Age-related variation in coagulation factors in non-valvular atrial fibrillation patients receiving direct oral anticoagulants.

Age is a significant risk factor for ischemic stroke. However, the influence of aging on coagulation parameters in non-valvular atrial fibrillation (NVAF) patients treated with direct oral anticoagulants (DOACs) remains unclear. A total of 775 samples were collected from 224 NVAF patients receiving apixaban, edoxaban or rivaroxaban. The samples were categorized into three age groups: (i) ≤ 64 years, (ii) 65-74 years, and (iii) ≥ 75 years (apixaban: N = 48, 108, 119; edoxaban: N = 63, 68, 126; rivaroxaban: N = 115, 90, 38, respectively). Coagulation parameters including fibrinogen (Fbg), factor II, factor V, factor VII, factor X, and D-dimer, were compared between the three age groups for each drug. The slopes in the correlation between drug concentrations and modified diluted prothrombin time (mdPT) were also assessed. Fbg and factor V increased with age, while factor II and factor X decreased. Factor VII and D-dimer showed no significant differences across age categories. The slope in response to drug concentrations was similar between the age groups. In NVAF patients treated with apixaban, edoxaban and rivaroxaban, some coagulation parameters exhibited age-related variation. However, the response of mdPT to drug concentration was consistent across age categories.

Plasma-derived human factor X concentrate for the treatment of patients with hereditary factor X deficiency.

INTRODUCTION: Hereditary factor X (FX) deficiency (HFXD) is an autosomal recessive rare bleeding disorder that leads to defects in the FX protein. Depending on the degree of deficiency, patients may be at risk of life-threatening bleeding episodes. Historical treatments for FX deficiency include prothrombin complex concentrates, which can increase the risk of thrombosis, and fresh frozen plasma, which can cause volume overload and transfusion reactions. Plasma-derived FX (pdFX), a single-factor, high-purity, high-potency human FX treatment, was approved in 2015 in the United States and in 2016 in Europe for on-demand treatment and prophylaxis of bleeding episodes and perioperative management of patients with HFXD. METHODS: Five studies that examined the use of pdFX in patients with mild (plasma FX activity [FX:C] ≥5 IU/dL), moderate (FX:C ≥1 and <5 IU/dL), or severe (FX:C < 1 IU/dL) HFXD were reviewed: TEN01, TEN02 and TEN03 were prospective, open-label, multicentre, nonrandomised studies, and TEN05 and TEN06 were multicentre retrospective studies. RESULTS: When used as an on-demand treatment, pdFX was judged by investigators to be successful in treating 41/42 (97.6%), 2/3 (66.6%) and 79/79 (100%) bleeds in TEN01, TEN02 and TEN05, respectively. When used prophylactically, pdFX was judged 'excellent' for the prevention of bleeds in nine (100%) and eight (100%) patients in TEN02 and TEN05, respectively. Perioperative treatment and pharmacokinetics were also assessed. pdFX was safe and well tolerated. CONCLUSIONS: Together, these studies support the use of pdFX for on-demand treatment of bleeding, routine prophylaxis, and perioperative management of bleeding in patients with HFXD.

Preclinical development and characterization of a human plasma-derived high-purity factor X concentrate for therapeutic use.

INTRODUCTION: Hereditary factor X deficiency is a rare bleeding disorder, with limited treatment options. This paper describes the approach to pre-clinical development and characterization of a high-purity plasma-derived factor X concentrate, to achieve orphan drug marketing authorization for the treatment of hereditary factor X deficiency. METHODS: A chromatographic process was developed, to purify factor X from human plasma for fractionation. The product was characterized using in vitro, in vivo and ex vivo tests for potency, purity, thrombogenicity, immunogenicity, toxicity and stability. RESULTS: The production process complied with good pharmaceutical manufacturing practice. It achieved 6000-fold purification and 100-fold concentration of the factor X protein compared to human plasma. The factor X protein was 94%-96% pure. Other residual plasma proteins were well below levels in plasma, minimizing potential interference in hemostasis after therapeutic administration. Effective virus-reduction during manufacture, and the absence of thrombogenicity, toxicity and immunogenic potential were confirmed, addressing the main safety concerns historically associated with plasma-derived therapeutics. The freeze-dried product remained stable between +2°C and +30°C for at least three years. After reconstitution with water for injections, the factor X activity was maintained for at least 48 h at +18°C to +22°C. CONCLUSION: Targeted pre-clinical development of the first highly-purified concentrate to treat hereditary factor X deficiency is described. Following international guidelines for nonclinical safety testing, particular strategies were adopted for unmodified products derived from human blood plasma. This approach may also be relevant to the development of other ultra-orphan medicinal products.

