Hemophilia Patients Research Articles

The Use of a Pegylated Liposome in a Phase II Trial to Enhance the Potency and Extend the Dosing Interval of Prophylactic Standard Half-Life FVIII, without Increasing the Dose

Background: Prophylactic recombinant FVIII replacement therapy currently relies on the frequent intravenous (IV) administration (once every other day/2-3 times weekly) of Standard Half-Life (SHL) FVIII at a dose 20-40 IU/kg. The evolution of Extended Half-Life (EHL) FVIII has extended the dosing interval to every 4 days or 2-3 times weekly although this also relies on administering higher doses (30-60 IU/kg). Co-formulation of a standard dose (35IU/kg) of SHL FVIII with Pegylated liposomes (PEGLip) can enhance the coagulation performance of FVIII by enhancing clotting activity and its duration of efficacy, ultimately enabling an extended dosing interval. Such benefits may also be conferred if instead of co-formulating prior to injection, the PEGLip is administered after FVIII has been injected. We have developed PEGLip ("XLR8") as the first independent adjuvant product to increase the efficacy of any SHL rFVIII, increasing their dosing intervals and providing haemostatic cover with a lower dose then is possible with current EHL rFVIII replacement products. The XLR8 adjuvant approach used with SHL factors may provide a safe, cost-effective way to reduce injection burden(potentially improving compliance) and the amount of (expensive) FVIII consumed Aims: To demonstrate (a) that PEGLip administered intravenously (IV) to severe haemophilia A (HA) patients that have received a prophylactic dose of rFVIII immediately beforehand prolongs haemostatic cover and (b) to establish a greater dosing interval. Methods: Stage A: Fourteen severe haemophilia A patients were given single IV injections of FVIII (simoctocog alfa) at a dose 35 IU/kg, which were followed after 15 minutes by single infusions of PEGLip 22mg/kg PEGLip and assessed for clotting activity at 0 hours (pre-injection) and at 20min, 1, 2, 4, 8, 24 hours, and daily thereafter up to 7 days using Rotational Thromboelastometry. Stage B: Patients received IV injections of FVIII followed by an injection of PEGLip for 6-weeks at a frequency determined by the investigator based on results obtained during Stage A. Results: These are shown in the table below. Treatment with PEGLip-FVIII was highly tolerated with no inhibitor generation. No adverse drug reactions were reported. The mean frequency of administration of PEGLip-FVIII was every 4.9±1.4 days. The mean number of bleeding episodes reported during Stage B was significantly reduced by 84% to 0.18±0.37 per month compared with 1.10±0.64 per month recorded during the 24 weeks prior to enrollment. Conclusion: The separate injection of PEGLip following a standard-of-care prophylactic injection of FVIII in severe HA patients demonstrated efficacy in preventing spontaneous bleeds with an extended dosing interval of 4.9 days. Over the course of a year this could reduce the injection burden of every-other-day SHL administration by 50%, i.e. 91 injections vs. 182 injections, potentially improving patient compliance and convenience. Compared to a once-every-4-day injection of 45 IU/kg, using 35 IU/kg per administration would reduce consumption of rFVIII by 22%, This trial has looked at the enhancement of a 4th SHL generation, B-domain deleted FVIII. Further work is required to establish if different forms of SHL can also benefit from this enhancement and also whether it can help current EHL products to maintain homeostasis at even longer dosing intervals and lower doses. Acknowledgements: The Authors acknowledge the co-operation of the following clinicians in undertaking the study: Margarita Timofeeva1, Tatiana Pospelova2, Marina Kosinova3, Igor Kurtov4,Alexandr Myasnikov5, 1Scientific Research Institute of Hematology and Blood Transfusion, Kirov, Russian Federation, 2State Medical University, City Hematology Centre, Novosibirsk, Russian Federation, 3District Clinical Hospital, Kemerovo, Russian Federation, 4State Medical University, Samara, Russian Federation, 5Republican Hospital n.a. V.A. Baranov, Petrozavodsk, Russian Federation. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Augmenting the Persistence and Efficacy of Engineered Regulatory T Cells to Suppress Anti-Drug Antibody Formation

