Efanesoctocog Alfa Prophylaxis for Patients with Severe Hemophilia A.

BACKGROUND: Efanesoctocog alfa provides high sustained factor VIII activity by overcoming the von Willebrand factor-imposed half-life ceiling. The efficacy, safety, and pharmacokinetics of efanesoctocog alfa for prophylaxis and treatment of bleeding episodes in previously treated patients with severe hemophilia A are unclear. METHODS: We conducted a phase 3 study involving patients 12 years of age or older with severe hemophilia A. In group A, patients received once-weekly prophylaxis with efanesoctocog alfa (50 IU per kilogram of body weight) for 52 weeks. In group B, patients received on-demand treatment with efanesoctocog alfa for 26 weeks, followed by once-weekly prophylaxis with efanesoctocog alfa for 26 weeks. The primary end point was the mean annualized bleeding rate in group A; the key secondary end point was an intrapatient comparison of the annualized bleeding rate during prophylaxis in group A with the rate during prestudy factor VIII prophylaxis. Additional end points included treatment of bleeding episodes, safety, pharmacokinetics, and changes in physical health, pain, and joint health. RESULTS: In group A (133 patients), the median annualized bleeding rate was 0 (interquartile range, 0 to 1.04), and the estimated mean annualized bleeding rate was 0.71 (95% confidence interval [CI], 0.52 to 0.97). The mean annualized bleeding rate decreased from 2.96 (95% CI, 2.00 to 4.37) to 0.69 (95% CI, 0.43 to 1.11), a finding that showed superiority over prestudy factor VIII prophylaxis (P<0.001). A total of 26 patients were enrolled in group B. In the overall population, nearly all bleeding episodes (97%) resolved with one injection of efanesoctocog alfa. Weekly prophylaxis with efanesoctocog alfa provided mean factor VIII activity of more than 40 IU per deciliter for the majority of the week and of 15 IU per deciliter at day 7. Prophylaxis with efanesoctocog alfa for 52 weeks (group A) improved physical health (P<0.001), pain intensity (P = 0.03), and joint health (P = 0.01). In the overall study population, efanesoctocog alfa had an acceptable side-effect profile, and the development of inhibitors to factor VIII was not detected. CONCLUSIONS: In patients with severe hemophilia A, once-weekly efanesoctocog alfa provided superior bleeding prevention to prestudy prophylaxis, normal to near-normal factor VIII activity, and improvements in physical health, pain, and joint health. (Funded by Sanofi and Sobi; XTEND-1 ClinicalTrials.gov number, NCT04161495.).

Analyzing and modeling massive transfusion strategies and the role of fibrinogen-How much is the patient actually receiving?

BACKGROUND: Hemorrhage is a leading cause of preventable death in trauma, cardiac surgery, liver transplant, and childbirth. While emphasis on protocolization and ratio of blood product transfusion improves ability to treat hemorrhage rapidly, tools to facilitate understanding of the overall content of a specific transfusion strategy are lacking. Medical modeling can provide insights into where deficits in treatment could arise and key areas for clinical study. By using a transfusion model to gain insight into the aggregate content of massive transfusion protocols (MTPs), clinicians can optimize protocols and create opportunities for future studies of precision transfusion medicine in hemorrhage treatment. METHODS: The transfusion model describes the individual round and aggregate content provided by four rounds of MTP, illustrating that the total content of blood elements and coagulation factor changes over time, independent of the patient's condition. The configurable model calculates the aggregate hematocrit, platelet concentration, percent volume plasma, total grams and concentration of citrate, percent volume anticoagulant and additive solution, and concentration of clotting factors: fibrinogen, factor XIII, factor VIII, and von Willebrand factor, provided by the MTP strategy. RESULTS: Transfusion strategies based on a 1:1:1 or whole blood foundation provide between 13.7 and 17.2 L of blood products over four rounds. Content of strategies varies widely across all measurements based on base strategy and addition of concentrated sources of fibrinogen and other key clotting factors. DISCUSSION: Differences observed between modeled transfusion strategies provide key insights into potential opportunities to provide patients with precision transfusion strategy.