The safety of the combination therapy of recombinant factor VIIa and plasma-derived factor VIIa and factor X for refractory hemorrhage in acquired hemophilia A.

Acquired hemophilia A (AHA) is a rare, life-threatening hemorrhagic disease caused by autoantibodies against factor VIII (FVIII), and bypassing agents (BPA) are used to control bleeding. However, some cases need a change of BPA or BPAs given sequentially or in combination for refractory bleeding. A 71-year-old man was admitted with subcutaneous hemorrhage. Laboratory investigations showed prolongation of activated partial thromboplastin time (APTT) and low-coagulation FVIII activity and FVIII inhibitor; we, therefore, diagnosed AHA. He was treated with recombinant factor VIIa (rFVIIa) BPA and prednisolone. However, his symptoms did not improve sufficiently, thus we switched BPA to activated prothrombin complex concentrate. Unfortunately, this was not effective and he suffered hemorrhagic shock. Therefore, we selected rFVIIa, with plasma-derived FVIIa and factor X (pd-FVIIa/FX) as combination therapy, and hemostasis was achieved without thrombosis. This case suggests that the combination of rFVIIa and pd-FVIIa/FX short-term can be well tolerated for refractory hemorrhage in AHA.

Role of individual factor X concentrate pharmacokinetic studies in perioperative management of AL amyloidosis-associated acquired factor X deficiency.

BACKGROUND: AL amyloidosis is associated with acquired factor X (FX) deficiency. Experience related to its management is limited to case reports and series using prothrombin complex concentrate, fresh frozen plasma, plasma exchange, recombinant activated factor seven, and desmopressin with limited and variable efficacy. FX concentrate has not been widely used in its management. STUDY DESIGN AND METHODS: We report our experience with the perioperative use of FX concentrate (Coagadex) in two patients with AL amyloidosis-associated acquired FX deficiency requiring surgery, using their individual pharmacokinetic studies to manage perioperative hemostasis. Pharmacokinetic studies involved obtaining post-infusion FX activity at 10 min, 2, and 4 h following the administration of FX concentrate to calculate the FX half-life. RESULTS: Both patients' plasma FX activity was successfully increased to provide perioperative hemostatic support. Monitoring FX activity post-surgery was also utilized to maintain FX activity levels to prevent post-operative bleeding. CONCLUSION: Pharmacokinetic studies have a useful role in tailoring preoperative FX repletion in patients with AL amyloidosis associated with acquired FX deficiency.

Decrease in in vivo coagulant potential of emicizumab in a patient with hemophilia A and inhibitor complicated with infectious mononucleosis.

Emicizumab prophylaxis significantly reduces bleeding episodes in patients with hemophilia A (PwHA). There is little information on coagulant potentials in emicizumab-treated PwHA with infection, however. We encountered an emicizumab-treated PwHA with inhibitor, complicated with Epstein-Barr virus-associated infectious mononucleosis (IM) in phase 1/2 study (ACE001JP/ACE002JP). Although it was a typical clinical course of IM, activated partial thromboplastin time was mildly prolonged but rotational thromboelastometry revealed severely impaired coagulant potential. The blood concentration of emicizumab decreased moderately in the low concentration range, resulting in an increased risk of bleeding and possibly leading to severe ileocecal bleeds requiring coil embolization. The blood concentrations of factors IX/X little decreased and antiemicizumab antibodies did not develop, however. After the influence by IM resolved, his coagulant potentials gradually recovered with the recovery of emicizumab concentration, and parameters by global coagulation assays improved. An IM case for emicizumab-treated PwHA may need to monitor using global coagulation assays.

