Emicizumab Improves Ex Vivo Clotting Function in Patients with Mild/Moderate Hemophilia A.

BACKGROUND: Emicizumab prophylaxis is a promising treatment that reduces bleeding events in severely affected patients with hemophilia A (PwHA). It is anticipated that emicizumab could be similarly effective in mild/moderate PwHA (PwMHA) although this effect has not been investigated. AIM: We evaluated ex vivo coagulant effects of emicizumabin PwMHA. METHODS: Clot waveform analysis (CWA) triggered by prothrombin time/activated partial prothrombin time-mixed reagents was utilized to examine coagulant effects of emicizumabin factor (F)VIII-deficient plasma mixed with recombinant (r)FVIIIand in native plasmas from 16 PwMHA. The CWA parameter, adjusted-|min1| (Ad|min1|), was used. Increases in Ad|min1| (ΔAd|min1|) mediated by emicizumab were calculated from the slopes of regression lines in the presence of rFVIII. RESULTS: Ad|min1| in FVIII-deficient plasma with various concentrations of rFVIII negatively correlated with ΔAd|min1|by adding emicizumab, and these data were defined as standard reference values. Ad|min1| (4.57 ± 0.50) in 16 PwMHA increased to 5.05 ± 0.54 and 5.37 ± 0.60 by adding emicizumab at 50 and 100 µg/mL, respectively, but remained lower than the normal range (7.22 ± 0.21). ΔAd|min1| levels were 1.5 to 2-fold higher in five cases and 0.4 to 0.6-fold lower in four cases, compared with reference values determined by rFVIII. In some cases, genetic analyses suggested that specific point mutations could have contributed to these findings. Further studies using rFVIII mutants indicated, however, that the differences in ΔAd|min1| were not related to individual FVIII gene defects. CONCLUSION: Emicizumab enhances coagulation potential in PwMHA. Assessment of ex vivo coagulant activity of emicizumab could be helpful for predicting coagulant potentials prior to treatment in these patients.

BAY 81-8973 demonstrated efficacy, safety and joint status improvement in patients with severe haemophilia A in the LEOPOLD I extension for ≤2 years.

OBJECTIVES: BAY 81-8973 (Kovaltry® ), a full-length, unmodified, recombinant human factor VIII, provided excellent bleeding control for patients with haemophilia A in the pivotal 1-year LEOPOLD I trial. The LEOPOLD I extension evaluated long-term efficacy and safety of BAY 81-8973 prophylaxis. METHODS: After completing LEOPOLD I, patients continued receiving 20-50 IU/kg BAY 81-8973 two- or three-times weekly in the extension. Outcomes included annualised bleeding rate (ABR) and haemostasis during surgery. RESULTS: Fifty-five patients aged 12-65 years participated in the extension. Median (range) exposure days during the 2-year total study period was 309 (115-355). No patient switched regimens. Median (Q1; Q3) ABR for all bleeds was 2.0 (1.0; 6.1) during the pivotal study, 2.0 (0.0; 5.2) during the extension, and 2.0 (0.5; 5.5) combined. The proportion of joint bleeds affecting target joints decreased (pivotal study: 90.9%, extension: 60.0%). Haemostasis was assessed as excellent/good in all five major surgeries. One serious adverse event (myocardial infarction) occurred in a patient with cardiovascular risk factors. No patients developed inhibitors. CONCLUSIONS: BAY 81-8973 prophylaxis efficacy outcomes in the pivotal study were maintained or, in the case of joint protection, improved during the extension, with a safety and tolerability profile consistent with previous experience.

Effect of emicizumab on global coagulation assays for plasma supplemented with apixaban or argatroban.

