Hemophilia A Research Articles

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.

Health Care Resource Use, Comorbidities, and Costs of Hemophilia A Patients in France: A Nationwide Claims Database Analysis

Background and objectives Hemophilia A is an inherited bleeding disorder characterized by a deficiency in blood clotting factor VIII (FVIII). Its severity varies based on the degree of FVIII deficiency, with the most severe cases experiencing frequent spontaneous hemorrhages (FVIII levels < 1 IU/dL). Treatment options include on-demand administration following a hemorrhage or prophylaxis to prevent bleeding. The most frequent complication is the production of inhibitory antibodies against the coagulation factors, leading to more aggressive and expensive treatments. The aim of this study was to describe Hemophilia A patients according to severity in France in 2021, including sociodemographic characteristics and comorbidities, current treatments, healthcare resource use and related costs. Methods This study used the French health-insurance claims database (SNDS) containing pseudonymized individual data for over 66 million people. Hemophilia A patients are fully covered in France and might be identified by the ICD-10 code D66. Patients alive on January 1st, 2021, were selected after exclusion of those presenting with Willebrand disease and other rare bleeding disorders. Comorbidities were identified through validated algorithms. An age and gender matched control group without Hemophilia A was randomly selected in the general population: for each HA patient a subject of the same age, gender and region of residence was randomly selected among the overall population of French citizens (excluding HA patients). Sub-group analyses were performed according to the treatment pattern (on demand / in prophylaxis) and the presence of inhibitors (defined with the treatment: emicizumab before October 2019, high dose of factor VIII or bypassing agents). Direct costs were estimated in a societal perspective. Results 5,507 patients with Hemophilia A were identified. Mean age was 36 years and 97.3% were males. Compared to controls, hemophilia patients had significantly (p<0.05) more frequently an HIV infection, hepatitis B or C, and a hepatic disease (Figure 1). There were no significant differences for chronic cardiopathy, coronary artery disease, chronic heart failure and arrhythmia. Respectively 4,056 (73.7%), 36 (0.7%), 1,243 (22.6%) and 172 (3.1%) patients were treated on demand without and with inhibitors and in prophylaxis without and with inhibitors. Compared to controls, patients with hemophilia A had more frequent consultations with general practitioners and hospital specialists, visits to emergency unit, with nurses and physiotherapists (Table 1). They also were more frequently treated with analgesics and corticosteroids but less frequently with non-steroid anti-inflammatory drugs. The proportion of hemophilia A patients hospitalized was higher than controls, overall and also for bleeding episodes and for orthopedic surgery. The mean annual direct medical costs (drugs, consultations, hospitalizations, ...) varied strongly according to treatment modalities and presence of inhibitors: €11,471 for patients treated on demand without inhibitors (versus €1,806 for their matched controls)€76,332 for patients treated on demand with inhibitors (versus €2,288 for their matched controls)€247,937 for patients treated in prophylaxis without inhibitors (versus €1,159 for their matched controls)€349,616 for patients treated in prophylaxis with inhibitors (versus €1,342 for their matched controls). The majority of the costs was related to antihemophilic drugs: 64%, 60%, 94% and 93% respectively in the 4 treatment groups. Conclusion: These results highlight the burden of hemophilia A in terms of comorbidities, healthcare consumptions and cost. The cost of Hemophilia A varied greatly with disease severity and presence of inhibitors and was mostly due to the antihemophilic drugs.

Severe Recurrent Bleedings in Infant with a Factor VII Deficiency (Case Report)

Factor VII deficiency considered the most common of rare bleeding disorders. The symptoms of this affection can begin at any age, although the most severe cases are apparent in infancy. However, up to one-third of people with factor VII deficiency never have any bleeding problems. Symptoms can range from epistaxis up to cerebral hemorrhage. We here report the case of a child, diagnosed with factor VII deficiency with severe recurrent Bleedings (umbilical haemorrhage, hemarthrosis. lingual hematoma, gastrointestinal and cerebral bleeding). Prophylaxis with rFVIIa in a schedule based on 20-30 μg/kg of rFVIIa one, twice or three times a week has been described as the therapeutic regimen with the best outcomes in terms of reduction of bleeding's severity and frequency. Our patient underwent early prophylaxis with a 30 μg/kg of rFVIIa a week schedule. Unfortunately, prophylaxis hasen't been successful to prevent further bleedings. The evolution was marked by occurrence of several gastrointestinal and cerebral bleeding, then death by a cerebral hemorrhage at the age of 6 months. Congenital Factor VII deficiency is a rare cause of bleeding disorder, which should be suspected in a healthy bleeding child presenting in infancy when platelets and aPTT is normal with a deranged PT.

An intronic RNA element modulates Factor VIII exon-16 splicing.

Pathogenic variants in the human Factor VIII (F8) gene cause Hemophilia A (HA). Here, we investigated the impact of 97 HA-causing single-nucleotide variants on the splicing of 11 exons from F8. For the majority of F8 exons, splicing was insensitive to the presence of HA-causing variants. However, splicing of several exons, including exon-16, was impacted by variants predicted to alter exonic splicing regulatory sequences. Using exon-16 as a model, we investigated the structure-function relationship of HA-causing variants on splicing. Intriguingly, RNA chemical probing analyses revealed a three-way junction structure at the 3'-end of intron-15 (TWJ-3-15) capable of sequestering the polypyrimidine tract. We discovered antisense oligonucleotides (ASOs) targeting TWJ-3-15 partially rescue splicing-deficient exon-16 variants by increasing accessibility of the polypyrimidine tract. The apical stem loop region of TWJ-3-15 also contains two hnRNPA1-dependent intronic splicing silencers (ISSs). ASOs blocking these ISSs also partially rescued splicing. When used in combination, ASOs targeting both the ISSs and the region sequestering the polypyrimidine tract, fully rescue pre-mRNA splicing of multiple HA-linked variants of exon-16. Together, our data reveal a putative RNA structure that sensitizes F8 exon-16 to aberrant splicing.

Abstract 15468: Factor VII Induced Coronary Thrombosis

Case Description: 69-year-old male with a history of factor VII deficiency and coronary artery disease (CAD) with a stent in the distal left anterior descending (LAD) artery, underwent diagnostic laparoscopy for suspected appendiceal carcinoma. He is a non-smoker, has good exercise tolerance and takes aspirin only three times a week, due to epistaxis. Post-surgery, he complained of 10/10 substernal chest pain. Initial troponin (TnI) was 0.11 ng/dL, peaking at >80 ng/dL in 2 hours. EKG was compatible with an anterior wall STEMI. An emergent coronary angiogram showed a patent distal LAD stent and a 99% occlusive lesion in the mid-LAD, which was treated with a drug-eluting stent. With careful clinical judgment and hematology consultation, dual antiplatelet therapy was continued despite a history of coagulopathy. On probing, it was discovered that the patient received two doses of recombinant factor VII (rVII) prior to the surgery to reduce operative bleeding. Discussion: Recombinant factor VII is known to cause serious arterial and venous thromboembolic events. This risk increases to almost 10% in patients who are elderly with concomitant vascular disease. In our patient with prior history of CAD and in the setting of acute surgical stress, exogenous factor VII unbalanced the coagulation system leading to a STEMI. Surgical teams should be aware of the detrimental consequences of administration of rVII in high cardiovascular risk patients and seek alternative hemostatic strategies. Prothrombotic agents should be used with caution and close monitoring for acute coronary syndromes, especially in patients with a high risk of CAD.

