The importance and evolution of bleeding disorder registries.

Registries are excellent sources of data to address questions that are typically not evaluated in randomized clinical trials, including natural history, disease prevalence, treatment approaches and adverse events, and models of care. Global and regional registries can provide data to identify differences in outcomes and in haemophilia care between countries, economic settings, and regions, while facilitating research and data sharing. In this manuscript, we highlight five bleeding disorder registries: Country registries from Australia and China, Paediatric Network on Haemophilia Management (PedNet) data on children who have received emicizumab, data from the European Haemophilia Safety Surveillance (EUHASS) system, and data on women and girls with haemophilia from the World Federation of Haemophilia (WFH) registries. Data from these and other bleeding disorder registries have been and will continue to be used to advance patient care, understand treatment patterns and adverse reactions, and identify areas of increased need and focus.

Potential for prolongation of fibrinogen concentrates post-reconstitution.

BACKGROUND AND OBJECTIVES: Reconstituted fibrinogen concentrate is considered stable for 8-24 h based on product monographs. Given the long half-life of fibrinogen in vivo (3-4 days), we hypothesized that reconstituted sterile fibrinogen protein would remain stable longer than 8-24 h. Extending the expiry date for reconstituted fibrinogen concentrate could decrease wastage and facilitate reconstitution in advance to minimize turnaround times. We performed a pilot study to define the stability of reconstituted fibrinogen concentrates over time. MATERIALS AND METHODS: Reconstituted Fibryga® (Octapharma AG) from 64 vials was stored in the temperature-controlled refrigerator (4 °C) for up to 7 days with functional fibrinogen concentration measured serially using the automated Clauss method. The samples were frozen, then thawed and diluted with pooled normal plasma in order for them to be batch tested. RESULTS: Reconstituted fibrinogen samples stored in the refrigerator showed no significant reduction in functional fibrinogen concentration for the entire 7-day study period (p = 0.63). Duration of initial freezing had no detrimental effect on functional fibrinogen levels (p = 0.23). CONCLUSION: Fibryga® can be stored at 2-8 °C post-reconstitution for up to one week with no loss in functional fibrinogen activity based on Clauss fibrinogen assay. Further studies with other fibrinogen concentrate formulations and clinical in vivo studies may be warranted.

A review of the pharmacokinetics, efficacy and safety of high-purity factor X for the prophylactic treatment of hereditary factor X deficiency.

INTRODUCTION: Hereditary factor X (FX) deficiency (FXD) is a rare autosomal recessive bleeding disorder. Plasma-derived FX (pdFX) is a high-purity FX concentrate approved in the United States and Europe for the treatment and prophylaxis of bleeding episodes and for peri-operative management in patients with hereditary FXD (HFXD). AIM: To review pharmacokinetic dosing, efficacy, and safety data for pdFX as routine prophylaxis for HFXD. METHODS: Summary of the published pharmacokinetic and safety data from TEN01, TEN02, TEN05, and real-world publications of pdFX for prophylaxis. RESULTS: Pharmacokinetic modelling data from the phase 3 TEN01 study supported administration of pdFX 25 IU/kg twice weekly for routine prophylaxis in adolescents/adults (aged ≥12 years). Results from nine paediatric patients in the phase 3 TEN02 study and eight adolescents/adults (aged ≥12 years) in the retrospective data-collection TEN05 study, along with real-world evidence, showed that routine prophylaxis with pdFX ≈40 IU/kg twice weekly in patients aged <12 years and pdFX ≈25 IU/kg twice weekly in patients aged ≥12 years was effective in bleeding prevention. CONCLUSIONS: pdFX was well tolerated in clinical studies, with no new safety signals identified during routine prophylactic use. Based on current evidence, it is recommended that routine prophylaxis with pdFX be initiated at 25 IU/kg twice weekly in adults/adolescents ≥12 years of age, and at a dosage of 40 IU/kg twice weekly in children <12 years of age. Thereafter, FX levels should be closely monitored, and dosages should be adjusted according to clinical response and to maintain trough levels ≥5 IU/dl.

Prophylaxis in children with haemophilia in an evolving treatment landscape.

