Changes in coagulation potential over time after administration of recombinant activated factor VII in an emicizumab-treated hemophilia A patient with inhibitors.

We describe a 67-year-old patient with hemophilia A and inhibitors (PwHA-I) receiving emicizumab prophylaxis who underwent surgical treatment for pseudoaneurysm. He was treated with a bolus infusion of recombinant factor VIIa (rFVIIa; 79 µg/kg) immediately before surgery, and a second dose of rFVIIa after an initial treatment on day 1. A third rFVIIa bolus was infused 17 h after the second dose on day 2, and the treatment was continued every 24 h on day 3 and day 4. Treatment with rFVIIa was discontinued on day 4. No perioperative bleeding or thrombotic events were observed. Coagulation potentials at 8 h after rFVIIa administration determined by clot waveform analysis (CWA) and thrombin generation assay (TGA) were within near-normal ranges, and results at 17 h after rFVIIa administration showed coagulation function comparable to that in the patient without rFVIIa. Our experimental data suggest that the coagulation potential in FVIII-deficient plasma spiked with both 0.28 µg/mL (11.2 µg/kg) rFVIIa and emicizumab was equivalent to or greater than that spiked with 2.2 µg/mL (90 µg/kg) rFVIIa alone. Thus, administration of rFVIIa every 8 h may be feasible for managing perioperative treatment in emicizumab-treated PwHA-I.

Evaluating clinically translatable conditioning for platelet gene therapy in murine hemophilia A with inhibitors.

BACKGROUND: Platelet gene therapy is effective in hemophilia A (HA) mice even with inhibitors. Fludarabine (Flu), along with busulfan (Bu) or melphalan (Mel), preconditioning has been shown to be highly effective for hematopoietic stem cell transplantation in the clinic. OBJECTIVES: To evaluate the efficacy of Bu-Flu and Mel-Flu preconditioning in platelet gene therapy of HA with inhibitors. METHODS: Bu-Flu and Mel-Flu were used to condition HA mice preimmunized with recombinant human factor (F)VIII. An optimal 660 centigray total body irradiation was used as a control regimen in parallel. Platelet-FVIII expression was introduced by transplantation of 2bF8 lentivirus (LV)-transduced hematopoietic stem cells. Animals were analyzed by fluorescence-activated cell sorting, quantitative polymerase chain reaction, FVIII assays, and tail bleeding tests. RESULTS: Bu-Flu, but not Mel-Flu, enabled successful 2bF8 gene therapy. All recipients achieved >55% chimerism post hematopoietic stem cell transplantation in both Bu-Flu and 660 centigray groups, with comparable copy numbers of 2bF8 cassette and the platelet-FVIII levels. The bleeding phenotype was rescued in 2bF8LV-transduced recipients. FVIII inhibitor titers declined with time, with comparable disappearance time of inhibitors between the 2 groups. When animals were rechallenged with recombinant human FVIII after the titers dropped to undetectable levels, no inhibitors were detected in 2bF8LV-transduced recipients. In contrast, all untransduced transplanted control mice produced inhibitors. These data demonstrate that immune tolerance was established in 2bF8LV-transduced primed HA mice under Bu-Flu conditioning. CONCLUSION: Bu-Flu preconditioning allows for successfully introducing platelet-FVIII expression to restore hemostasis and induce immune tolerance in primed HA mice, suggesting that this approach is a promising clinically translatable strategy for gene therapy of HA with inhibitors.

Ultra-Long factor VIII: a major step forward toward a hemophilia-free mind.

A remarkable step forward in the treatment of hemophilia A has recently been achieved with the development of an Ultra-Long modified factor (F)VIII. Leveraging expertise gained with fusion to immunoglobulin Fc fragments, disconnecting FVIII from endogenous von Willebrand factor (via a D'-D3 fragment), and benefiting from the pharmacokinetic prolongation provided by the addition of hydrophilic polypeptides, efanesoctocog alfa opens a new era in the treatment of hemophilia A. The term Ultra-Long FVIII has been proposed to designate it and differentiate it from extended half-life FVIII. The level of FVIII correction within the normal range for several days provided by this molecule should allow an increasing number of patients to free themselves from the physical and psychological constraints of hemophilia A. Certainly, the burden of weekly intravenous infusions persists but is compensated by a correction of hemostasis whose amplitude and duration remain unmatched by other therapeutic options currently available.