Plasma-derived factor VIIa and factor X mixture agent (MC710) prophylaxis in haemophilia B patients with inhibitors.

INTRODUCTION: Haemophilia B patients with factor IX inhibitors have particularly unmet needs for conventional therapy. AIM: Phase II/III clinical trial, multicentre, open-label, prospective, self-controlled study was conducted to assess MC710 prophylaxis in haemophilia B patients with inhibitors. METHODS: We enrolled haemophilia patients who had received episodic or prophylactic treatment with bypassing agents up to that time. The participants continued their conventional therapy for 24 weeks and then MC710 was prophylactically infused intravenously every 2 or 3 days at 60 to 120 µg as FVIIa per kilogram of body weight for 24 weeks. The primary endpoint was the annual bleeding rate (ABR) requiring bypassing agents, which was compared intraindividually between the conventional therapy period and the MC710 prophylaxis period. RESULTS: A total of 11 male haemophilia B patients were enrolled. The median ABR ratio for each participant (the prophylaxis period ABR divided by the conventional therapy period ABR) was .33 (2.1/6.5), range from .00 to 3.77. ABR ratios for 9 of the 11 patients ranged from .00 to .60, and 3 of the 9 patients had zero bleeding events during the prophylaxis period. Meanwhile, ABR ratios for the remaining two patients were 2.53 and 3.77, respectively. Although a fibrinogen decrease recovered by the dose reduction was reported for only one participant as the sole adverse drug reaction in this study, no thrombotic events or other safety concerns were reported. CONCLUSION: MC710 prophylaxis is considered to be decrease the bleeding rate in haemophilia B patients with inhibitors without safety concerns.

From a bispecific monoclonal antibody to gene therapy: A new era in the treatment of hemophilia A.

The treatment of hemophilia A has progressed amazingly in recent years. Emicizumab, a bispecific-humanized monoclonal antibody, is able to improve coagulation by bridging activated factor IX and factor X. Emicizumab is administered subcutaneously and much less often compared to factor VIII products. It has low immunogenicity, does not require dose adjustment, and can be administered regardless of the presence of factor VIII inhibitors. Thrombin generation assays but not factor VIII activity are indicated to guide and monitor the treatment. Emicizumab has enabled the conversion of patients with severe forms into patients with milder forms of hemophilia A. It has reduced the number of bleeding episodes compared to both on-demand and prophylactic substitution therapy and has an excellent safety profile. Gene therapy can elevate factor VIII plasma levels for many years after a single treatment course, could offer long-term protection from bleeding episodes, and minimize or eliminate the need for substitutive treatment with factor VIII concentrates. Gene therapy can provoke an immune response, manifested by an increase in common liver enzymes, that require immunotherapy. Long term monitoring is necessary to identify possible adverse effects. Future objectives are: the development of an ideal viral vector, the possibility of its re-administration, the use of gene therapy in hemophiliac children, and determining whether it can be successfully used to induce immune tolerance to factor VIII ceteri paribus. The future will determine the place of each type of treatment and group of patients for which it is indicated.

Emicizumab: a novel drug in hemophilia A prophylaxis - a narrative review.

