measured in an assay designed to detect weak TF binding. We therefore determined the TF-independent activity of PC-FVIIa using FXa and thrombin generation assays. For some experiments, phospholipid vesicles were incubated with rFVIIa or PC-FVIIa. Plasma levels of FX were added and FXa generation was assessed using a chromogenic substrate. In these assays, the rate of FX activation by PC-FVIIa was significantly higher than that of rFVIIa (Figure 1). To determine the ability of PC-FVIIa to promote thrombin generation, we performed a modified calibrated automated thrombography assay in the absence of TF. Hemophilia A plasma was incubated with PC-FVIIa or rFVIIa in the presence of phospholipid. Subsequent thrombin generation was assessed by monitoring cleavage of a fluorogenic substrate. No appreciable thrombin generation was seen in plasma alone. Adding rFVIIa resulted in a shorter lag time than PC-FVIIa. However, PC-FVIIa led to significantly higher peak thrombin concentration and endogenous thrombin potential compared to rFVIIa. Finally, we used a prothrombinase detection system to determine the activity of PC-FVIIa on the surface of platelets activated with thrombin plus a collagen receptor agonist to generate highly procoagulant platelets. Once again, the rate of thrombin generation was significantly higher with PC-FVIIa as compared to rFVIIa, consistent with a higher rate of FX activation on the platelet surface. Taken together, these data suggest that the PC-FVIIa chimera has the potential for increased hemostatic efficacy compared to rFVIIa. Additional studies will characterize the in vivo activity of PC-FVIIa. However, the lack of affinity for TF represents a potential advantage for PC-FVIIa since long-term exposure to high levels of rFVIIa can lead to thrombosis in TF-rich tissues. As such, PC-FVIIa warrants further study as a potential therapeutic agent with unique characteristics compared to rFVIIa. Disclosures Fager: Otello Medical Inc.: Research Funding. Hoffman:Novo Nordisk A/S: Honoraria, Research Funding. Monroe:Novo Nordisk: Honoraria, Research Funding.

What does the ‘Cochrane database of systematic reviews’ tell us about hemophilia?

ABSTRACTIntroduction: The purpose of this article is to review which data about hemophilia are currently provided by the Cochrane database of systematic reviews (CDBSR). Methodological consideration: All statements about hemophilia in the Cochrane Collaboration are based on evidence generated in randomized controlled clinical trials.Areas covered: There is a high degree of evidence that prophylaxis preserves joint function in children with hemophilia compared to on-demand treatment. Also, that recombinant factor VII activated (rFVIIa) and activated prothrombin complex concentrates (APPCs) have similar efficacy and safety. In patients with hemophilia or von Willebrand disease who undergo minor oral surgery or dental extractions, antifibrinolytic therapy has not been shown to be effective in the prevention of oral bleeding; the possible benefit of physical exercise in hemophilia remains unclear. The effectiveness and safety of the gene therapy have not been proven. Evidence suggests that prophylaxis with bypassing agents may be effective in reducing bleeding in hemophilic patients with inhibitor.Expert opinion: Hemophilia physicians should follow the recommendations of the CDBSR.

Emicizumab for the treatment of haemophilia A: a narrative review.

One of the most serious complications of the treatment of severe haemophilia A is the development of alloantibodies against exogenous factor VIII (FVIII). Inhibitors render factor replacement therapy ineffective, exposing patients to a remarkably high risk of morbidity and mortality. Besides the well-known bypassing agents (i.e. activated prothrombin complex concentrate and recombinant activated factor VII) used to treat or prevent bleeding in haemophilia patients with inhibitors, there is growing interest in newer haemostatic therapies that are not based on the replacement of the deficient FVIII. This review will focus on the most interesting among these innovative therapies, emicizumab, and will provide an update on its current stage of clinical development.

Haemostasis action of VELSEAL-T in a haemophilia A patient with external bleeding

Abstract VELSEAL-Tis an innovative haemostatic medical device for the control of bleeding. Incorporating a clotting agent (thrombin) and anti-fibrinolytic agent (tranexamic acid), it enables rapid coagulation when blood flows into the dressing, leading to sealing and stabilisation of wound surfaces. A 36-year-old known to have mild haemophilia A presented with profuse bleeding from the forehead after injury following a fall on concrete surface. He attended hospital after 18 hours of injury as bleeding continued as soon as pressure was released from the injury site. A VELSEAL-T patch was applied to the injury site with the patient’s full consent. The bleeding stopped after 60 seconds, but the patient was instructed to hold the patch in place for a further 60 seconds. After two minutes of tight pressure application, there was no more oozing of blood from the injury site. This case shows that VELSEAL-T can be used as an aid in stopping external bleeding in haemophilia patients. Further trials should be undertaken to evaluate the safety and efficacy of this product.

Non-factor replacement therapy for haemophilia: a current update.

One of the most challenging issues facing us in the treatment of haemophilia is the development of alloantibodies against infused factor VIII (FVIII) or factor IX (FIX). Inhibitors render factor replacement therapy ineffective, exposing patients to an unacceptably high risk of morbidity and mortality. Besides the well-known bypassing agents (i.e. activated prothrombin complex concentrate and recombinant activated factor VII) used to treat or prevent bleeding in haemophilia patients with inhibitors, there is growing interest in a new class of therapeutic agents which act by enhancing coagulation (i.e. emicizumab) or inhibiting anticoagulant pathways (i.e. fitusiran and concizumab). This review will focus on these innovative therapies, providing an update on their current stage of clinical development.