Primary prophylaxis implementation and long-term joint outcomes in Swedish haemophilia A patients.

INTRODUCTION: Primary prophylaxis is the gold standard in severe haemophilia A (SHA) but time to escalate the prophylaxis regimen varies. AIM: Assess prophylaxis implementation and long-term joint health outcomes in SHA with primary prophylaxis. METHODS: Adult male patients born after 1980, with SHA on primary prophylaxis, started before the age of 3 years and second joint bleed, and no history of FVIII inhibitors, were enrolled. Repeated joint-health examinations were performed with HJHS or HEAD-US; VERITAS-PRO assessed adherence. RESULTS: Thirty patients were enrolled with, at inclusion, median age 33.5 years, annualized bleed rate and joint bleed rate 0, and FVIII consumption 4232 IU/kg/year, respectively. The median age was 1.2 years, at prophylaxis start once weekly with a median FVIII dose of 47.7 IU/kg, and 1.7 years, by the time escalation to a final regimen had occurred, with a median infusion frequency of thrice weekly and FVIII dose 41.7 IU/kg, respectively. Older age correlated with later transition to escalated prophylaxis (p < .001). Longer time to escalated prophylaxis correlated to more bleeds (p < .001). Median HJHS increased slowly, reaching 4 at 35-40 years. HJHS at 15-20 years correlated with higher HJHS afterwards. Median total HEAD-US score was 1 and correlated with HJHS (p < .001). Median VERITAS-PRO score was 36, indicating good treatment adherence. CONCLUSION: Primary prophylaxis is effective but does not completely prevent the gradual development of arthropathy in SHA. Joint assessments with HJHS should start at an early age, as they correlate with arthropathy in later life. Prophylaxis escalation should proceed expeditiously to prevent bleeds.

von Willebrand disease: what does the future hold?

von Willebrand disease (VWD) is characterized by its heterogeneous clinical manifestation, which complicates its diagnosis and management. The clinical management of VWD has remained essentially unchanged over the last 30 years or so, using von Willebrand factor (VWF) concentrates, desmopressin, and anti-fibrinolytic agents as main tools to control bleeding. This is in contrast to hemophilia A, for which a continuous innovative path has led to novel treatment modalities. Despite current VWD management being considered effective, quality-of-life studies consistently reveal a higher than anticipated burden of VWD on patients, which is particularly true for women. Apparently, despite our perceived notion of current therapeutic efficiency, there is space for innovation with the goal of reaching superior efficacy. Developing innovative treatments for VWD is complex, especially given the heterogeneity of the disease and the multifunctional nature of VWF. In this perspective article, we describe several potential strategies that could provide the basis for future VWD treatments. These include genetic approaches, such as gene therapy using dual-vector adenoassociated virus and transcriptional silencing of mutant alleles. Furthermore, protein-based approaches to increase factor FVIII levels in VWD-type 3 or 2N patients are discussed. Finally, antibody-based options to interfere with VWF degradation (for congenital VWD-type 2A or acquired von Willebrand syndrome-type 2A) or increase endogenous VWF levels (for VWD-type 1) are presented. By highlighting these potential strategies, we hope to initiate an innovative path, which ultimately would allow us to better serve VWD patients and their specific needs.

Clinical phenotype, fibrinogen supplementation, and health-related quality of life in patients with afibrinogenemia.

Due to the low prevalence of afibrinogenemia, epidemiologic data on afibrinogenemia are limited, and no data are available on health-related quality of life (HRQoL). We conducted a cross-sectional international study to characterize the clinical features, the fibrinogen supplementation modalities, and their impact on HRQoL in patients with afibrinogenemia. A total of 204 patients (119 adults and 85 children) from 25 countries were included. The bleeding phenotype was severe: 68 (33.3%) patients having at least one bleed per month and 48 (23%) a history of cerebral bleeding. About 35% (n = 72) of patients were treated with fibrinogen concentrates or cryoprecipitates as prophylaxis, 18.1% (n = 37) received ≥1 injection per week, and 16.6% (n = 34) were on home treatment. A thrombotic event was reported in venous and/or arterial territories by 37 (18.1%) patients. Thrombosis occurred even in young patients, and recurrence was frequent (7.4%). The total HRQoL was lower in children than in adults. Discomfort linked to treatment and limitations to sports and leisure were the main concerns. Women and children were particularly affected in family relationships. In multivariate analyses, younger age, residence in Asia or Africa, and a previous thrombotic event were statistically correlated with a worse HRQoL. In summary, our study underlines the severe bleeding and thrombotic phenotype and their impact on HRQoL in afibrinogenemia. The optimal strategy for fibrinogen supplementation needs to be determined. This trial was registered at www.clinicaltrials.gov as #NCT03484065.