Background Adoptive cell therapy (ACT) using engineered antigen specific regulatory T cells (Tregs) is a powerful tool for delivering immune tolerance in autoimmune disease, transplantation and in suppressing undesirable anti-drug antibody (ADA) responses against therapeutic proteins. An important example of the latter is hemophilia A (HA), a genetic disorder characterized by deficiency of the blood clotting protein, factor VIII (FVIII). Replacement therapy with recombinant FVIII can be neutralized by ADA development in up to 30% of severe HA patients. We previously showed that ACT with Tregs expressing a chimeric CD3ε based T cell receptor fusion construct (TRuC), encoding extracellular antibody fragments with specificity to human FVIII, suppressed ADA formation to FVIII in a preclinical HA model [Mol Ther. 2021 29(9):2660-2676]. Ensuring adequate in vivo persistence and a suppressive phenotype without risk of plasticity are major concerns that impede translation of ACT with engineered Tregs. Here we evaluate a synthetic single chain antibody fusion IL2 cytokine product (IL2-IC) to selectively expand adoptively transferred FVIII-TRuC Tregs in vivo. We then combine IL2-IC delivery with FVIII-TRuC Tregs expressing the co-inhibitory receptor PD-L1 to test improved suppression to ADA formation. Methods IL2-IC was generated by fusing IL-2 cytokine to the anti-IL-2 monoclonal antibody F5111 via a flexible linker. This complex specifically delivers IL2 to cells that express high levels of IL2 receptor α (IL2Rα) (i.e., Tregs) while avoiding interaction with cells that express low levels (i.e., Tconv, NK and CD8+ T cells). To assess whether IL2-IC could expand TRuC Tregs in vivo, 2x106 FVIII TRuC Tregs were injected intravenously (IV) into HAmice followed 5 hrs later with low dose IL2-IC or IL2 fused to an irrelevant Ab (FITC-IC) as control. 24 hrs later, mice received 2 international units (IU) of FVIII, and spleens were assayed on days 3 and 6. Murine PD-L1 was co-expressed in FVIII TRuC Tregs and in vitro assessed by stimulating TRuC PDL1 Tregs with 2IU FVIII alone or in combination with 2 ug/ml of PD1-Fc to understand the impact of PDL1 signaling on the Treg phenotype. In vivo, 0.5x106 FVIII TRuC PD-L1 Tregs were IV injected in HAmice followed 5 hrs later by mock, IL2-IC or FITC-IC IV injections. 24 hrs later, mice received weekly IV injections of 1IU FVIII. Results IL2-IC treated FVIII TRuC Tregs were preferentially expanded over endogenous Tregs (fold expansion 7.47 vs 4.56 respectively) in spleens on day 3 post ACT. Whereas both IL2-IC and FITC-IC treated FVIII TRuC Tregs had higher division indices over mock treatment (4.047 ± 0.03 and 5.070 ± 0.07 over 2.00 ± 0.00), only IL2-IC treated FVIII TRuC Tregs showed increased frequencies (1.72% ± 0.376% of CD4+ T cells) as compared to FITC-IC (0.28% ± 0.005% of CD4+ T cells) or mock treatment (0.23% ± 0.023% of CD4+ T cells). FITC-IC treatment nonspecifically expanded CD8+ Tconv cells as well as NK cells, whereas IL2-IC selectively expanded Tregs. PD1-Fc triggered PD-L1 signals in FVIII stimulated TRuC Tregs resulted in significant upregulation of Treg associated activation markers FoxP3, CD69, LAP, CTLA4, PD1, ICOS and BCL2 in vitro. In vivo, IL2-IC administration combined with FVIII TRuC PD-L1 ACT led to complete suppression of ADA formation in HA mice. At 4 weeks, mice that only received FVIII infusions developed high functional ADA titers (29.53 ± 19.58 BU/mL), while IL2-IC, TRuC PDL1 Treg and TRuC PDL1 Treg + IL2-IC groups had significantly lower titers of 1.117 ± 0.952 BU/mL, 1.805 ± 0.702 BU/mL and 0.423 ± 0.243 BU/mL, respectively. FITC-IC combined with PDL1 TRuC Tregs resulted in high ADAs of average 109 ± 21.31 BU/mL, confirming the requirement for the IL2Rα targeting antibody to selectively expand Tregs. Conclusion We show that the PD-L1/PD1 axis is an important pathway that can be exploited to improve the suppressive capacity of engineered Tregs. We also demonstrate that exogenous administration of the novel IL2-IC can robustly expand FVIII TRuC Tregs. These 2 strategies can be readily combined to selectively expand and enhance the suppressive capacity of engineered Tregs. The concepts defined here can be extended for improving the persistence and suppressive potential of engineered Tregs for various autoimmune disorders and to prevent transplant rejection. We are currently evaluating long term suppression of ADA responses using this approach.

Blood-Induced Inflammation in Hemophilia

We previously showed that the acute-phase reactants IL-6, CRP and LBP are elevated in the blood of hemophilia patients in response to acute and recent bleeding. The systemic elevation of acute-phase markers in hemophilia patients was associated with increased activation of monocytes, which exhibit deficits of M2 markers such as CSF1-R, CD163 and Tie2. These deficits correlate with impaired differentiation of monocytes into macrophages thus resulting in the diminished ability of hemophilia macrophages to invade clot and phagocytose red blood cells. As macrophages are central to wound healing and tissue regeneration, we hypothesize that the diminished phagocytic activity of hemophilia macrophages contributes to blood-induced inflammation and joint degeneration in hemophiliacs with hemarthrosis. To assess the effect of joint bleeding on inflammation, we induced a needle-puncture injury of the knee in transgenic mice with hemophilia A. While this process produced only a minor injury in coagulation competent control mice, we observed an extensive hematoma on d1 and d7 in the knees of hemophilia mice as shown by gross and histological examination. By day 28, the hematoma was completely absorbed. The degenerative changes of the knee joints that followed the bleeds included synovia hyperplasia, fibrosis and decline in bone density. Joint bleeding reached a plateau on day 1-7 in hemophilia mice. Immunohistochemistry for myeloperoxidase revealed during this time a massive influx of neutrophil granulocytes into punctured joints that subsided at day 28 when the hematoma was replaced by arthrofibrosis. In addition, acute bleeding-induced inflammation was reflected by a steep increase of interleukin 6 in the blood circulation of knee-punctured hemophilia mice that reached a maximum at day 7 and then fell towards baseline levels at day 28. CD68-positive wound macrophages, on the other hand, were first observed in punctured knees on day 7 and persisted until the end of the observation period on day 28, when most of the macrophages were loaded up with hemosiderin. None of these complications occurred in punctured wildtype mice with normal clotting activity. The deposition of hemosiderin-loaded macrophages in the punctured joints of hemophilia mice suggests that failure to remove red blood cells from the wound area leads to inflammation and subsequent joint degeneration. This failure to clear red blood cells and their proinflammatory components appeared to be specific to hemophilia mice, as we observed rapid absorption of sizable hematomas after injection of anticoagulated blood into the knee joint of coagulation-competent wildtype mice, which in contrast to punctured hemophilia mice showed no signs of inflammation or joint destruction 7 days after blood injection. Together, these data show that hemarthrosis in hemophilia represents a relevant inflammatory stimulus that correlates strongly with joint degeneration. Moreover, the data indicate that inflammation in hemophilia is caused by impaired removal of red blood cells from injured joints, which may lead to the release of pro-inflammatory hemoglobin degradation products and subsequent arthrofibrosis.

Esplorhem: Evaluation of Spanish Experience of Using Florio® Haemo Digital Medical Device for Treatment Monitoring in Hemophilia Patients. a Preliminary Report

Esplorhem: Evaluation of Spanish Experience of Using Florio® Haemo Digital Medical Device for Treatment Monitoring in Hemophilia Patients. a Preliminary Report

Active Lifestyle in Patients with Hemophilia A or B with Inhibitors on Once-Daily Subcutaneous Concizumab Prophylaxis: Results from the Phase 3 explorer7 Study