INTRODUCTION: For children with haemophilia, early initiation of prophylaxis is crucial to prevent life-threatening bleeds and maintain joint health throughout life. Options for prophylaxis have recently increased from replacement therapy with standard or extended half-life coagulation factor products to include other haemostasis products, such as the non-replacement therapy emicizumab. AIM: To review key factors that determine the choice of prophylaxis in young children. METHODS: Key clinical questions on the implementation of prophylaxis for haemophilia in children were identified and PubMed was searched for evidence supporting guidance on the implementation of prophylaxis. RESULTS: The results of the literature search and the practical experience of the authors were used to build consensus on when to start prophylaxis, the pros and cons of the products available to guide the choice of product, and practical aspects of starting prophylaxis to guide the choice of regimen. CONCLUSIONS: In this era of increasing therapeutic choices, available information about the range of treatment options must be considered when initiating prophylaxis in young children. Parents or care givers must be sufficiently informed to allow informed shared decision making. Although plentiful data and clinical experience have been gathered on prophylaxis with clotting factor replacement therapy, its use in young children brings practical challenges, such as the need for intravenous administration. In contrast, our relatively brief experience and limited data with subcutaneously administered non-replacement therapy (i.e., emicizumab) in this patient group imply that starting emicizumab prophylaxis in young children requires careful consideration, despite the more convenient route of administration.

Association of four-factor prothrombin complex concentrate with subsequent plasma transfusion: A retrospective cohort study.

OBJECTIVE: To assess whether patients prescribed four-factor prothrombin complex concentrate (4FPC) received less plasma during the following 24-hour period than those treated for the same indications who received only plasma. INTRODUCTION: It is unclear whether 4FPC is associated with a reduction in subsequent plasma transfusion. This is important for minimising transfusion-associated risks and for inventory management. MATERIALS AND METHODS: We retrospectively studied patients treated for bleeding or coagulopathy. Individuals receiving 4FPC were matched by indication to patients treated with only plasma. Blood products received during 24-hour follow up were compared between 4FPC and plasma-only patients. RESULTS: There was no difference in the number of patients receiving additional plasma (19 (21%) 4FPC patients vs 31 (34%) plasma-only patients, P = .07) nor in the median number of additional plasma units received (0 units for both groups, interquartile range [0, 0] for 4FPC patients vs [0, 1] for plasma-only patients, P = .09). Subgroup analysis comparing patients who received 4FPC for on-label vs off-label indications found no difference in the number of patients receiving plasma nor in the median number of plasma units received. CONCLUSION: 4FPC was prescribed to a diverse set of patients, and administration was not associated with reduced plasma transfusion at our institution.

Clinical application of Web Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo): Patterns of blood sampling and patient characteristics among clinician users.

BACKGROUND: Use of population pharmacokinetics (PopPK) to facilitate PK-informed prophylaxis in clinical practice has gained momentum among haemophilia providers due to the accessibility of tools such as the Web Accessible Population Pharmacokinetic Service-Hemophilia (WAPPS-Hemo) and availability of extended half-life (EHL) factor concentrates. It is unknown how clinicians implement PopPK. AIM: To investigate the evolution of PopPK use in clinical practice by comparing blood sampling strategies, patient features, and factor group between initial and recent periods of WAPPS-Hemo availability. METHODS: PK data for haemophilia A and haemophilia B patients from two time periods were extracted from the WAPPS-Hemo database: early availability (10/2015-09/2016) and recent use (10/2017-09/2018). We compared patient characteristics (age, body weight, haemophilia type), product type and dose, and blood sampling times between the time frames. RESULTS: Over 1900 eligible infusions were submitted to WAPPS-Hemo during the periods studied, with 85% representing FVIII concentrates. In the recent cohort, PK profiles were requested for younger patients (median age 18 vs 26 years), with increased proportional EHL FVIII use (29% vs 14% of infusions). High-use centres generally submitted fewer blood samples per infusion than non-high-use centres, although the number of samples collected by non-high-use centres decreased significantly over time. During both periods, blood sample timing was generally consistent with ISTH recommended windows. CONCLUSION: The use of WAPPS-Hemo by haemophilia providers grew by over threefold between the time periods investigated. While sampling times have included key time points proposed first by Björkman since early WAPPS-Hemo usage, a trend towards minimizing sampling was observed.

Laboratory measurement of factor replacement therapies in the treatment of congenital haemophilia: A United Kingdom Haemophilia Centre Doctors' Organisation guideline.