Recombinant VWF fragments improve bioavailability of subcutaneous factor VIII in hemophilia A mice.

Conventional treatment of hemophilia A (HA) requires repetitive IV injection of coagulation factor VIII (FVIII). Subcutaneous administration of FVIII is inefficient because of binding to the extravascular matrix, in particular to phospholipids (PLs), and subsequent proteolysis. To overcome this, recombinant dimeric fragments of von Willebrand factor (VWF) containing the FVIII-stabilizing D3 domain were engineered. Two fragments, called VWF-12 and VWF-13, demonstrated high binding affinity to recombinant human FVIII (rhFVIII) and suppressed PL binding in a dose-dependent manner. High concentrations of VWF fragments did not interfere with the functional properties of full-length VWF in vitro. The HA mouse model was used to study the effects of VWF-12 or VWF-13 on the in vivo pharmacokinetics of rhFVIII, demonstrating (1) no significant impact on rhFVIII recovery or half-life after a single IV administration; (2) enhanced bioavailability (up to 18.5%) of rhFVIII after subcutaneous administration; and (3) slow absorption (peak concentration, 6 hours) and prolonged half-life (up to 2.5-fold) of rhFVIII after subcutaneous administration. Formation of anti-FVIII antibodies was not increased after administration of rhFVIII/VWF-12 subcutaneously compared with rhFVIII IV. A single subcutaneous dose of rhFVIII/VWF-12 provided protection in the HA tail-bleeding model for up to 24 hours. In summary, recombinant VWF fragments support FVIII delivery through the subcutaneous space into vascular circulation without interfering with VWF or FVIII function. Slow resorption and excretion of FVIII after subcutaneous administration highlight the potential application of VWF fragments for subcutaneous FVIII prophylaxis in HA.

A hemophilia A mouse model for the in vivo assessment of emicizumab function.

The bispecific antibody emicizumab is increasingly used for hemophilia A treatment. However, its specificity for human factors IX and X (FIX and FX) has limited its in vivo functional analysis to primate models of acquired hemophilia. Here, we describe a novel mouse model that allows emicizumab function to be examined. Briefly, FVIII-deficient mice received IV emicizumab 24 hours before tail-clip bleeding was performed. A second infusion with human FIX and FX, administered 5 minutes before bleeding, generated consistent levels of emicizumab (0.7-19 mg/dL for 0.5-10 mg/kg doses) and of both FIX and FX (85 and 101 U/dL, respectively, after dosing at 100 U/kg). Plasma from these mice display FVIII-like activity in assays (diluted activated partial thromboplastin time and thrombin generation), similar to human samples containing emicizumab. Emicizumab doses of 1.5 mg/kg and higher significantly reduced blood loss in a tail-clip-bleeding model using FVIII-deficient mice. However, reduction was incomplete compared with mice treated with human FVIII concentrate, and no difference in efficacy between doses was observed. From this model, we deducted FVIII-like activity from emicizumab that corresponded to a dose of 4.5 U of FVIII per kilogram (ie, 9.0 U/dL). Interestingly, combined with a low FVIII dose (5 U/kg), emicizumab provided enough additive activity to allow complete bleeding arrest. This model could be useful for further in vivo analysis of emicizumab.

Plasma-derived FVIII/VWF complex shows higher protection against inhibitors than isolated FVIII after infusion in haemophilic patients: A translational study.

