[Show abstract][Hide abstract] ABSTRACT: In the phase 3 B-LONG [Recombinant Factor IX Fc Fusion Protein (rFIXFc) in Subjects with Haemophilia B] study, rFIXFc dosed every 1–2 weeks was safe and efficacious in previously treated subjects with haemophilia B. To date, there are no evaluations of transitioning from conventional to long-acting factor IX (FIX) prophylaxis. This post-hoc analysis of B-LONG subjects compared prophylaxis with other FIX products and rFIXFc. Pre- and on-study data were analysed to assess dosing regimen, weekly FIX consumption and annualized bleeding rates (ABRs). Population pharmacokinetics models were used to generate FIX activity profiles with rFIXFc and recombinant FIX prophylaxis. Thirty-nine subjects, previously treated prophylactically, were evaluated. Prior to study, most subjects (69·2%) received twice-weekly FIX infusions; on study, subjects infused rFIXFc once every 1–2 weeks with c. 30–50% reductions in weekly consumption. On-study estimated mean ABRs were lower than pre-study estimated mean ABRs. Models predicted that rFIXFc administered 50 iu/kg weekly and 100 iu/kg every 10 d would maintain steady-state FIX trough levels ≥1 iu/dl in 95·4% and 89·2% of subjects, respectively. These results indicate that patients receiving rFIXFc prophylaxis can markedly reduce infusion frequency and FIX consumption, have a greater likelihood of maintaining FIX activity >1 iu/dl and experience fewer bleeding episodes compared with prior FIX prophylaxis.
British Journal of Haematology 09/2014; · 4.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: IntroductionRecently, rapid immunoassays have been developed to allow the detection of antibodies anti-PF4/heparin. In this prospective study, we evaluated the performances of a automatized immunoassay (HemosIL HIT-Ab) in comparison with an ELISA (Zymutest HIA IgG) used for the diagnosis of heparin-induced thrombocytopenia (HIT) in association with the 4T's score.Methods
According to the 4T's score, samples with score ≤3 had no further analysis. Two immunological assays Zymutest HIA IgG and HemosIL HIT-Ab were performed in samples with score ≥4. In patients with at least one positive immunological assay or two negative immunological assays but with high-pretest probability (4T's score ≥6), HIT was screened by one functional assay using washed platelets.ResultsThe sensitivities of both assays were excellent and comparable (100%). The specificity was 92.3% for ELISA and 91.2% for HemosIL HIT-Ab. The analysis of the operating characteristics showed that both assays have almost identical ROCs (AUROC, 0.9951 and 0.9853, respectively, for ELISA and HemosIL HIT-Ab) and the calculating of the κ coefficient revealed a good agreement (0.67).Conclusion
Performance characteristics of the HemosIL HIT-Ab are comparable to the Zymutest HIA IgG. The HemosIL HIT-Ab can be used in association with the 4T's score to rule out HIT.
International journal of laboratory hematology 07/2014; · 1.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An ideal medical biology internal quality control (IQC) plan should both monitor the laboratory methods efficiently and implement the relevant clinical-biological specifications. However, many laboratories continue to use the 12s quality control rule without considering the high risk of false rejection and without considering the relationship of analytical performance to quality requirements. Alternatively, one can move to the Bayesian arena, enabling probabilistic quantification of the information coming in, on a daily basis from the laboratory's IQC tests, and taking into account the laboratory's medical and economic contexts. Using the example of one-stage clotting factor VIII assay, the present study compares frequentist (12s quality control rule) and Bayesian IQC management with respect to prescriber requirements, process start-up phase issues, and abnormal scenarios in IQC results. To achieve comparable confidence, the traditional 12s quality control rule requires more data than the Bayesian approach in order to detect an increase in the random or systematic error of the method. Moreover, the Bayesian IQC management approach explicitly implements respect of prescriber requirements in terms of calculating the probability that the variable in question lies in a given predefined interval: for example, the factor VIII concentration required after knee surgery in a hemophilia patient.
