Accuracy and clinical role of digital templating for total knee arthroplasty performed on haemophilic knees.

INTRODUCTION: In total knee arthroplasty (TKA), choosing the correct implant size is important. There is lack of data on accuracy of templating on haemophilic knees. Our aim was to test the accuracy of 2D digital templating for TKA on haemophilic arthropathy (HA) of knee. MATERIALS AND METHODS: TKAs performed on HA between January 2011 and January 2022 were screened. Osteoarthritis (OA) group was created as control group by a one-to-one matching regarding type of implant used. Intra- and interobserver correlations were measured in HA, then correlation between templated and implanted sizes was investigated in four assessments (femur AP, femur lateral, tibia AP, tibia lateral), then compared with OA group. Fifty-eight knees in each group included. RESULTS: Regarding intraobserver correlation in HA, there was excellent correlation for femur AP [.93 (.73-.98)], femur lateral [.98 (.91-.99)], and tibia AP (1.0) templating. Regarding interobserver correlation in HA, excellent correlation was observed for femur lateral [.93 (.74-.98)] and tibia AP templating [.90 (.65-.97)]. Regarding correlation of templated and applied sizes in HA; tibia AP, tibia lateral and femur lateral templating showed good correlation [.81 (.70-.89), .86 (.77-.91), .79 (.67-.87) while femur AP templating showed moderate correlation [.67 (.50-.79)]. Comparing HA and OA, there was no difference in correlation levels regarding femur AP, femur lateral, tibia AP and tibia lateral templating (p = .056, p = .781, p = .761, p = .083, respectively). CONCLUSION: Although 2D digital templating shows comparable correlation in HA and OA, clinical applicability of templating on HA appears to be limited in its current state.

Kinetic Modeling for BT200 to Predict the Level of Plasma-Derived Coagulation Factor VIII in Humans.

Lack of Factor VIII (FVIII) concentrates is one of limiting factors for Hemophilia A prophylaxis in resource-limited countries. Rondaptivon pegol (BT200) is a pegylated aptamer and has been shown to elevate the level of von Willebrand Factor (VWF) and FVIII in previous studies. A population pharmacokinetic model for BT200 was built and linked to the kinetic models of VWF and FVIII based on reasonable assumptions. The developed PK/PD model for BT200 described the observed kinetic of BT200, VWF, and FVIII in healthy volunteers and patients with mild-to-moderate hemophilia A from two clinical trials. The developed model was evaluated using an external dataset in patients with severe hemophilia A taking recombinant FVIII products. The developed and evaluated PK/PD model was able to describe and predict concentration-time profiles of BT200, VWF, and FVIII in healthy volunteers and patients with hemophilia A. Concentration-time profiles of FVIII were then predicted following coadministration of plasma-derived FVIII concentrate and BT200 under various dosing scenarios in virtual patients with severe hemophilia A. Plasma-derived products, that contain VWF, are more accessible in low-resource countries as compared to their recombinant counterparts. The predicted time above 1 and 3 IU/dL FVIII in one week was compared between scenarios in the absence and presence of BT200. A combination dose of 6 mg BT200 once weekly plus 10 IU/kg plasma-derived FVIII twice weekly maintained similar coverage to a 30 IU/kg FVIII thrice weekly dose in absence of BT200, representing only 22% of the FVIII dose per week.

Optimizing the management of inherited blood disorders in a changing market: Findings from the AMCP Market Insights Program.