Factor VIII Is an Endothelial Factor That Promotes Vessel Stability

Background: Hemophilia A (HA) is a rare bleeding disorder caused by the absence or dysfunction of factor VIII (FVIII). Clinical manifestations include spontaneous bleedings that primarily consist of hemarthroses and intracranial hemorrhages. Attenuated microvascular endothelial functionality is observed in HA patients suggesting a dysfunction in endothelial cells (ECs). Current therapeutic practice consists of replacement therapy with recombinant FVIII (rFVIII), either as needed to treat acute hemorrhages, or as prophylaxis to prevent bleeds. It is well established that FVIII is largely secreted by ECs and in particular by sinusoidal endothelial cells in the liver. Healthy and HA ECs can be isolated from the peripheral blood as blood outgrowth endothelial cells (BOECs) or can be differentiated from induced pluripotent stem cells (iPSCs). Here we show that, in addition to its role in blood coagulation, FVIII plays a role in endothelial cell functionality. Aims: To elucidate the potential impact of FVIII on EC stability and to investigate the effect of different rFVIII products on the maintenance of EC functionality. Methods: BOECs isolated from HA patients and healthy donors were used. HA BOECs were treated in vitro with B-domain deleted (BDD; simoctocog alfa) or full-length (FL) rFVIII products, and EC functionality was evaluated by tubulogenic, migration, permeability and proliferation assays. The impact of the different rFVIII products on vessel formation and permeability was evaluated in vivo in NOD/SCID γ-Null (NSG) and NOD/SCID γ-Null HA (NSG-HA) mice. Results: In vitro results demonstrated a weakening in tubulogenesis, migration potential and permeability in HA ECs vs healthy ECs and a significant enhancing of tubule network formation in HA BOECs treated with BDD-rFVIII or FL-rFVIII. Quantification of nodes, junctions, branches and the total length of the vessel-like structures confirmed that treatment of HA BOECs with BDD-rFVIII or FL-rFVIII improved HA BOEC function. Moreover, migration assays of HA BOECs treated with BDD-rFVIII or FL-rFVIII showed that the migration ability of HA BOECs was improved after treatment with either of the rFVIII products. We also evaluated whether rFVIII could ameliorate cell permeability. When treated with either rFVIII, the HA BOEC monolayer was less permeable to fluorescein isothiocyanate (FITC)-labeled dextran compared with that from non-treated HA BOECs. Vessel permeability assays in vivo demonstrated a significant reduction of dye extravasation in NSG-HA mice treated with rFVIII, with an improvement in mice treated with BDD-rFVIII compared with FL-rFVIII. Conclusion: In conclusion, information about the possible extra-coagulative role of FVIII may be crucial to understand the key molecular targets missing in HA patients at the cellular level that impair EC functionality. Knowledge of the possible effect of different rFVIII products on ECs functionality can lead to new therapeutic approaches potentially resulting in safer and more efficient treatment of HA.

Congenital Factor VII Deficiency : A Retrospective Analysis of 14 Cases from One Hospital

Objective To explore the clinical characteristics, laboratory findings,diagnosis, treatment, and prognosis of congenital factor VII (FVII) deficiency. Methods Clinical data of 14 patients of congenial FVII deficiency diagnosed from Jan 2019 to Jun 2022 were retrospectively analyzed. Results Of the 14 patients,there were 8 males and 6 females with median age 31.5 (1.3~70) years. Family history was found in 2 cases. There were 7 cases with bleeding symptoms, of which were mucocutaneous bleeding (1 case), gingival bleeding (2 cases), menorrhagia (3 cases), hemoptysis (1 case ), post-surgery hemorrhage (1 case), and 1 case with cerebral infarction. Menorrhagia occurred in 3 cases (75% of female patients who were in fertile age). Laboratory findings were characterized by significantly prolonged prothrombin time (PT) (19.2~58.9s) , of which could be corrected by mixed normal plasma, normal partial thromboplastin time (APTT), and decreased FVII activity (FVII:C) (2.4~24.7%). 1 case and his family members received gene mutation analysis and compound Heterozygous mutation (heterozygous deletion mutation and heterozygous missense mutation) was found in the proband. 3 cases were treated with prothrombin complex concentrates (PCC), 1 case with PCC and human recombinant activated FVII (rhFVIIa). 10 patients with no or mild bleeding symptoms did not receive any replacement therapy. Conclusion Most patients with congenital FVII deficiency have mild or no bleeding symptom, but have a tendency to excessive bleeding after surgery or trauma. There is no significant correlation between FVII:C and the severity of bleeding symptoms. Prophylaxis could be applied in patients with severe bleeding symptom. Gene mutation test is significant for diagnosis, prognosis prediction of the disease.

AAV-Mediated Expression of a Single-Chain FVIII Mimetic Antibody Efficiently Corrects Bleeding in Haemophilia a Mice

Background: The recent approval of gene therapy for haemophilia A (HA) using adeno-associated viruses (AAVs) marks an important and long-awaited landmark as it is associated with markedly reduced bleeding events whilst overcoming the demands of regular life-long administration of factor concentrates or antibodies with FVIII mimetic activity. However, the benefits of AAV gene therapy in severely affected HA patients are likely to be short-lived as clinical data from most of the advanced trials show a gradual decline in transgenic Factor VIII (FVIII) levels over time. The reasons for this decline in expression remain unexplained but may be due in part to the packaging of an oversized FVIII expression cassette into AAV vectors. This hypothesis is supported by the fact that such decline in transgene expression has not been observed in other gene therapy approaches in clinic where the transgene expression cassette is within the packaging limits of AAV vectors. Therefore, we explored an alternative therapy approach for HA that utilises an expression cassette encoding a novel FVIII mimetic bispecific antibody (Bi8) that remains within the packaging constrains of AAV vectors, thus potentially improving the prospects of long-term control of the bleeding diathesis in severely affected HA subjects. . Methods: Bi8, is a small 54kDa single-chain bispecific antibody designed as a tandem of single-chain fragment variables (scFvs) targeting Factors IXa (FIXa) and X (FX). FVIII mimetic activity of recombinant Bi8 protein was evaluated in vitro using (1) the catalytic conversion of purified FX into FXa in a chromogenic assay, and (2) factor XIa (FXIa)-triggered thrombin generation assay (TGA) and activated partial thromboplastin time (aPTT) using spiked human HA plasma. Bi8 sequences were cloned in an AAV expression cassette downstream of a strong liver-specific promoter, pseudotyped with AAV serotype 8 capsid and evaluated in vitro as well as in vivo, including in FVIIIKO mice to assess potency in a tail vein transection assay, kinetics of Bi8 expression and the occurrence of anti-drug antibodies (ADAs). Results: In preliminary experiments, we demonstrated that the single-chain format used for Bi8 retained haemostatic functions. When tested in a chromogenic assay, recombinant Bi8 protein showed kinetics of FXa formation identical to that of emicizumab. Furthermore, Bi8 spiked in human HA plasma at 350nM corrected the clotting time (17.2 sec) in an aPTT assay to levels observed with emicizumab (22.7 sec). TGA with recombinant Bi8 and emicizumab showed comparable efficacy with peaks of thrombin generation at 354.2 and 358.4nM respectively. Next, human hepatocyte HuH7 cells were transduced with AAV8 encoding Bi8 (AAV8_Bi8) vectors in vitro, leading to the expression of a fully functional bispecific antibody with an activity/antigen ratio of 0.99 when compared to the recombinant Bi8 protein. Three doses of AAV8_Bi8 vector were then evaluated in 6-8 weeks old, male FVIIIKO mice, with a single intravenous infusion of 4e 11; 4e 12 and 1.2e 13 vector genome (vg) per kilo. Expression of the bispecific antibody was detectable in plasma for all 3 doses and peaked 2 weeks post-infusion with respective concentrations of 4.5; 47.4 and 178.8nM (Panel A). Transgenic expression was then stably maintained for 12 weeks and ADAs were not detected in any of the treated animals. When challenged in a bleeding assay, haemostasis was secured in all cohorts of mice infused with AAV-Bi8 vectors, including at the lowest dose of 4e 11 vg/kg where the average total blood loss was reduced to 401.2μL (median 406.2μL) compared to 760.4μL (median 773.1μL) in non-treated FVIIIKO mice (Panel B). Conclusion: This study establishes the feasibility of using AAV vectors to deliver an expression cassette encoding Bi8, a novel FVIII mimetic antibody formatted as a single-chain tandem-scFv, leading to circulating concentrations of bispecific antibody at levels that can secure haemostasis and reduce blood loss in a murine model of HA. This non FVIII-based expression cassette meets the packaging capacity of AAVs and therefore provides an alternative approach for AAV-mediated gene therapy for HA that may be better suited for stable long-term expression than FVIII transgenes.