Blood coagulation & fibrinolysis: an international journal in haemostasis and thrombosis 03/2014; · 1.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Thirty per cent of patients with mild haemophilia A (MHA) present markedly different FVIII: C level when assayed by one-stage clotting and two-stage chromogenic assays. It is, therefore, a real clinical challenge to predict the individual bleeding risk of these patients. The aim of the present work was to study the relationship between the bleeding tendency of these patients with the results of a panel of phenotypic and genotypic tools. Thirty-six patients with MHA were included in this multicentre prospective clinical study. The severity of bleeding symptoms was evaluated using the ISTH/SSC score. FVIII:C levels were measured using an activated partial thromboplastin time-based one-stage FVIII assay (FVIII: C1) and three commercial chromogenic kits (FVIII:CR). FVIII antigen levels, thrombin generation measurement and FVIII gene mutation analysis were also performed. Our results showed that a one-stage FVIII: C assay cannot rule out the diagnosis of MHA, a combined use of FVIII:C1 with a FVIII:CR is suitable for detecting MHA. We observed that FVIII:CR results better reflected the clinical bleeding tendency of patients compared to FVIII:C1. We also observed a relationship between thrombin generation (TG) capacity and FVIII:CR of these patients. FVIII gene mutation analysis showed mutations previously reported in MHA patients with discrepant FVIII:C measurements, but with no predictive value of the individual bleeding phenotype of patients. Overall, we observed a relationship between chromogenic FVIII:C results, TG assay and bleeding tendency of patients with discrepant FVIII:C measurements, while FVIII:C1 was not well correlated with clinical bleeding phenotype in this particular population.
[Show abstract][Hide abstract] ABSTRACT: The development of inhibitors and the need for frequent venous access for FVIII injection are major challenges in current haemophilia treatment. Presently available recombinant FVIII (rFVIII) products produced in hamster cell lines are associated with inhibitor formation in up to 32% of previously untreated patients. The new human cell line-derived recombinant human FVIII (Human-cl rhFVIII) protein is the first native, unmodified truly human rFVIII product produced in a human cell line without additive animal proteins. The aim of using a human cell line for the production of rFVIII is the avoidance of non-human epitopes on rFVIII, thereby potentially reducing the rate of inhibitor development, avoiding allergic reactions and allowing personalized prophylaxis with the chance of fewer infusions. Studies to date show that prophylaxis with Human-cl rhFVIII prevents 96% of bleeding events in adults with severe haemophilia A when compared to on-demand treatment. Available pharmacokinetic data with a mean half-life of 17.1 h allow personalized prophylaxis with the chance of fewer infusions. Studies in previously treated children and adults indicate that Human-cl rhFVIII is efficacious and safe in the prevention and treatment of bleeding episodes and that none of the treated patients developed inhibitors or allergic reactions thus far.
[Show abstract][Hide abstract] ABSTRACT: Haemophilia A (HA) is an X-linked recessive bleeding disorder, caused by a wide variety of mutations in the factor VIII (F8) gene, leading to deficiency in the activity of coagulation FVIII. These mutations can affect all the F8 exons from the initiation codon to the termination codon, however, only few molecular changes in the promoter region of the F8 gene were reported so far. Here, we describe six nucleotide variations (c.-51G>A, c.-218T>C, c.-219C>T, c.-219delC, c.-221T>A and c.-664G>A) detected in the F8 promoter and their correlation with clinical phenotype of the patients. Potential role of these mutations in HA was also assessed. Causality was demonstrated with transient transfection experiments using luciferase reporter gene plasmids and computational analysis. Two molecular changes (c.-51G>A and c.-664G>A) did not seem to affect the promoter function of the F8 gene whereas c.-218T>C, c.-219C>T, c.-219delC, c.-221T>A mutations had an impact on the F8 promoter function and were responsible for HA. Furthermore, these mutations were associated with resistance to 1-deamino-8-d-argininevasopressin (desmopressin) therapy when they were causative. When molecular variation was detected in F8 promoter, we propose to use prediction software and to verify predictions by reporter gene analysis. If the mutation is causative, it will be probably associated with a lack of therapeutic response to desmopressin and this clinical implication should be considered by clinicians.