Emicizumab is a bi-specific humanized monoclonal antibody mimicking the factor (F) VIII cofactor activity in mediating the activation of FX by FIXa. Recent observations showed that emicizumab when added to pooled normal plasma (PNP), hemophilic plasma or PNP added with unfractionated heparin is able to interfere with coagulation assays. To further explore the mechanisms of assay interference we investigated the effect of emicizumab on global coagulation assays for the PNP added with two direct oral anticoagulants, apixaban or argatroban. Aliquots of PNP were added with purified apixaban or argatroban at a concentration of 500 ng/mL and emicizumab at concentrations ranging from 0 to 100 µg/mL. Plasma samples were then tested for the activated partial thromboplastin time (APTT) and for thrombin generation (the latter for the apixaban plasma only). Emicizumab at a 25-50 µg/mL shortened the APTT of the PNP with or without apixaban or argatroban. The extent of correction was greater for the apixaban or argatroban plasma and amounted to 35% or 42%, respectively. The parameters of thrombin generation (lag-time and time-to-peak) for the PNP supplemented with apixaban were shortened by 30% or 25%, respectively and the endogenous thrombin potential and the peak-thrombin were marginally affected. Emicizumab attenuates in vitro the anticoagulant activity of the PNP induced by apixaban or argatroban as documented by the correction of prolonged APTT and velocity of thrombin generation (i.e., lag-time and time-to-peak). Whether the above effects have any relevance in vivo is unknown.

Induction and Impact of Anti-Drug Responses Elicited by a Human Recombinant Coagulation Factor FXaI16L in Preclinical Species.

This paper presents a systemic investigation of ADA development and ADA impact of a human coagulation factor in nonclinical species during drug development and provides insights into potential implications in human if a similar ADA occurs. FXaI16L-induced ADA response was characterized in monkey, mouse, rat, and dog in different studies, and ADA effects on pharmacokinetic and/or pharmacodynamics of FXaI16L were further examined in ADA-negative and ADA-positive animals. After repeated administrations, FXaI16L elicited a dose and exposure day-dependent ADA response which ranged from no response to a transient or persistent response. Increase in exposure day and increase in dose generally enhanced ADA incidence except for a decrease in ADA incidence was observed in monkeys after repeated high-dose administrations. The observable ADA impact on pharmacokinetics was only found in some ADA+ animals and included decrease in clearance and increase in systemic exposure but no increase in half-life. In addition, no or limited effect on pharmacodynamics by ADA was observed. The earliest ADA response was observed after three exposure days, marked elevation of drug exposure was observed in some animals at log titer > 2.0, and the highest antibody titer excited was about 4 (Log10) in all species. A correlation between ADA induction and accumulative exposure after various repeat treatments in different species was found for FXaI16L. In addition, potential immunogenicity risk and mitigation of ADA in clinics are discussed.

Impact of Prophylaxis on Bone Mineral Metabolism in Children With Hemophilia.

In this study, we aimed to investigate changes in calcium (Ca) metabolism in hemophilia patients (PWH). We also aimed to investigate the importance of diagnosis and treatment of factors impairing calcium metabolism and the significance of early diagnosis and prophylaxis with respect to these subjects. For all patients, serum calcium, phosphorus, alkaline phosphatase, 25 hydroxy vitamin D (25-OHD), parathormone (PTH), and calcitonin levels were evaluated. Bone mineral density (BMD) was assessed by dual-energy x-ray absorptiometry. Low BMD scores and 25-OHD deficiency were observed in 29 (74.4%) and 34 (87.2%) patients, respectively. Prophylaxis of PWH did not differ significantly in terms of 25-OHD levels and BMD scores. Patients in the prophylaxis group had significantly higher PTH levels (P=0.042). A negative correlation was found between PTH measurements and Z-score (P=0.008). In summary, our findings, with a small number of PWH in our study group, suggest that biochemical markers of bone turnover may be used to detect bone loss. Follow-up through annual BMD measurements coupled with appropriate exercise programs could be recommended.

Baby hamster kidney cell-derived recombinant factor VIII: a quarter century of learning and clinical experience.

INTRODUCTION: Management and care of individuals with hemophilia A advanced immensely with the introduction of recombinant factor VIII (rFVIII) replacement products. This review provides a historical overview of rFVIII development with a focus on Bayer's rFVIII (with albumin) and sucrose-formulated rFVIII (rFVIII-FS), the only rFVIII products cloned in baby hamster kidney (BHK) cells with >25 years of proven safety and efficacy. Areas covered: We review the advances in rFVIII technology and the efficacy and safety data for BHK-derived rFVIII/rFVIII-FS from clinical trials, investigator-initiated studies, and observational studies. Innovative products with new treatment potentials (eg, BAY 81-8973 and BAY 94-9027) built on this established safety and efficacy profile are also briefly discussed. The literature search strategy included targeted searches (PubMed) with manual article selection and other product-specific searches. Expert commentary: Development of rFVIII products and related improvements in viral safety and manufacturing efficiency have guaranteed an adequate supply of factor products worldwide and increased prophylaxis use. The net effects have been joint health preservation, reduction in morbidity and mortality, and quality-of-life enhancements. Current treatment challenges include lack of adherence to prophylaxis and inhibitor development; extended-half-life rFVIII products and non-FVIII replacement therapies in development may help overcome these challenges.