Emicizumab Use in Infancy: A Survey of United States Pediatric Hemophilia Treatment Center Medical Directors

Introduction: Emicizumab, a bispecific antibody directed against activated factor IX and factor X, is a subcutaneous non-factor prophylactic option for individuals with hemophilia A (HA). The safety and efficacy of emicizumab has been demonstrated in both adult and pediatric patients. It was approved by the United States (U.S.) Food and Drug Administration for routine prophylaxis to prevent or reduce bleeding episodes in individuals with HA, ages newborn and older, both with (2017) and without (2018) factor VIII (FVIII) inhibitors. Despite this approval, data on emicizumab in infants are limited. The HAVEN 2 pediatric clinical trial had only two infants under 24 months of age, though interim analysis of the HAVEN 7 trial demonstrated emicizumab efficacy and safety in infants. Thus, the optimal use of emicizumab in infants under 12 months of age remains unclear. The objective of this study was to understand the rationale and treatment decisions regarding initiation of emicizumab prophylaxis in children under 12 months of age among pediatric Hemophilia Treatment Center (HTC) Medical Directors in the U.S. Methods: An electronic survey was conducted from April to May 2023 of U.S. HTC Medical Directors via REDCap. Invitations were sent to all individuals listed as HTC Directors at pediatric medical centers on the Center for Disease Control and Prevention database. The survey included two hemophilia patient case scenarios associated with 15 multiple-choice questions and additional free-text options. The first case was of a 9-month-old male with severe HA, without prior bleeding history or exposure to FVIII, who presented for his initial visit to an HTC. The second case was a 3-month-old male with severe HA receiving FVIII replacement therapy for an intracranial hemorrhage. This study was approved by the Baylor College of Medicine Institutional Review Board. Results: Overall, 33 of 97 (34%) pediatric HTC Medical Directors participated in the survey. One survey was minimally completed and excluded for a total of 32 surveys included in the final analysis. The majority of participants had over 15 years of experience caring for patients with HA (n=21, 65.6%) and represented HTCs with over 250 patients (n=22, 68.8%; Table 1). For previously untreated or minimally treated infants (Case 1), 96.9% of responses (n=31) stated they would consider starting emicizumab prophylaxis; 45.2% (n=14) would consider initiating it as young as 1 week of age. The most common reason cited for starting emicizumab in an infant was to prevent an intracranial hemorrhage (n=17, 53.1%) followed by the desire to avoid central line placement (n=7, 21.9%). The majority of respondents did not wait for a minimum number of factor exposure days prior to starting emicizumab (n=31, 96.9%) nor did they report regularly exposing infants to FVIII concentrate until 50 EDs are reached (n=29, 90.6%). After the initial loading phase, the majority of respondents selected an emicizumab dosing regimen of every 2 weeks (n=19, 59.4%). There was a varied approach to monitoring for inhibitor development after starting emicizumab; 40.6% (n=13) reported monitoring at regular intervals between every 6 to 24 months, whereas 46.8% (n=15) did not report following a set schedule and instead obtain FVIII inhibitor testing only after FVIII exposure (Table 2). For infants receiving FVIII replacement for treatment of an intracranial hemorrhage (Case 2), 96.9% (n=31) of participants stated they would transition to emicizumab as a prophylactic agent. Over half (n=16, 51.6%) stated they would initiate emicizumab during the treatment period for the hemorrhage rather than waiting until therapy completion. For providers that use emicizumab in moderate hemophilia, emicizumab was reported to be used routinely by 27.3% (n=6) and on a case-by-case basis in 40.9% (n=9, Table 2) in infants with moderate HA. Conclusion: Pediatric HTC Medical Directors in the U.S. report commonly utilizing emicizumab in infants under 12 months of age despite the lack of robust data in this age group. This practice is consistent with recommendations by the National Hemophilia Foundation's Medical and Scientific Advisory Council. With the completion of clinical trials focused on infants with HA, along with additional long-term outcomes data, more specific guidance around initiation, follow-up and monitoring may be available to inform the optimal management for these patients.

Results from an Association-Scan of the Extended MHC-Class-II Region Using Novel Association-Based Statistical Methods Establish That DQ Allotypes and Race Independently Influence the Risk of Factor VIII Inhibitor Development in Hemophilia-A Patients