[Show abstract][Hide abstract] ABSTRACT: Standardization of pre-analytical conditions is the obligatory step for all potential diagnostic tests. Spatial clot growth (Thrombodynamics) is a new global hemostasis assay that considers spatial organization of coagulation. The principal parameter is rate of fibrin clot growth from the tissue-factor coated surface. In this work we studied the pre-analytical variables of Thrombodynamics assay that include conditions of blood collection, sample preparation and storage.
Blood of apparently healthy volunteers was used. Eight types of citrate blood collection tubes were tested, centrifugation conditions for plasma preparation were evaluated and impact of plasma freezing/thawing was tested.
Among the blood collection tubes tested, BD Vacutainer glass tubes showed a significantly higher clot growth rate compared to plastic tubes. There was no difference between 3.2% and 3.8% of sodium citrate. For plasma preparation, a single 15min centrifugation at 1 600g shows significantly increased clot growth rate compared to plasma obtained by two sequential centrifugations (15min 1 600g, 5min 10 000g). There was no significant difference between 1 600g and 2 100g if the second centrifugation was performed. For the second centrifugation there was no difference between 20min at 1 600g and 5min at 10 000g. Frozen-thawed plasma showed increased clot growth rate compared to fresh plasma.
The data represent the necessary steps for the standardization of Thrombodynamics assay and for the formulation of the operating guide.
[Show abstract][Hide abstract] ABSTRACT: Patients with haemophilia A and inhibitors are at high risk for severe bleeding, progression of joint disease and deterioration of health-related quality of life (HRQoL). To determine the impact of prophylaxis with an activated prothrombin complex concentrate (aPCC) on HRQoL, HRQoL was assessed using the Short-Form (SF)-36 Health Survey and the EQ-5D questionnaire in subjects ≥14 years participating in a prospective, randomized, crossover study comparing 6 months of aPCC prophylaxis with 6 months of on-demand therapy. Eighteen of 19 patients completed the survey or questionnaire before and after the on-demand therapy and prophylaxis periods. A general trend towards improved HRQoL after prophylaxis was observed for the 18 evaluable patients in all SF-36 dimensions except for vitality/energy and physical functioning. After prophylaxis, 'good responders,' defined as patients experiencing ≥50% reduction in bleeding, exhibited statistically and clinically significant differences in the physical component score (P = 0.021), role - physical (P = 0.042), bodily pain (P = 0.015), and social functioning (P = 0.036). Similarly, the EQ-5D health profile showed a trend towards improvement after prophylaxis in all evaluable patients. Among the good responders, improvements did not differ from those observed after on-demand treatment. EQ visual analogue scale values were slightly improved following prophylaxis for all evaluable patients and the EQ-5D utility index improved in the good responders only. During prophylaxis, patients missed significantly fewer days from school or work because of bleeding than during on-demand treatment (P = 0.01). In conclusion, by significantly reducing bleeding frequency in good responders, aPCC prophylaxis improved HRQoL compared with on-demand treatment.
