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.

Phase 1b Study to Evaluate Safety, Tolerability, and Maximum Tolerated Dose of PF-05230907 for Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: This study aimed to determine the maximum tolerated dose and to evaluate the overall safety and tolerability of single doses of PF-05230907 in subjects with acute intracerebral hemorrhage. METHODS: Individuals presenting with intracerebral hemorrhage were enrolled in a phase 1, multicenter, open-label clinical trial. A Bayesian modified continual reassessment method design based on treatment-emergent thromboembolic or ischemic events was adopted. Sequential dosing, an external data monitoring committee, and prespecified stopping rules were incorporated as safeguards. RESULTS: Twenty-one subjects received PF-05230907. The mean (±SD) age in years and intracerebral hemorrhage volume in mL at baseline were 62 (±9) and 18 (±11), respectively. Two treatment-emergent thromboembolic or ischemic events occurred (deep vein thrombosis and cerebral ischemia), in the 30 µg/kg dose group. There were no other clear drug-related toxicities at dose levels ranging from 5 to 30 µg/kg. At the time of study termination, the maximum tolerated dose was estimated to be 24 µg/kg, with a mean fitted dose-toxicity estimate of 11.9% (95% CI, 1.2%-27.4%). CONCLUSIONS: Single doses of PF-05230907 appeared to be tolerated across a range of doses in the intracerebral hemorrhage population, with thrombotic events observed only at the highest dose level tested. Recruitment within the recommended therapeutic window of opportunity remains a challenge. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02687191.

Plasma-derived Factor X therapy for treatment of intracranial bleeding in a patient with Factor X deficiency: a case report.

BACKGROUND: Factor X (FX) deficiency (FXD) is an extremely rare autosomal recessive hereditary hematologic disorder, affecting approximately one in 1,000,000 of the general population. CASE REPORT: This case report describes an infant with hereditary severe FXD who presented with a spontaneous, life-threatening intracranial hemorrhage and was treated with the first licensed plasma-derived FX (pdFX) concentrate. On admission, laboratory assays showed severe coagulopathy of unknown cause; the patient was empirically treated using a multimodal hemostatic approach with prothrombin complex concentrate, fresh-frozen plasma, and tranexamic acid. Subsequent single-factor coagulation and genetic analyses confirmed the hereditary FXD diagnosis, and the therapeutic regimen was changed to a targeted regimen of 250 IU pdFX daily. Based on careful monitoring of the coagulation profile, pdFX administration frequency was increased to twice daily, followed by a reduction to once every 18 hours. The patient was discharged after 7 weeks of hospitalization in good clinical condition and now receives prophylactic pdFX three times weekly.

Intracranial Hemorrhage as the First Manifestation of Severe Congenital Factor X Deficiency in a 20-Month-Old Male: Case Report and Review of the Literature.

Factor X deficiency (FXD) is a rare bleeding disorder, which can result in severe bleeding symptoms such as intracranial hemorrhage (ICH). The most common bleeding symptoms are epistaxis and gum bleeding. ICH is reported in 9-26% of all patients with FXD, mostly during the first month of life. Here, we present a rare case of a male presenting with ICH at the age of 20 months as the first manifestation of FXD. Secondary prophylaxis with factor X substitution once weekly prevented further bleeding.

[CORRECTION OF HEMOSTASIS WITH BLOOD PRODUCTS IN THE SURGICAL TREATMENT OF CONGENITAL HEART DISEASE IN INFANTS AND YOUNG CHILDREN].

The article deals with the safety and efficiency of recombinant activated factor VII (Coagil VII, Russia) and prothrombin complex concentrate (protromplex-600, Baxter Austria) in the neonatal and pediatric cardiac surgery. The study included 56 children aged from 7 days to 5.5 years underwent surgery with cardiopulmonary bypass for congenital heart defects repair. Clinical and laboratory evidences suggest that Coagil VII and protromplex-600 effective for bleeding stop. The drugs have no negative impact on hemodynamics. We did not identify allergic reactions and thrombosis associated with the introduction of drugs in the pen operative period.

Factor X deficiency and pregnancy: preconception counselling and therapeutic options.