In this market insights program, AMCP brought together a panel of experts representing various stakeholders: national and regional health plans, integrated health care systems, employer benefits groups, clinical experts, the Centers for Disease Control and Prevention, and patient advocacy organizations. The objectives were to gain insights into the current and evolving treatments in hemophilia, sickle cell disease, and ß-thalassemia; measure the effects of recently approved therapies on clinicians, payers, and patients; recognize emerging trends within the stop-loss market; address potential issues and obstacles related to monitoring and reporting outcomes; and identify concerns associated with both existing and emerging contracting and reimbursement models. This article aims to summarize expert perspectives on health care system challenges and strategies concerning the management of inherited blood disorders and to advance managed care professionals' understanding of their role in supporting care for these patients. The experts emphasized that when shaping coverage policies, a patient-centered approach is crucial, focusing on preserving organ function to maintain eligibility for future gene therapies among individuals with inherited blood disorders. These strategies, including benefit design modifications, specialized provider networks, and centralized mechanisms like registries, are vital for evaluating effectiveness, facilitating decision-making, and managing costs and risks associated with new and emerging treatment options for inherited blood disorders.

Reconstruction of the historic time course of blood-borne virus contamination of clotting factor concentrates, 1974-1992.

Factor VIII and IX clotting factor concentrates manufactured from pooled plasma have been identified as potent sources of virus infection in persons with hemophilia (PWHs) in the 1970s and 1980s. To investigate the range and diversity of viruses over this period, we analysed 24 clotting factor concentrates for several blood-borne viruses. Nucleic acid was extracted from 14 commercially produced clotting factors and 10 from nonremunerated donors, preserved in lyophilized form (expiry dates: 1974-1992). Clotting factors were tested by commercial and in-house quantitative PCRs for blood-borne viruses hepatitis A, B, C and E viruses (HAV, HBV, HCV, HEV), HIV- types 1/2, parvoviruses B19V and PARV4, and human pegiviruses types 1 and 2 (HPgV-1,-2). HCV and HPgV-1 were the most frequently detected viruses (both 14/24 tested) primarily in commercial clotting factors, with frequently extremely high viral loads in the late 1970s-1985 and a diverse range of HCV genotypes. Detection frequencies sharply declined following introduction of virus inactivation. HIV-1, HBV, and HAV were less frequently detected (3/24, 1/24, and 1/24 respectively); none were positive for HEV. Contrastingly, B19V and PARV4 were detected throughout the study period, even after introduction of dry heat treatment, consistent with ongoing documented transmission to PWHs into the early 1990s. While hemophilia treatment is now largely based on recombinant factor VIII/IX in the UK and elsewhere, the comprehensive screen of historical plasma-derived clotting factors reveals extensive exposure of PWHs to blood-borne viruses throughout 1970s-early 1990s, and the epidemiological and manufacturing parameters that influenced clotting factor contamination.

[Novel treatment strategies for acquired hemophilia A].

Acquired hemophilia A (AHA) is a bleeding disorder caused by autoantibody (inhibitor) production targeting blood coagulation factor VIII (FVIII). It is characterized by sudden onset, and often causes extensive and severe bleeding in soft tissue. Acquired hemophilia A is diagnosed when coagulation tests show normal PT, prolonged APTT, decreased FVIII activity, normal VWF activity, and positive FVIII inhibitor. Hemostatic therapy mainly consists of bypass therapy, which activates the extrinsic coagulation pathway, bypassing the need for FVIII or factor IX. Emicizumab, a bispecific antibody that substitutes for FVIII function, can be used to prevent bleeding. Immunosuppressive therapy is necessary to suppress or eradicate inhibitors. The majority of patients go into remission with treatment, but some die from bleeding symptoms or infections associated with immunosuppressive therapy.

Efanesoctocog Alfa Prophylaxis for Children with Severe Hemophilia A.