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE: Bleeding is the main complication of warfarin therapy, even patients with an INR in the target range can suffer bleeding, suggesting that INR does not perfectly reflect the therapeutic effect of warfarin. We hypothesized the INR might underestimate the level of anticoagulation in a subject with a lower factor IX (FIX) level than average. METHODS & RESULTS: We modeled warfarin anticoagulation in our in vitro thrombin generation (TG) model by adjusting the levels of vitamin K-dependent factors to those of patients with an INR of 2-3. Variation in FIX had a marked effect on TG but had no effect on the PT-INR. A prospective observational, cross-sectional clinical study including 341 consecutive patients admitted to the emergency department with an INR between 2 and 3, showed a statistically lower FIX activity in bleeders (p=0.004) compared to others. No correlation was found between TG capacity and PT-INR results (p=0.36).However, in patients, presenting with warfarin-related hemorrhage, TG was significantly lower (p<0.001) than others. And a correlation on the boundary of significance was observed between TG capacity and FIX levels (p=0.09). CONCLUSION: These data demonstrates that patients who bleed when their PT-INR is in the target range 2-3 might have defective TG related to a lower level of FIX than expected. This article is protected by copyright. All rights reserved.
Journal of Thrombosis and Haemostasis 04/2013; · 6.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Most health care professionals involved in the management of people with haemophilia (PWH) believe that exercise is beneficial and its practice is widely encouraged. This article aims to demonstrate that appropriate exercise (adapted to the special needs of the individual PWH) may be beneficial for all PWH through improved physical, psychosocial and medical status. Based on evidence gathered from the literature, many PWH, particularly those using long-term prophylaxis or exhibiting a mild/moderate bleeding phenotype, are as active as their healthy peers. PWH experience the same benefits of exercise as the general population, being physically healthier than if sedentary and enjoying a higher quality of life (QoL) through social inclusion and higher self-esteem. PWH can also gain physically from increased muscle strength, joint health, balance and flexibility achieved through physiotherapy, physical activity, exercise and sport. Conversely, very little data exist on activity levels of PWH in countries with limited resources. However, regarding specific exercise recommendations in PWH, there is a lack of randomized clinical trials, and consequently formal, evidence-based guidelines have not been produced. Based on published evidence from this review of the literature, together with the clinical experience of the authors, a series of recommendations for the safe participation of PWH in regular physical activities, exercises and sport are now proposed. In summary, we believe that appropriately modified programmes can potentially allow all PWH to experience the physical and psychosocial benefits of being physically active which may ultimately lead to an improved QoL.
[Show abstract][Hide abstract] ABSTRACT: Hemophilia is a bleeding disorder afflicting about 1 in 5000 males. Treatment relies upon replacement of the deficient factor and response to treatment both in clinical research and practice is based upon subjective parameters such as pain and joint mobility. Existing laboratory assays quantify the amount of factor in plasma, which is useful diagnostically and prognostically, however, these assays are limited in their ability to fully evaluate the clot-forming capability of patients. Newer assays, known as global assays, provide a far more detailed view of thrombin generation and clot formation, and have been studied in hemophilia for about 10 years. They have the potential to offer a more objective measure of both the hemophilic phenotype as well as the response to treatment. In particular, in patients who develop inhibitors to deficient clotting factors in whom bypassing agents are required for hemostasis, these assays offer the opportunity to determine the laboratory response to these interventions where traditional coagulation assays cannot. This review will discuss the physiology of hemostasis as it relates to global assays, review the existing literature, and discuss several controversial issues surrounding the assays. Lastly, a vision of the future clinical uses of these assays will be briefly described.