Hemophilia-A (HA) is caused by heterogeneous factor (F) VIII gene ( F8) mutations, variably deficient plasma FVIII activity and reduced to absent intrinsic-pathway amplification of coagulation. Infused therapeutic-FVIII-proteins (tFVIIIs) prevent bleeding in all HA patients but ~30% with severe HA and ~7.5% with non-severe HA become refractory with the development of neutralizing anti-tFVIII-antibodies called “FVIII inhibitors (FEIs)”. HLA-class-II (HLAII) molecules are critical for the development of FEIs and several association studies on different HA patient populations clearly implicate an important role for the highly polymorphic encoding HLA-D loci in the variable frequency of immunogenicity observed for tFVIIIs infused in different subjects with HA. However, the results from these studies were often conflicting, and none have undergone true independent confirmation. We use the ImmunoChip to genotype each subject in the PATH study simultaneously for the >900 single-nucleotide-variations (SNVs) distributed across the extended MHC-class-II (MHCII) region-which includes the classical- and non-classical-HLAII-genes and -pseudogenes-and then evaluated each independently for associations with FEI risk while accounting for the non-independence of data due to genetic relatedness and F8 mutational heterogeneity using novel statistical methods. The “lifetime-FEI-status” of the 438 North American HA patients in PATH-whose racial-identity/ethnic-ancestry was self-reported as either black-African (n=200) or white-European (n=238)-was the dependent variable of interest. The F8-mutation data and a genetic-relatedness matrix were incorporated into a binary linear mixed model of genetic association with lifetime-FEI-status (Yes vs. No), with ‘Yes’ designating those patients having FEIs of either any titer (AT), i.e., >0.4 Bethesda Units (BUs) mL -1, or only high-titer (HT), i.e., ≥5.0 BUs mL -1. Following the analytical procedure used in prior studies designed to identify determinants of FEI risk, we conducted the extended-MHCII-region-wide association screen-against the 926 distinct SNVs with high-quality genotypes that passed QC-of lifetime-FEI-status on two groups of FEI-positive patients, i.e., those with AT-FEIs, or those with only HT-FEIs. HA patients in the HT-FEI group are suspected to be more homogeneous with respect to the underlying immunobiology as they appear clinically to have induced full adaptive immunity. In contrast, HA patients in the AT-FEI group are heterogenous as some will have transient FEIs, which spontaneously disappear, and others will have FEIs that may remain low-titer (LT) despite continued infusions of tFVIIIs. We found several SNPs that were not only significantly associated in both FEI groups-or significant and suggestive respectively in the HT- and AT-groups-but also increased in significance (i.e., their p-values decreased) under the HT analysis ( Figure 1). The latter observation indicates that these results correspond to true associations that became more apparent as sources of “noise” were removed upon going from the AT to HT analysis. These included a SNP in the 3'-UTR of DQB1 (rs1049225, p-value=5.7E-7) and two intergenic HLAII region SNPs (rs2647012, p-value=1.1E-5; and rs2858324, p-value=1.1E-5). The DQB1 SNP reached an ImmunoChip-wide significance threshold in the HT analysis (i.e., a p-value <5.9E-7) and extended-MHCII-region-wide significance in the AT analysis (i.e., p-value <5.4E-5). Although the two HLAII-intergenic SNPs were not ImmunoChip-wide significant, they were significant across the MHCII region (i.e., p-value <5.4E-5). We found two SNPs that were significant and suggestive, respectively, in the HT- and AT-FEI analyses (rs9276189, p-value=1.3E-5; and rs2856717, p-value=3.3E-5), as well as one SNP that was significant in the HT-FEI analyses but not significant or suggestive in the AT analysis (rs9271366, p-value=1.9E-6). Our results establish that a novel DQB1 genetic variant is associated with FEI risk and confirm that HLA-DQ-allotypes and race independently influence the rate of FEI development in HA ( Figure 2).

Longitudinal Patient Analysis Suggests a Positive Correlation of IL-10/IL-6 and FVIII Inhibitor Amount

Hemophilia A (HA) is the most common X-linked bleeding disorder caused by a deficiency in coagulation factor VIII (FVIII). Inhibitor development in up to 30% of HA patients is the most challenging complication in HA treatment and has been associated with several patient-related risk factors such as gene mutation and residual plasma factor VIII concentrations. Treatment related risk factors are under debate. However, HCV infections were recently shown to correlate with low level inhibitor abundance, potentially as a result of chemokine and cytokine regulation. Therefore, the aim of this study was to evaluate a potential connection between proinflammatory cytokine levels and FVIII-specific B cell responses in HA patients without infections, but with other comorbidities that might modulate cytokine levels. Thus, several clinical parameters and concentrations of plasmatic proinflammatory cytokines (IL-1ß, IL-6, IL-8, IL-10, IL-12p70, TNF, IFNa, IFNg, TNFa, MCP-,1 IL-17A, IL-18, IL-23 and IL-33) were quantified from different patient samples. At first, the influence of proinflammatory cytokines on inhibitor development was assessed in a HA patient, who had an intron 22 inversion and was also diagnosed with type 1 diabetes. Prophylactic treatment began at the age of 9 months with 30IU/kg Octanate, and after four days of exposure, the formation of inhibitors was initially detected. Longitudinal cytokine analysis in plasma samples of that patient revealed differential regulation patterns of cytokines. IL-1b, IFNg, TNFa, IL-6, IL-10 and IL-12p70 tended to increase upon inhibitor occurrence, whereas other cytokines remained unchanged (MCP-1, IL-8, IL-17A, IL-18 and IL-23) or decreased (IFNa2 and IL-33). Next, a correlation analysis was performed, assuming that proinflammatory cytokines might stimulate B cells to produce antibodies. This analysis involved all cytokines that were found to be elevated upon inhibitor formation. The comparison of clinical and laboratory data from that patient revealed a strong association of inhibitor levels and IL-10 expression (Pearson r = 0,9391; R squared = 0,8818) as well as with IL-6 (Pearson r = 0,9290; R squared = 0,8630). Furthermore, a modest correlation was observed for IL-1b (Pearson r = 0,5277; R squared = 0,2785), IFNg (Pearson r = 0,3413; R squared = 0,1165), IL-12p70 (Pearson r = 0,3547; R squared = 0,1258), and TNFa (Pearson r = 0,3070; R squared = 0,09422). Other proinflammatory cytokines with a rather stable profile upon inhibitor initiation like MCP-1 (Pearson r = -0,06810; R squared = 0,004638) and IL-18 (Pearson r = 0,2245; R squared = 0,05042) seemed not to be directly correlated with inhibitor occurrence. Finally, we aim to investigate the potential impact of IL-10 and IL-6 on inhibitor production and/or FVIII immune tolerization across various patient groups and conditions. Therefore, we will compare patients with detectable inhibitor titers, those who have successfully eradicated inhibitors, and individuals without inhibitor titers (with normal recovery). Preliminary data suggest a positive correlation between both cytokines and active inhibitor presence. However, to reach a definitive conclusion, the sample size will be/should be increased.

Emicizumab Prophylaxis in Infants with Severe Hemophilia A without Factor VIII Inhibitors: Results from the Primary Analysis of the HAVEN 7 Study