BACKGROUND: Once-weekly efanesoctocog alfa provides high sustained factor VIII activity with superior bleeding prevention as compared with prestudy factor VIII prophylaxis in previously treated patients 12 years of age or older with severe hemophilia A. Data on outcomes of efanesoctocog alfa treatment in children younger than 12 years of age with severe hemophilia A are limited. METHODS: We conducted a phase 3, open-label study involving previously treated patients younger than 12 years of age with severe hemophilia A. Patients received prophylaxis with once-weekly efanesoctocog alfa (50 IU per kilogram of body weight) for 52 weeks. The primary end point was the occurrence of factor VIII inhibitors (neutralizing antibodies against factor VIII). Secondary end points included annualized rates of treated bleeding episodes, bleeding treatment, safety, and pharmacokinetics. RESULTS: A total of 74 male patients were enrolled (38 with an age of <6 years and 36 with an age of 6 to <12 years). No factor VIII inhibitors developed. Most adverse events were nonserious. No serious adverse events that were assessed by the investigator as being related to efanesoctocog alfa were reported. In the 73 patients treated according to the protocol, the median and model-based mean annualized bleeding rates were 0.00 (interquartile range, 0.00 to 1.02) and 0.61 (95% confidence interval, 0.42 to 0.90), respectively. A total of 47 patients (64%) had no treated bleeding episodes, 65 (88%) had no spontaneous bleeding episodes, and 61 (82%) had no episodes of bleeding into joints. A total of 41 of 43 bleeding episodes (95%) resolved with one injection of efanesoctocog alfa. Mean factor VIII activity at steady state was more than 40 IU per deciliter for 3 days and more than 10 IU per deciliter for almost 7 days after dose administration. The geometric mean terminal half-life was 40.0 hours. CONCLUSIONS: In children with severe hemophilia A, once-weekly prophylaxis with efanesoctocog alfa provided high sustained factor VIII activity in the normal to near-normal range (>40 IU per deciliter) for 3 days and more than 10 IU per deciliter for almost 7 days after administration, leading to effective bleeding prevention. Efanesoctocog alfa was associated with mainly nonserious adverse events. (Funded by Sanofi and Sobi; XTEND-Kids ClinicalTrials.gov number, NCT04759131.).

Humanistic burden of haemophilia A without inhibitors: A cross-sectional analysis of the HemoLIFE study.

AIM: To evaluate the impact of haemophilia A without inhibitors on humanistic outcomes in patients and caregivers. Herein, we report a cross-sectional analysis of the baseline data of persons with haemophilia (PWH) participating in the prospective study HEMOLIFE. METHODS: These data are part of a prospective, observational, and multicentre study currently being conducted in 20 hospitals in Spain by haematologists. We included subjects 12 years or older diagnosed with haemophilia. The evaluations included the Maladjustment Scale, Haemophilia-Specific Quality of Life Questionnaire for Adults (HaemoQol)/HaemoQol Short Form (Children), haemophilia-specific version of the Work Productivity and Impairment Questionnaire plus the Classroom Impairment Questionnaire (WPAI+CIQ:HS), Haemophilia Activity List (HAL)/Paediatric Haemophilia Activities List (pedHAL), visual analogue scale (VAS) for evaluating pain, Coping Pain Questionnaire-Reduced (CAD-R), and Hospital Anxiety and Depression Scale (HADS). RESULTS: A total of 81 PWH were recruited at 18 centres; 66 PWH were ≥18 years (i.e., adults), and PWH 15 were <18 years (i.e., paediatric patients). Out of the 79 evaluable subjects, 16 (20%) showed an impact of haemophilia on daily life, and the areas most affected were "leisure time" (58% showed maladjustment) and "work/studies" (47% showed maladjustment). Patients reported a higher impact of haemophilia on quality of life (mean [SD] of the transformed score) in the dimensions of "sport" (49.4 [28.6]), "physical health" (40.5 [25.8]) and "future" (37.7 [28.9]). In adults, according to HAL scores, greater impairment of function was observed in "lying/sitting/kneeling/standing," "function of legs" and "leisure activities and sports," with mean normalized scores of 64.7, 65.1 and 69.0, respectively. Productivity was mostly impacted by presenteeism. The pain was infrequent and moderate. According to the HADS scores, nine (11.5%) patients had clinical anxiety and depression. CONCLUSION: PWH without inhibitors exhibited impairments in adjustment, quality of life and functionality, especially related to leisure and sports activities, and exhibit relevant levels of anxiety and depression.

Oral surgery in people with inherited bleeding disorder: A retrospective study.

