Bleeding management: rFVIIIFc in hemophilia A and liver transplantation

BACKGROUND

In patients with severe hemophilia A prolonged bleeding may occur even in cases of minor trauma or surgery.

OBJECTIVE

To investigate the feasibility and efficacy of a recombinant extended half-life (EHL) FVIII concentrate for perioperative bleeding management in a patient with severe hemophilia A undergoing liver transplantation.

MATERIAL AND METHODS

Prior to transplantation FVIII activity and perioperatively required FVIII supply were estimated. In an individualized approach efmoroctocog alfa was supplemented if the intrinsic clotting time in the thrombelastometry was > 170 s.

RESULTS

The patient perioperatively received a total of 28,000 IU efmoroctocog alfa. No signs of hemorrhage or complications were detected and no further intervention was necessary.

CONCLUSION

The present case demonstrates that the use of an EHL FVIII is suitable for a successful perioperative bleeding control even in hemophilia patients at a high bleeding risk during major surgery. Due to the EHL constant FVIII levels could be achieved with relatively few injections. In order to confirm the obtained results, more real-world data in different operative settings are essential. Further research is needed on the use of thrombelastometry to guide substitution of factor VIII perioperatively.

Inhibitor; An Uncommon But Vexing Challenge In North Indian Patients With Hemophilia A

Factor VIII replacement is the mainstay of treatment in hemophilia A but may lead to the development of inhibitors. While a vexing clinical problem, some observations suggest that the presence of inhibitors may not necessarily portend a higher bleeding risk. Our aim was to assess the prevalence and clinicopathological correlates of inhibitors in a well characterized cohort of Indian patients with HA patients. We retrospectively reviewed the clinical details and laboratory findings of consecutive hemophilia A patients attending a north-Indian tertiary-care center from 2010 to 2020. Among 592 patients with HA, inhibitors were detected in 35 patients (5.9%). Prevalence of inhibitors in moderate and severe hemophilia was 4.2% and 6.7%, respectively. Most patients with inhibitors had history of transfusion with factor VIII alone (54.3%) or a combination of factor VIII concentrate and other blood-products (42.9%). Intracranial bleed was significantly more frequent in patients with inhibitors compared to those without inhibitors (20% vs. 4.1%; p-0.001). Time dependent and immediately acting inhibitors were seen in 60% and 40% patients, respectively. High-titre (> 5 BU) and low-titre inhibitors (< 5 BU) were detected in 28 (80%) and 7 (20%) patients, respectively. Prevalence of inhibitors in our cohort was 5.9% and most had high-titre, time dependent inhibitors. These patients may have a higher risk of intracranial bleeding.

Impact of pharmacokinetics to reduce bleeding in a cohort of patients with severe hemophilia A in a personalized comprehensive management program

In recent decades, hemophilia A treatment has been focused on body weight, without taking pharmacokinetic parameters into account. Previous research has shown that the individual pharmacokinetic response is more effective in predicting the required dose of clotting factor. We want to evaluate the impact on reducing the frequency of bleeding in patients treated with recombinant factor VIII, based on a personalized comprehensive management program. Our aim was to compare the results of a standard comprehensive treatment program (stage I) vs. a personalized pharmacokinetic - based treatment program (stage II) in a cohort of 60 patients with severe hemophilia without inhibitors. The median age was 15.5 years (3-68). The annual bleeding rate (ABR) was 1.03 (62 episodes) in the first stage and 0.58 (35 episodes) in the second one, (p=0.004). By type of bleeding, the impact of the intervention differs significantly in spontaneous bleeding (p=0.007) and a 73% reduction in the first stage. There were no significant differences in traumatic bleeding. The use of pharmacokinetics (PK) for personalized dosing of patients with severe hemophilia A, significantly reduces ABR and spontaneous bleeding, improving the patient’s quality of life and costs for the health system.