Correction of human hemophilia A whole blood abnormalities with a novel bypass agent: zymogen-like FXa(I16L).

BACKGROUND: Approximately 30% of hemophilia A (HA) and 5% of hemophilia B patients develop inhibitors to protein replacement therapy, and this is the major cause of disease-related morbidity in the developed world. We previously developed zymogen-like factor Xa (FXa) molecules with impaired active site maturation, enabling a greater half-life than wild-type FXa while maintaining full procoagulant function in the prothrombinase complex. Here we evaluated the ability of zymogen-like FXa(I16L) to correct whole blood thromboelastometry abnormalities of severe HA subjects with and without inhibitors. METHODS: Fourteen severe HA subjects without and five with inhibitors were enrolled at baseline ( FVIII: C < 1%) > 5 half-lives from factor or bypass therapy. The subjects' whole blood was evaluated by thromboelastography (ROTEM(®) ) using INTEM analysis with two concentrations of FXa(I16L) or recombinant factor VIIa (rFVIIa). RESULTS: With 0.1 nm FXa(I16L) , clot time (CT, in minutes [min]) among HA subjects without and with inhibitors (mean = 2.87 min, 95% CI = 2.58-3.15 min, and mean = 2.9 min, 95% CI = 2.07-3.73 min, respectively) did not significantly differ from control CT (mean = 2.73 min, 95% CI = 2.62-2.85 min). Addition of 20 nm rFVIIa, simulating a 90-µg/kg dose, resulted in significantly prolonged CTs for HA subjects without and with inhibitors (mean = 5.43 min, 95% CI = 4.53-6.35 min, and mean = 4.25 min, 95% CI = 3.32-5.17 min, respectively) relative to controls. CONCLUSIONS: FXa(I16L) restored thromboelastometry CT to control values in severe HA subjects with and without inhibitors. The findings corroborate previous animal data and demonstrate the first evidence of zymogen-like FXa(I16L) correcting human HA subjects' whole-blood abnormalities and support the use of FXa(I16L) as a novel hemostatic agent.

Half-life extended factor VIII for the treatment of hemophilia A.

Prophylactic infusion of factor VIII (FVIII) prevents joint bleeding and other hemorrhages in patients with hemophilia A. Conventional FVIII concentrates have a short half-life, with an average of about 12 h in adults, ranging in individual patients between 6 and 24 h, and even shorter in younger children. Therefore, effective prophylaxis requires frequent intravenous injection, usually three times per week or every other day. Several technologies are currently under investigation to extend the half-life of FVIII, including Fc fusion (Eloctate, Elocta, efmoroctocog alfa), addition of polyethylene glycol (turoctocog alfa pegol [N8-GP], BAY 94-9027, BAX 855), and a single-chain construct (CSL627). This review summarizes characteristics of products in clinical development and discusses their potential benefits.

Prophylaxis vs. on-demand treatment with BAY 81-8973, a full-length plasma protein-free recombinant factor VIII product: results from a randomized trial (LEOPOLD II).