Three-year outcomes of valoctocogene roxaparvovec gene therapy for hemophilia A.

BACKGROUND: Valoctocogene roxaparvovec transfers a human factor (F)VIII coding sequence into hepatocytes of people with severe hemophilia A to provide bleeding protection. OBJECTIVES: To present 3-year efficacy and safety in the multicenter, open-label, single-arm, phase 3 GENEr8-1 trial. METHODS: GENEr8-1 enrolled 134 adult males with severe hemophilia A who were receiving FVIII prophylaxis. Efficacy endpoints included annualized bleeding rate, annualized FVIII utilization, FVIII activity (chromogenic substrate assay; imputed as 1 IU/dL at baseline and 0 IU/dL after discontinuation), and the Haemophilia-Specific Quality of Life Questionnaire for Adults. Safety was assessed by adverse events (AEs). RESULTS: At week 156, 131 of 134 participants remained in the study; overall, 17 of 134 resumed prophylaxis. Mean annualized bleeding rate for treated bleeds decreased from 4.8 (SD, 6.5) bleeds/y at baseline to 0.8 (SD, 2.3; P < .0001) bleeds/y after prophylaxis (prophylaxis cessation to last follow-up) and 0.97 (SD, 3.48) bleeds/y during year 3. Annualized FVIII utilization decreased 96.8% from baseline after prophylaxis and 94.2% during year 3. At week 156, mean and median FVIII activity were 18.4 (SD, 30.8) and 8.3 IU/dL, respectively. FVIII activity decrease was lower between years 2 and 3 than between years 1 and 2. At the end of year 3, clinically meaningful improvements in the Haemophilia-Specific Quality of Life Questionnaire for Adults Total Score were observed (mean change from baseline, 6.6; 95% CI, 4.24-8.87; P < .0001). Mild alanine aminotransferase elevations remained the most common AE during year 3 (23.7% of participants). A serious AE of B-cell acute lymphoblastic leukemia was considered unrelated to treatment. CONCLUSION: Hemostatic efficacy was maintained, and safety remained unchanged from previous years.

Endothelial specific isoform of type XVIII collagen (COL-18N): A marker of vascular integrity in haemophilic arthropathy.

BACKGROUND: Haemophilic arthropathy (HA) is a major complication in haemophilia. Collagens IV, XV and XVIII are responsible for maintaining the integrity of the vessel wall in the joint. Following joint remodelling and damage, the short isoform of collagen type XVIII (COL-18N) is degraded, releasing measurable fragments. Our goal was to quantify the specific isoform COL-18N in haemophilia A patients and to assess its relation to the clinical and radiological data as well as haemophilia joint health score (HJHS), functional independence score for haemophilia (FISH), and haemophilia quality of life (Haemo-Qol). METHODS: This cross-sectional study included 50 haemophilia A patients recruited from the Paediatric Haematology and Oncology unit, Ain Shams University, Cairo, Egypt. Quantification of COL-18N was done by ELISA. Assessment of joint state clinically using FISH and HJH scores and radiologically by X-rays and ultrasound. RESULTS: Haemophilia A patients had significantly higher median COL-18N levels compared to the control group. Inhibitor positive and negative haemophilia A patients as well as those on non-steroidal anti-inflammatory drug and those not had comparable COL-18N levels. Patients with ≥2 target joints had significantly higher COL-18N level compared to those with one or those without target joints. There were significant positive correlations between COL-18N level and the total HJHS, Haemo-Qol, the HEAD-US score and annual bleeding rate. CONCLUSION: Our results demonstrated a high level of COL-18N in haemophilia A patients and argued its benefit as a potential marker for monitoring the development of haemophilic arthropathy and tailoring the optimal treatment to prevent further joint damage.

Regression Analysis to Estimate the Factor VIII Activity of Patients with Hemophilia A Without Inhibitor who Received Emicizumab Therapy.