[Show abstract][Hide abstract] ABSTRACT: INTRODUCTION: Prothrombin complex concentrates (PCC) are haemostatic blood preparations indicated for urgent anticoagulation reversal, though the optimal dose for effective reversal is still under debate. The latest generation of PCCs include four coagulation factors, the so-called 4-factor PCC. The aim of this study was to compare the efficacy and safety of two doses, 25 and 40 IU/kg, of 4-factor PCC in vitamin K antagonist (VKA) associated intracranial haemorrhage. METHODS: We performed a phase III, prospective, randomised, open-label study including patients with objectively diagnosed VKA-associated intracranial haemorrhage between November 2008 and April 2011 in 22 centres in France. Patients were randomised to receive 25 or 40 IU/kg of 4-factor PCC. The primary endpoint was the International Normalised Ratio (INR) 10 minutes after the end of 4-factor PCC infusion. Secondary endpoints were changes in coagulation factors, global clinical outcomes and incidence of adverse events (AEs). RESULTS: A total of 59 patients were randomised: 29 in the 25 IU/kg and 30 in the 40 IU/kg group. Baseline demographics and clinical characteristics were comparable between the groups. The mean INR was significantly reduced to 1.2 - and [lessthan or equal to] 1.5 in all patients of both groups - 10 min after 4-factor PCC infusion. The INR in the 40 IU/kg group was significantly lower than in the 25 IU/kg group 10 min (p=0.001), 1 hour (p=0.001) and 3 hours (p=0.02) after infusion. The 40 IU/kg dose was also effective in replacing coagulation factors such as PT (p=0.038), FII (p=0.001), FX (p<0.001), protein C (p=0.002) and protein S (0.043), 10 min after infusion. However, no differences were found in hematoma volume or global clinical outcomes between the groups. Incidence of death and thrombotic events was similar between the groups. CONCLUSIONS: Rapid infusion of both doses of 4-factor PCC achieved an INR of 1.5 or less in all patients with a lower INR observed in the 40 IU/kg group. No safety concerns were raised by the 40 IU/kg dose. Further trials are needed to evaluate the impact of the high dose of 4-factor PCC on functional outcomes and mortality. Trial registration: Eudra CT number 2007-000602-73.
Critical care (London, England) 01/2013; 17(1):R4. · 4.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Factor VIII Inhibitor Bypassing Activity (FEIBA) can effectively achieve haemostasis in haemophilia patients with inhibitors. Further evaluation of FEIBA in surgical settings is of significant interest considering the relatively limited prospective data published to date. The aim of the study is to evaluate the perioperative efficacy and safety of FEIBA in haemophilia patients with inhibitors. Haemophilia patients with inhibitors who underwent surgical procedures and received FEIBA for perioperative haemostatic control were prospectively enrolled in an open-label, noninterventional, postauthorization study [SURgical interventions with FEIBA (SURF)]. Outcome measures included haemostatic efficacy, safety, FEIBA exposure and blood loss associated with the perioperative use of FEIBA. Thirty-five surgical procedures were performed at 19 centres worldwide in patients with congenital haemophilia A, congenital haemophilia B, or acquired haemophilia A. Haemorrhagic risk was severe in 37.1% (13 of 35) of the procedures, moderate in 25.7% (9 of 35) and mild in 37.1% (13 of 35). One moderate risk surgery was excluded from the efficacy analyses because it did not meet all protocol requirements. Haemostasis was judged to be 'good' or 'excellent' in 91.2% (31 of 34) of surgical procedures and 'fair' in 8.8% (3 of 34). Among the 12 adverse events, three were serious adverse events (SAEs), two of which were unrelated to FEIBA therapy; one SAE, a clot in an arteriovenous fistula, was deemed to be possibly related to therapy. This prospective investigation confirms that FEIBA can be safely and effectively used when performing surgical procedures in haemophilia patients with inhibitors.