Background: Due to challenges of factor (F)VIII administration, many infants with severe hemophilia A (HA) do not receive prophylaxis until ≥1 year of age. Emicizumab can be administered subcutaneously from HA diagnosis, which may reduce risk of spontaneous and traumatic bleeds, including intracranial hemorrhage. This primary analysis of HAVEN 7 (NCT04431726) evaluates the efficacy, safety, and pharmacokinetics (PK) of emicizumab in infants ≤12 months of age with severe HA without FVIII inhibitors. Methods: HAVEN 7 is a Phase IIIb, multi-center, open-label study. Informed consent from parents/caregivers and ethics approval have been obtained. Participants received subcutaneous emicizumab 3mg/kg weekly for 4 weeks, then every 2 weeks for 52 weeks; for the 7-year long-term follow-up, participants could continue on this dosing regimen or switch to either 1.5mg/kg weekly or 6mg/kg every 4 weeks. Efficacy endpoints include treated bleeds, all bleeds, treated spontaneous bleeds, and treated joint bleeds. Annualized bleed rates (ABRs) are estimated using a negative binomial regression model. Safety endpoints include adverse events (AEs), thromboembolic events (TEs), thrombotic microangiopathies (TMAs), and immunogenicity (anti-emicizumab antibodies [ADAs] incidence and de novo FVIII inhibitors development). PK endpoints include plasma trough emicizumab concentrations. Results: At the primary analysis clinical cut-off date (CCOD; May 22, 2023),55 participants had received emicizumab for ≥52 weeks (median [range] treatment duration: 100.3 [52-118] weeks); all were male, with median (range) age at enrollment of 4.0 months (9 days-11 months; 45.5% [n=25] <3 months; 54.5% [n=30] ≥3-≤12 months), and age at CCOD of 29.0 (12-39) months. Prior to the study, 30 (54.5%) were minimally treated (≤5 exposure days), and 25 (45.5%) were previously untreated participants (PUP). Model-based ABR (95% confidence interval [CI]) for treated bleeds was 0.4 (0.30-0.63), with 54.5% of participants (n=30) having zero treated bleeds ( Table 1). ABRs for all bleeds and treated joint bleeds were 2.0 (95% CI: 1.49-2.66) and 0.0 (0.01-0.09), respectively. No intracranial hemorrhage occurred. Overall, 207 bleeds (treated or untreated) were reported in 46 participants (83.6%), 87.9% traumatic ( Table 1). In total, 42 treated bleeds, all traumatic, were reported in 25 participants (45.5%). No participant had >3 treated bleeds. Thirty-seven participants (67.3%) had 0-3 bleeds, and 9 (16.4%) had no bleeds. Two participants had >10 bleeds, all untreated and none in joint/muscle: 27 bleeds in one participant (19 traumatic, 8 spontaneous), and 21 in the other (all traumatic). Emicizumab dose was up-titrated from 3mg/kg biweekly to weekly in one participant per investigator request based on decreasing emicizumab levels measured locally. The participant experienced three treated and two untreated bleeds (all traumatic) before and after up-titration, respectively. All 55 participants had ≥1 AE, and 9 (16.4%) had ≥1 emicizumab-related AE (all Grade 1 injection-site reaction). No AE led to treatment changes or withdrawal ( Table 2). Sixteen participants (29.1%) reported 30 serious AEs (SAEs), all considered serious due to hospitalization, none considered emicizumab-related. An anaphylactic reaction was reported in one participant (1.8%) following food allergy, not considered emicizumab-related. No deaths, TEs, or TMAs occurred. Evaluable PK data in 55 participants showed mean trough emicizumab concentrations increased during loading, with values of 62.0µg/mL (95% CI: 58.3-65.6) at Week 5. Thereafter, steady-state concentrations were sustained at 57-66µg/mL. Emicizumab concentrations were higher than those with the same dosing regimen in the HAVEN 2 and 3 studies (46-48µg/mL None of the 55 participants tested positive for ADAs at any timepoint (baseline, Week 5 or 12-weekly thereafter). One PUP was confirmed positive for FVIII inhibitors on Day 603 after three FVIII exposure days (traumatic bleeds treatment). At the CCOD, confirmatory titer was pending for another PUP testing positive for FVIII inhibitors on Day 428, after 10 FVIII exposure days (post tonsillectomy bleed management). Conclusions: This primary analysis of HAVEN 7 confirms that emicizumab is efficacious and well tolerated in infants with severe HA without FVIII inhibitors. PK profiles were similar to previous studies in adult populations.

Pharmacodynamic Biomarkers in Infants with Hemophilia A Receiving Emicizumab in HAVEN 7

Background: Emicizumab, a bispecific antibody that mimics the cofactor function of activated factor (F)VIII, demonstrated a favorable safety and efficacy profile in infants with severe hemophilia A (HA) without FVIII inhibitors in HAVEN 7 (NCT04431726; Pipe et al. Blood 2022, 140[S1]: 457-459). It is known that some coagulation factors including FIX and FX, the binding targets of emicizumab, have lower plasma levels during the first 6 months of life. This research investigates whether the developing coagulation system impacts the pharmacodynamics (PD) of emicizumab prophylaxis in infants with HA enrolled to HAVEN 7 from birth to ≤ 12 months of age. Methods: Informed consent from the parents/legally authorized representative and ethics approval were obtained. PD was assessed by activated partial thromboplastin time (aPTT), FVIII activity using a chromogenic assay containing human FIX and FX (considered FVIII-like activity), and by FXIa-triggered thrombin generation (TG) assay. Plasma antigen levels of FIX and FX were determined using immunoassays. Plasma samples from 110 healthy infants (HIs; n=42, 0-3 months old; n=68, >3-24 months old) collected separately were also measured to generate age matched reference ranges. Results: In HAVEN 7, PD biomarkers, and FIX and FX plasma levels were assessed in 55 participants during the first 52 weeks of emicizumab exposure (data cut-off May 22, 2023). At baseline, mean FVIII activity was <1 IU/dL, mean TG peak height was zero, and aPTT was prolonged as expected due to the deficiency of FVIII. By the first post-baseline visit (Week 3), aPTT was normalized to the age matched reference range in most participants and was then generally maintained in the normal range throughout the treatment period. Mean (SD) FVIII-like activity increased to 22.52 (6.05) U/dL at Week 5 after the four loading doses of emicizumab and was sustained at 21-26 U/dL thereafter. Mean (SD) TG peak height increased to 67.37 (27.21) nM at Week 5 and was sustained at 67-88 nM throughout the treatment period. Mean plasma FIX and FX concentrations were not affected by emicizumab treatment. The PD biomarkers, and FIX and FX plasma levels were also analyzed as a function of age group. The loading period (first 4 weeks) was excluded and only “steady state” measurements were considered for the PD markers. All measurements were considered for FIX and FX plasma levels. Mean (SD) FVIII-like activity of 18.14 (5.40) U/dL in the youngest participants (1-2 months old) increased to 23.57 (7.64) U/dL at 3-4 months old and was similar (23-28 U/dL) in the older age groups. Age did not have a significant impact on mean TG peak height. There was no age effect on aPTT. Mean (SD) plasma FIX and FX antigen concentrations were 4.40 (1.09) µg/mL and 6.24 (1.29) µg/mL in the <1 month old participants, increased progressively with age until about 9 months old, and then stayed around 9-10 µg/mL for both FIX and FX. Lower plasma levels of FIX and FX, as well as FVIII activity were also observed in the HIs ≤3 months vs. >3 months of age. There was no significant difference in TG between ≤ 3 months vs. >3 months of age in HIs. FVIII-like activity increased with increasing emicizumab concentrations in a linear fashion up to emicizumab concentrations of 100 µg/mL. Hence, the lower FVIII-like activity in the youngest participants could be partially explained by lower mean “steady state” trough emicizumab concentrations of 48.3 µg/mL at 1 month of age, which then increased to approx. 60 µg/mL at 4-5 months of age and older. TG peak height increased with increasing emicizumab concentrations but showed large variability. Lower FIX and FX plasma levels during the first 9 months of age may also have an impact on the PD results. Even though the levels were lower in the youngest participants, increases in FVIII-like activity and TG were seen at “steady state” emicizumab in all age groups as expected based on previous studies of emicizumab. The sample sizes were small in some of the age groups analyzed. Conclusions: FVIII-like activity and thrombin generation increased, and aPTT was normalized after starting emicizumab prophylaxis in HAVEN 7. Increase with age was seen on FVIII-like activity as well as FIX and FX levels. The PD profiles of emicizumab in infants with HA were consistent with those previously observed in older children and adults with HA. Hence, even with lower levels of FIX and FX observed at the youngest participants, emicizumab showed the expected PD response.