Women with factor X deficiency (FXD) who want to become pregnant face uncertain risks to themselves and to an unborn infant from haemorrhagic complications during pregnancy and at parturition. Women with FXD may also experience difficulty achieving pregnancy secondary to haemorrhagic symptoms of the reproductive organs. Case reports describe differences in bleeding phenotypes and pregnancy outcomes that are not easily correlated with prepregnancy bleeding symptoms or factor X levels. The aim of this article is to identify factors for consideration and information to assist the physician in counselling women with FXD who want to become pregnant, and to offer guidelines for management where appropriate. We identified cases of pregnancy among women with FXD and their outcomes from the literature; 15 women with 24 pregnancies were identified and 18 were successful. The women in this small cohort did not have an increased rate of spontaneous abortion, (8.3% vs. 13.5% in the general US population) but did have a 2.5-fold increased risk of preterm labour (37.5% vs. 12.2% in the general US population). The role of prophylaxis to control reproductive haemorrhagic symptoms, including haemorrhagic complications of pregnancy has not yet been defined, but use of prophylaxis may allow more women to be able to attempt pregnancy. Women who had access to a tertiary care centre with a multidisciplinary team including an obstetrician with high-risk obstetric training, a haematologist, a perinatologist, and access to a reference laboratory and blood bank were able in most cases to successfully deliver healthy, term infants.

Efficacy of prophylaxis and genotype-phenotype correlation in patients with severe Factor X deficiency in Iran.

We aimed to evaluate the effect of regular prophylaxis with a Factor X (FX) concentrate for patients with severe FXD in Iran and to assess the correlation of the genotype and phenotype in these patients. Ten patients with severe FXD (FX activity <1%) were enrolled and characterized during 2010-2011. Prophylaxis with 20 IU FX P Behring per kg body weight was administered once a week. FX levels, were monitored at baseline, 15 and 30 min, 1, 3, 6, 12, 24, 48, 72 and 96 h after starting prophylaxis. All patients were followed for 1 year. The mean age of the patients was 15 ± 7.8 years (age range of: 6-27 years). One patient had anaphylactic reaction after the first infusion, and the treatment was stopped. During one-year follow-up after starting prophylaxis, no bleeding symptoms occurred in any patient who tolerated and remained on the prophylaxis programme and all of them had a FX level of 1% or above. The maximum level of FX activity has been observed at 15 min after starting prophylaxis. A level of 1.5-3.5% was detected after 96 h. Homozygous mutations p.Arg40Thr (Arg-1Thr), p.Gly51Arg and p.Glu69Lys were detected in patients with intracranial haemorrhage. In our patients, significant decrease in symptoms without any complication after administration of FX, was demonstrated in all except one patient who had an anaphylactic reaction. It seems that the dose of 20 IU kg(-1) could be probably the best choice for patients with severe FXD, who require regular prophylaxis.

Impact of infusion speed on the safety and effectiveness of prothrombin complex concentrate: a prospective clinical trial of emergency anticoagulation reversal.

Prothrombin complex concentrate (PCC) infusion is preferred for emergency reversal of coumarin therapy. Rapid infusion can potentially save crucial time; however, the possible impact of high infusion speed on PCC safety and effectiveness has not been delineated. In a prospective multinational clinical trial with 43 patients receiving PCC (Beriplex P/N) for emergency reversal of coumarin therapy, infusion speeds were selected by the investigators. In a two-phase statistical analysis, the influence of baseline patient variables and dose on selected infusion speed was assessed. Then, the effect of infusion speed on reduction in international normalized ratio (INR) and on thrombogenicity marker pharmacokinetics was evaluated. Infusion speed ranged widely from 2.0 to 40.0 mL min(-1) with a median of 7.5 mL min(-1). Selection of infusion speed was not significantly influenced by gender, age, body mass index, presence of acute bleeding, indication for coumarin therapy, baseline INR, or PCC dose. Infusion speed was higher by a median of 2.2 mL min(-1) (95% confidence interval, 1.0-4.3 mL min(-1)) among patients receiving Beriplex P/N volumes > or =80 mL compared with smaller infusion volumes. Infusion speed did not affect INR attained 30 min following PCC infusion. None of the evaluated thrombogenicity marker pharmacokinetic parameters was affected by infusion speed. Infusions in one patient with questionable hemostatic efficacy and another with a possibly PCC-related thromboembolic event were at moderate and slow speeds, respectively. This study provides the first direct evidence that Beriplex P/N can be rapidly infused for emergency coumarin therapy reversal without altering safety or effectiveness.

The role of prophylaxis in bleeding disorders.

