Biochemical characterization of LR769, a new recombinant factor VIIa bypassing agent produced in the milk of transgenic rabbits

Eptacog beta for the management of patients with haemophilia A and B with inhibitors: A European perspective

Eptacog beta (activated), a recombinant human factor VIIa (rFVIIa), was approved by the US Food and Drug Administration (FDA) in 2020 (SEVENFACT®, LFB & HEMA Biologics) and the European Medicines Agency (EMA) in 2022 (CEVENFACTA®, LFB). In Europe, eptacog beta is indicated for the treatment of bleeds and the prevention of bleeds during surgery or invasive procedures in adults and adolescents (≥12 years old) with congenital haemophilia A or B with high-titre inhibitors (≥5 BU) or with low-titre inhibitors who are expected to have a high anamnestic response to factor VIII or factor IX, or to be refractory to increased dosing of these factors. The efficacy and safety of eptacog beta were evaluated in three Phase III clinical studies, PERSEPT 1, 2 and 3. For the EMA filing dossier, the analysis of data from PERSEPT 1 and 2 differed from the analysis used to support the filing in the US. In this review, we summarise current data regarding the mode of action, clinical efficacy and safety of eptacog beta for the management of haemophilia A and B in patients with inhibitors from a European perspective. In addition to providing a valuable summary of the analyses of the clinical data for eptacog beta conducted for the EMA, our review summarises the potential differentiators for eptacog beta compared with other current bypassing agents.

Advances and challenges in the purification of recombinant coagulation factors: A review

Hemostasis is a complex process for the cessation of bleeding from an injured blood vessel, involving the interplay of 12 coagulation factors in the coagulation cascade with activated blood platelets and the vessel wall. Hence, the coagulation factors are important to control hemorrhage. However, the low abundance of many coagulation factors in human plasma proteins limited their production in therapeutic drugs and their clinical applications. With the development of modern biotechnology, commercially manufactured recombinant coagulation factors became available as hemostatic therapeutics, emerging a huge potential in pharmaceutical manufacturing market. Unlike antibodies, whose standard operation unit or platform purification processes in the industrial-scale downstream processing has been well-established, the complexity in post-translational modification and differences in structures of the coagulation factors posed specific challenges with respect to the downstream processing, which have long been limiting their industrial-scale production. This review presents a comprehensive overview of the technological development of commercially manufactured recombinant coagulation factors, with emphasis on their advances and challenges in the separation and purification processes. Firstly, the licensed products of the plasma derived and recombinant coagulation factors are summarized. Then, typical recombinant coagulation factors, i.e. factors VII, VIII and IX, are introduced with detailed discussion on their preparative separation procedures for both the licensed products of industrial-scale and the experimental cases of laboratory-scale. Finally, perspectives and challenges in the future development of the purification technology of recombinant coagulation factors are highlighted to provide new insight into the design of cost-effective purification processes of recombinant coagulation factors.

Efficacy and safety evaluation of eptacog beta (coagulation factor VIIa [recombinant]-jncw) for the treatment of hemophilia A and B with inhibitors

INTRODUCTION

Bypassing agents (BPAs) are used to treat acute bleeding episodes, manage bleeding during perioperative care, and prophylactically minimize bleed occurrence in persons with hemophilia A or B with inhibitors (PwHABI). However, the effectiveness of BPAs that have been prescribed for the last several decades can be variable, motivating the development of a new recombinant activated factor VII, eptacog beta.

AREAS COVERED

This review covers key eptacog beta findings from phase 1b and phase 3 (PERSEPT) clinical trials, which formed the basis for its regulatory approval to treat PwHABI ages 12 and older. Descriptions of eptacog beta structure and glycosylation profile, mechanism of action, preclinical study results, and cost analyses are also presented.

EXPERT OPINION

PwHABI have had only two options for bleed treatment for the past several decades. With its distinct glycosylation profile, eptacog beta offers a novel therapy aiming to improve upon BPAs currently in use, providing an option with more than one dosing regimen and a rapid response that allows most bleeds to be treated with just one dose. This has become particularly important given the use of subcutaneous medications (e.g., emicizumab) for prophylaxis of bleeding. Clinicians should consider eptacog beta as a BPA for all PwHABI.