BACKGROUND: Emicizumab, a bispecific monoclonal antibody for hemophilia A (HA), has strong pharmacodynamic effects in several coagulation assays resulting in dosing difficulties with Factor VIII (FVIII) concentrates during bleeding emergencies. MATERIALS AND METHODS: Single and multiple regression models were studied to estimate FVIII activity using 27 archived plasma samples from three patients with HA without inhibitor under emicizumab treatment. Explanatory variables were FVIII chromogenic assay (CSA), Ad|min1|, Ad|min2|, the number of seconds of APTT, and the FVIII one-stage assay (OSA), which were measured without idiotype antibodies. The response variable was FVIII OSA measured with idiotype antibodies. RESULTS: In the simple linear model, the FVIII CSA regression coefficient was 1.04 and the intercept was -14.55 (r2 = 0.95; p < 0.001). In the multiple regression model, FVIII OSA and FVIII CSA were selected based on the Akaike Information Criterion, with regression coefficients of 1.74 and 1.15, respectively, and an intercept of -92.03 (r2 = 0.96, p < 0.001). CONCLUSIONS: The regression models can estimate the FVIII:C levels in patients with HA receiving emicizumab and would be useful in a bleeding emergency and/or surgery.

Can Hemophilia Impact on the Oral Health Conditions of Children and Adolescents? A Systematic Review and Metanalysis

Abstract Objective: To analyze if the oral health conditions in children and adolescents are associated with hemophilia (PROSPERO-42020168192). Material and Methods: The search strategy was performed in PubMed, Scopus, Lilacs/BBO, Web of Science, Cochrane, and Grey literature databases. Two independent researchers assessed the risk of bias in these studies by the Newcastle-Ottawa Scale. For the meta-analysis, the clinical conditions data were extracted as numerical variables according to their indexes, such as dental caries experience (dmft/DMFT), gingival condition (Modified Gingival Index - IGM), and oral hygiene (Plaque Index - PI). The quality of the evidence of the meta-analysis was evaluated by the GRADE tool (GRADEproGDT). Results: From a total of 431 studies, 27 were included, and 10 were included in the meta-analysis. The studies presented a moderate risk of bias, ranging from 2 to 7 points. The dental caries experience in primary (-0.62; CI95%: -1.68-0.43) and permanent dentitions (-0.05; CI95%: -0.69-0.59), gingival condition (-0.12; CI95%: -0.27-0.03), and oral hygiene (0.36; CI95%: -0.06-0.77) did not differ between the groups. Conclusion: Based on studies with very weak evidence, there were no differences in the oral health conditions of children and adolescents with and without hemophilia (AU).

Multiyear Factor VIII Expression after AAV Gene Transfer for Hemophilia A.

BACKGROUND: The goal of gene therapy for patients with hemophilia A is to safely impart long-term stable factor VIII expression that predictably ameliorates bleeding with the use of the lowest possible vector dose. METHODS: In this phase 1-2 trial, we infused an investigational adeno-associated viral (AAV) vector (SPK-8011) for hepatocyte expression of factor VIII in 18 men with hemophilia A. Four dose cohorts were enrolled; the lowest-dose cohort received a dose of 5 × 1011 vector genomes (vg) per kilogram of body weight, and the highest-dose cohort received 2 × 1012 vg per kilogram. Some participants received glucocorticoids within 52 weeks after vector administration either to prevent or to treat a presumed AAV capsid immune response. Trial objectives included evaluation of the safety and preliminary efficacy of SPK-8011 and of the expression and durability of factor VIII. RESULTS: The median safety observation period was 36.6 months (range, 5.5 to 50.3). A total of 33 treatment-related adverse events occurred in 8 participants; 17 events were vector-related, including 1 serious adverse event, and 16 were glucocorticoid-related. Two participants lost all factor VIII expression because of an anti-AAV capsid cellular immune response that was not sensitive to immune suppression. In the remaining 16 participants, factor VIII expression was maintained; 12 of these participants were followed for more than 2 years, and a one-stage factor VIII assay showed no apparent decrease in factor VIII activity over time (mean [±SD] factor VIII activity, 12.9±6.9% of the normal value at 26 to 52 weeks when the participants were not receiving glucocorticoids vs. 12.0±7.1% of the normal value at >52 weeks after vector administration; 95% confidence interval [CI], -2.4 to 0.6 for the difference between matched pairs). The participants had a 91.5% reduction (95% CI, 88.8 to 94.1) in the annualized bleeding rate (median rate, 8.5 events per year [range, 0 to 43.0] before vector administration vs. 0.3 events per year [range, 0 to 6.5] after vector administration). CONCLUSIONS: Sustained factor VIII expression in 16 of 18 participants who received SPK-8011 permitted discontinuation of prophylaxis and a reduction in bleeding episodes. No major safety concerns were reported. (Funded by Spark Therapeutics and the National Heart, Lung, and Blood Institute; ClinicalTrials.gov numbers, NCT03003533 and NCT03432520.).