BACKGROUND: BAY 81-8973 is a new full-length human recombinant factor VIII product manufactured with technologies to improve consistency in glycosylation and expression to optimize clinical performance. OBJECTIVES: To demonstrate superiority of prophylaxis vs. on demand therapy with BAY 81-8973 in patients with severe hemophilia A. PATIENTS/METHODS: In this multinational,randomized, open-label crossover study (LEOPOLD II;ClinicalTrials.gov identifier: NCT01233258), males aged 12­65 years with severe hemophilia A were randomized to twice-weekly prophylaxis (20-30 IU kg(-1)), 3-times-weekly prophylaxis (30-40 IU kg(-1)), or on-demand treatment with BAY 81-8973. Potency labeling for BAY 81-8973 was based on the chromogenic substrate assay or adjusted to the one-stage assay. Primary efficacy endpoint was annualized number of all bleeds (ABR). Adverse events (AEs)and immunogenicity were also assessed. RESULTS: Eighty patients (on demand, n = 21; twice-weekly prophylaxis, n = 28; 3-times-weekly prophylaxis, n = 31) were treated and analyzed. Mean ± SD ABR was significantly lower with prophylaxis (twice-weekly, 5.7 ± 7.2; 3-times-weekly, 4.3 ± 6.5; combined, 4.9 ± 6.8) vs. on-demand treatment (57.7 ± 24.6; P < 0.0001, ANOVA). Median ABR was reduced by 97% with prophylaxis (twice-weekly, 4.0;3-times-weekly, 2.0; combined, 2.0) vs. on-demand treatment (60.0). Median ABR was higher with twice-weekly vs. 3-times-weekly prophylaxis during the first 6-month treatment period (4.1 vs. 2.0) but was comparable in the second 6-month period (1.1 vs. 2.0). Few patients reported treatment-related AEs (4%); no treatment-related serious AEs or inhibitors were reported. CONCLUSIONS: Twice weekly or 3-times-weekly prophylaxis with BAY 81-8973 reduced median ABR by 97% compared with on-demand therapy, confirming the superiority of prophylaxis. Treatment with BAY 81-8973 was well tolerated.

Vitamin D levels in children with severe hemophilia A: an underappreciated deficiency.

Osteoporosis in hemophilic patients is a significant problem. The causes of osteoporosis in hemophilic patients are lack of adequate exercise, multiple hemorrhage and inflammation, and low vitamin D levels. The aim of this study was to retrospectively determine the frequency of vitamin D deficiency and insufficiency in children with severe hemophilia A. Forty-seven children with severe hemophilia were included in the study. None of the patients had previously received vitamin D supplementation. No patient had clinical or radiologic findings of rickets or seropositivity of hepatitis C virus or HIV. The mean age of the patients was 11.64 ±â€Š5.70 (range, 2-18) years. The mean vitamin D level was 16.35 ±â€Š7.49 ng/ml (range, 3.25-33.80). Vitamin D levels were below 10 ng/ml (severe vitamin D deficiency) in 9 cases (19%), between 10 and 19.99 ng/ml (vitamin D deficiency) in 23 cases (49%), between 20 and 29.99 ng/ml (vitamin D insufficiency) in 13 cases (28%), and above 30 ng/ml (normal vitamin D level) in 2 cases (4%). The mean serum levels of 25-hydroxy vitamin D in the children with hemophilia during winter and autumn were significantly lower than that during summer (P = 0.0028 and P = 0.0091, respectively). A majority of our hemophilic patients (96%) had low vitamin D levels. The study showed that the risk of vitamin D deficiency is the most highest during winter and autumn. Normal lifelong vitamin D levels are especially important in hemophilia because of the possible synergistic effect of vitamin D levels on periarticular and general osteoporosis, which is intrinsic to hemophilic conditions. We advise routine checking of vitamin D levels twice a year and vitamin D supplementation to maintain its level between 30 and 100 ng/ml.

Current management of the hemophilic child: a demanding interlocutor. Quality of life and adequate cost-efficacy analysis.

Hemophilias are the most known inherited bleeding disorders. The challenges in the management of hemophilic children are different from those in adults: prophylaxis regimen removed the hallmark of crippling disease with lifelong disabilities; individualized regimens are being implemented in order to overcome venous access problems. Presently, at least in high-income countries, advances in treatment of hemophilia resulted in continuous improvement of the patients' quality of life and life expectancy. Inhibitors remain the most severe complication of hemophilia therapy. The treatment' compliance is the key to achieve a successful management. The patient, his family, the medical and psychological team are the players of a comprehensive care system. The current management of hemophilic children is the example of huge resource investments enabling long-term benefits in particular quality of life as a primary objective of the healthcare process.

Efficacy and safety using autotransfusion system with postoperative shed blood following total knee arthroplasty in haemophilia.