INTRODUCTION: The objectives were to describe the peri-operative management of people with inherited bleeding disorders in oral surgery and to investigate the association between type of surgery and risk of developing bleeding complications. MATERIALS AND METHODS: This retrospective observational study included patients with haemophilia A or B, von Willebrand disease, Glanzmann thrombasthenia or isolated coagulation factor deficiency such as afibrinogenemia who underwent osseous (third molar extraction, ortho-surgical traction, dental implant placement) or nonosseous oral surgery between 2014 and 2021 at Bordeaux University Hospital (France). Patients and oral surgery characteristics were retrieved from medical records. Odds ratio (OR) and 95% confidence interval (CI) were estimated using logistic regression. RESULTS: Of the 83 patients included, general anaesthesia was performed in 16%. Twelve had a bleeding complication (14.5%) including six after osseous surgery. The most serious complication was the appearance of anti-FVIII inhibitor in a patient with moderate haemophilia A. All bleeding complications were managed by a local treatment and factor injections where indicated. No association was observed between type of surgery (osseous vs. nonosseous) and risk of bleeding complications after controlling for sex, age, disease type and severity, multiple extractions, type of anaesthesia and use of fibrin glue (OR: 3.21, 95% CI: .69-14.88). CONCLUSION: In this study, we have observed that bleeding complications after oral surgery in people with inherited bleeding disorders were moderately frequent and easily managed. However, in this study, we observed a serious complication highlighting the necessity of a thorough benefit-risk balance evaluation during the preoperative planning of the surgical and medical protocol.

Effects of resistance training on muscle strength in adults with haemophilia: A systematic review and meta-analysis.

INTRODUCTION: Although resistance training is frequently prescribed for people with haemophilia (PWH), no previous meta-analyses have quantified the effect of this intervention on muscle strength, nor the implications of the intervention's modality and duration. AIM: (1) To determine the effects of resistance training on muscle strength in adults with haemophilia; (2) To determine the most effective duration and modality among the exercise protocols. METHODS: A systematic search from inception until 28 November 2023 was conducted in PubMed, Embase, Web of Science, CENTRAL and CINAHL databases. We included randomised controlled trials or before-after studies that involved resistance training without other physiotherapy co-interventions. Study selection, data extraction and risk of bias assessment were independently performed by two reviewers. Disagreements were resolved in consultation with a third author. The level of evidence was determined according to the GRADE methodology. RESULTS: Seven studies were included. Measurements of knee extensor strength and elbow extensor strength were included in the meta-analysis. Subgroup analysis showed significant effects for both elastic resistance protocols (SMD: 0.54; 95% CI: 0.02-1.07) and conventional training (isometric and weight-based equipment) (SMD: 0.88; 95% CI: 0.50-1.25), demonstrating small and moderate effect sizes respectively. Additionally, both protocols of duration 5-7 weeks (SMD: 1.16, 95% CI: 0.63-1.69) as well as those of duration ≥8 weeks (SMD: 0.57, 95% CI: 0.20-0.94) showed a significant difference. CONCLUSION: Resistance training is effective in improving muscle strength of the knee and elbow extensors in PWH. Both elastic resistance and conventional training show benefits.

Reduced doses of emicizumab achieve good efficacy: Results from a national-wide multicentre real-world study in China.