SUMMARY: The rationale for long-term prophylaxis in more severe forms of von Willebrand's disease (VWD) is obvious, as mucosal bleeding and haemophilia-like joint bleeds resulting in chronic morbidity may occur. However, the experience with prophylactic treatment in this group is scanty. An international VWD Prophylaxis Network (VWD PN) was established in 2006. The VWD PN will investigate prophylaxis with retrospective and prospective studies. Eighteen centres in Europe and North America are recruiting patients and an additional 40 centres are preparing for or evaluating participation. In the absence of randomized prospective studies for most rare bleeding disorders, guidelines for prophylaxis are a subject of controversy. In situations where there is a strong family history of bleeding, long-term prophylaxis is administered in selected cases. Short intervals of prophylaxis can also be given before some surgeries or during pregnancy. The benefits of prophylaxis must be balanced by the risk of side effects. Therefore, it is essential to delineate its management in a specialized comprehensive care environment. In haemophilia, decades of clinical experience and numerous retrospective and, recently, prospective studies clearly demonstrate that prophylactic treatment is superior to on-demand treatment, regardless of whether the outcome is the number of joint- or life-threatening bleeds, arthropathy evaluated by X-ray or MRI, or quality of life measured by generic or haemophilia-specific instruments. Optimal prophylactic treatment should be started early in life (primary prophylaxis) but various options exist for the dose and dose interval. These depend on the objective of treatment in the individual patient, which, in turn, is dependent on resources in the health care system.

Fixed-Dose Four-Factor Prothrombin Complex Concentrate for Vitamin K Antagonist Reversal: Does One Dose Fit All?

Four-factor prothrombin complex concentrate (4F-PCC) has emerged as the preferred option for emergent reversal of vitamin K antagonists (VKAs); however, the optimal dosing strategy is unknown. Although several studies have attempted to determine the optimal dose of 4F-PCC using a variety of dosing regimens, no dosing strategy has been found to be superior. Many of these studies have evaluated a low, fixed dose of 4F-PCC rather than individualized dosing as recommended in product labeling. The purpose of this review was to evaluate the efficacy and safety of various fixed-dose strategies of 4F-PCC for emergent VKA reversal and to assess limitations of the existing literature. A search of the PubMed database was performed from the earliest available date through 2018 for relevant articles describing fixed-dose 4F-PCC for VKA reversal. Reference lists of relevant articles were also manually reviewed. Most currently available studies are primarily observational and heterogeneous in design. A very low fixed dose of 500 IU is likely inadequate for successful VKA reversal, but increased fixed doses of 1000-1500 IU have found some degree of success and may be considered for VKA reversal. However, many of these studies consistently identified a trend toward international normalized ratio (INR) reversal failure in patients presenting with high baseline INR values or intracranial hemorrhage, suggesting that higher 4F-PCC doses are needed in these patients. Available studies are underpowered to determine whether a dose-dependent association with thrombotic risk exists. Additional large, randomized studies are needed to determine the optimal dosing strategy and ascertain the role for fixed-dose 4F-PCC.

Acquired Factor X Deficiency in Patients With Primary Light Chain Amyloidosis.

Acquired factor X (FX) deficiency is a rare but serious complication of primary amyloidosis, presumably caused by the binding of amyloid proteins to the clotting factors. The prolonged prothrombin time, partial thromboplastin time, and low FX level, which are correctable by mixing study, are the disease hallmarks. An immediate goal of care is to stop bleeding. Clotting factor replacement requires close monitoring of coagulogram and FX levels due to varying FX clearance among patients. High-purity FX is currently approved for hereditary FX deficiency and has been successfully used in some acquired FX deficiency cases. Ongoing bleeding risk complicates the treatment decision. Novel therapies yielding rapid and deep response reduce amyloid protein production and improve long-term outcome.

Use of a High-Purity Factor X Concentrate in Turkish Subjects with Hereditary Factor X Deficiency: Post Hoc Cohort Subanalysis of a Phase 3 Study.

Hereditary factor X (FX) deficiency is a rare bleeding disorder more prevalent in countries with high rates of consanguineous marriage. In a prospective, open-label, multicenter phase 3 study, 25 IU/kg plasma-derived factor X (pdFX) was administered as on-demand treatment or short-term prophylaxis for 6 months to 2 years. In Turkish subjects (n=6), 60.7% of bleeds were minor. A mean of 1.03 infusions were used to treat each bleed, and mean total dose per bleed was 25.38 IU/kg. Turkish subjects rated pdFX efficacy as excellent or good for all 84 assessable bleeds; investigators judged overall pdFX efficacy to be excellent or good for all subjects. Turkish subjects had 51 adverse events; 96% with known severity were mild/moderate, and 1 (infusion-site pain) was possibly pdFX-related. These results demonstrate that 25 IU/kg pdFX is safe and effective in this Turkish cohort (ClinicalTrials.gov identifier: NCT00930176).