The purpose of this study was to evaluate the efficacy and safety of postoperative wound drain salvage and autotransfusion system in haemophilic patients undergoing elective total knee arthroplasty (TKA). No literature exists on reinfusing drained blood in patient with haemophilia undergoing TKA. Eighty-eight knees of 66 patients received cemented TKA due to end-stage haemophilic arthropathy (group I; with autotransfusion in 59 knees, group II; without autotransfusion in 29 knees). In group I, the postoperative shed blood was transfused within 6 h after surgery. The amount of blood drainage and reinfused blood, rate and amount of allogenic transfusion, postoperative change of haemoglobin level, prothrombin time (PT) and activated partial thromboplastin time were analysed. The mean postoperative blood drainage was 932 ± 479 mL in group I and 830 ± 492 mL in group II (P > 0.05). The mean volume of blood reinfused was 530 ± 265 mL in group I. Allogenic transfusion was needed in six knees (10.2%) of group I and eight knees (27.6%) of group II (P = 0.036). The mean volume of allogenic transfusion was 480 ± 49 mL in group I and 1041 ± 691 mL in group II (P > 0.05). Changes of all the laboratory results before and after TKA showed no statistically significant difference except PT was prolonged in group I (P = 0.008) at postoperative day 1. Moreover, there was no significant complication related to either reinfusion or allogenic transfusion in both groups. This study showed that reinfusion of drained blood is a simple, safe and efficacious method in patients with haemophilia undergoing TKA.

Correlation between endogenous VWF:Ag and PK parameters and bleeding frequency in severe haemophilia A subjects during three-times-weekly prophylaxis with rFVIII-FS.

Patients with severe haemophilia A experience frequent and spontaneous bleeding, causing debilitating damage to joints and decreasing quality of life. Prophylaxis with factor VIII (FVIII) reduces joint damage if initiated early. Circulating FVIII levels may be influenced by endogenous von Willebrand factor (VWF), a chaperone protein that binds and stabilizes FVIII. The aim of this study was to determine whether endogenous VWF antigen (VWF:Ag) levels are correlated with FVIII pharmacokinetic (PK) parameters and clinical outcomes in patients with severe haemophilia A. Previously treated, non-inhibitor patients in a multinational, randomized, double-blind, Ph II study received prophylaxis with once-weekly BAY 79-4980 (35 IU kg(-1)) or thrice-weekly recombinant sucrose-formulated FVIII (rFVIII-FS; 25 IU kg(-1)). PK parameters were evaluated at weeks 1 and 26. The number of bleeds per patient during the study was captured as part of the core efficacy endpoint. Spearman rank correlations assessed relationships of VWF:Ag levels with patient age, PK and annualized bleeding rate. Of 131 study patients (aged 13-64 years; BAY 79-4980, n = 63; rFVIII-FS, n = 68), 27 (21%; n = 15 and 12 respectively) were evaluable for PK assessment. Baseline VWF:Ag levels correlated with patient age (P < 0.0001). There was no significant difference in PK results between treatments; thus, PK parameters and VWF levels of all patients were analysed together. AUC(norm) and T1/2 significantly increased with increased VWF:Ag (P < 0.001); clearance significantly decreased with increased VWF:Ag (P = 0.002). Annualized bleeding rate in patients treated with 3× per week rFVIII-FS significantly correlated with VWF:Ag and age (P = 0.038 and 0.021 respectively). PK parameters as well as the clinical outcome significantly correlated with endogenous VWF:Ag. The improved clinical outcome in subjects with high VWF:Ag levels may be explained by VWF:Ag influence on FVIII PK.

Continuous infusion in haemophilia: current practice in Europe.

Summary. Continuous infusion (CI) of factor VIII (FVIII) is an effective method for replacement therapy in haemophilia. Recently, concerns have been raised regarding association of CI with the development of inhibitors. The aim of this study was to gain information on the current practices in Europe regarding CI and the true inhibitor incidence after this mode of therapy. In a cross sectional study performed in 22 Comprehensive Care Centres (CCCs), we evaluated CI techniques, treatment protocols, efficacy, safety and complications of CI including inhibitors. Thirteen (59%) CCCs reported a total of 1079 CI treatments, given peri-operatively or for major bleeds, in 742 patients. Most centres used 'adjusted dose' CI aimed at median target FVIII level of 0.8 IU mL(-1). CI was haemostatically very effective with a low incidence of complications: median incidence of postoperative bleeding was 1.8%, six centres observed phlebitis in 2-11% of CI treatments. Only nine (1.2%) patients developed inhibitors (0.45% of 659 severe and 7.2% of 83 mild haemophilia patients). Additional analysis of inhibitor patients revealed several confounding factors (low number of prior FVIII exposure days, high steady-state factor levels during CI, high-risk genotype). In this unprecedentedly large cohort, CI treatment appears to be an effective and safe treatment that does not increase the risk of inhibitor development in patients with severe haemophilia. Thus, previous small case series reports suggesting that CI may increase inhibitors cannot be confirmed. Inhibitor risk in mild haemophilia could not be evaluated as the influence of other, potentially confounding, risk factors could not be excluded.