INTRODUCTION: Reduced doses of emicizumab improve the affordability among patients in developing countries. However, the relationship between variant dose selection and efficacy in the real world of China is still unclear. AIM: This study aimed to investigate the efficacy and safety of emicizumab especially in those on reduced dose regimens in a real-world setting. METHODS: We carried out a multicentre study from 28 hospitals between June 2019 and June 2023 in China and retrospectively analysed the characteristics including demographics, diagnosis, treatment, bleeding episodes, and surgical procedures. RESULTS: In total, 127 patients with haemophilia A, including 42 with inhibitors, were followed for a median duration of 16.0 (IQR: 9.0-30.0) months. Median age at emicizumab initiation was 2.0 (IQR: 1.0-4.0) years. Median (IQR) consumption for loading and maintenance was 12.0 (8.0-12.0) and 4.2 (3.0-6.0) mg/kg/4 weeks, respectively. While on emicizumab, 67 (52.8%) patients had no bleeds, whereas 60 (47.2%) patients had any bleeds, including 26 with treated bleeds. Compared to previous treatments, patients on emicizumab had significantly decreased annualized bleeding rate, annualized joint bleeding rate, target joints and intracerebral haemorrhage. Different dosages had similar efficacy except the proportion of patients with treated spontaneous bleeds and target joints. Adverse events were reported in 12 (9.4%) patients. Postoperative excessive bleeding occurred following two of nine procedures. CONCLUSION: This is the largest study describing patients with HA receiving emicizumab prophylaxis on variant dose regimens in China. We confirmed that nonstandard dose is efficacious and can be considered where full-dose emicizumab is ill affordable.

Functional clinical motor performance tests to assess potential fall risks in patients with haemophilia: A case-control study.

INTRODUCTION: Patients with haemophilia (PwH) are at increased risk of falls due to haemophilic arthropathy. Yet, studies on clinical tests associated with the risk of falling are scarce in PwH. AIMS: (1) To evaluate the feasibility of different clinical motor performance tests associated with the risk of falling in PwH; (2) to evaluate PwH's performance of these tests compared to a control group; (3) to identify possible influencing factors that affect performance. METHODS: Twenty-nine severe and moderate PwH (57.0 years, IQR: 48.0-61.5) and 29 healthy age- and BMI-matched control participants (CG) performed 13 different clinical tests (SPPB, timed up and go, push and release, functional reach, single-leg stance, knee and grip strength). Haemophilia joint health score (HJHS), kinesiophobia (TSK-11), subjective physical performance (HEP-Test-Q), falls efficiency (FES-I) and falls were assessed. RESULTS: No adverse events occurred. PwH showed impaired performance in all clinical tests, a lower falls efficiency and a higher HJHS than CG. PwH with higher HJHS, lower HEP-Test-Q and higher TSK-11 scores showed higher deficits. Largest discrepancies were observed in the single-leg stance with eyes open and knee extensor strength, where orthopaedically majorly affected PwH showed worse performance compared to minorly affected PwH and the CG, respectively. The prevalence of ≥1 fall in the last year was 27.6% (PwH) and 10.3% (CG). CONCLUSION: These clinical tests are feasible in PwH. Impaired joint status, a high kinesiophobia and low physical performance impair performance. These tests can be used by clinicians for gaining specific information on functional motor abilities of patients.

Hemophilia Gene Therapy: Another Blessing or Another Curse?

Medical therapies for hemophilia patients over the past 60 years have included several blessings and a curse. The long-sought cure with gene therapy may have finally arrived. Unfortunately, preclinical animal models are now raising concerns for genotoxicity with gene therapy. Although no cancers have been detected in humans, it may be a few decades before we know if gene therapy for hemophilia is another blessing, or another curse.

Case Report: Effective management of adalimumab-induced acquired hemophilia A with the CyDRI protocol.

Introduction: Acquired Hemophilia A (AHA) is a rare autoimmune disorder characterized by the emergence of inhibitors that specifically target coagulation Factor VIII, frequently resulting in severe bleeding episodes. Methods: We conducted a retrospective analysis of the medical records of a 68-year-old male patient who presented with adalimumab-induced AHA. Results: The patient received adalimumab, a tumor necrosis factor inhibitor antibody, as part of his treatment for rheumatoid arthritis. The patient's clinical journey, characterized by intense bleeding and coagulopathy, was effectively managed with the application of recombinant Factor VIIa (rFVIIa) and the CyDRi protocol. Discussion: The case emphasizes the importance of prompt coagulation assessment in patients with bleeding symptoms receiving disease-modifying therapy for rheumatoid arthritis that includes adalimumab therapy, considering the rare yet life-threatening nature of AHA. Additionally, this report provides an extensive review of the existing literature on drug-induced AHA, with a special emphasis on cases linked to immunomodulatory medications. Through this two-pronged approach, our report aims to enhance understanding and awareness of this severe complication among healthcare providers, promoting timely diagnosis and intervention.