Gene therapy for hemophilia: Current status and laboratory consequences.

Since the cloning and characterization of the factor VIII (FVIII) and factor IX genes in the mid-1980s, gene therapy has been perceived as having significant potential for the treatment of severe hemophilia. Now, some 35 years later, these proposals are close to being realized through the licensing of the first clinical gene therapy product. Adeno-associated viral vector-mediated gene therapy for hemophilia A and B has been extensively investigated in preclinical models over the past 20 years, and since 2011, there has been increasing evidence in early phase clinical trials that this therapeutic strategy can provide safe and effective rescue of the hemostatic phenotype in severe hemophilia. As the uptake of hemophilia gene therapy progresses, it is clear that many aspects of the gene therapy process require crucial laboratory support to ensure safe and effective outcomes from his new therapeutic paradigm. These laboratory contributions extend from evaluations of the gene therapy vehicle, assessments of the patient immune status for the vector, and ultimately the performance of assays to determine the hemostatic benefit of the gene therapy and potentially of its long-term safety on the host genome. As with many aspects of past hemophilia care, the safe and effective delivery of gene therapy will require an informed and coordinated contribution from laboratory science.

Variability of treatment modalities and intensity in patients with severe haemophilia A on prophylaxis: Results from the Italian national registry.

BACKGROUND: A shift from a standard to a personalized prophylaxis has been increasingly adopted in patients with severe haemophilia A (SHA). This approach has raised the likelihood of a significant variability in the prophylactic approaches and the relative Factor VIII (FVIII) consumptions. The aim of our study was to assess the treatment variability of SHA patients without inhibitors and on prophylaxis regimen in Italy. MATERIAL AND METHODS: Data reported in the National Registry of Congenital Coagulopathies (NRCC) were analysed to assess treatment distribution within SHA patients without inhibitors, focussing on FVIII consumption in 2017, associated with prophylaxis regimen. The analysis was stratified based on age groups and Italian regions to describe the variability of FVIII consumption in Italy. RESULTS: In 2017, the Registry reported the therapeutic plans of 1068 SHA patients without inhibitors on prophylaxis. The mean (95% CI) individual consumption ranges from 123 127 IU (99 736-146 518) in the age group 0-6 years to 345 000 IU (336 000-354 000) in the age group >20 years. A significant FVIII consumption variability was identified within the adult population. Regions with less than 50 patients reported the higher variability in mean FVIII consumption per patient-year within the different age groups. Similar difference in FVIII consumption variability was reported also in the age groups comparing "low," "middle" and "high" patient volume regions. DISCUSSION: A reliable estimation of FVIII consumption for patients' treatment is necessary to manage and plan the appropriate budget and keep treatment's costs affordable. However, without the implementation of a methodology aiming to assess the overall value produced by these FVIII consumptions, the scenario will keep driven by FVIII consumptions, its costs and the budget available. An effort by haemophilic community, haemophilia treatment centres and institutions is required to develop and share this cultural shift in improving haemophilia management and assessment.

Acquired hemophilia A associated with Epstein-Barr-virus-associated T/natural killer-cell lymphoproliferative disease: A case report.