Introduction: Concizumab is an anti-tissue factor pathway inhibitor (TFPI) monoclonal antibody, currently in clinical phase 3 trials as a once-daily subcutaneous prophylaxis for all hemophilia subtypes. Physical activity was historically discouraged in patients with hemophilia, but recent studies have reported improvements in proprioception, muscle strength and joint health with appropriate physical activities. Here we report, for the first time, results of an exploratory analysis on physical activity from the concizumab explorer7 study (NCT04083781) in patients with hemophilia A or B with inhibitors (HAwI/HBwI). Methods: In explorer7, patients from outside the concizumab program, as well as patients previously treated on-demand in explorer6 (NCT03741881; non-interventional study), were recruited and randomized 1:2 to no prophylaxis, who continued their on-demand treatment with a bypassing agent as usual (arm 1), or concizumab prophylaxis (arm 2).Physical activity data were collected using the ActiGraph tracker, which was worn on the patients’ non-dominant wrist. Patients were instructed to wear the tracker for two consecutive weeks prior to concizumab treatment start, if not already collected in explorer6 (baseline values) and for eight consecutive weeks at the end of the main part (≥32 weeks on concizumab prophylaxis). Analysis of covariance with treatment, type of hemophilia and bleeding frequency prior to screening as fixed effects and the respective baseline value as covariate, was used to compare the change in physical activity parameters from baseline to end of main part between groups. The patients were also interviewed about sport activity by site staff prior to concizumab treatment (baseline) and at the end of the main part to determine the patient's participation in low- (e.g., walking), moderate- (e.g., running/jogging) or high-risk (e.g., rugby) activities. Results: A total of 52 male patients with HAwI/HBwI were randomized to no prophylaxis (arm 1; n=19) and concizumab prophylaxis (arm 2; n=33). In total, 25 randomized patients were not included in this analysis (n=10 from arm 1 and n=15 from arm 2); 4 patients did not restart treatment following pause due to thromboembolic events in patients in explorer7 and 8, 6 patients were withdrawn, and 15 patients did not have data from baseline and/or the end of the main part of the study (e.g., broken device, device not being able to transfer data, patients forgetting to wear the device). Patients on concizumab prophylaxis had an increased percentage of awake time spent in moderate physical activity, and moderate-to-vigorous physical activity compared with patients on no prophylaxis (Table 1), with an estimated difference of 4.19% (95% confidence interval [CI]: 0.15-8.24; P=0.043) and 4.41% (95% CI: 0.38-8.44; P=0.033), respectively. For example, if the mean awake time was 12 hours, this translates to 30 minutes of moderate, or moderate-to-vigorous physical activity in patients on concizumab prophylaxis. Mean levels of physical activity relative to awake time were similar at baseline for both groups. Results of the sport activity ratings for patients who completed the main part of the study showed that at baseline, no patients reported participating in low-to-moderate, moderate, moderate-to-high or high-risk sports (Table 2). At the end of main part, patients participated in low-to-moderate-risk (1 patient; 7.7%), moderate-risk (1 patient; 7.7%) and moderate-to-high-risk (1 patient; 7.7%) sports in the concizumab prophylaxis group, and one patient (9.1%) participated in low-to-moderate-risk sports in the no prophylaxis group. Conclusion: Increased percentage awake time spent in moderate, or moderate-to-vigorous physical activity was observed in patients on once-daily, subcutaneous concizumab prophylaxis, with a significant estimated difference compared with patients with no prophylaxis. While the results should be interpreted with caution due to the smaller cohort of patients included in the current exploratory analysis, prophylactic treatments such as concizumab could encourage patients to spend more time engaging in physical activity that is also of appropriate (higher) risk, which could in turn improve their muscle strength and joint health. Changes in physical activity were also investigated in hemophilia patients without inhibitors in explorer8 phase 3 study. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Anxiety and Depression in Patients with Haemophilia a without Inhibitors and Their Caregivers Included in Hemolife, Non Interventional Study in the Spanish Population

Introduction Haemophilia is a pathology with a great impact on the sufferer and their environment, that is perceived in the family as an exceptional event, interferes with the daily lives of patients and caregivers, emotionally, occupationally and socially1. Joint damage remains a major complication associated with hemophilia that is widely accepted as one of the most debilitating symptoms and has a significant negative impact on health-related quality of live (HRQOL) for adults with severe hemophilia, who frequently experience anxiety and depression. The quality of life of caregivers of haemophilia patients is also affected by the disease2. This abstract presents the baseline results of a sample of patients and caregivers with severe haemophilia A participating in HEMOLIFE study related to anxiety and depression as measured by the Hospital Anxiety and Depression Scale (HADS). Methods Multicenter, prospective, observational study to assess changes in socio-occupational impact1 over a 12-month period in patients ≥ 12 years with moderate or severe haemophilia A without inhibitors and their caregivers (people who share the burden of the disease in the family environment). Information related to depression and anxiety has been collected using the HADS questionnaire3,4. HADS is a 14-item scale with seven items each for anxiety and depression subscales. Patients and caregivers completed the HADS via the study App. Results The study included 81 patients with a mean age of 33 years (81.5% adults), 40% with a partner, 46% workers and 34% students. Forty-seven percent of the patients had comorbidities, the most frequent being haemophilic arthropathy (12%), HIV (10%) and arterial hypertension (10%), hepatitis C (9%), obesity (5%), hypercholesteremia (5%) and diabetes mellitus (5%). In terms of severity, 83% had severe haemophilia. All patients were receiving prophylactic treatment with plasma or recombinant factor VIII (51%), extended half-life factor VIII (31%) and emicizumab (18%), and in 80% the regimen was more than once a week. Twelve caregivers were included in the study with a mean age of 48 years, most of them were women (83.3.%), without university degree (91.7%) and married or with partner (83.3.%); 33.3% was unemployed. Most caregivers have 1 child with hemophilia (75.0%) and 87,5% had at least 2 children. The mother was the caregiver in half of patients, in 33.3% of the cases it was the partner and in 16.7% the father. Mean time caring for person with hemophilia was 19.5 years. Of the 81 patients included in the study 78 completed the HADS and all 12 caregivers included in the study completed the HADS. In the patients the mean (standard deviation) score of the anxiety scale was 6.2 (4.3) and of the depression scale 4.2 (4.5). In caregivers the score on the anxiety scale was 8.0 (5.4) and on the depression scale 5.8 (4.0), in both cases higher than in patients. Percentage of subjects in the category borderline / abnormal for anxiety and depression was higher in caregivers than in patients: 41.7% vs 37.2% and 41.7% vs 16.7% respectively. Results are shown in table 1. Conclusions Depression and anxiety are two important issues to consider in the haemophilia patient environment, both for the patient and the caregiver5. The results of this analysis seem to suggest that caregivers are more affected than patients in these two aspects. Depression and anxiety are two relevant aspects in the environment of haemophilia patients and their presence should be regularly assessed in both patients and caregivers in order to take measures to avoid unfavorable evolution.