Eptacog beta efficacy and safety in the treatment and control of bleeding in paediatric subjects (<12 years) with haemophilia A or B with inhibitors

Introduction

Eptacog beta is a new recombinant activated human factor VII bypassing agent approved in the United States for the treatment and control of bleeding in patients with haemophilia A or B with inhibitors 12 years of age or older.

Aim

To prospectively assess in a phase 3 clinical trial (PERSEPT 2) eptacog beta efficacy and safety for treatment of bleeding in children <12 years of age with haemophilia A or B with inhibitors.

Methods

Using a randomised crossover design, subjects received initial doses of 75 or 225 μg/kg eptacog beta followed by 75 μg/kg dosing at predefined intervals (as determined by clinical response) to treat bleeding episodes (BEs). Treatment success criteria included a haemostasis evaluation of ‘excellent’ or ‘good’ without use of additional eptacog beta, alternative haemostatic agent or blood product, and no increase in pain following the first ‘excellent’ or ‘good’ assessment.

Results

Treatment success proportions in 25 subjects (1–11 years) who experienced 546 mild or moderate BEs were 65% in the 75 μg/kg initial dose regimen (IDR) and 60% in the 225 μg/kg IDR 12 h following initial eptacog beta infusion. By 24 h, the treatment success proportions were 97% for the 75 μg/kg IDR and 98% for the 225 μg/kg IDR. No thrombotic events, allergic reactions, neutralising antibodies or treatment‐related adverse events were reported.

Conclusion

Both 75 and 225 μg/kg eptacog beta IDRs provided safe and effective treatment and control of bleeding in children <12 years of age.

The safety of activated eptacog beta in the management of bleeding episodes and perioperative haemostasis in adult and paediatric haemophilia patients with inhibitors

Introduction

Haemophilia patients with inhibitors often require a bypassing agent (BPA) for bleeding episode management. Eptacog beta (EB) is a new FDA‐approved recombinant activated human factor VII BPA for the treatment and control of bleeding in haemophilia A or B patients with inhibitors (≥12 years of age). We describe here the EB safety profile from the three prospective Phase 3 clinical trials performed to date.

Aim

To assess EB safety, immunogenicity and thrombotic potential in children and adults who received EB for treatment of bleeding and perioperative care.

Methods

Using a randomized crossover design, 27 subjects in PERSEPT 1 (12‐54 years) and 25 subjects in PERSEPT 2 (1‐11 years) treated bleeding episodes with 75 or 225 μg/kg EB initially followed by 75 μg/kg dosing at predefined intervals as determined by clinical response. Twelve PERSEPT 3 subjects (2‐56 years) received an initial preoperative infusion of 75 μg/kg (minor procedures) or 200 μg/kg EB (major surgeries) with subsequent 75 μg/kg doses administered intraoperatively and post‐operatively as indicated. Descriptive statistics were used for data analyses.

Results

Sixty subjects who received 3388 EB doses in three trials were evaluated. EB was well tolerated, with no allergic, hypersensitivity, anaphylactic or thrombotic events reported and no neutralizing anti‐EB antibodies detected. A death occurred during PERSEPT 3 and was determined to be unlikely related to EB treatment by the data monitoring committee.

Conclusion

Results from all three Phase 3 trials establish an excellent safety profile of EB in haemophilia A or B patients with inhibitors for treatment of bleeding and perioperative use.

Exploratory in vitro evaluation of thrombin generation of eptacog beta (recombinant human fviia) and emicizumab in congenital haemophilia A plasma

Introduction/Aim

Eptacog beta is a recombinant activated human factor VII approved to treat and control bleeding in haemophilia A and B patients with inhibitors. Emicizumab is a factor VIIIa mimetic antibody approved for prophylactic treatment of haemophilia A with and without inhibitors (HAI and HA, respectively). Inhibitor patients treated with emicizumab should expect breakthrough bleeding that requires bypassing agent treatment to restore haemostasis. The aim of this study is to quantify the in vitro thrombin generation induced by the addition of eptacog beta to HAI and HA plasma containing emicizumab.