[Show abstract][Hide abstract] ABSTRACT: Immune tolerance induction (ITI) can eliminate factor VIII (FVIII) inhibitory antibodies that appear during FVIII replacement therapy. If first-line ITI fails, switching to a different FVIII concentrate, especially one containing von Willebrand factor (VWF), has been advocated. The objective of the study was to assess the efficacy and safety of Haemate(®) P, a plasma-derived FVIII concentrate containing high levels of VWF, as ITI in severe haemophilia A patients who had failed at least one prior ITI attempt with a different FVIII concentrate. In this multicentre, observational study, Haemate(®) P was administered at a starting dose of 83-308 IU kg(-1) day(-1) (1500-6000 IU day(-1) ). Efficacy was assessed by standard criteria (e.g. Bethesda titre, FVIII recovery and half-life), and bleeding characteristics. Nine patients from six haemophilia centres were treated with Haemate(®) P after failing one (n = 2), two (n = 5) or three (n = 2) prior ITI courses. The median time from inhibitor detection to Haemate(®) P treatment was 5.4 years. The median Haemate(®) P dose was 134 IU kg(-1) , and the median treatment duration 32 months. During median of 47 months of follow-up, complete response, partial response and treatment failure were observed in one, three and five patients respectively. Five patients experienced seven adverse events (AEs), including two serious AEs (sepsis). Haemate(®) P was discontinued due to an AE in one patient with a partial response. Haemate(®) P salvage ITI resulted in complete or partial tolerization in four of nine patients (44%) who had failed previous ITI attempts using different FVIII concentrates.
[Show abstract][Hide abstract] ABSTRACT: Background and Objectives Total knee replacement (TKR) is the treatment of choice in case of end-stage knee arthropathy, the main complication of haemophilia. We report here a retrospective evaluation of 72 total knee replacement in 51 haemophilia A and B patients using continuous infusion of factor concentrates (CIFC). Materials and Methods Patients were evaluated on the basis of the following efficacy and safety criteria: range of motion, surgery-related blood loss by three different methods, factor consumption and occurrence of short and long term complications. Results Kaplan-Meier analysis showed a removal-free survival of TKRs of 88.4% 10 years after surgery. Most patients were satisfied with their prosthesis and described pain relief and improved mobility and better quality of life after surgery. The long term follow-up showed a mean range of motion at 86° with a flexion deformity of 4°. The blood loss differed significantly according to the method used for measurement. No life-threatening bleeding occurred. Twenty six haematomas (36.1%) and 2 haemarthroses (2.7%) occurred in 38.8% of cases during the first three postoperative weeks, with no significant impact on the orthopaedic outcome. The average factor consumption during hospitalization was 79 IU/kg/day for patients with haemophilia A and 99 IU/kg/day for patients with haemophilia B. Infections occurred in 4.1% of patients. One patient with severe haemophilia A developed an inhibitor. Conclusions The multidisciplinary approach and the homogeneous management of our large cohort allowed the achievement of excellent functional results. Our results confirmed previously reported data on the safety and efficacy of CIFC in situations requiring intensive factor replacement, such as TKR surgery.
[Show abstract][Hide abstract] ABSTRACT: Recombinant factor IX (rFIX) is increasingly used to treat patients with hemophilia B. CHO (Chinese Hamster Ovary) cells are commonly used for the production of rFIX but they have a limited capacity for introducing post-translational modifications (PTM) leading to incomplete γ-carboxylation, low phosphorylation and sulfation profiles as compared with plasma-derived preparations. Imperfect PTM might have an impact on the activity of Factor IX molecule. Several studies in animal models as well as clinical trials have previously reported a lower recovery of rFIX compared to plasma-derived FIX concentrates. In the present study, we aimed to produce a rFIX having a profile of PTM similar to plasma-derived FIX, using human hepatoma cell line HuH-7. We showed that rFIX produced by HuH-7 cells followed the classical intracellular pathway before secretion. In addition, improved PTM were associated with fully active molecule compared to plasma-derived and recombinant control FIX molecules. Secreted rFIX presented as a single band at the correct molecular weight. HuH-7 cellular clones were obtained and they secreted a biologically active human FIX. FIX was then purified for a detailed evaluation of PTM. Glycosylation and sialylation profiles were similar to plasma-derived and rFIX and mass spectrometry analysis demonstrated the presence of phosphorylated and sulfated forms of rFIX. These data strongly support that HuH-7 cells may represent an effective cellular system for production of rFIX exhibiting PTM similar to plasma-derived FIX.