INTRODUCTION: Hemophilia A is a genetically conditioned disease leading to hemostatic disorders due to factor VIII (FVIII) deficiency. The treatment of hemophilia has evolved throughout the past years and has significantly changed. One of the newest drugs for prophylactic treatment is the humanized bispecific IgG antibody - emicizumab, which binds with factor IXa and factor X, bridging those factors and thus mimicking the activity of factor VIII. AREAS COVERED: The literature search was done via the PubMed database, with the emphasis on clinical trials and case reports, describing the off-label emicizumab use. This review presents an extensive summary and considers the advantages and disadvantages (side-effects) of emicizumab, describing additional clinical situations, where emicizumab has been successfully used. In our review, we cover information about the mechanisms of action, indications, and efficacy and discuss some chosen case reports about off-label emicizumab use. EXPERT OPINION: Its convenient administration method (subcutaneous) and frequency of injections (from once a week to once a month) makes it a more comfortable treatment, limiting injection-site reactions, hospital stays, costs of prophylaxis, and significantly increasing patients' quality of life. Adverse effects are scarce and rarely serious - the most common ones are reactions at the injection-site and upper respiratory tract infections.

Deficiency of the splicing factor RBM10 limits EGFR inhibitor response in EGFR-mutant lung cancer.

Molecularly targeted cancer therapy has improved outcomes for patients with cancer with targetable oncoproteins, such as mutant EGFR in lung cancer. Yet, the long-term survival of these patients remains limited, because treatment responses are typically incomplete. One potential explanation for the lack of complete and durable responses is that oncogene-driven cancers with activating mutations of EGFR often harbor additional co-occurring genetic alterations. This hypothesis remains untested for most genetic alterations that co-occur with mutant EGFR. Here, we report the functional impact of inactivating genetic alterations of the mRNA splicing factor RNA-binding motif 10 (RBM10) that co-occur with mutant EGFR. RBM10 deficiency decreased EGFR inhibitor efficacy in patient-derived EGFR-mutant tumor models. RBM10 modulated mRNA alternative splicing of the mitochondrial apoptotic regulator Bcl-x to regulate tumor cell apoptosis during treatment. Genetic inactivation of RBM10 diminished EGFR inhibitor-mediated apoptosis by decreasing the ratio of (proapoptotic) Bcl-xS to (antiapoptotic) Bcl-xL isoforms of Bcl-x. RBM10 deficiency was a biomarker of poor response to EGFR inhibitor treatment in clinical samples. Coinhibition of Bcl-xL and mutant EGFR overcame the resistance induced by RBM10 deficiency. This study sheds light on the role of co-occurring genetic alterations and on the effect of splicing factor deficiency on the modulation of sensitivity to targeted kinase inhibitor cancer therapy.

Serum or Plasma for Quantification of Direct Oral Anticoagulants?

BACKGROUND: Direct oral anticoagulants are increasingly replacing vitamin K antagonists for prevention of stroke in patients with atrial fibrillation, partly owing to the lack of a need for routine monitoring. Therapeutic drug monitoring may still be warranted under certain circumstances. It is generally assumed that serum and plasma can be interchangeably used for this purpose. The aim of this study was to investigate possible differences between the serum, citrate-plasma, and ethylenediaminetetraacetic acid (EDTA)-plasma concentrations of apixaban and rivaroxaban in a larger patient group and their relation to factor X measurements. METHODS: Plasma and serum samples were drawn during the same venipuncture from patients treated with apixaban or rivaroxaban. Drug levels were measured using ultrahigh-performance liquid chromatography combined with tandem mass spectrometry. Three sample matrices were obtained from 8 healthy volunteers for measurement of factor X antigen and activity. RESULTS: Mean concentrations of apixaban and rivaroxaban were 16.8% and 36.6% higher in serum than in citrate-plasma, respectively (both P < 0.001). The corresponding differences in serum versus EDTA-plasma were 4.5% for apixaban and 13.1% for rivaroxaban (both P < 0.001). Factor X antigen measurements in citrate-plasma, EDTA-plasma, serum with clot activator, and serum without additives yielded comparable results, and factor X activity was significantly higher in serum than in plasma. CONCLUSIONS: Apixaban and rivaroxaban concentrations were significantly higher in serum than in plasma. The difference was more pronounced with rivaroxaban and was larger between serum and citrate-plasma than between serum and EDTA-plasma. Higher factor X activity in serum may explain the observed concentration differences. The choice of matrix is, thus, important when interpreting therapeutic drug monitoring results and in research involving analyses of direct oral anticoagulants. The authors recommend citrate-plasma as the preferred matrix.