Homeopathic medicines substantially reduce the need for clotting factor concentrates in haemophilia patients: results of a blinded placebo controlled cross over trial.

BACKGROUND: Modern management of haemophilia patients is expensive: 90% of expenditure is on clotting factor concentrates. Any intervention which reduces the need for clotting factor concentrates in these patients without compromising the quality of life is of interest. AIMS AND OBJECTIVES: To investigate the effectiveness of individualised homeopathic medicines in reducing the requirement of factor concentrates in haemophilia patients. MATERIALS AND METHODS: In a single blind placebo controlled cross over trial 28 consecutive persons with haemophilia (PWH) with severe (24) or moderately severe (4) disease received standard management with placebo homeopathy for 1 year and active homeopathic treatment in the subsequent year with the same conventional management. There was no wash out period. They received standard managements for any acute emergency during the study period. Development of inhibitor during the study period was a withdrawal criterion. Sample size for the trial was calculated as 24 PWH. Transfusion requirements, bleeding scores, pain scores were evaluated blind by independent experts. Homeopathic medicines were selected by experienced homeopathic physicians depending on clinical condition of the patient. Chi-squared and paired t tests were used in statistical analysis. RESULTS: 28 patients were recruited. Homeopathic medicines improved frequency of bleeding, extent of bleeding, blood products consumed and pain scores (P<0.0001). There was also significant improvement in well being. Plasma levels of clotting factors did not change. No patients developed inhibitors during the study there were no dropouts. CONCLUSION: Individualised homeopathic medicines may have an important supportive role in the management of PWH, where blood products and factor concentrates are not easily available. Larger, perhaps multicentric trials are warranted.

Pharmacokinetics and ex vivo whole blood clot formation of a new recombinant FVIII (N8) in haemophilia A dogs.

N8, a new recombinant factor VIII (rFVIII) compound developed for the treatment of haemophilia A, is produced in Chinese hamster ovary (CHO) cells and formulated without human- or animal-derived materials. The aim of the present study was to compare the pharmacokinetics (PK) and the procoagulant effect, measured by ex vivo whole blood clot formation, of N8 and a commercial rFVIII in a cross-over study in haemophilia A dogs. N8 and Advate® (100 IU kg⁻¹) were administered intravenously to three haemophilia A dogs. Blood was sampled between 0 and 120 h postdose and FVIII:C analysed. PK parameters maximum plasma concentration, area under the curve, half-life (t(½)), clearance, mean residence time (MRT) and volume of distribution and incremental recovery were calculated. Whole blood clotting time (WBCT) and thromboelastography (TEG®) were used to determine the haemostatic potential. No adverse reactions were observed with N8 or Advate ®. N8 and Advate® exhibited similar PK parameters, with t(½) 7.7-11 h and MRT 11-14 h. Both rFVIII compounds corrected the prolonged WBCT (> 48 min) to the range of normal dogs (8-12 min), i.e. N8 to 7.5-10.5 min and Advate® to 7.5-11.5 min. N8 and Advate® also normalized the whole blood clot formation according to TEG®. The native whole blood clotting assays (WBCT, TEG®) appeared to be more sensitive to low concentrations of FVIII than assays in citrated plasma samples. In conclusion, comparison of N8 and Advate ® in haemophilia A dogs revealed similar safety, similar PK and similar effects in whole blood clot formation assays.

Clinical features and outcome of acquired haemophilia A. Interim analysis of the Düsseldorf study.