Treatment Burden and Patient Preference in Patients with Hemophilia A or B with Inhibitors on Concizumab Prophylaxis: Results from the Phase 3 explorer7 Study

Introduction: Concizumab is a humanized, recombinant monoclonal antibody that acts to inhibit tissue factor pathway inhibitor to enhance coagulation. Patients with hemophilia A or B with inhibitors (HAwI/HBwI) received concizumab as a once-daily subcutaneous prophylactic treatment in the phase 3 explorer7 study (NCT04083781). In the explorer7 primary analysis, concizumab prophylaxis was shown to reduce the annualized bleeding rate for patients with either HAwI or HBwI when compared with no prophylaxis. Concizumab was also considered to be safe and well tolerated for HAwI/HBwI, with the latter patient population having the greatest unmet medical need. Subcutaneous administration of concizumab using a pen device may contribute to a lower treatment burden when compared with intravenous factor replacement therapy. Here, we present data on patient-reported treatment burden and patient preference from patients with HAwI/HBwI treated with concizumab in explorer7. Methods: A total of 133 patients aged ≥12 years were either randomized 2:1 to concizumab prophylaxis (arm 2; n=33) or no prophylaxis (arm 1; n=19) or assigned to non-randomized concizumab prophylaxis treatment (arms 3 or 4; n=81) based on the treatment they were receiving before entering the study. Patients were prompted to complete the Hemophilia Treatment Experience Measure (Hemo-TEM; Brod et al. abstract presented at ISTH 2022 [PB0654]) questionnaire at baseline (Week 0) and Week 24. In addition, patients were asked to complete the hemophilia patient preference questionnaire (H-PPQ) at Week 24. Results from both questionnaires were reported as exploratory endpoints in the study. Due to technical reasons, a number of patient-reported outcomes records could not be collected for statistical analysis. Analysis of covariance was applied to estimate mean change in Hemo-TEM domain and total scores from baseline to Week 24 in arms 1 and 2, with treatment, type of haemophilia and bleeding frequency prior to screening as factors, and the baseline value as a covariate. Descriptive statistics were used to describe the results of the H-PPQ questionnaire. Results: The Hemo-TEM total score improved in patients on concizumab prophylaxis (n=19) from baseline to Week 24 (mean estimate -17.0 points [95% CI: -23.7; -10.3]), while patients on no prophylaxis (n=6) did not experience an improvement (mean estimate 3.0 points [95% CI: -9.4; 15.3]). The estimated treatment difference in Hemo-TEM total score between the two arms was statistically significant (-19.9 points [95% CI: -34.3; -5.6]; P=0.009; Figure 1). Improvements were observed across all Hemo-TEM domains for patients on concizumab prophylaxis, with significant improvements in the domains "injection difficulties", "interference", and "emotional impact" (Figure 1). A total of 99 patients received the H-PPQ questionnaire; 77 (78%) indicated that they preferred concizumab over their previous treatment, while only one patient (1%) preferred their previous treatment (16 patients did not respond, and 5 patients had no preference). Out of the 83 patients who responded, 93% preferred concizumab over their previous treatment. The three main reasons for their treatment preference were "fewer bleeds" (75%), "require less time" (43%), and "less painful to inject" (33%). Conclusion: A lower treatment burden was observed for daily concizumab prophylaxis as patients generally reported better Hemo-TEM domain and total scores. For the Hemo-TEM total score, the estimated treatment difference between concizumab and no-prophylaxis arms was statistically significant. Most patients who responded to the H-PPQ questionnaire preferred concizumab prophylaxis over their previous treatment. Intravenous injection of replacement factor products poses a major burden to hemophilia patients. The observed improvements in treatment burden with subcutaneous administration of concizumab may have the potential to also improve treatment adherence and thereby achieve better clinical outcomes for patients with hemophilia. The combination of effective prophylaxis and reduced bleeding (especially in HBwI) together with lower treatment burden of subcutaneous delivery resulted in a clear patient preference in favor of concizumab. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Characteristics and Healthcare Utilization of Patients with Mild or Moderate Hemophilia A in the US - an Analysis from the Picnichealth Cohort

Background: People with mild or moderate hemophilia A (HA) constitute 40-52% of all people with HA; nonetheless, they are a poorly characterized population in real-world data and published literature (Witkop et al. Blood 2021). To better understand this population, we used a novel platform, PicnicHealth, which integrates real-world data from patients' medical records and patient-reported outcomes, including bleeding occurrence, treatment for bleeds, and pain (Skinner et al. Blood 2021; Witkop et al. Blood 2021). We aim to study the epidemiology of mild and moderate HA and evaluate the effects of various demographic variables and the COVID-19 pandemic on use of healthcare facilities. Methods: People with HA (PwHA) have been enrolled into the PicnicHealth online record management platform since June 2020. Inclusion criteria for this cohort with mild or moderate HA were based on baseline factor (F)VIII activity level (mild, >5-50%; moderate, 1-5%). Records were collected from all known healthcare providers and facilities, including hematology, primary care, and other specialty care, in addition to laboratory reports, imaging reports, pathology, and any inpatient or outpatient encounter since the diagnosis. Descriptive statistical analyses were performed to summarize cohort characteristics. Results: As of June 2022, there were 113 PwHA enrolled in PicnicHealth who met the inclusion criteria for this analysis, of whom 68 (60.2%) had mild HA and 45 (39.8%) had moderate HA. In total, 90 (79.6%) participants were male and 23 (20.4%) were female. The majority identified as 'White' (n=77; 68.1%), followed by 'More than one race or unreported' (n=25; 22.1%), 'Black or African American' (n=8; 7.1%), and 'other race' (n=3; 2.7%). The median age at diagnosis was 12.5 years (Q1, Q3: 1.96, 29.8). Only 8 participants (7.1%) had evidence of FVIII inhibitors during their lifetime. The median (Q1, Q3) Hemophilia Joint Health Score was 4.00 (3.00, 9.00) and the median (Q1, Q3) annualized bleed rate was 0.17 (0, 3.63). In terms of treatment, in the 2 years prior to enrollment, 36 (31.9%) participants had received FVIII prophylaxis, 73 (64.6%) had received FVIII on demand, and 10 (8.8%) had received emicizumab (Table 1). In the 2 years prior to enrollment, participants with mild or moderate HA visited a healthcare facility a median (Q1, Q3) of 7 (4, 11) times and a hematology practitioner a median (Q1, Q3) of 2 (1, 3) times. The majority of the visits to hematology practitioners were to medical doctors (93%), with a smaller number to nurse practitioners or allied health professionals (7%). There was no notable difference in the median number of visits to healthcare facilities or hematologists according to disease severity, race, or inhibitor status. The five states with the highest number of healthcare facility visits by hemophilia patients were California (24.7%), Indiana (7.1%), Michigan (5.9%), Texas (5.9%), and Virginia (4.3%). Finally, we assessed the impact of the COVID-19 pandemic on participants' visits to healthcare facilities. Between January 2019 and July 2021, there were no apparent changes to emergency care visits. For routine care visits, there have been variations since the pandemic began, which may be attributable to lockdown restrictions, although the number of these does not strictly correlate with COVID-19 case numbers (Figure 1). The study is limited by potential bias resulting from participant reporting and the retrospective nature of data collection. Conclusions: Our study provides valuable insights into the characteristics and utilization of healthcare of the under-represented cohort of people with mild or moderate HA. We found notable variation in the geographical distribution of healthcare facilities and visits by PwHA across different states. As expected, routine visits by patients fluctuated during the COVID-19 pandemic. The data generated from this study may aid planning for, and delivery of, the most appropriate and effective care for this group of patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Preventable Causes Dominate Mortality in Hemophilia : A Retrospective Observational Study from India