Methods

Thrombin generation assays were performed using HAI and HA plasma. Thrombin generation parameters were examined using a fixed effects model with inhibitor titre, eptacog beta concentration and emicizumab concentration as main effects, and eptacog beta concentration with inhibitor and emicizumab concentration with inhibitor as interaction effects.

Results

A significant increase in peak thrombin, ETP and velocity was observed when combinations of eptacog beta (0, 1, 2 or 5 µg/ml) and emicizumab (0, 50 or 100 µg/ml) were evaluated in HA and HAI plasma; the effect remained below that observed in Normal Plasma (NP). A small shortening of lag time below that of NP was observed.

Conclusions

Eptacog beta and emicizumab induced thrombin generation in haemophilia A plasma (with and without inhibitors) with the thrombin generation parameters remaining below those of normal plasma. These data provide in vitro proof of concept supporting the concept of use of eptacog beta for the treatment and control of breakthrough bleeding in patients on emicizumab prophylaxis.

Increased Accumulation and Retention of rhFVIIa (eptacog beta) in Knee Joints of Hemophilia A Mice Compared to Wild-Type Mice

Our earlier studies showed that recombinant human factor VIIa (rhFVIIa) administered intravascularly in mice disappeared rapidly from the circulation. However, a small fraction of rhFVIIa that entered extravascular remained functionally active for an extended period. The present study aims to investigate the dose-dependency of rhFVIIa accumulation and retention in mouse knee joints and test whether the hemophilic condition affects rhFVIIa sequestration in joints. Wild-type and FVIII^-/- mice were injected with three doses of rhFVIIa (eptacog beta, 90, 250, and 500 μg/kg) via the tail vein. At varying times following rhFVIIa administration, blood and knee joints were collected to measure FVIIa activity and antigen levels in plasma and joint tissues. Joint tissue sections were analyzed by immunohistochemistry for the presence of rhFVIIa. Vascular permeability was assessed by either Evans Blue dye or fluorescein dextran extravasation. The study showed that rhFVIIa accumulated in knee joints of wild-type and FVIII^-/- mice in a dose-dependent manner. rhFVIIa antigen and FVIIa activity could be detectable in joints for at least 7 days. Significantly higher levels of rhFVIIa accumulation were observed in knee joints of FVIII^-/- mice compared with that of wild-type mice. Immunohistochemical analyses confirmed higher levels of rhFVIIa retention in FVIII^-/- mice compared with wild-type mice. Additional studies showed that FVIII^-/- mice were more permissible to vascular leakage. In conclusion, the present data demonstrate a dose-dependent accumulation of rhFVIIa in knee joints, and the hemophilic condition enhances the entry of rhFVIIa from circulation to the extravascular. The present data will be useful in improving rhFVIIa prophylaxis.

Eptacog beta: a novel recombinant human factor VIIa for the treatment of hemophilia A and B with inhibitors

INTRODUCTION

Hemophilia A and B are X-linked recessive disorders caused by the deficiency of factor VIII or factor IX, respectively. Bleeding episodes are treated with factor replacement therapy. The most serious complication of this treatment is the development of inhibitors. In such patients, bypassing agents, such as activated recombinant human factor VII (rhFVIIa) or plasma-derived activated prothrombin complex concentrates, are administered to prevent or treat bleeding episodes. The high cost of the current bypassing agents limits their availability in emerging countries. Areas covered: Authors reviewed the published data on the development and clinical testing of eptacog beta, a new second-generation rhFVIIa produced in the milk of transgenic rabbits. The available data indicate that activated eptacog beta exhibits structural (N- and O- glycosylation), pharmacodynamic and pharmacokinetic characteristics similar to activated eptacog alfa, its main competitor, but binds slightly better to platelets and HUVEC, and it is safe and effective. Expert commentary: This critical review of available data on activated eptacog beta shows that it represents an alternative source of rhFVIIa at potentially lower cost with easily expandable manufacturing capacity that could contribute to cover the future patient needs.