Assay discrepancies can occur with laboratory monitoring of FVIII and FIX replacement therapy, particularly for the extended half-life products. This guideline collates current published data and provides advice on appropriate choice of assays for laboratory measurement of replacement therapy for patients with Haemophilia A and B without inhibitors. It is recommended that each haemophilia centre should ensure that appropriate laboratory assays are available for FVIII and FIX products in local clinical use. Patient samples should be assayed against calibrators traceable to WHO Plasma International Standards. Assay discrepancies are common especially for the extended half-life FVIII and FIX products, and assays of these products may need to be verified with the specific CFC being used.

Evaluation of postoperative clinical outcomes in Jehovah's Witness patients who receive prothrombin complex concentrate during cardiac surgery.

BACKGROUND: Patients who refuse allogeneic blood transfusions (alloBT) on the basis of religious doctrine, such as Jehovah's Witnesses (JWs), can pose a challenge when undergoing surgical procedures. During cardiac surgery, special considerations regarding surgical techniques and blood loss minimization strategies can lead to improved outcomes. Limited literature exists to guide the use of four-factor prothrombin complex concentrate (4PCC) in this patient population undergoing cardiac surgery. STUDY DESIGN AND METHODS: This retrospective, single-center study evaluated the impact of 4PCC on hemoglobin (Hgb) change from baseline to postoperative nadir within a 7-day period among patients who refused alloBT during cardiac surgery. This study identified patients who refused alloBT from January 2011 to June 2017. Multivariable linear regression was used to control for confounding variables to evaluate the effectiveness of 4PCC. RESULTS: During the study timeframe, 79 patients met inclusion criteria, all of whom identified as JWs, and underwent cardiac surgery. Of these, 19 received intraoperative 4PCC. Multivariable linear regression found no difference in Hgb change in patients who received 4PCC vs those who did not. No significant differences were found in mortality, thromboembolic complications, or in-hospital postoperative events. CONCLUSIONS: In JWs undergoing cardiac surgery who refuse alloBT, intraoperative use of 4PCC was not associated with a difference in Hgb change within 7 days postoperatively when adjusting for confounding variables. In the event of excessive blood loss, the utilization of 4PCC may provide a viable option in JW patients who undergo cardiac surgery where few options exist to mitigate blood loss.

Three-factor prothrombin complex concentrates for refractory bleeding after cardiovascular surgery within an algorithmic approach to haemostasis.

BACKGROUND/OBJECTIVES: Prothrombin complex concentrates (PCC) are increasingly administered off-label in the United States to treat bleeding in cardiovascular surgical patients and carry the potential risk for acquired thromboembolic side-effects after surgery. Therefore, we hypothesized that the use of low-dose 3-factor (3F) PCC (20-30 IU/kg), as part of a transfusion algorithm, reduces bleeding without increasing postoperative thrombotic/thromboembolic complications. MATERIALS/METHODS: After IRB approval, we retrospectively analysed 114 consecutive, complex cardiovascular surgical patients (age > 18 years), between February 2014 and June 2015, that received low-dose 3F-PCC (Profilnine® ), of which seven patients met established exclusion criteria. PCC was dosed according to an institutional perioperative algorithm. Allogeneic transfusions were recorded before and after PCC administration (n = 107). The incidence of postoperative thromboembolic events was determined within 30 days of surgery, and Factor II levels were measured in a subset of patients (n = 20) as a quality control measure to avoid excessive PCC dosing. RESULTS: Total allogeneic blood product transfusion reached a mean of 12·4 ± 9·9 units before PCC and 5·0 ± 6·3 units after PCC administration (P < 0·001). The mean PCC dose was 15·8 ± 7·1 IU/kg. Four patients (3·8%) each experienced an ischaemic stroke on postoperative day 1, 2, 4 and 27. Seven patients (6·5%) had acquired venous thromboembolic disease within 10 days of surgery. Median factor II level after transfusion algorithm adherence and PCC administration was 87%. CONCLUSIONS: 3F-PCC use for refractory bleeding after cardiovascular surgery resulted in reduced transfusion of allogeneic blood and blood products. Adherence to this algorithmic approach was associated with an acceptable incidence of postoperative thrombotic/thromboembolic complications.

Approach to the Coagulopathic Patient in the Intensive Care Unit.

