Fibrinogen concentrate for treatment of bleeding and surgical prophylaxis in congenital fibrinogen deficiency patients.

BACKGROUND: Congenital fibrinogen deficiency is an ultra-rare disorder in which patients can experience severe and/or frequent bleeding episodes (BEs). Here, we present the largest prospective study to date on the treatment of this disorder. METHODS: Hemostatic efficacy of human fibrinogen concentrate (HFC; FIBRYGA® , Octapharma AG) for treatment of bleeding or surgical prophylaxis was assessed by investigators and adjudicated by an independent data monitoring and endpoint adjudication committee (IDMEAC) according to a four-point scale, using objective criteria. Thromboelastometry maximum clot firmness (MCF) was also determined. RESULTS: Twenty-five afibrinogenemia patients were treated with HFC: 24 for on-demand treatment of 89 BEs, and nine as prophylaxis for 12 surgeries. For BEs, treatment success (rating of excellent or good) evaluated by investigators was 96.6% (90% confidence interval [CI], 0.92-0.99; two missing ratings, classified as failures) and by the IDMEAC was 98.9% (90% CI, 0.95-0.999). Mean ± standard deviation (SD) increase in MCF was 5.8 ± 2.5 mm one hour after the first HFC infusion (mean ± SD dose, 61.88 ± 11.73 mg/kg). For the 12 surgeries (median [range] HFC dose/surgery, 85.80 mg/kg [34.09-225.36]), intraoperative and postoperative treatment success were both rated 100% (90% CI, 0.82-1.00) by investigators and the IDMEAC. Three adverse events were possibly treatment related, including a moderate case of thrombosis. There were no deaths, no severe allergic or hypersensitivity reactions, and no clinical evidence of neutralizing antifibrinogen antibodies. CONCLUSIONS: Human fibrinogen concentrate was efficacious for on-demand treatment of bleeding and as surgical prophylaxis, with a favorable safety profile, in patients with congenital afibrinogenemia.

Efficacy and safety of a new human fibrinogen concentrate in patients with congenital fibrinogen deficiency: an interim analysis of a Phase III trial.

BACKGROUND: Fibrinogen concentrate is the preferred choice for fibrinogen replacement in congenital fibrinogen deficiency. This study investigated hemostatic efficacy of a new plasma-derived, double virus-inactivated (using two dedicated virus inactivation/elimination steps) human fibrinogen concentrate for on-demand treatment of bleeding episodes (BEs) and surgical prophylaxis. STUDY DESIGN AND METHODS: In this planned interim analysis of a prospective, multinational Phase III study (NCT02267226), 13 patients with afibrinogenemia (≥12 years) received fibrinogen concentrate (FIBRYGA, Octapharma AG). Hemostatic efficacy was assessed by investigators and an independent data monitoring and endpoint adjudication committee (IDMEAC) using objective four-point criteria and by thromboelastometry maximum clot firmness (MCF). RESULTS: Fibrinogen concentrate was used on-demand to treat 23 BEs in 11 patients, with 21 (91.3%) requiring a single infusion only. Treatment success was 95.7% (90% confidence interval [CI], 0.81-1.00; assessment missing for one BE) by investigators and 100% (90% CI, 0.88-1.00) by IDMEAC. Mean MCF increased significantly from 0.0 to 6.5 mm (95% CI, 5.65-7.40; p < 0.0001) at 1 hour postinfusion of a median (range) dose of 58.8 (33.9-101.7) mg/kg per BE. Four patients received fibrinogen concentrate as surgical prophylaxis, with intraoperative and postoperative treatment success rated 100% (90% CI, 0.50-1.00) by investigators and IDMEAC (median [range] dose per surgery 93.5 [34.1-225.4] mg/kg). No additional hemostatic interventions were required. No deaths, thromboses, or seroconversions were reported. CONCLUSION: These data showed that the new fibrinogen concentrate was efficacious for on-demand treatment of acute bleeding and surgical prophylaxis in congenital afibrinogenemia patients.

Use of objective efficacy criteria for evaluation of von Willebrand factor/factor VIII concentrates.

von Willebrand disease (VWD) is the most common inherited coagulation disorder and is typically treated by restoring the deficient von Willebrand factor (VWF) with exogenous VWF or by stimulating release of endogenous VWF with desmopressin. Assessment of treatment efficacy is complex because there are no standardized criteria or consistent methodology in their application. The traditionally used four-point Likert scale, with criteria that are not clearly defined or easily quantifiable, relies on a subjective rating of efficacy, and is thus open to observer bias. This article presents a novel approach to assessing efficacy of VWF replacement therapy. A new objective scoring system for assessment of the treatment efficacy of bleeding episodes (objective set of criteria for evaluation of treatment efficacy in VWD) was developed to assess a new-generation human plasma-derived VWF/coagulation factor VIII concentrate (Wilate). This manuscript analyzes the results obtained using a traditional subjective scoring system for hemostatic efficacy and compares them with results obtained when a specifically developed set of stringent objective and well defined success/failure criteria are applied in a clinical trial setting. This new assessment tool provided improved objectification of the subjective judgments obtained from the recipients of the replacement therapy. A validated tool like this could ultimately be applied to clinical comparability studies for the multiplicity of new generation replacement products, as healthcare providers, regulatory agencies, and manufacturers must now consider the additional benefits conveyed by treatment modalities, such as treatment duration, alternative dosing regimens, and treatment frequency. The objective criteria appear to be more robust and present a more conservative assessment of treatment efficacy while avoiding observer and recipient bias and inconsistencies. This new approach may be a more suitable alternative for hemostatic assessment of coagulation products in VWD patients than the currently used subjective methods.