UNLABELLED: We have performed a monocenter study on 29 consecutive patients with acquired haemophilia A who were referred for diagnosis and treatment to the Düsseldorf Haemophilia Comprehensive Care Center between March 2001 and February 2010. PATIENTS, METHODS: 18 men (age: 44-86 years) and 11 women (age: 20-83 years). For laboratory evaluation, a standardized staged protocol of aPTT, FVIII:C activity and concentration, mixing studies with patient and normal plasma, and quantification of inhibitor titers (Bethesda assay) was used. Diagnostic work-up included elaborate examinations for any underlying disease. RESULTS: In 18 (62%) of the 29 patients with acquired haemophilia A, an underlying disorder was identified, including 9 patients with respiratory diseases (31%), 7 patients with autoimmune disorders (24%), one with malignancy, and one with postpartum state, while in 11 patients (38%) acquired haemophilia A remained idiopathic. Haemotherapy of bleeding, suppression or elimination of the inhibitor, and induction of immunotolerance to endogenous FVIII:C were performed according to a treatment algorithm. Predefined clinical endpoints were control of bleeding, eradication of the inhibitor, complete or partial remission (CR, PR), relapse, or early death (< or =30 days). Of the 29 patients in total, 22 individuals achieved CR (76%), three had PR, one relapsed, and three died within 30 days (one of acute myocardial infarction while on antihaemorrhagic treatment, one of sepsis while on immunosuppression due to active acquired haemophilia A, one of lung bleeding in association with pre-existing pulmonary sarcoidosis). CONCLUSION: This monocenter study demonstrates that control of life-threatening bleeding, eradication of the inhibitor, and induction of tolerance to endogenous FVIII have significantly improved the clinical outcome of acquired haemophilia A. Our data also suggest a shift in underlying disorders associated with acquired haemophilia A, whereby, in comparison to published studies, a relative increase in the proportion of patients with respiratory diseases is present.

New coagulant agent (ankaferd blood stopper) for open hemorrhages in hemophilia with inhibitor.

The treatment of hemophilia A patients with inhibitor could be very expensive. Ankaferd blood stopper (ABS) is a unique folkloric medicinal plant extract, which has historically been used in Turkish traditional medicine as a hemostatic agent. In this article, a 16-year-old boy was presented with uncontrolled bleeding, despite the treatment of factor VIII, rVIIa, factor VIII inhibitor bypass activity (FEIBA), cyclophosphamide, and prednisolone at circumcision site that resolved with ABS in minutes. Our patient with hemophilia A and inhibitor is the first clinical pediatric case.

Carbon monoxide releasing molecule-2 increases the velocity of thrombus growth and strength in hemophilia A, hemophilia B and factor VII-deficient plasmas.

Carbon monoxide derived from carbon monoxide releasing molecules (CORMs) has been demonstrated to enhance normal plasma thrombus speed of growth and strength in vitro. We tested the hypothesis that tricarbonyldichlororuthenium (II) dimer (CORM-2) improves the velocity of formation and strength of hemophiliac plasma thrombi as determined by thrombelastography. Plasma deficient (<1% normal activity) in factor VIII (FVIII; n = 11 individuals), factor IX (FIX; n = 5 individuals) or factor VII (FVII; n = 4 individuals) was exposed to 0 or 100 micromol CORM-2, with coagulation initiated with tissue factor. Coagulation kinetics were monitored with thrombelastography for 15 min. Paired t-tests were used to analyze FVIII-deficient plasma results; relative change was used to describe the other plasma types tested. In FVIII-deficient plasma, CORM-2 exposure significantly (P < 0.05) increased the velocity of thrombus formation (84%) and strength (48%) compared with plasma not exposed to CORM-2. FXI-deficient clots demonstrated an increase in velocity of formation (63%) and strength (43%) after CORM-2 exposure. Lastly, CORM-2 exposure increased FVII-deficient plasma velocity of formation (45%) and strength (63%). CORM-2 markedly enhanced the velocity of clot growth and strength in hemophiliac plasma. These findings serve as the rationale to determine whether CORMs could be utilized as hemostatic agents.

Differential response to bypassing agents complicates treatment in patients with haemophilia and inhibitors.

The bypassing agents factor eight inhibitor bypassing activity (FEIBA) anti-inhibitor coagulant complex and recombinant activated factor VII (rFVIIa) have been established as safe and effective therapies for treating bleeding episodes in haemophilia patients with inhibitors. However, the efficacy of each bypassing agent can vary, and neither agent is universally effective. The reasons for such variability have yet to be confirmed, but may involve patient-specific factors and the mechanisms of action (MOAs) and pharmacokinetic profiles of these two agents. This issue underscores the necessity of both products in the comprehensive care of patients with haemophilia and inhibitors. The objective of this review is to discuss the evidence of a differential haemostatic response to bypassing agents and the potential roles of MOA and patient-specific factors in contributing to the differences in response.