Inhibitor development, safety and efficacy of Advate® among previously treated patients with hemophilia A in a postmarketing surveillance in Japan

Rurioctocog alfa (recombinant factor VIII: Advate^®) is available for the control of bleeding in patients with hemophilia A in Japan. To evaluate the inhibitor development, safety, and efficacy of rurioctocog alfa, a non-interventional and observational postmarketing surveillance was conducted on 352 previously treated Japanese patients aged 1-76 years with ≥ 4 exposure days under the conditions of routine clinical practice. A post-hoc comparison of the mean annualized bleeding rates which required treatment with rurioctocog alfa detected a statistically significant difference (P < 0.0001) between patients treated on regular prophylaxis (8.5 bleeds/year) and patients treated on an on-demand basis (36.6 bleeds/year). Favorable prophylactic and on-demand hemostatic efficacy ("excellent" or "good") were shown in 88.5-100% of patients across all treatment regimens. A total of 22 events of adverse drug reactions were reported in 13 male patients. Of the 352 patients, 3 (0.9%) patients, all of whom had ≤ 50 exposure days before enrollment, developed de novo FVIII inhibitor. No deaths or allergic reactions were reported. Rurioctocog alfa was found to be well-tolerated and effective among patients with hemophilia A in a postmarketing routine clinical practice.

The inhibitors - a challenge for the management of patients with hereditary haemophilia A

INTRODUCTION

Our research strategy was aimed at evaluating the possible implication of the type of factor VIII product administered as substitution treatment to haemophilia A patients in the occurrence of inhibitors and their consequences on the management.

METHODS

Scientific articles from July 2015 to July 2017 were searched using the PubMed and PubMed Central databases. The used search terms included "haemophilia A", "inhibitors", "plasma-derived factor VIII" and "recombinant factor VIII".

RESULTS

The risk factors for inhibitors occurrence may be patients-related (genetic and nongenetic) and treatment-related. The possibility of a correlation between the increased purity of factor VIII given as substitution treatment and the occurrence of inhibitors is discussed in the light of literature data. Plasma-derived factor VIII is less immunogenic, but not entirely safe from the point of view of the possibility of transmitting biological agents. It is obvious that there is not enough plasma-derived factor VIII for the planet's needs. Recombinant factor VIII products have revolutionized the treatment of patients with haemophilia A over the past 3 decades by the disappearance of transfusion-related infections and their complications. They are safer in terms of pathogens and the new long-acting factor VIII products are based on recombinant DNA technology.

CONCLUSION

Plasma-derived or recombinant factor VIII products must co-exist on the market for the benefit of haemophilic patients. Future solutions could be: less immunogenic factor VIII products, nonfactor replacement strategies, or bispecific antibody that mimics the function of coagulation factor VIII.

Perioperative safety and hemostatic efficacy of Advate® in patients with hemophilia A in a postmarketing surveillance in Japan

Rurioctocog alfa (recombinant factor VIII: Advate^®) is available for the control of bleeding among patients with hemophilia A in Japan. To evaluate the perioperative safety and hemostatic efficacy of Advate^®, a postmarketing surveillance was conducted in Japanese patients undergoing surgery in a real-world setting. A total of 74 surgical procedures performed in 58 subjects aged 0-75 years, including three females, were studied. A hemostatic efficacy rating of "excellent" or "good" was reported in 73/74 surgical procedures (98.6%). Perioperative bleeding was successfully controlled by Advate^® in five subjects with positive FVIII inhibitors (2.4-9.1 BU/mL). Advate^® was administered at higher initial bolus doses (114-385 IU/kg) and at higher rates by subsequent initial continuous infusion (8.3-15 IU/kg/hour) in the five subjects with inhibitor than in the subjects without inhibitor (n = 47; mean initial bolus dose: 53.4 IU/kg; subsequent mean initial continuous infusion: 3.8 IU/kg/h). Adverse drug reactions were reported in 7/74 (9.5%) procedures, two of which were the development of de novo FVIII inhibitors. Overall, the perioperative use of Advate^® in a real-world setting was found to be safe and effective among Japanese patients with hemophilia A.