INTRODUCTION: Presence of von Willebrand factor (VWF) in FVIII concentrates offers protection against neutralizing inhibitors in haemophilia A (HA). Whether this protection is more evident in plasma-derived (pd) FVIII/VWF or recombinant (r) FVIII concentrates remains controversial. AIM: We investigated the protection exerted by VWF against FVIII inhibitors in an in vivo mouse model of HA exposed to pdFVIII/VWF or to various rFVIII concentrates. METHODS: Haemophilia A mice received the different FVIII concentrates after administration of vehicle or an inhibitory IgG purified from a commercial pool of HA plasma with inhibitors and FVIII:C recoveries were measured. Furthermore, using a novel clinically oriented ex vivo approach, Bethesda inhibitory activities (BU) of a commercial pool of HA plasma with inhibitors were assessed using normal plasma, or plasma from severe HA patients, without inhibitors, after treatment with the same concentrates. RESULTS: in vivo studies showed that pdFVIII/VWF offers markedly higher protection against inhibitors when compared with any of the FVIII products without VWF. More importantly, in the ex vivo studies, plasma from patients treated with pdFVIII/VWF showed higher protection against inhibitors (P values ranging .05-.001) in comparison with that observed in plasma from patients who received FVIII products without VWF, regardless of the type of product evaluated. CONCLUSION: Data indicate that FVIII+VWF complexes assembled in the circulation after rFVIII infusion are not equivalent to the naturally formed complex in pdFVIII/VWF. Therefore, rFVIII infused into HA patients with inhibitors would be less protected by VWF than the FVIII in pdFVIII/VWF concentrates.

Effectiveness of long-term prophylaxis using pdFVIII/VWF concentrate in patients with inherited von Willebrand disease.

BACKGROUND: Patients with symptomatic von Willebrand disease (VWD) should be offered long-term prophylaxis (LTP) to prevent recurrent bleedings. Our objective was to evaluate the effectiveness and safety of Voncento®, a plasma-derived FVIII/VWF concentrate (ratio 1:2.4), administrated in LTP. METHODS: We included patients from the OPALE study (May 2016 to April 2021), a French multicenter observational study following patients with inherited VWD, who received a Voncento® LTP during the study period. RESULTS: Among the 130 OPALE-study patients, 23 patients (12 women) received a LTP and were therefore included. The median (range) age was 16 (1-85) years; 16 patients were type 3, 1 was type 2A, 6 were type 2B. Before inclusion, 19 (83%) were under LTP and 4 (17%) received on-demand (OD) treatment. The indications for initiating prophylaxis in the overall population were joint bleeding (43%), ear, nose, and throat (ENT) bleeding including epistaxis or oral bleeding (39%), and recurrent muscle hematoma (22%). The medians (ranges) dose of Voncento® per infusion, frequency, and weekly dose were 45 (33-109) IU/kg, 2 infusions per week, and 96 (44-222) IU/kg/week, respectively. The median (range) annualized bleeding rate (ABR) was 0.8, 0.7 (0-3.5), and 0 (0-2.3) for type 2A, 2B, 3 patients, respectively. There was no difference regarding to the dose, frequency of infusion, or in terms of ABR in 9/19 patients who replaced previous concentrates with Voncento®. During the study period, no adverse event was reported. CONCLUSION: These results suggest that Voncento® is effective to prevent recurrent bleedings in patients symptomatic VWD.

In Vitro Comparison of Recombinant and Plasma-Derived von Willebrand Factor Concentrate for Treatment of Acquired von Willebrand Syndrome in Adult Extracorporeal Membrane Oxygenation Patients.