Efficacy, safety and pharmacokinetics of a new high-purity factor X concentrate in women and girls with hereditary factor X deficiency.

Essentials Plasma-derived factor X concentrate (pdFX) is used to treat hereditary factor X deficiency. pdFX pharmacokinetics, safety and efficacy were assessed in factor X-deficient women/girls. Treatment success rate was 98%; only 6 adverse events in 2 subjects were possibly pdFX related. On-demand pdFX 25 IU kg-1 was effective and safe in women/girls with factor X deficiency. SUMMARY: Background A high-purity, plasma-derived factor X concentrate (pdFX) has been approved for the treatment of hereditary FX deficiency, an autosomal recessive disorder. Objective To perform post hoc assessments of pdFX pharmacokinetics, safety and efficacy in women and girls with hereditary FX deficiency. Patients/Methods Subjects aged ≥ 12 years with moderate/severe FX deficiency (plasma FX activity of < 5 IU dL-1 ) received on-demand or preventive pdFX (25 IU kg-1 ) for ≤ 2 years. Results Of 16 enrolled subjects, 10 women and girls (aged 14-58 years [median, 25.5 years]) received 267 pdFX infusions. Mean monthly infusions per subject were higher among women and girls (2.48) than among men and boys (1.62). In women and girls, 132 assessable bleeding episodes (61 heavy menstrual bleeds, 47 joint bleeds, 15 muscle bleeds, and nine other bleeds) were treated with pdFX, with a 98% treatment success rate versus 100% in men and boys. Mean pdFX incremental recovery was similar in the two groups (2.05 IU dL-1 versus 1.91 IU dL-1 per IU kg-1 ), as was the mean half-life (29.3 h versus 29.5 h). Of 142 adverse events in women and girls, headache was the most common (12 events in six subjects). Six events (two infusion-site erythema, two fatigue, one back pain, one infusion-site pain) in two subjects were considered to be possibly pdFX-related. Following the trial, pdFX was used to successfully maintain hemostasis in two subjects undergoing obstetric delivery. Conclusions pdFX was well tolerated and effective in women and girls with FX deficiency. Although women and girls had different bleeding symptoms and sites than men and boys, their pdFX pharmacokinetic profile was comparable.

[Initial treatment of venous thromboembolic events]. / Traitement initial de la maladie thrombo-embolique veineuse.

Initial treatment of venous thromboembolic events is currently based on antithrombotics. This treatment is validated and identical for deep vein thrombosis (DVT) and pulmonary embolism. For distal DVT, this treatment has still to be validated. This reference therapeutic strategy is firstly parenteral and based on low-molecular-weight heparins (LMWH) or fondaparinux, subcutaneously prescribed at fixed dosage based on body weight without any systematic dose adjustment on hemostasis tests. Unfractionated heparin is steel the reference treatment in case of severe renal insufficiency. This parenteral treatment has to be relieved by vitamin K antagonists (VKA). VKA has to be co-administrated for at least 3 days, without any loading dose and can be early initiated. VKA dose needs to be adjusted in order to maintain INR between 2 and 3. However, in case of cancer, LMWH have to be carried on for 6 months. A part this antithrombotic treatment, thrombolytics are recommended in case of massive PE and vena cava filter should be used in case of recurrence despite adequate antithrombotic treatment or in case of contraindication to antithrombotic.

Plasma-derived human factor X concentrate for on-demand and perioperative treatment in factor X-deficient patients: pharmacology, pharmacokinetics, efficacy, and safety.