Background and Objective: Bleeding symptoms in people with Hemophilia (PwH) can range from mild ecchymosis to fatal Central Nervous System (CNS) bleeding. With the advent of Clotting Factor Concentrates (CFCs) and prophylaxis there has been improved life expectancy in PwH in developed countries. However, in low middle income countries (LMIC) like India with a huge hemophilia burden (22,594 cases as per the data by World Hemophilia Federation global survey 2020, with probably far more undiagnosed/ undocumented cases), the mean per-capita factor use(Factor VIII -0.27IU,Factor IX 0.01) is far less than developed countries. Lack of access to safe and effective treatment is a major factor that influences the mortality rate in Hemophilia. This retrospective observational study was done to assess the cause of death in PwH in Kerala state of India. Methods: PwH with Hemophilia A and B registered under patient organizations (PO) in different districts of Kerala from 2015 January to 2022 April were included in the study. A questionnaire was structured and telephonic interview done to collect information on date of birth, Hemophilia type, severity, inhibitor status, target joint, HIV and HCV status, family history, type of treatment (prophylaxis/episodic).Hemophilia severity was categorized as severe (<0.01 IU/mL), moderate (0.01-0.05 IU/mL), or mild (>0.05-0.40 IU/mL). Information on Hemophilia severity, type and inhibitor status were verified with medical reports available with PO. Further data on immediate cause of death, place of death, availability of CFCs at the time of death and the distance of the patient's home to the hospital were collected over telephone. Cause of death was categorized into death due to bleeding, death due to other causes related to hemophilia and death due to causes not related to hemophilia. Statistical analysis was done using the IBM SPSS software version 20. Results: Out of 1032 PwH contacted during this study period there were total 34 death reported, which estimates to 32.9 deaths per 1000 patients.25 (73.5 %) were cases of Hemophilia A and 9 (26.5 %) cases of Hemophilia B. Twenty four patients (70.6%) had severe disease; three(8.8 %) had inhibitors. The cause of death was bleeding in 19(55.88 %) cases, Hemophilia related but not bleeding in 8 (23.52 % cases) and in 7 cases (20.6 %) death was due to causes not related to Hemophilia. The most common cause of death due to bleeding was intracranial bleed seen in 14 (41.17 %) cases, followed by death due to gastrointestinal bleed in 3 cases (8.82 %), hemoptysis and chronic bleed from wound comprised 1 (2.95%) each of all causes of death. In non-bleeding but Hemophilia related category hepatitis C associated liver failure was the cause of death in 8 (23.52 %) cases. In not Hemophilia related causes, cause of death was pneumonia in 4 (11.76 % causes), Myocardial infarction in 2(5.88 %) (refer figure 1). The age at death varied from 1 year to 77 years with mean age being 39.6 years. Out of these 5(17.64 %) deaths occurred in children less than 18 years of age of which 4(80 % )were due to bleeding. Three (8.8 %) deaths were reported at home. The distance from home to hospital ranged from 17.3 kilometer (km) to 257 km with a mean distance of 118 km. All the patients who died were neither on prophylaxis nor on home therapy. Conclusion: Majority of the patients who died had a preventable cause of death. Access to prophylaxis would have prevented deaths caused due to bleeding. None of the patients who died were on prophylaxis which is the standard of care for Hemophilia. None of these patients received home therapy and had to travel for long distances to acquire the factors. Improved access to safer clotting factor concentrates will help to prevent transfusion transmitted infection related deaths. Adequate sustainable supply and availability of factors at affordable costs, along with implementation of prophylaxis for PwH will be useful to bring down the mortality rate among hemophilia patients in LMICs. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Patients with Hemophilia and Their Caregivers Prefer Treatment Attributes That Enable a More Active Lifestyle with Lower Risk of Inhibitor Development