BACKGROUND: Coagulopathic bleeding is common during adult extracorporeal membrane oxygenation (ECMO), and acquired von Willebrand syndrome is a contributing factor. We compared ECMO patient blood samples that were treated in vitro with recombinant von Willebrand Factor concentrate and plasma-derived von Willebrand Factor concentrate. Our hypothesis was that recombinant von Willebrand Factor (vWF) would have greater efficacy in increasing vWF function. Secondarily, we hypothesized that recombinant vWF would have less impact on thrombin generation. METHODS: Thirty ECMO patients and 10 cardiac surgical controls were enrolled in the study. ECMO patient blood samples were treated in vitro with low- and high-dose recombinant vWFs and low- and high-dose plasma-derived vWFs. Whole blood ristocetin-induced platelet aggregation (RIPA), plasma ristocetin cofactor activity (RCo), and thrombin generation were compared between ECMO patient blood samples and control blood samples and between vWF-treated ECMO patient blood samples and nontreated samples. RESULTS: ECMO patient blood samples had severely reduced median RIPA compared to control samples 2 ohms (1-12 [25th-75th percentile]) vs 20 ohms (11-42) (P < .001). Treatment of ECMO patient blood samples with high-dose recombinant vWF significantly increased median RIPA to 10 ohms (2-15) (P < .001), while low-dose recombinant vWF and low- and high-dose plasma-derived vWFs did not significantly increase RIPA; 6 ohms (3-14), 4 ohms (1-13), and 6 ohms (2-10), respectively (P = .25, >.99, and >.99). Treatment with high-dose recombinant vWF and low- and high-dose plasma-derived vWFs significantly increased median plasma RCo to 4.7 international units (IU)/mL (3.7-5.9), 3.3 IU/mL (2.7-4.8), and 3.9 IU/mL (3.4-5.3), respectively, compared to controls 1.8 IU/mL (1.5-2.3) (all P < .001). Treatment with low- and high-dose plasma-derived vWFs significantly increased mean endogenous thrombin potential (6270.2 ± 2038.7 and 6313.1 ± 1913.3) compared to nontreated samples (5856.7 ± 1924.6) (P = .04 and .006), whereas treatment with low- and high-dose recombinant vWFs had no significant effect on mean endogenous thrombin potential (5776.1 ± 2087.3 and 5856.2 ± 1946.4) (P > .99 for both comparisons). CONCLUSIONS: In vitro treatment of ECMO patient blood samples with high-dose recombinant vWF was superior to low-dose recombinant vWF and plasma-derived vWF in terms of improving RIPA. In addition, recombinant vWF treatment did not increase endogenous thrombin potential, which may reduce overall thrombotic risk if it used to treat acquired von Willebrand syndrome in ECMO patients.

Early cryoprecipitate transfusion versus standard care in severe postpartum haemorrhage: a pilot cluster-randomised trial.

There is a lack of evidence evaluating cryoprecipitate transfusion in severe postpartum haemorrhage. We performed a pilot cluster-randomised controlled trial to evaluate the feasibility of a trial on early cryoprecipitate delivery in severe postpartum haemorrhage. Pregnant women (>24 weeks gestation), actively bleeding within 24 h of delivery and who required at least one unit of red blood cells were eligible. Women declining transfusion in advance or with inherited clotting deficiencies were not eligible. Four UK hospitals were randomly allocated to deliver either the intervention (administration of two pools of cryoprecipitate within 90 min of first red blood cell unit requested plus standard care), or the control group treatment (standard care, where cryoprecipitate is administered later or not at all). The primary outcome was the proportion of women who received early cryoprecipitate (intervention) vs. standard care (control). Secondary outcomes included consent rates, acceptability of the intervention, safety outcomes and preliminary clinical outcome data to inform a definitive trial. Between March 2019 and January 2020, 199 participants were recruited; 19 refused consent, leaving 180 for analysis (110 in the intervention and 70 in the control group). Adherence to assigned treatment was 32% (95%CI 23-41%) in the intervention group vs. 81% (95%CI 70-90%) in the control group. The proportion of women receiving cryoprecipitate at any time-point was higher in the intervention (60%) vs. control (31%) groups; the former had fewer red blood cell transfusions at 24 h (mean difference -0.6 units, 95%CI -1.2 to 0); overall surgical procedures (odds ratio 0.6, 95%CI 0.3-1.1); and intensive care admissions (odds ratio 0.4, 95%CI 0.1-1.1). There was no increase in serious adverse or thrombotic events in the intervention group. Staff interviews showed that lack of awareness and uncertainty about study responsibilities contributed to lower adherence in the intervention group. We conclude that a full-scale trial may be feasible, provided that protocol revisions are put in place to establish clear lines of communication for ordering early cryoprecipitate in order to improve adherence. Preliminary clinical outcomes associated with cryoprecipitate administration are encouraging and merit further investigation.