Identification of a modified coagulation factor X with enhanced activation properties as potential hemostatic agent.

Hemophilia A and hemophilia B are X-linked inherited bleeding disorders caused by a deficiency of coagulation factor VIII and IX, respectively. Standard of care is prophylactic factor replacement therapy; however, the development of neutralizing antibodies against these factors represents serious complications underlining the need for alternative treatment approaches. Human coagulation factor X has a central role within the blood coagulation system making it an attractive target for the development of alternative treatment strategies for patients with hemophilia. This study focuses on a modified variant of the human coagulation factor X with enhanced hemostatic bypass activity due to insertion of a factor IX derived activation sequence. This molecule design leads to the direct activation of the modified factor X protein by factor XIa allowing it to bypass the need for coagulation factor VIIIa/factor IXa. The modified variant was able to correct in-vitro activated partial prothrombin time of human and murine factor VIII/factor IX deficient plasma. Furthermore, reduced blood loss in factor VIII knock-out mice was observed after intravenous application of the modified factor X variant. In conclusion, these data suggest that the factor X variant described here could potentially serve as a bypassing agent independent of the inhibitor status of hemophilia patients. However, more research is needed to further investigate the potential of this molecule.

Prophylaxis Using a Mixture of Plasma-Derived Activated Factor VII and Factor X (pdFVIIa/FX) in a Patient with Hemophilia B Complicated by Inhibitors and Allergy to Factor IX Concentrates: A Case Report.

Treating patients with hemophilia and inhibitors is often problematic. The presence of inhibitors negatively impacts the effectiveness of treatment to achieve hemostasis especially in patients with hemophilia B, owing mainly to allergic reactions to factor IX (FIX) concentrates and the low success rate of immune tolerance therapy. A 9-month-old boy had intracranial hemorrhage and was diagnosed with hemophilia B. After replacement therapy, he developed inhibitors and an allergic reaction to FIX. Prophylactic therapy was initiated with recombinant activated factor VII (rFVIIa) and later switched to pdFVIIa/factor X (FX; 120 µg/kg as the FVII dose, every other day) because of a recurrence of intracranial hemorrhage. Since then, he remained well without life-threatening bleeding for more than 2 years. Our case suggests that pdFVIIa/FX may be useful for prophylactic therapy in hemophilia B complicated by inhibitors and allergic reaction to FIX concentrates.

Plasma-derived factors VIIa and X mixtures (Byclot®) significantly improve impairment of coagulant potential ex vivo in plasmas from acquired hemophilia A patients.

A combined product of plasma-derived factor (F)VIIa and FX (pd-FVIIa/FX; Byclot®) is currently available for the hemostatic treatment of hemophilia A and B patients with inhibitors in Japan. Limited information is available, however, on its coagulant effect in acquired hemophilia A (AHA). In the present study, we assessed the coagulant effect of pd-FVIIa/FX on impairment of coagulation potentials in AHA. The bypassing agents, pd-FVIIa/FX, recombinant FVIIa (rFVIIa), and activated prothrombin complex concentrates (aPCC) were spiked with normal plasma preincubated with anti-FVIII monoclonal antibody (AHA-model plasma), and added to plasmas from AHA patients. Clot waveform analysis (CWA) triggered by the mixture of tissue factor and ellagic acid was subsequently performed. In the AHA-model, pd-FVIIa/FX improved all of the CWA parameters in a dose-dependent manner, irrespective of epitope specificity, with significant improvements relative to rFVIIa and aPCC. The coagulant effect of pd-FVIIa/FX at 1.6 µg/mL (corresponding to 120 µg/kg infusion) at the maximum therapeutic dose was outside the normal range. Moreover, the addition of pd-FVIIa/FX led to a greater improvement in the coagulant potentials in AHA plasmas than those of rFVIIa and/or aPCC. These data suggest that pd-FVIIa/FX significantly improves the impaired coagulant potentials in AHA and is potentially therapeutic.