To serve and protect: The modulatory role of von Willebrand factor on factor VIII immunogenicity

Hemophilia A is a bleeding disorder characterized by the absence or dysfunction of blood coagulation factor VIII (FVIII). Patients are treated with regular infusions of FVIII concentrate. In response to treatment, approximately 30% of patients with severe hemophilia A develop inhibitory antibodies targeting FVIII. Both patient and treatment related risk factors for inhibitor development have been described. Multiple studies comparing the immunogenicity of recombinant and plasma-derived FVIII have yielded conflicting results. The randomized controlled SIPPET (Survey of Inhibitors in Plasma-Product Exposed Toddlers) trial demonstrated an increased risk of inhibitor development of recombinant FVIII when compared to von Willebrand factor (VWF)-containing plasma-derived FVIII. Presently, it is unclear which mechanism underlies the reduced immunogenicity of plasma-derived FVIII. In this review we address the potential role of VWF on FVIII immunogenicity and we discuss how VWF affects the immune recognition, processing and presentation of FVIII. We also briefly discuss the potential impact of glycan-composition on FVIII immunogenicity. It is well established that VWF shields the uptake of FVIII by antigen presenting cells. We have recently shown that VWF binds to the surface of dendritic cells. Here, we present a novel model in which surface bound FVIII-VWF complexes regulate the internalization of FVIII. Binding of FVIII to VWF is critically dependent on sulfation of Tyr1699 (HVGS numbering) in the light chain of FVIII. Incomplete sulfation of Tyr1699 has been suggested to occur in several recombinant FVIII products resulting in a loss of VWF binding. We hypothesize that this results in alternative pathways of FVIII internalization by antigen presenting cells which are not regulated by VWF. This hypothetical mechanism may explain the reduced immunogenicity of VWF containing plasma-derived FVIII concentrates as found in the SIPPET study.

Analysis of the Japanese subgroup in LEOPOLD II: a phase 2/3 study of BAY 81-8973, a new recombinant factor VIII product

BAY 81-8973, a new full length recombinant FVIII product, has been developed for prophylaxis and on-demand therapy in patients with hemophilia A. LEOPOLD II was a phase 2/3 study comparing prophylaxis versus on-demand treatment with BAY 81-8973. The analysis herein evaluated the clinical profile in Japanese subjects enrolled in LEOPOLD II. The LEOPOLD II was an open-label randomized crossover study. Our analysis evaluated the efficacy using the annualized bleeding rate, safety, and pharmacokinetics in Japanese subjects with severe hemophilia A enrolled in LEOPOLD II. The median annualized bleeding rate was 59.9/year in the on-demand group and 1.9/year in the prophylaxis group for Japanese subjects. There were no study drug-related adverse events in the Japanese subjects. None of the subjects developed FVIII inhibitors. There were no apparent clinical differences in efficacy, safety, and pharmacokinetics between the Japanese and the non-Japanese subjects. Data for the Japanese subjects showed annualized bleeding rates to be remarkably lower in the prophylaxis group compared to the on-demand group and that BAY 81-8973 exhibited a good safety profile and tolerability. These results were similar for the non-Japanese subjects. The results support adoption of BAY 81-8973 for treatment of Japanese subjects with severe hemophilia A.

The F309S mutation increases factor VIII secretion in human cell line

OBJECTIVES

The capacity of a human cell line to secrete recombinant factor VIII with a F309S point mutation was investigated, as was the effect of the addition of chemical chaperones (betaine and sodium-4-phenylbutyrate) on the secretion of factor VIII.

METHODS

This work used a vector with a F309S mutation in the A1 domain to investigate FVIII production in the HEK 293 human cell line. Factor VIII activity was measured by chromogenic assay. Furthermore, the effects of chemical drugs on the culture were evaluated.

RESULTS

The addition of the F309S mutation to a previously described FVIII variant increased FVIII secretion by 4.5 fold. Moreover, the addition of betaine or sodium-4-phenylbutyrate increased the secretion rate of FVIIIΔB proteins in HEK 293 cells, but the same effect was not seen for FVIIIΔB-F309S indicating that all the recombinant protein produced had been efficiently secreted.

CONCLUSION

Bioengineering factor VIII expressed in human cells may lead to an efficient production of recombinant factor VIII and contribute toward low-cost coagulation factor replacement therapy for hemophilia A. FVIII-F309S produced in human cells can be effective in vivo.