Hepatitis E virus: Efficacy of pasteurization of plasma-derived VWF/FVIII concentrate determined by pig bioassay.

BACKGROUND: Hepatitis E virus (HEV) is the leading cause of acute hepatitis throughout the world. Increasing blood component transfusion-associated HEV infections highlight the need for reliable virus inactivation procedures for plasma derivatives from pooled plasma donations. STUDY DESIGN AND METHODS: An animal infection study was conducted to evaluate the efficiency of HEV inactivation by pasteurization during the manufacturing process of the von Willebrand Factor/Factor VIII (VWF/FVIII) concentrate Haemate P/Humate-P (CSL Behring, Marburg, Germany). For this purpose, groups of pigs were inoculated with stabilized VWF/FVIII intermediate spiked with HEV-positive liver homogenate and exposed to increasing incubation times of 0, 3, 6, and 10 h at 60°C. Animals were evaluated for virus replication over 27 days and in a subsequent trial over 92 days. RESULTS: Virus replication was detected in animals up to the 6-h pasteurization group. In contrast, pasteurization for 10 h did not reveal virus detection when the observation period was 27 days. In an additional experiment using the 10-h pasteurized material, two individuals started virus excretion and seroconverted when the observation period was extended to 92 days. Based on the total infection rate (2 of 12) of the animals inoculated with the sample pasteurized for 10 h, a virus reduction factor of at least 4.7 log10 is calculated. CONCLUSION: This study demonstrates that pasteurization at 60°C for 10 h of an HEV-positive plasma derivative leads to the effective reduction of infectivity, resulting in a VWF/FVIII product with an appropriate margin of safety for HEV.

A Unique Case of Acquired Hemophilia A Presenting with Transient Ischemic Attack.

Acquired hemophilia A (AHA) is a rare but serious condition, usually associated with significant spontaneous or traumatic bleeding and a high mortality rate. In this report, we describe the case of an elderly patient presenting a transient ischemic attack concurrently with AHA. A thrombotic event in AHA is occasionally associated with the use of bypassing agents for treatment, but a spontaneous thrombotic event has not ever been described.

First observation of inhibitor development against efmoroctocog alfa in France.

In patients with severe haemophilia receiving clotting factor concentrates, the risk of immunisation against their usual treatment is still patent and feared. New haemophilia drug treatments with an extended half-life have become available over the past few years. The risk of inhibitor development to these new treatments is unclear. We report the case of a 51-year-old man with severe haemophilia A, who was previously treated with no history of inhibitor development. Soon after a switch in his treatment to efmoroctocog alfa he developed an inhibitor against this recombinant Fc fusion extended half-life FVIII (rFc-FVIII) product. The patient was on an on-demand treatment regimen and was treated for mucosal bleeding. The inhibitor was characterised as type I, with classical epitope mapping. The spontaneous evolution of this inhibitor was favourable, but an anamnestic response led to a switch in his treatment to emicizumab.

Pro-Con Debate: Fibrinogen Concentrate or Cryoprecipitate for Treatment of Acquired Hypofibrinogenemia in Cardiac Surgical Patients.

Cryoprecipitate has been the gold standard for treating acquired hypofibrinogenemia in cardiac surgery for nearly 50 years. More recently, fibrinogen concentrate has been used off-label in the United States and is the standard in European countries and Canada to treat the acquired hypofibrinogenemia during cardiac surgery. Fibrinogen concentrate has multiple potential advantages including rapid reconstitution, greater dose predictability, viral inactivation during processing, and reduced transfusion-related adverse events. However, because fibrinogen concentrate lacks the other components contained in the cryoprecipitate, it may not be the "ideal" product for replacing fibrinogen in all cardiac surgical patients, particularly those with longer cardiopulmonary bypass duration. In this Pro-Con commentary article, we discuss the advantages and disadvantages of using fibrinogen concentrate and cryoprecipitate to treat acquired hypofibrinogenemia in cardiac surgical patients.