Key learning objectives: Evaluating patients with coagulopathy in intensive careManaging coagulopathy in intensive careUnderstand the complications and limitations of various therapies How to cite this article: Singh MY. Approach to the Coagulopathic Patient in the Intensive Care Unit. Indian J Crit Care Med 2019;23(Suppl 3):S215-S220.

Prophylactic treatment of bleeding episodes in children <12 years with moderate to severe hereditary factor X deficiency (FXD): Efficacy and safety of a high-purity plasma-derived factor X (pdFX) concentrate.

BACKGROUND: Hereditary factor X (FX) deficiency (FXD) affects 1:500 000-1:1 000 000 people worldwide. A novel, high-purity plasma-derived FX concentrate (pdFX) is available in the United States and European Union as replacement therapy for FXD, but data are scarce on pdFX use in children <12 years. AIM: This prospective, open-label phase 3 study assessed the safety, efficacy and pharmacokinetics of pdFX in children <12 years with moderate/severe FXD. METHODS: Subjects aged <12 years with basal plasma FX activity (FX:C) <5 IU/dL received pdFX as prophylactic and on-demand treatment, with doses adjusted to maintain FX:C > 5 IU/dL. After ≥26 weeks and ≥50 exposure days, investigators rated pdFX efficacy for preventing/decreasing bleeds. Secondary endpoints included number and severity of bleeds, trough FX:C and incremental recovery. Safety parameters were adverse events (AEs), inhibitor development and changes in laboratory parameters. RESULTS: The study enrolled 9 subjects (0-5 years, n = 4; 6-11 years, n = 5) with severe (n = 8) or moderate (n = 1) FXD. At end of study, investigators rated pdFX efficacy excellent for all subjects. Ten bleeds occurred (n = 3 subjects; 6 major, 3 minor, 1 unassessed for severity). Trough FX:C levels remained >5 IU/dL for all subjects after the last dose adjustment study visit. Mean incremental recovery was significantly lower for younger vs older subjects (1.53 vs 1.91 IU/dL per IU/kg; P = .001). All AEs were unrelated to treatment; no inhibitor development or clinically significant changes in laboratory parameters were observed. CONCLUSIONS: These results demonstrate the efficacy and safety of pdFX for treating children <12 years with moderate/severe hereditary FXD.

Lack of evidence for the transmission of hepatitis E virus by coagulation factor concentrates based on seroprevalence data.

BACKGROUND: Whether hepatitis E virus (HEV) infection can be transmitted by coagulation factor concentrates remains unclear. OBJECTIVES: The HEV seroprevalence in blood donors and recipients of coagulation factor concentrates was compared to obtain evidence of whether a transmission of HEV by coagulation factor concentrates could occur. METHODS: Archived samples from whole blood donors and patients who had received coagulation factor concentrates were investigated for the presence of anti-HEV IgG by ELISA. Western blotting was used to confirm the positive samples that showed reactivity in the ELISA. RESULTS: Of 357 blood donors, 68 (19%) presented IgG antibodies against HEV. Two of 92 patients who had received coagulation factor concentrates (2·2%) and 1 of the 69 patients who had received plasma-derived products (1·5%) tested positive for anti-HEV IgG. The seroprevalence of HEV in the patient group was significantly lower (P = 0·038) than that in the donor group. The two positive patients were a 72-year-old man treated with plasma-derived products and a 5-year-old girl treated with a recombinant coagulation factor concentrate. CONCLUSION: HEV seroprevalence was significantly higher in the blood donors than in the patients with a history of coagulation factor concentrate administration. In one of two patients with detectable anti-HEV IgG antibodies, the coagulation factor concentrate was not the probable source of infection. Our data suggest that HEV is efficiently inactivated during the manufacturing process of coagulation factor concentrates. Thus, testing for the presence of HEV RNA in plasma donated for the preparation of coagulation factor concentrates may not be necessary.

Replacement therapy for coronary artery bypass surgery in patients with hemophilia A and B.

There are only a few cases of patients with hemophilia A and B who have undergone coronary artery bypass surgery. High levels of replacement therapy with factor concentrate either with bolus or continuous infusion are usually required pre-operatively and during the first post-operative days in order to maintain the coagulation deficient factor levels greater than 80% of normal. Heparinization during cardiopulmonary bypass appears to be safe and intra-operative blood salvage using cell saver techniques reduce the need for transfusions.