[Possibility of using coagulation factor â ¡ and factor â © for warfarin monitoring in Chinese pulmonary embolism patients].

Objective: To explore the possibility of using coagulation factor Ⅱ and Ⅹ (FⅡ and FⅩ) for warfarin monitoring among Chinese pulmonary embolism patients. Methods: Blood samples were collected from pulmonary embolism patients who were taking warfarin as anticoagulant and who were from Peking Union Medical Collaege Hospital during Mar 2016 and Oct 2018. Activity of coagulation factor Ⅱ/Ⅹ and International Normalized Ratio (INR) level were detected. Correction analysis was used to investigate the relationship between activity of coagulation factor Ⅱ/Ⅹ and INR. Receiver Operating Characteristic (ROC) curve was used to analyze the diagnostic ability of FⅡ and FⅩ. Results: A total of 157 blood samples were collected in this research. When 1.5≤INR≤3.0, FⅡ (r=-0.768, P<0.001) and FⅩ(r=-0.690, P<0.001) were in inverse correlations with INR. Area under ROC curve (AUC) for FⅡ and FⅩ was 0.961 and 0.965 (P<0.001) when we used INR<2.0 as the criteria of anticoagulant inadequacy. AUC of ROC for FⅡ and FⅩ was 0.885 and 0.890 (P<0.001) when we used INR≤3.0 as the criteria of not over-anticoagulation. Conclusion: FⅡ and FⅩ activity can be used as the therapeutic markers of warfarin in Chinese pulmonary embolism patients.

Perioperative safety and haematostatic efficacy of a new bypassing agent pd-FVIIa/FX (Byclot) in haemophilia patients with high-responding type inhibitors.

: The novel agent pd-FVIIa/FX is a 1 : 10 protein weight mixture of activated factor VII (FVIIa) and factor X (FX) derived from donated blood plasma. A phase III clinical trial of pd-FVIIa/FX revealed high efficacy for bleeding episodes in haemophilia patients with inhibitors. However, up to now, only one case of this new agent being used for surgery had been reported. The objective of this study is to evaluate the perioperative haemostatic efficacy and safety of pd-FVIIa/FX in haemophilia patients with inhibitors. We retrospectively reviewed 25 operation charts from 14 haemophilia patients with high-responding inhibitors using pd-FVIIa/FX during the perioperative period. Efficacy was evaluated by attending physicians and results divided into four groups (excellent, good, fair, and poor). The operation chart was provided by nine Japanese medical institutes with expertise in haemophilia management. Out of the total of 25 surgical procedures, 44% (11/25) were classified as major surgery and the remainders were minor surgeries. In all of the surgeries but one, rFVIIa and/or APCC were administered in combination or sequential method. In all cases except one, the haemostatic efficiency rate was judged as excellent or good by treating physicians for an overall efficacy rate of 96%. No thrombotic adverse effects were reported. This study's results suggest that both combination and sequential therapy of pd-FVIIa/FX and other bypassing agents are well tolerated and effective for the control of perioperative bleeding in haemophilia patients with high-responding inhibitors.

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.

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.

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).

A new modeling approach allowing prediction and comparison of the long-term outcomes of treatments for hemophilia B.

AIM: To develop a modeling approach to compare clinical outcomes of nonacog beta pegol to a standard-acting factor IX (FIX) product. METHODS: Regression analysis linked FIX activity to bleed rates. Pharmacokinetic parameters were used to estimate FIX activity over time. The probability of bleeds was estimated for both treatment arms. A Markov model estimated the presence of target joints and annualized bleed rates (ABRs). RESULTS: Higher FIX activity showed reduced ABRs (p < 0.001). Target joints resulted in higher bleed rates (p < 0.001). When FIX activity levels and bleed risks were applied to the Markov model, ABRs for nonacog beta pegol and its comparator were 2.40 and 6.36, respectively. CONCLUSION: This model provides a starting point for assessing the added value of new FIX products.