Successful intraosseous factor VIII application in a haemophilic emergency.

WHAT IS KNOWN AND OBJECTIVES: Intravenous (IV) replacement therapy with plasma derived or recombinant factor VIII (FVIII) and factor IX concentrates is the mainstay for treatment of patients with haemophilia A and B. Therefore, the current therapy is particularly dependent on the presence of a secure IV access especially in case of emergency. CASE DESCRIPTION: A life-threatening bleeding event in an 8-month-old boy is managed by intraosseous (IO) infusion of recombinant FVIII concentrate. No adverse events have been observed 6 months after the application, and complete heeling has been reported. WHAT IS NEW AND CONCLUSION: Venous application of factor concentrate remains inevitable in any haemophilic emergency. In case IV access is lacking, an IO institution of factor might be considered. To our knowledge, this represents the first reported case of IO application of recombinant FVIII concentrate in a patient with haemophilia.

Product type and the risk of inhibitor development in nonsevere haemophilia A patients: a case-control study.

Inhibitor development is a major complication of treatment with factor VIII concentrates in nonsevere haemophilia A. It has been suggested that plasma-derived factor VIII (FVIII) concentrates elicit fewer inhibitors than recombinant FVIII concentrates, but studies in severe haemophilia A patients have shown conflicting results. We designed a case-control study to investigate the clinical and genetic risk factors for inhibitor development in nonsevere haemophilia A patients. We investigated whether the type of FVIII concentrate was associated with inhibitor development in nonsevere haemophilia A patients. This nested case-control study includes 75 inhibitor patients and 223 controls, from a source population of the INSIGHT study, including all nonsevere haemophilia A patients (FVIII:C 2-40%) that were treated with FVIII concentrates in 33 European and one Australian centre. Cases and controls were matched for date of birth and cumulative number of exposure days (CED) to FVIII concentrate. A conditional logistic regression model was used to calculate unadjusted and adjusted odds ratios. No increased risk for inhibitor development was found for any type of FVIII concentrate; either when comparing recombinant FVIII concentrates to plasma-derived FVIII concentrates (adjusted odds ratio 0·96, 95% confidence interval (CI) 0·36-2·52) or for specific types of FVIII concentrates.

AAV5-Factor VIII Gene Transfer in Severe Hemophilia A.

BACKGROUND: Patients with hemophilia A rely on exogenous factor VIII to prevent bleeding in joints, soft tissue, and the central nervous system. Although successful gene transfer has been reported in patients with hemophilia B, the large size of the factor VIII coding region has precluded improved outcomes with gene therapy in patients with hemophilia A. METHODS: We infused a single intravenous dose of a codon-optimized adeno-associated virus serotype 5 (AAV5) vector encoding a B-domain-deleted human factor VIII (AAV5-hFVIII-SQ) in nine men with severe hemophilia A. Participants were enrolled sequentially into one of three dose cohorts (low dose [one participant], intermediate dose [one participant], and high dose [seven participants]) and were followed through 52 weeks. RESULTS: Factor VIII activity levels remained at 3 IU or less per deciliter in the recipients of the low or intermediate dose. In the high-dose cohort, the factor VIII activity level was more than 5 IU per deciliter between weeks 2 and 9 after gene transfer in all seven participants, and the level in six participants increased to a normal value (>50 IU per deciliter) that was maintained at 1 year after receipt of the dose. In the high-dose cohort, the median annualized bleeding rate among participants who had previously received prophylactic therapy decreased from 16 events before the study to 1 event after gene transfer, and factor VIII use for participant-reported bleeding ceased in all the participants in this cohort by week 22. The primary adverse event was an elevation in the serum alanine aminotransferase level to 1.5 times the upper limit of the normal range or less. Progression of preexisting chronic arthropathy in one participant was the only serious adverse event. No neutralizing antibodies to factor VIII were detected. CONCLUSIONS: The infusion of AAV5-hFVIII-SQ was associated with the sustained normalization of factor VIII activity level over a period of 1 year in six of seven participants who received a high dose, with stabilization of hemostasis and a profound reduction in factor VIII use in all seven participants. In this small study, no safety events were noted, but no safety conclusions can be drawn. (Funded by BioMarin Pharmaceutical; ClinicalTrials.gov number, NCT02576795 ; EudraCT number, 2014-003880-38 .).