New findings on inhibitor development: from registries to clinical studies.

The high incidence of inhibitors against factor VIII (FVIII) concentrates in patients with haemophilia A has encouraged debate as to whether product-type plays a role. There is debate in the literature as to whether rFVIII concentrates are associated with a higher incidence of inhibitors compared to pdFVIII products. The management of haemophilia in patients with inhibitors includes on-demand/prophylaxis treatment with bypassing agents, and/or immune tolerance induction (ITI). However, these options create an economic and emotional burden on patients, their families and healthcare practitioners. Although ITI eliminates inhibitors successfully in 60-80% of cases, it is costly. Despite high costs, preliminary data from a decision analytical model have indicated that ITI is economically advantageous compared with on-demand/prophylactic treatment with bypassing agents. In patients with persistent inhibitors and those who are not candidates for ITI or have failed ITI, bleeding-related mortality and morbidity increase and quality of life decreases, compared with non-inhibitor patients. This article provides an update on the risk of inhibitor development and discusses best management approaches for patients with high-risk factors for inhibitor development.

Correlation between plasma fibrinogen and FIBTEM thromboelastometry during liver transplantation: a comprehensive assessment.

BACKGROUND: Thromboelastometry may reduce red blood cell (RBC) transfusion in liver transplantation (LT). Fibrinogen concentration is a primary determinant of FIBTEM maximum clot firmness (MCF), but several factors could affect the correlation between FIBTEM MCF and fibrinogen values. We aimed to investigate (1) the concordance between fibrinogen level and FIBTEM MCF and (2) the association of fibrinogen level and FIBTEM MCF with RBC transfusion during LT. METHODS: A post hoc analysis of data from a randomized, multicentre, double-blind, saline/fibrinogen trial was used (NCT01539057). A total of 86 adult patients were included. RESULTS: The Lin concordance coefficient (LCC) between FIBTEM MCF and fibrinogen levels with the model formula 1·3679 + 0·05414* FIBTEM MCF was poor overall (LLC [95% CI]: 0·387 [0·340 to 0·432]) and moderate for the preperfusion period (LLC [95% CI]: 0·789 [0·747 to 0·824]), but very poor for the postreperfusion period (LLC [95% CI] 0·170 [0·105 to 0·233]). The model assessed for RBC transfusion for FIBTEM MCF showed an area under the curve of 0·788 [0·745-0·832]. Patients with FIBTEM MCF values <8 mm had a significantly higher likelihood of receiving RBC than patients with higher values. (OR [95% CI]: 2·08 [1·30-3·33], P = 0·002). FIBTEM MCF values over 10 mm do not appear to reduce the likelihood of RBC transfusion. CONCLUSION: FIBTEM MCF is not a good indicator of plasma fibrinogen values after graft reperfusion. FIBTEM MCF >8 mm during the LT procedure is associated with less RBC transfusion. FIBTEM MCF values over 10 mm could lead to unnecessary fibrinogen administration.

Von Willebrand disease - the 'Dos' and 'Don'ts' in surgery.

Von Willebrand disease (VWD) is the most common genetic bleeding disorder. VWD is caused by a deficiency or dysfunction of von Willebrand factor (VWF), a plasma protein that mediates the initial adhesion of platelets at sites of vascular injury and binds and stabilises coagulation factor VIII (FVIII) in the blood. Prophylaxis of surgical bleeding in patients with VWD requires consideration of the individual situation, including the type of procedure and the bleeding rate, before decisions about treatment type, dose, duration and adjunctive therapy with antifibrinolytics or antithrombotic prophylaxis can be made. Although desmopressin (DDAVP)-stimulated release of endogenous VWD is an effective treatment strategy in many patients, plasma concentrates containing VWF are the preferred option for most patients undergoing surgical procedures. Recommendations for the management of surgery in patients with VWD are summarised, including the severity of VWD and the type of the surgical procedure.

Safety surveillance in haemophilia and allied disorders.