Background: The treatment landscape for hemophilia is evolving. Hence it is important to understand how people with hemophilia and their caregivers value attributes of existing and novel prophylactic treatments. A discrete-choice experiment (DCE) was used to quantify preferences for features of hemophilia treatments among adults and caregivers of children with hemophilia in the US. Methods: A cross-sectional, web-based DCE survey was administered to male adults (≥18 years) and caregivers of male children (≤17 years) living with hemophilia in the US. Respondents evaluated 8 pairs of hypothetical hemophilia treatment profiles defined by 6 attributes - number of annual spontaneous bleeding episodes, lifestyle benefits from improvement in function, route of administration, frequency of administration, risk of developing inhibitors or anti-drug antibodies, and risk of hospitalization due to adverse events (AEs). Attributes for the DCE were informed by a literature review and ranking exercise among adult patients, caregivers, physicians, and stakeholders. The DCE data were analyzed using a random parameters logit (RPL) model and used to calculate the maximum acceptable risk (MAR) of AEs respondents were willing to accept for specific improvements in other study attribute levels. MAR is calculated as the point where the disutility of an increase in risk balances the utility associated with an improvement in a treatment attribute. Results: The final sample included 151 adults (average age 40 years) and 151 caregivers (average age 38 years old, 92% female). For the adult sample, avoiding a 30% risk of developing inhibitors or anti-drug antibodies had the greatest relative importance, followed by improving the ability to live a more active life from limited to high, reducing the number of spontaneous bleeding episodes each year from 6 to 0, change in mode of administration from an intravenous (IV) with vial(s) and syringe to mix to a subcutaneous (Sub-Q) injection with pre-filled pen, reducing frequency of administration from once every 2-3 days to once a month, and avoiding a 5% risk of hospitalization due to AEs (Figure 1a). For caregivers, improving the ability to live a more active life from limited to high had the greatest relative importance, followed by avoiding a 30% risk of developing inhibitors or anti-drug antibodies, reducing the number of spontaneous bleeding episodes each year from 6 to 0 annual bleeds, avoiding a 5% risk of hospitalization due to AEs, reducing frequency of administration from once every 2-3 days to once a month, and a change in mode of administration from an IV with vial(s) and syringe to mix to a Sub-Q injection with vial(s) and syringe to mix (Figure 1b). In general, adults and caregivers preferred treatments that needed to be taken less frequently (e.g., once a month compared with every 2-3 days). Adults preferred a Sub-Q injection with a pre-filled pen compared with other routes of administration. Caregivers preferred Sub-Q options to an IV. Looking at the MAR results, caregivers were willing to accept higher risks of developing inhibitors or anti-drug antibodies than adults for improvements in other attributes. Caregivers were willing to accept a risk of developing inhibitors or anti-drug antibodies greater than 30% for an improvement in the ability to live a more active life from limited to high and 21% for a reduction in the number of spontaneous bleeding episodes each year from 6 to 0, compared to 26% and 17% for adults, respectively. Both groups were willing to accept similar levels of risk of hospitalization due to AEs for improvements in other attributes, accepting greater than 5% for improvements in the ability to live a more active life from limited to moderate or high and for a reduction in the number of spontaneous bleeding episodes each year from 6 to either 1 or 0 spontaneous bleeds. Conclusion: Patients and caregivers prefer treatments that enable more active lifestyle with lower risk of inhibitor development. Both groups valued the ability to lead an active life even over reducing spontaneous bleeding, with caregivers placing the most weight on this attribute suggesting that with the changing landscape in hemophilia treatments, patients and caregivers are willing to trade off benefits and risks of hemophilia treatments. These findings highlight the need for healthcare professionals and patients to share decision making based on clinical judgement and individual preferences. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Pilot, Multicenter and Cross-Sectional Study of Joint Health in Patients with Non-Severe Hemophilia

Introduction: Recent data indicate joint damage (JD) in non-severe hemophilia (nSH), but evidences are still scarce. In nSH, the discrepancy on basal factor (F) VIII or FIX (FVII/FIX) levels between the coagulative (coag) and chromogenic (chrom) assays makes it difficult to predict the bleeding phenotype in this group of patients. The global hemostatic capacity (GHC) evaluated by thrombin generation test (TGT) or thromboelastometry (ROTEM®), might be useful in this field, although there are only few available data. Objectives: To evaluate the JD in nSH patients as well as the correlation between JD, basal FVIII/FIX levels, age and GHC. We also aim to determine the degree of discrepancy between FVIII-chrom and FVIII-coag values in this group of patients. Methods: Cross-sectional, prospective and pilot study in 9 Spanish hospitals was performed. nSH patients ≥12 years old without (or history) of prophylactic treatment were included. Patients with coagulation disorders other than hemophilia were excluded. JD (HEAD-US>0), basal levels of FVIII-chrom, FVIII/FIX-coag, fibrinogen Clauss (Fib), TGT (Genesia®), ROTEM® (exTEM, inTEM and fibTEM), platelet (PTS) and erythrocyte counts (ERY) were determined. Statistical analyses were two-sided and a p-value < 0.05 was considered statistically significant. Results: A total of 56 patients: 6 moderate hemophilia (MoH) and 50 mild hemophilia (MiH) patients were included. The values of PTS, ERY and Fib were withing the normal ranges. The HEAD-US score was evaluated in 46 patients (6 MoH-A and 40 MiH-A patients; 276 joints in total) and indicated a higher % of patients with JD in the MoH group (100% of patients) vs. the 51.2% in the MiH (p=0.212). As expected, the median value of HEAD-US score was higher in MoH (MoH: 7.5 [5.0-12.0] vs. MiH: 1.0 [0.0-4.0], p= 0.019). Surprisingly, the median basal FVIII/FIX was similar between the groups with and without JD: 14.5 (11.0-20.0) IU/dL vs. 14.0 (11.0-17.0) IU/dL, respectively (p= 0.842). Another non-expected result was that 10% of MiH patients presented a target joint. No correlation was observed between HEAD-US score and GHC, age or basal FVIII/FIX levels. However, increasing basal FVIII/FIX levels affected the GHC by decreasing the CT-inTEM (clotting time: time to initiation of clot formation by the intrinsic pathway) (r= -0.715, p< 0.001), increasing the peak of thrombin generation (TG) (r= 0.334, p=0.014), shortening the time to reach the start tail (ST) of the TG curve (r= -0.271, p=0.048) and increasing the speed (velocity index, VI) of TG (r= 0.310, p= 0.024). As previously described, the increment of Fib incremented the lagtime (time to initiation of TG) and the time-to-peak of TG (r= 0.531, p<0.001 for both parameters), and also decreased the VI (r= -0.323, p= 0.022). Moreover as a typically described effect, increment of Fib increased the strength of the clot (Fib vs MCF-exTEM, MCF-inTEM and MCF-fibTEM (MCF=maximum clot firmness): r= 0.557, p= 0.006; r= 0.547, p= 0.008 and r= 0.417, p= 0.043, respectively). Increment in PTS decreased the clot formation time (CFT) and increased MCF (PTS vs CFT-inTEM and MCF-inTEM: r= -0.417, p= 0.034 and r= 0.638, p= 0.001, respectively). The degree of correspondence between FVIII-chrom and FVIII-coag was 79.5%. Conclusions: Patients with nSH may present JD. Neither basal FVIII/FIX levels, nor GHC, nor age correlated in our study with the degree of JD though wider studies are needed to confirm these findings. Although correlation between basal levels of FVIII/FIX and GHC was observed, none of these variables were able to explain the degree of JD. Target joints can be observed in patients with MiH, therefore additional studies are necessary to clarify the need of new therapeutic intervention in this group of patients. Future studies should address the relationship between degree of JD (values of HEAD-US) and patients' quality of life (QoL) to stablish cutoff values of HEAD-US score that may affect the QoL. The unexpected high % of nSH patients with JD urges the need for larger studies on JD in this population to clarify the need of new type of therapeutic intervention in this group of patients.