Transplacental Transfer of Emicizumab: Experience with Emicizumab in a Pregnant Female with Severe Hemophilia Α and an Inhibitor

Introduction: Severe hemophilia A (HA) in females is incredibly rare particularly if complicated by a high-titer factor VIII (FVIII) inhibitor. We report, to the best of our knowledge, the first-of-its-kind use of emicizumab (emi) ante/post-partum, its effect on the newborn, and its excretion in breast milk. Baseline details: 29-year-old-female was diagnosed with severe HA at age 1 following prolonged bleeding from a venipuncture site. She had no family history of HA. One stage FVIII activity (OSA) was less than 1%. She was compound heterozygous for F8 type 1 and type 2 intron 22 inversions. At 21 months of age, she developed a high-titer inhibitor (peak: 35 Bethesda unit[BU]). She was not treated with immune tolerance induction and had remained on factor eight inhibitor bypassing activity (FEIBA) as prophylaxis until transferring to our center. She was transitioned to monthly emi prophylaxis and recombinant FVIIa (rFVIIa, NovoSeven) for breakthrough bleeding at age 26. She was medically advised against pregnancy due to unclear safety profile of emi in pregnancy and theoretical concerns for an increased risk of bleeding and thrombotic complications associated with the use of bypassing agents in the peripartum setting. Nevertheless, she desired pregnancy and continued on emi prophylaxis every 4 weeks during her pregnancy. Clinical course in pregnancy: She had an uncomplicated antepartum course and did not require rFVIIa for breakthrough bleeds. Blood emi levels and FVIII inhibitor levels were measured in each trimester of pregnancy (Table 1). Her labor was induced with oxytocin while on rFVIIa and tranexamic acid (TXA) support. She had a spontaneous, unassisted vaginal delivery immediately complicated by post-partum hemorrhage resulting in estimated blood loss of 1100cc. She did not require blood transfusion. She continued on 90 mcg/kg rFVIIa support every 2 hours, gradually prolonging the dosing interval by 2 hours every 24 hours (q2, q4, q6, etc.), and experienced no further in-hospital bleeding. She delivered a healthy female newborn. The infant developed cephalhematoma but transcranial ultrasound was negative for intracranial bleeding. Cord blood was collected at the time of delivery and sent for emi level, FVIII activity and FVIII inhibitor titer (Table 2). FVIII inhibitor assay with bovine reagent (CBU) was performed using chromogenic substrate assay (CSA) after pre-analytical heat-inactivation of patient plasma. The infant's CSA FVIII level was measured using a bovine chromogenic FVIII assay, and FVIII was also assayed using a one-stage APTT-based assay. Mother opted to breast-feed the infant. Emi level was measured in breast milk (Table 1). Conclusion: In this highly unusual case, we demonstrate that emi crossed the placenta and is excreted in breast milk. We also demonstrate that the maternal FVIII inhibitor did not cross the placenta into the newborn. Drawing conclusions on the safety of emi despite placental and breast milk transmission and transmissibility of inhibitor based on a single case would be premature. The conglomeration of several rarities in a single case renders our report unique and insightful and provides a baseline experience for future cases.

Quality of Life in Emicizumab-Treated People with Hemophilia A in the ATHN 7 Hemophilia Natural History Study - an Assessment of Baseline PROMIS®-29 Scores

Background: People with hemophilia A (PwHA) experience frequent bleeding into joints, muscles and soft tissues due to a deficiency of factor (F)VIII, which has a substantial negative impact on their health-related quality of life (HRQoL). The American Thrombosis and Hemostasis Network (ATHN) ATHN 7 research study is: A Natural History Cohort Study of the Safety, Effectiveness, and Practice of Treatment for People with Hemophilia (NCT03619863). ATHN 7 prospectively monitors the use of hemophilia A (HA) and B therapies, including emicizumab. The aim of this abstract is to contribute to the literature on disease burden in PwHA. We describe baseline scores for a subset of adult PwHA enrolled in ATHN 7 who were receiving emicizumab and completed the Patient-Reported Outcomes Measurement Information System (PROMIS®) Profile-29 measure at the time of study entry. Methods: ATHN 7 is a longitudinal, prospective observational cohort study conducted at 26 ATHN-affiliated sites in the United States (US). Clinical and demographic information was collected at baseline. Participants completed patient-reported outcome measures, including PROMIS-29, at baseline. The PROMIS-29 Profile is a disease-agnostic measure capturing data across physical, mental, and social health domains: physical function, fatigue, sleep disturbance, pain intensity, pain interference, depressive symptoms, anxiety, and ability to participate in social roles/activities. PROMIS measures are scored using a standardized T-score metric with a reference population mean of 50 and a standard deviation (SD) of 10, based on the US general population. Higher scores indicate the participant is experiencing more of the concept being measured (positive or negative). No statistical comparisons were performed in this analysis. A mean standardized T-score of 0.5-1.0 SD worse than the reference population mean is defined as mild symptoms/impairment, 1.0-2.0 SD worse than the mean as moderate symptoms/impairment, and ≥2.0 SD worse than the mean as severe symptoms/impairment (HealthMeasures, 2023). Results: Overall, 67 participants in ATHN 7 receiving emicizumab at study entry completed PROMIS-29 at baseline ( Table 1). Participants had a median (min, max) age of 30.0 (18.0, 75.0) years. Disease severity at diagnosis was mild or moderate for 14 (20.9%) participants and severe for 53 (79.1%) participants. There were 12 (17.9%) PwHA with FVIII inhibitors. At time of study entry, participants had been receiving emicizumab for a median (min, max) of 126 (13.1, 254.0) weeks. Mean PROMIS-29 domain T-scores for the ability to participate in social roles and activities, and symptoms of anxiety, sleep disturbance, depression and fatigue at baseline all fell within 0.5 SD of the mean of the reference population ( Figure 1). PwHA in this analysis did however, demonstrate mild symptoms of pain interference (mean baseline T-score: 55.62; [normal: <55]). Mean baseline PROMIS-29 domain T-scores were also analyzed according to presence of FVIII inhibitors, disease severity, and age. PwHA with FVIII inhibitors had mild impairment of physical function (42.17 [normal: >45]) and mild symptoms of pain interference (58.64; [normal: <55]), while those without inhibitors had physical function (45.96; [normal: >45]) and pain interference (55.00; [normal <55]) within or on the boundary of 0.5 SD of the reference population. Similarly, people with severe HA without FVIII inhibitors had mild impairment of physical function (44.76; [normal >45]) and mild symptoms of pain interference (55.49; [normal: <55]), while people with mild/moderate HA without inhibitors had physical function (49.85; [normal: >45]) and pain interference (53.46; [normal: <55]) within 0.5 SD of the reference population. Physical function decreased with age, from 51.71 in the group aged ≤24 years (normal: >45) to 36.18 (moderate impairment) in the group aged ≥50 years, while pain interference increased with age, from 51.18 in the group aged ≤24 years (normal: <55) to 59.80 (moderate symptoms) in the group aged ≥50 years. Conclusions: In this analysis, we observed that HRQoL in PwHA receiving emicizumab, as measured by PROMIS-29 domain T-scores, generally did not differ from that of the US reference population. PwHA did report mild symptoms of pain interference. Results should be interpreted with caution given that no statistical tests were performed, and subgroup numbers are small.