The introduction of clotting factor concentrates has transformed the lives of persons with inherited bleeding disorders. With the use of prophylactic treatment, it is now possible to prevent bleeding in these individuals. The early concentrates were contaminated with the HIV and hepatitis C viruses (HCV) and resulted in major morbidity and mortality in the recipients. Current products are much safer, especially in terms of infectious agents, but other adverse events such as alloantibodies (inhibitors), allergic reactions and thrombotic risks remain of concern. Approximately 30% of previously untreated patients with severe haemophilia A develop inhibitors, making this the most important issue in haemophilia care today. Recently, it was suggested that one of the most commonly used concentrates was associated with a higher inhibitor risk, but this was not supported by the evidence from all studies. Good safety surveillance systems are essential for all diseases and products but are particularly so in the group of individuals with inherited bleeding disorders treated with clotting factor concentrates who have suffered disproportionately from the adverse effects of their treatment. National and multinational systems are now in place to allow reporting of adverse events in patients with inherited bleeding disorders. All clinicians treating individuals with inherited bleeding disorders should prospectively report adverse events to treatment even if they are believed to be common and well recognized.

The evolution of comprehensive haemophilia care in the United States: perspectives from the frontline.

The establishment of dedicated comprehensive treatment centres more than a half century ago transformed the management of haemophilia in the United States. Formerly, a disease associated with crippling disability and premature death, today, persons with haemophilia who are treated appropriately from infancy and do not develop inhibitors can expect a normal life expectancy and relatively few bleeding episodes. The evolution of the comprehensive haemophilia care, while chastened by the viral epidemics of the 1980s, has been marked by ongoing advances, including prophylaxis, immune tolerance induction, new drugs and gene therapy research. Current challenges include sustaining the comprehensive care model despite decreased funding and expanding the delivery and affordability of comprehensive haemophilia care.

Practical aspects of factor concentrate use in patients with von Willebrand disease undergoing invasive procedures: a European survey.

INTRODUCTION: The bleeding propensity in von Willebrand disease (VWD) is usually moderate or mild and patients with VWD do not need continuous treatment, but do require extra increased haemostatic cover when undergoing dental or surgical procedures. Desmopressin can be effective in certain patient groups and this has been considered in a previous publication. AIM: This paper now seeks to evaluate current knowledge and practice in the use of factor concentrate in the management of VWD patients undergoing invasive procedures. METHODS: A literature search was performed on the use of factor concentrates to cover invasive procedures and a survey of current practice in a number of specialist haematology centres across Europe represented by the European Haemophilia Strategy Board was conducted. RESULTS: Our review of the literature and the results of the survey showed considerable heterogeneity in treatment regimens, and a lack of consistency in reporting of the variables that determine factor concentrate dosing and monitoring. CONCLUSION: By analysing the literature, examining guidelines and using consensus deliberation, this survey allowed the group to develop recommendations for management of VWD patients undergoing invasive procedures.

Experience of a new high-purity factor X concentrate in subjects with hereditary factor X deficiency undergoing surgery.

INTRODUCTION: Maintaining haemostasis in surgery is challenging for hereditary rare bleeding disorders in which multi-coagulation-factor concentrates are the only therapeutic option. Hereditary factor X (FX) deficiency affects 1:500 000 to 1:1 000 000 individuals, and no specific replacement FX concentrate has been available. A high-purity, plasma-derived FX concentrate (pdFX) has been developed for patients with hereditary FX deficiency. AIM: Our objective was to assess the safety and efficacy of pdFX in subjects with FX deficiency undergoing surgery. METHODS: Subjects with hereditary mild-to-severe FX deficiency (basal plasma FX activity [FX:C] <20 IU dL(-1) ) undergoing surgery received pdFX preoperatively to raise FX:C to 70-90 IU dL(-1) and postoperatively to maintain levels >50 IU dL(-1) until the subject was no longer at risk of bleeding due to surgery. Efficacy of pdFX was assessed by blood loss during surgery, requirement for blood transfusion, postoperative bleeding from the surgical or other sites, and changes in haemoglobin levels. Safety was assessed by adverse events (AEs), development of inhibitors, and clinically significant changes in laboratory parameters. RESULTS: Five subjects (aged 14-59 years) underwent seven surgical procedures (four major and three minor). Treatment duration was 1-15 days. For each procedure, pdFX treatment was assessed as "excellent" in preventing bleeding and achieving haemostasis. No blood transfusions were required, no AEs related to pdFX were observed, and no clinically significant trends were found in any laboratory parameters. CONCLUSION: These data demonstrate that pdFX is safe and effective as replacement therapy in five subjects with mild-to-severe FX deficiency undergoing surgery on seven occasions.