Joint Status and Bleeding Phenotype Characterization in Severe and Non-Severe Hemophilia a and B

Introduction: Persons with hemophilia (PwH) A and B are known to have variable bleeding phenotypes and may have joint bleeding that is less clinically apparent. In recent years, musculoskeletal ultrasound (MSKUS) has become an established modality useful for evaluating joint status. Further, determination of individual bleeding phenotype can be challenging, but clinical tools including the International Society on Thrombosis and Haemostasis Bleeding Assessment Tool (ISTH-BAT), self-BAT, and the Beighton Hypermobility Score (BHS) have been developed. Methods: We hypothesize that presence and degree of joint disease, evaluated with MSKUS and physical assessment scoring, will correlate with severity of bleeding phenotype as characterized through clinical history, BAT assessment, and presence of joint hypermobility in PwH A and B. This will be accomplished through assessing baseline joint status and disease progression over time with MSKUS, as well as through use of the ISTH-BAT, self-BAT, and assessment of hypermobility with the BHS. Up to 100 individual subjects with severe, moderate, or mild hemophilia A or B will be enrolled and assessed at baseline and annually during the study period at our institution. Correlation of joint status with BHS and BAT scores will be analyzed with the generalized estimating equation (GEE) and other statistical methods. Results: Thus far, 15 male patients have been enrolled (Table 1). All moderate and severe hemophilia patients are on prophylactic therapies for bleed prevention, and 3 patients have history of inhibitors. Target joints were reported only in severe PwH. MSKUS measurements were completed using the JADE protocol1. Patient enrollment remains ongoing. Discussion: Knowledge pertaining to joint status and bleeding phenotype is PwH A and B is limited. This pilot study will assess the presence and degree of joint disease, evaluated with MSKUS and physical assessment scoring, and its correlation with severity of bleeding phenotype as characterized through clinical history, BAT assessment, and presence of joint hypermobility in PwH hemophilia A and B. The results will be used to justify a larger, multicenter study to expand understanding of joint status and bleeding phenotype in PwH.

Abstract 14633: A Case of Acute Coronary Syndrome With Incidental Acquired Factor VIII Deficiency With Inhibitor Present: How to Navigate Being Between a “Rock” and a Bleeding Disorder

Introduction: Acute coronary syndrome (ACS) occurring in the presence of a bleeding diathesis can make clinical decision-making difficult. We present a case of a non-ST elevation MI in the presence of an acquired factor VIII deficiency with an inhibitor present. Case: A 66-year-old male with a medical history significant for coronary artery disease and COPD presented with a 4-day history of persistent, profuse bleeding after attaining a laceration on his arm. Shortly after admission, he reported pressure-like chest pain relieved by sublingual nitroglycerin. His 5th generation troponin level was 61 ng/L on presentation and peaked at 600 ng/L 36 hours later. The EKG revealed ST depressions in leads V3 and V4 and T-wave flattening in leads V5 and V6. Transthoracic echocardiography revealed preserved ejection fraction but could not exclude wall motion abnormalities due to poor windows. Hematology was consulted due to uncontrolled bleeding, and the patient was diagnosed with acquired factor VIII deficiency with an inhibitor present. Low-dose heparin infusion was initiated. He was taken for a diagnostic left heart catheterization, which revealed left main with moderate obstruction, left anterior descending (LAD) with 70% proximal stenosis, and a small diagonal branch with 90% stenosis. The patient had been previously offered evaluation for coronary artery bypass graft(CABG) surgery but declined. CABG work up was ultimately deferred in favor of percutaneous coronary intervention based on literature review extrapolated from hemophiliac patients. The patient’s hematologic care is ongoing with recombinant antihemophilic factor, porcine sequence, prednisone, cyclophosphamide, and rituximab administration. Discussion: Choosing the type of coronary revascularization in coagulopathic patients poses a significant challenge. To avoid complications, a multidisciplinary approach to short- and long-term anticoagulation management is necessary. In this case we decided to use existing data that is based on hemophilia patients in the past with myocardial infarction where dual antiplatelet therapy is limited to 1 month with factor 8 activity maintained above 30%. Then transition to aspirin alone for maintenance with factor 8 levels maintained above 10%.

CHRONIC OSTEOMYELITIS DUE TO SALMONELLA TYPHI IN A HEMOPHILIA PATIENT-A CASE REPORT

Salmonella causes various intestinal and extra intestinal manifestations. Chronic osteomyelitis is commonly seen in patients with patients of haemophilia. Most common cause of chronic osteomyelitis is Staphylococcus aureus. Very rarely Salmonella typhi causes chronic osteomyelitis. So here we report a case of Chronic osteomyelitis with recurrent discharging sinus caused by Salmonella typhi in patient who was a known case of haemophilia highlighting the pathogenesis which would have resulted in such a clinical presentation. If not treated in time would lead to permanent disability.

Exploration of the minimum necessary FVIII level at different physical activity levels in pediatric patients with hemophilia A.

Physical activity can increase joint stability and reduce the risk of injury in hemophilia patients. There is limited clinical data on target trough FVIII levels during physical activity in hemophilia A patients. Hence, this study aimed to explore the target trough FVIII level required to avoid bleeding during different physical activities in hemophilia A patients. Patients with severe or moderate hemophilia A, who underwent pharmacokinetics (PK) tests at our center were enrolled in this study. Physical activities and clinical information such as bleeding were recorded. The FVIII level during physical activity was calculated by the WAPPS-Hemo. A total of 105 patients were enrolled in this study. A total of 373 physical activities were recorded, of which 57.6% (215/373) was low-risk activities and the remaining 42.4% (158/373) was medium-risk activities. Most common physical activities were bicycling (59.0%), swimming (43.8%), running (48.6%), and jumping rope (41.0%). The FVIII trough level of low-risk physical activity was 3.8 IU/dl (AUC = 0.781, p = 0.002) and moderate-risk physical activity was 7.7 IU/dl (AUC = 0.809, p < 0.001). FVIII trough levels [low-risk activities: 6.1 (3.1, 13.2) IU/dl vs. 7.7 (2.3, 10.5) IU/dl, moderate-risk activities: 9.6 (5.8, 16.9) IU/dl vs. 10.2 (5.5, 11.0) IU/dl] were not statistically different between the mild arthropathy group and the moderate-severe arthropathy group. Multiple bleeding risk tended to increase with physical activities classified as moderate-risk (OR [95% CI]: 3.815 [1.766-8.238], p = 0.001). The minimum necessary FVIII level increased with higher risk physical activity, irrespective of arthropathy.