The pharmacokinetic diversity of two von Willebrand factor (VWF)/ factor VIII (FVIII) concentrates in subjects with congenital von Willebrand disease. Results from a prospective, randomised crossover study.

The pharmacokinetic (PK) profiles of von Willebrand factor (VWF) /factor VIII (FVIII) concentrates are important for treatment efficacy and safety of von Willebrand disease (VWD) patients. This prospective, head-to-head, randomised crossover study compared the PK profile of a new, high purity, human plasma-derived (pd)VWF/FVIII concentrate, Wilate, with the PK profile of an intermediate purity (pd)VWF/FVIII concentrate, Humate-P, in VWD patients. Subjects with inherited VWD were randomised to a single intravenous dose (40 IU/kg VWF ristocetin cofactor activity [VWF:RCo]) of Wilate or Humate-P in Period 1, and switched to the other study drug in Period 2. Each period was preceded by a washout time of ≥ 7 days. Coagulation factor parameters were analysed at multiple time-points. Of 22 randomised subjects, 20 had evaluable PK profiles, which indicated comparability for VWF antigen and VWF:RCo between Wilate and Humate-P. The reported VWF:RCo average and terminal t1/2 of 10.4 and 15.8 hours (h), respectively, for Wilate and 9.3 h and 12.8 h for Humate-P, were not statistically different. Also, the mean VWF:RCo in vivo recoveries (Wilate 1.89, Humate-P 1.99 IU/dl per IU/kg) were similar between the two replacement therapies. Wilate showed parallel decay curves for VWF:RCo and FVIII clotting activity (FVIII:C) over time, while FVIII:C of Humate-P displayed a plateau between 0 and 12-24 h. This study demonstrated bioequivalent PK properties for VWF between Wilate and Humate-P. The PK profile of Wilate, combined with the 1:1 VWF/FVIII ratio, theoretically should facilitate dosing and laboratory monitoring of VWF replacement to prevent bleeding in individuals with VWD.

Long-term, low-intensity warfarin therapy for the prevention of recurrent venous thromboembolism.

BACKGROUND: Standard therapy to prevent recurrent venous thromboembolism includes 3 to 12 months of treatment with full-dose warfarin with a target international normalized ratio (INR) between 2.0 and 3.0. However, for long-term management, no therapeutic agent has shown an acceptable benefit-to-risk ratio. METHODS: Patients with idiopathic venous thromboembolism who had received full-dose anticoagulation therapy for a median of 6.5 months were randomly assigned to placebo or low-intensity warfarin (target INR, 1.5 to 2.0). Participants were followed for recurrent venous thromboembolism, major hemorrhage, and death. RESULTS: The trial was terminated early after 508 patients had undergone randomization and had been followed for up to 4.3 years (mean, 2.1). Of 253 patients assigned to placebo, 37 had recurrent venous thromboembolism (7.2 per 100 person-years), as compared with 14 of 255 patients assigned to low-intensity warfarin (2.6 per 100 person-years), a risk reduction of 64 percent (hazard ratio, 0.36 [95 percent confidence interval, 0.19 to 0.67]; P<0.001). Risk reductions were similar for all subgroups, including those with and those without inherited thrombophilia. Major hemorrhage occurred in two patients assigned to placebo and five assigned to low-intensity warfarin (P=0.25). Eight patients in the placebo group and four in the group assigned to low-intensity warfarin died (P=0.26). Low-intensity warfarin was thus associated with a 48 percent reduction in the composite end point of recurrent venous thromboembolism, major hemorrhage, or death. According to per-protocol and as-treated analyses, the reduction in the risk of recurrent venous thromboembolism was between 76 and 81 percent. CONCLUSIONS: Long-term, low-intensity warfarin therapy is a highly effective method of preventing recurrent venous thromboembolism.

Pharmacokinetic analysis of plasma-derived and recombinant F IX concentrates in previously treated patients with moderate or severe hemophilia B.

BACKGROUND: Hemophilia B is an X-linked bleeding disorder that affects approximately 1 in 25,000 males. Therapy for acute bleeding episodes consists of transfusions of plasma-derived (pd-F IX) or recombinant (r-F IX) concentrates. STUDY DESIGN AND METHODS: A double-blind, two-period crossover study was initiated to assess the pharmacokinetics of pd-F IX and r-F IX and to address patient-specific variables that might influence in vivo recovery. Study product was administered by a single bolus infusion (50 IU/kg) to 43 previously treated patients in the nonbleeding state, and F IX:C levels were measured over a period of 48 hours after infusion. RESULTS: The mean in vivo recovery in the pd-F IX group was 1.71 +/- 0.73 IU per dL per IU per kg compared with 0.86 +/- 0.31 IU per dL per IU per kg with r-F IX (p