Three-Year Interim Analysis Results of the AOZORA Study to Evaluate the Long-Term Safety and Joint Health in Children with Hemophilia A without Factor VIII Inhibitors Receiving Emicizumab

Background: Recurrent joint bleeding from a young age in people with hemophilia A (PwHA) may lead to hemophilic arthropathy, resulting in limited movement and chronic pain. Emicizumab is a bispecific monoclonal antibody that bridges activated factor (F) IX and FX to substitute for activated FVIII and provides stable plasma concentrations and maintenance of trough levels within the therapeutic range. Limitations in long-term joint health preservation have been reported with FVIII prophylaxis (Warren et al. Blood Adv 2020); it is expected that emicizumab may overcome these limitations, as joint health improvements have been demonstrated in PwHA aged 12-39 years (Kiialainen et al. Haemophilia 2022). Here, we report the 3-year interim analysis of the ongoing, open-label, Phase IV AOZORA study (JapicCTI-194701), analyzing long-term safety and joint health in pediatric PwHA without FVIII inhibitors receiving emicizumab (Shima et al. BMJ Open 2022). Methods: Eligible participants were aged <12 years with severe hemophilia A (HA) without FVIII inhibitors. Participants entered AOZORA as emicizumab-naïve or following the Phase III HOHOEMI study (Shima et al. Haemophilia 2019). Primary endpoints include adverse events (AEs), and joint health and function assessed by magnetic resonance imaging (MRI) and the Hemophilia Joint Health Score (HJHS) version 2.1. MRI evaluation uses the International Prophylaxis Study Group (IPSG) MRI scale; a positive IPSG score indicates pathological changes in the knee and/or ankle joints. Exploratory endpoints include annualized bleed rate (ABR) for treated bleeds and treated joint bleeds. All participants will receive emicizumab for 6 years from their first dose until study end. Results: Data cut-off was the last day of Week 145 for individual participants. Ten participants entered from HOHOEMI and 20 participants were newly enrolled. The median (range) age was 4.2 (0.7-11.1) years, all participants were male, and 27 (93.1%) participants had been treated with prior FVIII prophylaxis ( Table 1). One participant had 1 target joint (knee) at Week 1. In AOZORA, 5 (16.7%) participants experienced 7 emicizumab-related AEs: 6 injection site reactions in 5 participants and 1 case of anemia in 1 participant. Seven serious AEs, reported as unrelated to emicizumab, occurred in 5 (16.7%) participants. No thrombotic events or thrombotic microangiopathies occurred. Twenty-nine participants at Week 1 and 26 participants at Week 145 were assessed using the IPSG MRI scale. At Week 145, MRI scores remained at 0 for 11 (42.3%) of the 26 participants. Of 116 joints assessed at Week 1, 28 (24.1%) had soft tissue changes (effusion/hemarthrosis, synovial hypertrophy and/or hemosiderin deposition; Table 2). At Week 145, 104 joints were assessed and 33 (31.7%) of those had soft tissue changes. Of 10 (8.6%) joints with synovial hypertrophy and hemosiderin at Week 1, all had improved at Week 145 and synovial hypertrophy and hemosiderin were no longer present in 9 joints. One new joint developed synovial hypertrophy and hemosiderin at Week 145. The rest of the soft tissue changes were effusion/hemarthrosis, present in 21 (18.1%) joints at Week 1 and 31 (29.8%) at Week 145. Thirty participants at Week 1 and 27 participants at Week 145 were assessed using the HJHS v2.1. Eighteen (66.7%) participants' HJHS scores remained at 0 from Week 1 to Week 145 and 1 (3.7%) participant's remained at 4; 6 (22.2%) participants' scores improved; 2 (7.4%) participants' scores worsened. Mean (standard deviation) HJHS total score improved from 0.90 (1.79) at Week 1 to 0.44 (1.05) at Week 145. The mean (95% confidence interval [CI]) ABR for treated bleeds was 3.7 (0.94-9.80) prior to emicizumab and 0.7 (0.01-5.10) while receiving emicizumab. The mean (95% CI) ABR for treated joint bleeds was 0.4 (0.00-4.55) prior to emicizumab and 0.2 (0.00-4.04) while receiving emicizumab. Conclusions: This 3-year interim analysis of the AOZORA study confirmed the safety profile of emicizumab. The proportion of joints with effusion/hemarthrosis increased by Week 145. However, all joints with synovial hypertrophy and hemosiderin, which are strongly associated with the progression of arthropathy (Gualtierotti et al. J Thromb Haemost 2021), improved by Week 145. These results suggest that emicizumab is effective in maintaining and improving joint health in pediatric PwHA.

Gene-Centric Association Scans of Pleiotropic Immune-Mediated Disease Genes in the PATH Study Identify Novel Determinants of Factor VIII Inhibitor Risk in Hemophilia-A Patients and Confirm Race as an Independent Predictor

Hemophilia-A (HA) is caused by heterogeneous loss-of-function factor (F) VIII gene ( F8) mutations and deficiencies in plasma FVIII coagulant activity (FVIII:C) that impair intrinsic pathway coagulation amplification. The standard-of-care for severe HA patients is regular infusions of therapeutic FVIII proteins (tFVIIIs) but ~25-30% of all such subjects develop neutralizing anti-tFVIII-antibodies called “FVIII inhibitors (FEIs)” that leave them refractory to treatment and necessitate use of alternative therapies that are less safe and effective, and extremely expensive. We used the ImmunoChip genotyping platform and subjects in the Personalized Alternative Therapies for Hemophilia (PATH) study to scan immune-mediated disease (IMD) genes for novel and/or replicated genomic sequence variations associated with FEI risk while accounting for non-independence of data due to genetic relatedness and F8 mutational heterogeneity. The “enrollment-FEI-status” of 450 North American PATH study subjects-which include 446 that self-identified as being only either black-African (n=204) or white-European (n=242), and four that self-identified as being both white-European and either black-African (n=3) or Asian (n=1)-was the dependent variable. The F8 mutation data and a genetic relatedness matrix were incorporated into a binary linear mixed model of genetic association with the novel FEI outcome of enrollment-FEI-status based on whether or not FEIs of any titer (AT) developed-Yes (AT:FEIs+) versus No (AT:FEI-)-regardless of their “historical-FEI-status', i.e., whether or not they had ever developed FEIs of AT prior to study entry. We adopted a gene-centric association strategy to scan as ”candidates“ a subset of 101 genes-of the ~2,000 total immune system genes that are interrogated by the naturally occurring sequence variations able to be genotyped simultaneously on the ImmunoChip-which comprise what we refer to herein as ”pleiotropic-IMD-genes“ because they have been implicated previously in the development of either (i) two or more autoimmune diseases (n=80) or (ii) at least one autoimmune disease if they were also implicated in FEI risk previously (n=25). (Note that four of the pleiotropic-IMD-genes previously implicated in FEI risk were also in the 80 genes implicated previously in the development of multiple autoimmune diseases such that we scanned 101 distinct pleiotropic-IMD-genes for association with FEI development in the PATH study.) Enrollment-FEI-status was significantly associated with SNPs in NOS2A ( Figure 1) and B3GNT2 ( Figure 2), which are involved directly and indirectly, respectively, in anti-microbial-/-tumoral-immunity. Among the pleiotropic-IMD-genes previously implicated in FEI risk, we identified strong associations with SNPs in CTLA4 (p=2.2E-5). We also quantified the influence of the different F8 mutation types on FEI risk for the first time and demonstrated that the F8-mutation-effect underlies ~15% of the total heritability of FEI development. The additive genetic heritability together with the SNPs in the pleiotropic-IMD-genes were found to account for >50% of the patient-specific variability in FEI risk. Finally, race was shown to be a significant determinant of FEI risk independent of the effects of F8 mutation types and non- F8-genetics.