INTRODUCTION: Acquired hemophilia A (AHA) is a rare bleeding disorder caused by autoantibodies against factor VIII (FVIII). Hematological malignancies, especially lymphoid malignancies, are known to be underlying causes of AHA; however, thus far, there is no report of AHA associated with Epstein-Barr-virus-associated T/natural killer-cell lymphoproliferative disease (EBV-T/NK-LPD). Here, we present a case of AHA that developed during treatment for EBV-T/NK-LPD. HISTORY: A 69-year-old man visited our hospital because of general fatigue. Blood examination showed pancytopenia, and computed tomography revealed whole-body lymphadenopathy, but there were no findings indicating hematological malignancy from bone marrow aspiration and cervical lymph node biopsy. The level of EBV DNA in peripheral blood was extremely high, and he was diagnosed with EBV-T/NK-LPD. EBV-T/NK-LPD improved with prednisolone (PSL) administration. Seventeen months after starting treatment, the patient complained of back and right leg pain. At that time, he had been treated with low-dose PSL, and EBV-T/NK-LPD was well controlled. Imaging revealed hematoma of the right iliopsoas muscle. Prolonged activated partial thromboplastin time (APTT) was the only abnormal finding in a screening coagulation test. FVIII coagulant activity was below detection limit, and FVIII inhibitor level was increased. From these results, he was diagnosed with AHA.A higher dose of PSL was administered, and, after 1 month of treatment, FVIII activity gradually increased, and FVIII inhibitor level became undetectable. APTT also normalized, and complete remission was achieved and maintained for 13 months with low-dose PSL. During treatment, EBV-T/NK-LPD was well controlled. CONCLUSION: It is speculated that proliferating lymphocytes interfere with normal immune functions and that abnormal autoantibodies are produced from those lymphocytes in patients with LPD. Therefore, we speculate that EBV-infected and proliferating monoclonal NK cells might have modulated the immune system and produced autoantibodies against FVIII, thus causing AHA in this patient with EBV-T/NK-LPD.

Development of a Specific Monoclonal Antibody to Detect Male Cells Expressing the RPS4Y1 Protein.

Hemophilia is an X-linked recessive bleeding disorder. In pregnant women carrier of hemophilia, the fetal sex can be determined by non-invasive analysis of fetal DNA circulating in the maternal blood. However, in case of a male fetus, conventional invasive procedures are required for the diagnosis of hemophilia. Fetal cells, circulating in the maternal bloodstream, are an ideal target for a safe non-invasive prenatal diagnosis. Nevertheless, the small number of cells and the lack of specific fetal markers have been the most limiting factors for their isolation. We aimed to develop monoclonal antibodies (mAbs) against the ribosomal protein RPS4Y1 expressed in male cells. By Western blotting, immunoprecipitation and immunofluorescence analyses performed on cell lysates from male human hepatoma (HepG2) and female human embryonic kidney (HEK293) we developed and characterized a specific monoclonal antibody against the native form of the male RPS4Y1 protein that can distinguish male from female cells. The availability of the RPS4Y1-targeting monoclonal antibody should facilitate the development of novel methods for the reliable isolation of male fetal cells from the maternal blood and their future use for non-invasive prenatal diagnosis of X-linked inherited disease such as hemophilia.

Clot waveform analysis for perioperative hemostatic monitoring of arthroscopic synovectomy in a pediatric patient with hemophilia A and inhibitor receiving emicizumab prophylaxis.

Emicizumab reduces bleeding in patients with hemophilia A and inhibitors (PwHA-I). Coagulation potential during the perioperative period in emicizumab-treated PwHA-I undergoing surgery remains to be evaluated. We describe a 14-year-old boy with HA-I receiving emicizumab prophylaxis who experienced arthroscopic synovectomy. He was treated with a bolus infusion of recombinant factor VIIa (rFVIIa; 80 µg/kg) immediately before surgery, and treatment continued at the same dose every 3 h on day 1, every 4 h on day 2, and every 6 h on day 3. Treatment with rFVIIa was discontinued on day 4. No perioperative bleeding or thrombotic events were observed. Coagulation potential throughout the perioperative period was retrospectively assessed with an easy-to-use clot waveform analysis (CWA). Measurements from CWA returned to within or near the normal range, suggesting successful hemostatic management. Coagulation potentials assessed by CWA showed a significant correspondence with those from a thrombin generation assay (TGA) that is already in use. CWA and TGA could both provide useful data for assessing coagulation potential in the perioperative hemostatic management of emicizumab-treated PwHA-I.

Effect of the First Factor VIII Infusions on Immunological Biomarkers in Previously Untreated Patients with Hemophilia A from the HEMFIL Study.