Direct comparison of two extended half-life PEGylated recombinant FVIII products: a randomized, crossover pharmacokinetic study in patients with severe hemophilia A.

An open-label, crossover randomized study was performed to compare the pharmacokinetics (PK) of damoctocog alfa pegol and rurioctocog alfa pegol, two recombinant factor VIII (FVIII) products indicated in patients with hemophilia A, both conjugated to polyethylene glycol to reduce clearance and extend time in circulation. Adult patients (N = 18) with severe hemophilia A (FVIII < 1 IU/dL), previously treated with any FVIII product for ≥ 150 exposure days, were randomized to receive a single 50 IU/kg infusion of damoctocog alfa pegol followed by rurioctocog alfa pegol, or vice versa, with ≥ 7-day washout between doses. FVIII activity was measured using the one-stage clotting assay. PK parameters, including area under the curve from time 0 to the last data point (AUC0-tlast, primary parameter), dose-normalized AUC (AUCnorm), and time to threshold, were calculated based on 11 time points between 0.25 and 120 h post-dose and evaluated using a noncompartmental model. Due to differences in batch-specific vial content used for the study, actual administered median doses were 54.3 IU/kg for damoctocog alfa pegol and 61.4 IU/kg for rurioctocog alfa pegol. Based on actual dosing, a significantly higher geometric mean (coefficient of variation [%CV]) AUCnorm was observed for damoctocog alfa pegol (43.8 h kg/dL [44.0]) versus rurioctocog alfa pegol (36.0 h kg/dL [40.1, P < 0.001]). Based on population PK modeling, median time to reach 1 IU/dL was 16 h longer for damoctocog alfa pegol compared with rurioctocog alfa pegol. No adverse events or any immunogenicity signals were observed. Overall, damoctocog alfa pegol had a superior PK profile versus rurioctocog alfa pegol. Trial registration number: NCT04015492 ( ClinicalTrials.gov identifier). Date of registration: July 9, 2019.

Treatment patterns and bleeding outcomes in persons with severe hemophilia A and B in a real-world setting.

The current standard of care treatment for severe hemophilia A and B (SHA and SHB) is the prophylactic intravenous replacement of coagulation factor VIII or IX (FVIII/FIX) to prevent spontaneous bleeding. Persons with hemophilia without prophylactic treatment receive therapy in case of bleeding, i.e., on demand. To assess treatment patterns, utilization of products, and bleeding outcomes in a real-world cohort of persons with SHA and SHB, defined as FVIII or FIX activity < 1%, data was retrospectively collected from hemophilia-specific patient diaries used for home treatment, medical records, and entries into the Austrian Hemophilia Registry from the year 2012 to 2017. Fifty-three male persons with SHA (n = 47) and SHB (n = 6) were included; 26 with SHA and 5 with SHB were on prophylaxis, 8 and 1 switched therapy regimen, and 13 and 0 received on-demand therapy. Persons on prophylaxis used a mean factor FVIII or FIX dose of 71.7 and 40.1 IU/kg/week. Median (IQR) annualized bleeding rates (ABR) in SHA were 28.0 (23.4-31.3) in the on-demand, 4.9 (1.6-13.5) in the prophylaxis group, and 3.0 (2.0-6.8) in the prophylactic group of SHB. Three persons with SHA had zero bleeds during the observation period. On-demand therapy and hepatitis B and C were associated with higher ABR but not age, weight, and HIV positivity. Bleeding rates and the proportion of on-demand therapy in persons with hemophilia were high in our real-world cohort. Further improvement is needed, which might be facilitated with the advent of factor products with extended half-life or non-factor therapies.