Thrombosis Research 09/2012; 130(5):e266-73. · 3.13 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A growing number of publications have described the efficacy and safety of FEIBA as a first-line haemostatic agent for surgical procedures in haemophilia A patients with high-responding FVIII inhibitors. The aim of this study was to provide practical guidance on patient management and selection and also to communicate a standardized approach to the dosing and monitoring of FEIBA during and after surgery. A consensus group was convened with the aims of (i) providing an overview of the efficacy and safety of FEIBA in surgery; (ii) sharing best practice; (iii) developing recommendations based on the outcome of (i) and (ii). To date there have been 17 publications reporting on the use of FEIBA in over 210 major and minor orthopaedic and non-orthopaedic surgical procedures. Haemostatic outcome was rated as 'excellent' or 'good' in 78-100% of major cases. The reporting of thromboembolic complications or anamnestic response to FEIBA was very rare. Key to the success of FEIBA as haemostatic cover in surgery is to utilize the preplanning phase to prepare the patient both for surgery and also for rehabilitation. Haemostatic control with FEIBA should be continued for an adequate period postoperatively to support wound healing and to cover what can in some patients be an extended period of physiotherapy. Published data have demonstrated that FEIBA can provide adequate, well tolerated, peri and postoperative haemostatic cover for a variety of major and minor surgical procedures in patients with haemophilia A. The consensus recommendations provide a standardized approach to the dosing and monitoring of FEIBA.
[Show abstract][Hide abstract] ABSTRACT: The thrombin generation test (TGT) has demonstrated utility in evaluating overall hemostatic capacity both in bleeding and thrombotic disorders. Although the test is currently well accepted as a research tool, its role in clinical practice has not yet been defined through large prospective multicenter clinical studies. Such prospective studies have been limited by the lack of official standardization of the assay and its large inter-laboratory variability. This international study assessed the intra- and inter-assay imprecision of TGT as well as the inter-centre variability of results in one US and four European centres. Contact-inhibited plasmas from six healthy volunteers, one mild haemophilia A patient, and five patients with heterozygous prothrombin G20210 mutation were assayed. We demonstrated that, using identical equipement, standardized reagents, a carefully selected reference plasma for normalization of results and the same test procedure as described in our DVD, the assay variability was highly reduced compared to previously published data. Our results emphasize the importance of preheating on TGT results and the variability of the assay. In conclusion, our data demonstrated that the standardized TGT methodology evaluated in this study effectively reduces the variability of the assay to acceptable limits and may be used in clinical trials.
[Show abstract][Hide abstract] ABSTRACT: A recombinant fusion protein linking coagulation factor IX (FIX) with human albumin (rIX-FP) has been developed to facilitate hemophilia B treatment by less frequent FIX dosing. This first-in-human dose-escalation trial in 25 previously treated subjects with hemophilia B (FIX ≤ 2 IU/dL) examined the safety and pharmacokinetics of 25, 50, and 75 IU/kg rIX-FP. Patients in the 50-IU/kg cohort underwent a comparative pharmacokinetics assessment with their previous FIX product (plasma-derived or recombinant). No allergic reactions or inhibitors were observed. Four mild, possibly treatment-related adverse events were reported. In the 50-IU/kg cohort (13 subjects), the mean half-life of rIX-FP was 92 hours, more than 5 times longer than the subjects' previous FIX product. After 25 or 50 IU/kg rIX-FP administration, the baseline-corrected mean FIX activity remained elevated at day 7 (7.4 IU/dL and 13.4 IU/dL, respectively) and day 14 (2.5 IU/dL and 5.5 IU/dL, respectively). The incremental recovery of rIX-FP was higher than both recombinant and plasma-derived FIX (1.4 vs 0.95 and 1.1 IU/dL per IU/kg, respectively). These results demonstrated both the safety and improved pharmacokinetics of rIX-FP, thus indicating this new product with extended half-life as possibly able to control and prevent bleeding with less frequent injection. The trial was registered at www.clinicaltrials.gov as no. NCT01233440.