Total Knee Replacement in Hemophilic Arthropaties

In severely affected haemophilic patients arthropathy is a common problem which can lead to considerable pain and functional deficit.

Presepsin Levels in Positive and Negative Blood Cultures of Febrile Neutropenic Pediatric Patients with Malignancies in Dr. Soetomo General Hospital, Surabaya, Indonesia

This was observational research with cross sectional type of study conducted from January to October 2020 at Dr. Soetomo General Hospital, Surabaya. The subjects of the research were 30 children’s patients with febrile neutropenic episodes with malignancy based on the criteria of the American Society of Clinical Oncology and Infectious Disease Society of America, which were grouped into 2 groups based on blood culture results from secondary data. The control group was hemophilia patients without any complaint. The presepsin level was checked using ELISA. The differences in presepsin levels in positive and negative blood cultures and the control were analyzed using T2 free samples or Mann-Whitney U according to the data distribution. Median (min-max) presepsin levels in positive, negative and control cultures: 4.1(0.3 - 14) ng/mL, 2.95(0.2 - 13.8) ng/mL, 0.1(0.1 - 0.5)ng/mL. There is no significant difference in presepsin levels between positive and negative blood culture (p = 0.606). There is a significant difference between positive and negative culture presepsin levels towards controls (p = 0.001 and p = &lt;0.001). There is an increase in the level of presepsin in febrile neutropenic pediatric patients with malignancy, but this examination cannot differentiate between bacteremia and non-bacteremia infections.

LONG-TERM EVALUATION OF RADIOISOTOPE SYNOVECTOMY WITH YTTRIUM-90 AND RHENIUM-186 FOR CHRONIC SYNOVITIS IN PEDIATRIC HEMOPHILIA: AKDENIZ UNIVERSITY EXPERIENCE

OBJECTIVE: This study aimed to evaluate the effect of radioisotope synovectomy with Yttrium-90 and Rhenium-186 on the joints of patients with chronic hemophilic synovitis.MATERIAL AND METHODS: Retrospective analysis of radioisotope synovectomy using Yttrium-90 and Rhenium-186 in pediatric hemophilia patients treated in the Akdeniz University School of Medicine between June 2005 and September 2014 was carried out.RESULTS: Eighteen patients with severe hemophilia (mean age 12.55±4.93 years) underwent a total of 32 radioisotope synovectomy procedures: 13 elbow (40.6%), nine knee (28.2%), nine tibiotalar (28.2%), and 1 metatarsal (3.1%) joint. Ten patients (55.5%) had radioisotope synovectomy to a single joint; five patients (27.8%) had simultaneous radioisotope synovectomy to two joints. Three patients with inhibitors underwent a total of five radioisotope synovectomy procedures (15.6%). In 15 patients (83.3%), hemarthrosis was reduced after radioisotope synovectomy and no further treatment was required. The other three patients (four joints) underwent repeat radioisotope synovectomy after a mean of 20.75±14.77 months. The mean follow-up period of our patients was 8.81 ± 4.87 years [9.42 years (min-max; 1-22.58)]. Uncontrolled bleeding, need for additional dose factor treatment, radioisotope leakage, and local inflammatory reaction were not observed during and after radioisotope synovectomy.CONCLUSIONS: Radioisotope synovectomy is an effective treatment method that can be used to prevent permanent joint damage in hemarthrosis and to reduce the frequency of bleeding and the use of coagulation factors. Treatment of radioisotope synovectomy should be considered before progressive joint damage has developed.

Vincer EMO Project: Physical Activity for Haemophilic Patients. How We Faced Up SARS COV2 Pandemic

The SARS COVID pandemic has negatively impacted health care activities in the entire world, both in emergency and ordinary inpatient and outpatient regimes. Rehabilitation has also suffered a heavy penalty which has not spared research projects in specific sectors. The VINCEREMO project stems from the need to objectively evaluate the benefits of a regular personalized physical activity program on musculoskeletal health in patients with severe haemophilia A and B. These patients present in a high percentage of important functional limitations and reduction of trophism and muscle strength due to the consequences of haemophilic arthropathy. Multi-district impairments in addition with the high risk of bleeding hinder the performance of common recreational and sports activities, resulting in social isolation of patients, especially in childhood and youth age. Even if the SARS COVID pandemic interrupted the various rehabilitation activities in the expected mode of the project, we were also able to continue the training course thanks to personalized tele-rehabilitation programs, who supported patients during the lockdown period, maintaining good adherence to therapeutic proposals. The preliminary results of the controls at the end of the reference period showed positive changes in the outcome indicators.

Methods for anti-factor VIII antibody levels in haemophilia A patients - validation of a multiplex immunoassay and comparability with assays measuring non-neutralising and neutralising antibodies (inhibitors).

The development of neutralising (inhibitors) and non-neutralising antibodies (NNAs) is a complication to factor replacement therapy in haemophilia. The diagnostic methods available lack standardisation, have high inter-laboratory variation, and false-negative as well as false-positive results may affect treatment. Both functional inhibitors and NNAs may be detected with higher reproducibility, sensitivity and specificity using the immunological Luminex xMAP-based fluorescence-immunoassay (xFLI). Validation of our xFLI and comparability with enzyme-linked immunosorbent assay (ELISA) and chromogenic Nijmegen-Bethesda assay (CBA) for anti-FVIII antibodies in haemophilia A (HA) patients. The xFLI method was developed with full-length and B-domain deleted factor coupled to magnetic beads, optimised and validated for performance characteristics. Comparability with ELISA and CBA was evaluated in HA patient samples (n=112), serial samples in six inhibitor patients and reference interval and decision-limits in healthy donors (n=44). The intra- and inter-assay precision (CV%) for the xFLI method was below 6% and detection limit (LLOQ) .084ng/mL (NovoEight). All ELISA-positive samples were positive with either Advate or NovoEight. Additionally, 10.7%-14.3% were xFLI-positive and ELISA-negative. All but one CBA-positive sample was above 3SD with xFLI; one was between 2 and 3SD. 29.1% were xFLI-positive and CBA negative. The overall concordance between xFLI and ELISA was 82.1% and xFLI and CBA 77.9%. The anti-FVIII antibody xFLI method is adaptable to clinical practice and more sensitive and reproducible than ELISA and CBA. Actual NNA titers are determined to both full-length and B-domain deleted FVIII. The xFLI is thus valuable for confirmation of all anti-FVIII antibodies.