Outcome measures in hemophilia: current and future perspectives.

INTRODUCTION: Hemophilia can detrimentally affect patients' quality of life and likelihood of survival. In the evolving landscape of therapies, the therapeutic gain of each treatment must be understood to accurately position it in the therapeutic armamentarium. Accordingly, appropriate outcomes must be measured with appropriate tools. AREAS COVERED: Our narrative review (PubMed search for 'hemophilia AND outcome' until June 2023), provides a compendium of outcome measures used in hemophilia clinical research. To define each outcome measure's relative value and applicability, several characteristics are critically discussed. EXPERT OPINION: Bleeding assessment, first annual/annualized bleeding rate, remains central in evaluating the efficacy and safety of hemophilia treatments. As modern therapies improve clinical outcomes toward zero bleeding events, this endpoint may become less sensitive to detect differences between therapeutic approaches. Technological advancements necessitate the adaptation of outcome measures to address infrequent bleeding events, age-related comorbidities, and laboratory parameters with limited comparability after different treatments. Considerable effort has been dedicated to the development of tools that comprehensively assess coagulation, such as thrombin generation assays. Patient-reported outcome measures are gaining importance although limited by their subjectivity. A definitive set of research outcome measures remains elusive. Outcomes may need to be tailored to different therapeutic interventions.

Regular prophylaxis with activated prothrombin complex concentrates in pediatric hemophilia.

BACKGROUND: Regular prophylaxis with activated prothrombin complex concentrates (aPCCs) is effective in adult patients with hemophilia with inhibitors; however, data in children are scarce. METHODS: This was a single-center retrospective study at Saitama Children's Medical Center. Patients with severe and moderate hemophilia with inhibitors aged <15 years at the start of aPCCs prophylaxis were included. Medical records were retrospectively reviewed. RESULTS: We treated nine pediatric patients with hemophilia with inhibitors (median age, 1.9 years; age range, 1.3-12.9 years; inhibitor titers before treatment with aPCCs, 5.9-69 BU/mL) using prophylactic aPCCs (doses, 50-100 U/kg; 2-3 times/week). The median prophylactic period was 13 months (range: 5-31 months). The median annualized bleeding rate (ABR) during prophylactic treatment with aPCCs was 2 (range, 0-17). In four patients, ABR was reduced by 19%-100% with prophylactic aPCCs compared to on-demand aPCCs. An adverse effect of treatment was that a patient with hemophilia B developed nephrotic syndrome 34 months after starting regular prophylaxis with aPCCs. CONCLUSIONS: Regular prophylactic aPCCs reduced the ABR even in younger children with hemophilia A and B. Serious adverse events include nephrotic syndrome, which requires caution.

Characterization of zebrafish coagulation cofactors Fviii and Fv mutants and modeling hemophilia A and factor V deficiency.

The aim of this study is to characterize zebrafish coagulation cofactors fviii and fv mutant fish and assess if they phenocopy classical hemophilia A and factor V deficiency in humans. The embryos from fviii and fv zebrafish heterozygote mutants generated by ENU mutagenesis were purchased from the ZIRC repository. They were reared to adulthood and genotyped. The heterozygote male and female were crossed to get homozygote, heterozygote, and wild-type fish. Functional kinetic coagulation assays and bleeding assays were performed on normal and mutant adult fish, and venous laser injury assays were performed on the larvae. The DNA from fviii and fv mutants were sequenced to confirm if they have a premature stop codon in exon 19, and in exon 2, respectively, and in both mutants, the amino acid glutamine is replaced with a stop codon. Homozygous and heterozygous 5 days post fertilization (dpf) larvae for fviii and fv deficient mutants exhibited prolonged time to occlusion after venous laser injury compared to wild-type controls. The homozygous and heterozygous fviii adult mutants showed modest bleeding and delayed fibrin formation in the kinetic partial thromboplastin time (kPTT) assay with their plasma. fv homozygous larvae had poor survival beyond 12 dpf. However, heterozygous fv mutants exhibited heavy bleeding and prolonged fibrin formation in the kPTT and kPT assay compared with wild-type siblings. Our characterization showed fviii and fv mutants from ZIRC phenocopied to a considerable extent classical hemophilia A and factor V deficiency in humans, respectively. These models should be useful in studying and developing novel drugs that reverse the phenotype and in generating suppressor mutations to identify novel factors that compensate for these deficiencies.