Hemophilia A (HA) is an inherited bleeding disorder which requires continuous replacement with factor (F) VIII concentrate. The main complication of HA is the development of neutralizing alloantibodies which inhibit FVIII activity (inhibitors). The objective of this study was to investigate the effect of the first FVIII infusions on immunological biomarkers in previously untreated patients with HA. Plasma samples were collected at enrollment before any FVIII infusion (T0) and at inhibitor development (INB +/T1) or up to 35 exposure days without inhibitors (INB -/T1). Anti-FVIII antibodies (immunoglobulin M, immunoglobulin G [IgG] 1, IgG3, and IgG4), chemokines (CCL2, CCL5, CXCL8, CXCL9, and CXCL10), and cytokines (interleukin [IL]-2, IL-4, IL-6, IL-10, interferon-γ, tumor necrosis factor, and IL-17) were assessed. A total of 71 children with severe HA were included, of whom 28 (39.4%) developed inhibitors. Plasma levels of anti-FVIII IgG4, IL-6, and CXCL8 were higher at INB +/T1 when compared with INB -/T1. This group presented a mixed cytokine profile and higher plasma levels of CXCL9 and CXL10 when compared with INB +/T1. We conclude that exposure to FVIII triggers a proinflammatory response mediated by IL-6 and CXCL8 in patients with HA who developed inhibitors. Regardless of inhibitor status, the immune system of all HA patients is stimulated after infusions of FVIII.

A Preconditioning Strategy to Augment Retention and Engraftment Rate of Donor Cells During Hepatocyte Transplantation.

BACKGROUND: Hepatocyte transplantation has been extensively investigated as an alternative to orthotopic liver transplantation. However, its application in routine clinical practice has been restricted because of low initial engraftment and subsequent repopulation. METHODS: Using mice as a model, we have developed a minimally invasive and nontoxic preconditioning strategy based on preadministration of antibodies against hepsin to increase donor hepatocyte retention and engraftment rate. RESULTS: Liver sinusoid diameters decreased significantly with antihepsin pretreatment, and graft cell numbers increased nearly 2-fold in the recipients' liver parenchyma for 20 days after hepatocyte transplantation. Postoperative complications such as hepatic ischemia injury or apparent immune cell accumulation were not observed in recipients. In a hemophilia B mouse model, antihepsin preconditioning enhanced the expression and clotting activity of coagulation factor IX (FIX) to nearly 2-fold that of immunoglobulin G-treated controls and maintained higher plasma FIX clotting activity relative to the prophylactic range for 50 days after hepatocyte transplantation. Antihepsin pretreatment combined with adeno-associated virus-transduced donor hepatocytes expressing human FIX-Triple, a hyperfunctional FIX variant, resulted in plasma FIX levels similar to those associated with mild hemophilia, which protected hemophilia B mice from major bleeding episodes for 50 days after transplantation. Furthermore, antihepsin pretreatment and repeated transplantation resulted in extending the therapeutic period by 30 days relative to the immunoglobulin G control. CONCLUSIONS: Thus, this antihepsin strategy improved the therapeutic effect of hepatocyte transplantation in mice with tremendous safety and minimal invasion. Taken together, we suggest that preconditioning with antihepsin may have clinical applications for liver cell therapy.

Treatment of acquired hemophilia A, a balancing act: results from a 27-year Dutch cohort study.

Acquired hemophilia A (AHA) is a severe auto-immune bleeding disorder. Treatment of AHA is burdensome and optimal management is still unresolved. Therefore a retrospective nationwide multi-center cohort study (1992-2018) was performed to evaluate clinical presentation and treatment efficacy and safety of AHA in the Netherlands. Multivariate logistic and Cox regression analysis was used to study independent associations between patient characteristics and clinical outcomes. A total of 143 patients (median age 73 years; 52.4% male) were included with a median follow-up of 16.8 months (IQR 3.6-41.5 months). First-line immunosuppressive treatment was mostly steroid monotherapy (67.6%), steroids/cyclophosphamide (11.9%) and steroids/rituximab (11.9%), with success rates of 35.2%, 80.0% and 66.7% respectively, P < .05. Eventually 75% of patients achieved complete remission (CR). A high anti-FVIII antibody titer, severe bleeding and steroid monotherapy were associated with lower CR rates. Infections, the most important adverse event, occurred significantly more often with steroid combination therapy compared to steroids alone (38.7% vs 10.6%; P = .001). Overall mortality was 38.2%, mostly due to infections (19.2%) compared to 7.7% fatal bleeds. Advanced age, underlying malignancy and ICU admission were predictors for mortality. This study showed that AHA is characterized by significant disease-related and treatment-related morbidity and mortality. A high anti-FVIII titer, severe bleeding and steroid monotherapy were associated with a lower CR rate. The efficacy of steroid combination therapies however, was overshadowed by higher infection rates and infections represented the most important cause of death. The challenging and delicate balance between treatment effectivity and safety requires ongoing monitoring of AHA and further identification of prognostic markers.