Effect of Factor VIII and Von Willebrand Factor Activities on Number of Bleeding Events in Previously Treated Patients with Von Willebrand Disease on Regular Prophylaxis with a Plasma-Derived Von Willebrand Factor/Factor VIII Concentrate

Background: von Willebrand disease (VWD) is characterized by a deficiency or reduction of activity in von Willebrand factor (VWF). As VWF has a role in stabilizing coagulation factor VIII (FVIII), VWD patients often suffer from secondary FVIII deficiency. Current guidelines recommend that VWD patients with a history of severe and frequent bleeds should use long-term prophylaxis with factor replacement therapy. The WIL-31 study demonstrated the efficacy of prophylaxis with a plasma-derived VWF/factor VIII concentrate containing VWF and FVIII in a 1:1 activity ratio (pdVWF/FVIII; wilate ®) in adults and children with VWD. The primary endpoint was met, showing a decrease of 84% in the mean total annualized bleeding rate (ABR). As elevated levels of FVIII are associated with an increased risk for thrombosis, it is important to determine whether repeated dosing with pdVWF/FVIII leads to accumulation of FVIII over time. Aims: To investigate the activity levels of VWF and FVIII in patients with VWD receiving regular prophylaxis with pdVWF/FVIII. Methods: WIL-31 (NCT04052698) was a prospective, non-controlled, international, multicenter phase 3 trial that enrolled male/female patients, aged ≥6 years old with VWD type 1 (VWF:RCo <30 IU/dL), type 2 (except 2N) or type 3. Prior to entering the WIL-31 study, all patients had received on-demand treatment with a pdVWF/FVIII concentrate during a 6-month, prospective, observational, run-in study (WIL-29). Patients in WIL-31 received regular pdVWF/FVIII prophylaxis 2-3 times per week at a dose of 20-40 IU/kg for 12 months. VWF activity (VWF:RCo) and FVIII activity (measured by the chromogenic [Chr] and one-stage [OS] assays) were performed at baseline and throughout the study. Full pharmacokinetic (PK) analyses were performed in all patients aged 6-16 years, a single dose of 60 ± 10 IU/kg pdVWF/FVIII was administered. Samples were collected at up to 1 hour prior to injection and then at multiple time points post-injection (1-72 hours). Safety, including the occurrence of thrombotic events, was monitored throughout the study. Results: The overall study population included 33 patients, with a median age of 18 years consisting of 9 (27.3%) patients aged 6-11 years, 6 (18.2%) patients aged 12-16 years, and 18 (54.5%) patients aged ≥17 years. Six (18.2%) patients had severe type 1 VWD, 5 (15.2%) patients had type 2, and 22 (66.7%) patients had type 3. Baseline FVIII and VWF activities in WIL-31 were similar regardless of age group, and as expected were lower in patients with type 3 VWD compared with severe type 1 and type 2 (Figure 1). There was a negative correlation of baseline FVIII and VWF activity with the number of spontaneous bleeding episodes (BEs) during prophylaxis. Patients who had no spontaneous BEs during prophylaxis had higher baseline FVIII and VWF levels compared with those who had spontaneous BEs. Mean peak and trough FVIII and VWF activity levels remained consistent during the study and there was no accumulation of either factor over the 12-month prophylaxis period (Figure 2). Full PK assessments were performed according to protocol in 13 patients aged 6-16 years. The mean ± standard deviation in vivo half-life was 16.1±6.7, 16.2±7.7, and 9.8±7.7 hours, for FVIII Chr, FVIII OS, and VWF:RCo, respectively. No thrombotic events were observed. Conclusion: No accumulation of FVIII or VWF in the plasma was reported in 33 patients who received regular prophylaxis with pdVWF/FVIII for 12 months, regardless of VWD type and age.

Real-World Experience of People with Hemophilia A Receiving Turoctocog Alfa Pegol (N8-GP): Results from a Patient Experience Survey.

Turoctocog alfa pegol (N8-GP) is an extended half-life recombinant factor VIII molecule used for the treatment of hemophilia A (HA). The purpose of this study was to investigate real-world experiences of patients with HA treated with N8-GP. A 25-minute online survey was completed by adults (≥18 years) and caregivers of adolescents (12-16 years) with HA receiving N8-GP across six countries (Germany, Italy, Portugal, Spain, UK and US). Patients were recruited using a multichannel approach through recruitment panels, referrals from healthcare professionals and patient associations. The survey comprised a questionnaire with metrics including satisfaction and preferences for N8-GP, quality of life (QoL) and long-term impact. A total of 62 participants (98% male [n=61], mean age 29 years) comprising 46 patients and 16 caregivers completed the survey. Patients (60% non-severe [n=37] and 40% severe [25]) were on N8-GP for a mean period of 1.4 years. Patients expressed satisfaction (95%vs 42%, p<0.001) and preference (91% vs 9%, p<0.001) for N8-GP vs their previous treatments. Most patients with severe HA (87%, p=0.038) and patients on prophylaxis (84%, p<0.001) stated lower frequency of injections as their main reason for satisfaction, while improved QoL drove satisfaction for non-severe patients (81%, p=0.053). Overall, patients perceived that QoL score improved (74.8 vs 65.9, p=0.01) with N8-GP treatment compared with previous treatments. Flexibility to store at room temperature was one of the key convenience factors driving satisfaction. Patients believed that N8-GP can offer a long-term impact in areas such as ability to perform day-to-day activities (68%), independence to live like a person without hemophilia (63%), ability to travel (60%) with a feeling of optimism and hopefulness (82%). Lower frequency of injections, storage flexibility and improved QoL drove satisfaction and preference for N8-GP over previous treatments among patients with HA.

Minimum factor VIII levels to prevent joint bleeding in mild hemophilia A

AbstractThe severity of the bleeding phenotype in patients with hemophilia A (HA) broadly correlates with the degree of coagulation factor VIII (FVIII) deficiency in plasma. However, the FVIII level necessary to achieve the goal of zero joint bleeds remains unclear. This study aimed to identify the minimum FVIII level necessary to prevent joint bleeds in patients with HA. In this retrospective study, patients with congenital mild HA treated on demand, aged ≥16 years, with no history of FVIII inhibitors, followed at the Angelo Bianchi Bonomi Hemophilia and Thrombosis Center in Milan, were enrolled. We investigated 270 male patients with a median age of 45 years (16-88) and median lifelong FVIII of 21 IU/dL. One hundred patients (37%) had a lifelong history of at least 1 joint bleed. The mean annualized joint bleeding rate (AJBR) and spontaneous AJBR were 0.016 (standard deviation [SD], 0.032) and 0.001 (SD, 0.010), respectively. After adjusting for age, for each IU/dL increase in FVIII, there was a 6% reduction in AJBR and an 11% reduction in spontaneous AJBR. The minimum FVIII levels needed to prevent lifelong any joint bleeds and spontaneous joint bleeds resulted to be 19.2 IU/dL and 17.7 IU/dL, respectively. In this large cohort of persons with mild HA, we identified the minimum FVIII levels needed to prevent total and spontaneous joint bleeds (19.2 IU/dL and 17.7 IU/dL, respectively). These findings could suggest important implications for the accurate design of prophylactic therapies for persons with moderate and severe HA, including gene therapy.