Self-conducted sonographic monitoring of the knee in patients with haemophilia-A feasibility study.

INTRODUCTION/AIM: To evaluate whether patients with haemophilia (PwH) can be enabled to perform ultrasonography (US) of their knees without supervision according to the Haemophilia Early Arthropathy Detection with Ultrasound (HEAD-US) protocol and whether they would be able to recognize pathologies. METHODS: Five PwH (mean age 29.6 years, range 20-48 years) were taught the use of a portable US device and the HEAD-US protocol. Subsequently, the patients performed US unsupervised at home three times a week for a total of 6 weeks with a reteaching after 2 weeks. All images were checked for mapping of the landmarks defined in the HEAD-US protocol by a radiologist. In a final test after the completion of the self-sonography period, participants were asked to identify scanning plane and potential pathology from US images of other PwH. RESULTS: On the images of the self-performed scans, 82.7% of the possible anatomic landmarks could be identified and 67.5% of the requested images were unobjectionable, depicting 100% of the required landmarks. There was a highly significant improvement in image quality following reteaching after 2 weeks (74.80 ± 36.88% vs. 88.31 ± 19.87%, p < .001). In the final test, the participants identified the right scanning plane in 85.0% and they correctly identified pathology in 90.0% of images. CONCLUSION: Appropriately trained PwH can perform the HEAD-US protocol of their knee with high quality and are capable to identify pathologic findings on these standardized images. Asynchronous tele-sonography could enable early therapy adjustment and thereby possibly reduce costs.

Minimal interference of concizumab with standard clinical coagulation laboratory assays - An in vitro study.

INTRODUCTION: Non-factor replacement therapies are emerging as prophylactic treatment options in haemophilia A or B (HA/HB) with and without inhibitors. Concizumab is an anti-tissue factor pathway inhibitor (TFPI) monoclonal antibody preventing factor (F)Xa inhibition and enhancing thrombin generation. Based on experience with other non-factor therapies and extended half-life products, there is a focus on potential interference with common clinical coagulation assays used to monitor patients treated with concizumab. AIM: To evaluate the impact of concizumab on standard clinical coagulation assays. METHODS: Plasma samples (normal, HA/HB with/without inhibitors) in the presence/absence of added concizumab (250-16,000 ng/mL) were analysed in clinical assays including activated partial thromboplastin time (aPTT), prothrombin time (PT), FVIII and FIX one-stage clot and chromogenic substrate assay, assays for detecting FVIII or FIX inhibitors and other assays for coagulation factors. RESULTS: Concizumab did not impact PT assays, but resulted in a small shortening of aPTT (up to 5 s in haemophilia plasma and 0.4 s in normal plasma). Concizumab had no, or only a minor impact on FVIII and FIX activity assays or Bethesda inhibitor assays. FXI and FXII activity in normal plasma, as measured by single factor aPTT-based assay, was significantly increased in the presence of concizumab (+11% each). This was also the case for FVII and FX measured by PT-based assays using plasma with 25% of FVII or FX (+64% and +22%, respectively). CONCLUSION: The presence of concizumab did not, or only slightly, influence the outcome of standard clinical coagulation assays relevant for HA and HB.