INTRODUCTION: Hereditary factor X (FX) deficiency is a rare autosomal recessive bleeding disorder characterized mainly by mild-to-severe bleeding into the mucous membranes, muscles or joints. Previously, treatment options for hereditary FX deficiency were limited mostly to products that may not specify FX content (i.e. fresh frozen plasma and prothrombin complex concentrates) and that have associated safety concerns. To meet the need for a single-factor replacement therapy specifically for use in FX-deficient patients, a high-purity, high-potency, human plasma-derived FX concentrate (pdFX; Coagadex®; Bio Products Laboratory, Elstree, UK) has been developed and approved for treatment of perioperative bleeding and on-demand treatment in FX-deficient patients. Areas covered: The pharmacology, efficacy, and safety of pdFX are discussed, with a review of preclinical studies and clinical trial data that led to regulatory approval of pdFX in the United States and Europe. Expert opinion: As the first single-factor replacement therapy indicated for hereditary FX deficiency, pdFX is a safe and efficacious treatment option in patients aged ≥12 years with hereditary FX deficiency. Clinical studies of pdFX provide a dosing regimen for use in cases of bleeding episodes, surgery, and prophylaxis. Further studies are ongoing regarding use of pdFX long term and in patients aged ≤12 years.

Recurrent, isolated factor X deficiency in myeloma: repeated normalization of factor X levels after cytostatic chemotherapy followed by late treatment failure associated with the development of systemic amyloidosis.

We describe the case of a 64-year-old woman with isolated severe factor X deficiency associated with kappa light chain myeloma. At the time of diagnosis there was no evidence for amyloidosis. Complete remission (CR) of myeloma as well as normalization of factor X levels were achieved after cytostatic chemotherapy. Subsequently, factor X deficiency recurred twice without any evidence for relapse of myeloma. The first time factor X normalized again following cytostatic treatment, the second time, however, factor X deficiency was refractory to chemotherapy. Finally, relapse of myeloma became evident associated with rapidly progressing, systemic amyloidosis, which was fatal within a few months. Initially, factor X infusion studies showed a normal recovery, but when amyloidosis became overt the recovery decreased to 0%. We assume that factor X deficiency was due to a binding of factor X to kappa light chains associated with the proliferation of the malignant myeloma cell clone.

Clinical aspects of non-A, non-B hepatitis infection.

Although non-A, non-B hepatitis is usually a mild subclinical illness, 40% of cases of fulminant viral hepatitis are attributed to infection by this agent. The administration of coagulation factor IX concentrates before liver biopsy in 17 patients with chronic liver disease was followed by the development of hepatitis in four, which proved fatal in three cases. The diagnosis was confirmed by transmission in chimpanzees, and further studies demonstrated the existence of two types of non-A, non-B hepatitis with different incubation periods and specific ultrastructural changes in the hepatocytes. The progression of 40% of cases of acute viral hepatitis to chronic liver disease and the development of chronic liver disease in renal and hepatic transplant recipients is very disturbing. It is likely that this type of hepatitis is an aetiological factor in some cases of hepatitis B surface antigen-negative chronic active hepatitis.

Comparison of the spectrophotometric determination and the two-stage coagulation assay of tissue factor activity.

The tissue factor activity of human brain thromboplastin and 6 commercial thromboplastins was determined by a spectrophotometric method and a two-stage coagulation assay. The thromboplastins were incubated with an excess of Factor VII and Factor X, and the activation of Factor X was estimated from the rate of hydrolysis of the chromogenic substrate S-2222 and from the coagulation time of plasma enriched in phospholipids. The results obtained by the two methods were related linearly and showed a correlation coefficient of 0.89. The coefficient of variation was 11% in the spectrophotometric method and 25% in the two-stage coagulation assay.

Novel platelet products, substitutes and alternatives.

Despite the many advances in the safety, processing, and storage of conventional 22 degrees C liquid-stored allogeneic platelet concentrates, there still are significant drawbacks to the use of such products. Efforts to overcome these shortcomings have resulted in an array of novel platelet products, substitutes, and alternatives; which are currently at various stages of development. This review summarizes the recent developments in the frozen and cold storage of platelets; their pathogen inactivation; as well as the status of lyophilized platelets, infusible platelet membranes (IPMs), red cells bearing arginine-glycine-aspartic acid (RGD) ligands, fibrinogen-coated albumin microcapsules, and liposome-based agents; as potential alternatives to the use of conventional platelet transfusions. Pre-clinical studies have been encouraging for several of these novel products; however, to date, very few have entered human trials. Nonetheless, with the ongoing development of diverse products, those properties that may be necessary for their hemostatic effectiveness will become apparent. However, safety and efficacy must be demonstrated in pre-clinical and phase I to III clinical trials before these novel agents, substitutes and alternatives can be used clinically for patients with thrombocytopenia.