Bilateral renal haematuria and obstructive renal failure from acquired haemophilia A: a medical cause for a surgical problem.

A 55-year-old male presented to our emergency department with haematuria and abdominal pain. Investigations including a computed tomography (CT) scan revealed an intraluminal filling defect within the left collecting system, consistent in appearance with blood clot. With an initial working diagnosis of upper tract urothelial cell carcinoma, he was discharged with plans for an urgent cystoscopy and ureteroscopy. He subsequently represented with ongoing frank haematuria, anasarca, dropping haemoglobin and new right collecting system blood clot. Subsequent investigations showed that the patient had acquired haemophilia A resulting in the episodes of haematuria, highlighted after an elevated activated partial thromboplastic time prompted a thrombophilia screen. The patient was subsequently treated with factor eight inhibitor bypass activity, corticosteroids and cyclophosphamide.

Emicizumab-Induced Seronegative Full-House Lupus Nephritis in a Child.

Hemophilia A (HA) is a serious inherited bleeding disorder resulting from a deficiency of coagulation factor VIII (FVIII). Replacement therapy with intravenous infusion of FVIII can be associated with treatment failure in approximately one-third of patients secondary to the development of neutralizing alloantibodies (inhibitor). Emicizumab is a recombinant, humanized, bispecific monoclonal antibody that binds factor IXa and factor X and mimics FVIII. It has been licensed in many countries for the treatment of patients with HA with and without inhibitors with a favorable efficacy and safety profile. A 7-year-old child with severe HA and FVIII inhibitors, refractory to immune tolerance therapy, developed hematuria with nephrotic-range proteinuria after the first dose of emicizumab and subsequently also after a second dose 6 weeks later, which was associated with mild and transient leukopenia. Renal biopsy revealed a pattern of a full-house lupus nephritis. The patient fully and spontaneously recovered between 2 weeks after symptoms onset. In this report, we provide insights on a new and so far unreported renal complication associated to emicizumab treatment. Although emicizumab offers significant benefits for patient with HA, clinicians should be aware of this rare and potential serious renal adverse effect.

Activity of transgene-produced B-domain-deleted factor VIII in human plasma following AAV5 gene therapy.

Adeno-associated virus (AAV)-based gene therapies can restore endogenous factor VIII (FVIII) expression in hemophilia A (HA). AAV vectors typically use a B-domain-deleted FVIII transgene, such as human FVIII-SQ in valoctocogene roxaparvovec (AAV5-FVIII-SQ). Surprisingly, the activity of transgene-produced FVIII-SQ was between 1.3 and 2.0 times higher in one-stage clot (OS) assays than in chromogenic-substrate (CS) assays, whereas recombinant FVIII-SQ products had lower OS than CS activity. Transgene-produced and recombinant FVIII-SQ showed comparable specific activity (international units per milligram) in the CS assay, demonstrating that the diverging activities arise in the OS assay. Higher OS activity for transgene-produced FVIII-SQ was observed across various assay kits and clinical laboratories, suggesting that intrinsic molecular features are potential root causes. Further experiments in 2 participants showed that transgene-produced FVIII-SQ accelerated early factor Xa and thrombin formation, which may explain the higher OS activity based on a kinetic bias between OS and CS assay readout times. Despite the faster onset of coagulation, global thrombin levels were unaffected. A correlation with joint bleeds suggested that both OS and CS assay remained clinically meaningful to distinguish hemophilic from nonhemophilic FVIII activity levels. During clinical development, the CS activity was chosen as a surrogate end point to conservatively assess hemostatic efficacy and enable comparison with recombinant FVIII-SQ products. Relevant trials are registered on clinicaltrials.gov as #NCT02576795 and #NCT03370913 and, respectively, on EudraCT (European Union Drug Regulating Authorities Clinical Trials Database; https://eudract.ema.europa.eu) as #2014-003880-38 and #2017-003215-19.