Current status and future prospects of activated recombinant coagulation factor VIIa, NovoSeven®, in the treatment of haemophilia and rare bleeding disorders

rFVIIa, a human recombinant activated coagulation factor VII, has been used worldwide for more than two decades for the treatment of bleeding episodes and prevention of bleeding in patients undergoing surgery/invasive procedures with congenital haemophilia A or B with inhibitors (CHwI A or B), acquired haemophilia (AH), congenital factor VII deficiency and Glanzmann thrombasthenia (GT), refractory to platelet transfusion. The approved dosage, administration and indication of rFVIIa in the US, Europe and Japan differ, depending on the needs of the patient population and regulatory practices. This review presents an overview of the current status and future prospects, including that from a Japanese perspective, of using rFVIIa in the treatment of approved indications. The efficacy and safety of rFVIIa in the approved indications has been demonstrated in several randomised and observational studies and data from registries. The overall incidence of thrombosis across all approved indications in a retrospective safety assessment of clinical trials and registries, prelicensure studies and postmarketing surveillance studies of rFVIIa use was 0.17%. Specifically, the risk of thrombotic events was 0.11% for CHwI, 1.77% for AH, 0.82% for congenital factor VII deficiency and 0.19% for GT. Emerging non-factor therapies such as emicizumab have changed the treatment landscape of haemophilia A, including preventing bleeding in patients with CHwI. However, rFVIIa will continue to play a significant role in the treatment of such patients, particularly during breakthrough bleeding or surgical procedures.

Early stage clinical trials for the treatment of hemophilia A

INTRODUCTION

Hemophilia A is a severe bleeding disorder affecting about 1 in 5,000 males. The gold standard for prophylaxis and treatment of acute bleeding has been factor (F) VIII concentrate. A multitude of treatment modalities are now available and under clinical investigation.

AREAS COVERED

This review discusses ongoing/recently completed early-phase clinical trials registered on ClinicalTrials.gov in patients with hemophilia A through April 2022. These new pipeline therapies are focused on addressing the safety and efficacy of new factor-related products, non-factor related products, and gene therapy options for hemophilia.

EXPERT OPINION

Current standard of care effectively prevents and treats acute bleeding and has significantly improved the quality of life in hemophilia. The biggest challenges in the improvement of care are treatment-related burden and the burden of cost in developing countries. New drugs under development are likely to enter practice by the end of this decade and address many of the unmet needs particularly of those with severe disease. Data is limited in unique populations (e.g. congenital/inherited FVIII inhibitors, non-severe hemophilia A, women/girls with hemophilia and children) which are important areas for future research; additional clinical trials and long-term outcome data are necessary prior to incorporating these new therapies in our treatment arsenal.

A comparison between on-demand usage of rFVIIa vs prophylaxis use of emicizumab in high titer inhibitory hemophilia A patients in Iran: A cost-utility analysis

BACKGROUND

Hemophilia A (HA) is an inherited X-linked bleeding disease with costly treatment, especially for high titer inhibitory patients. Emicizumab, a new humanized bispecific antibody, has been approved for use to prevent or reduce the frequency of bleeding episodes in HA patients with inhibitors. This study evaluated the cost-utility of emicizumab prophylaxis (EP) in comparison with recombinant factor VII activated on-demand treatment in HA patients with inhibitors.

METHODS

A life-time Markov model with payer and societal perspectives was developed in different age groups with different annual bleeding rates (ABR). Efficacy of treatments were extracted from HAVEN trials. Utilities were retrieved from published evidence. Costs were calculated based on Iran food and drug administration official website, national tariff book for medical services and hospital data. One-way deterministic sensitivity analysis was performed.

RESULTS

EP was dominant choice in comparison with on-demand administration of recombinant factor VII activated in all age groups with ABR 20 and 25, and it remained dominant in patients with age 2 and age 12 at start point with ABR 16 and 17. The reported incremental cost-effectiveness ratio for the group with ABR 18 at the age 20, was 12,936 United States Dollars which is lower than the acceptable threshold of cost-effectiveness in Iran (1-3 gross domestic product per capita) and EP can be considered as cost-effective choice in this scenario.

CONCLUSION

EP was found to be a dominant and cost-effective choice for Iranian HA patients with factor VIII inhibitors with ABR 18 and above with considerable cost saving.

Eptacog Beta for Bleeding Treatment and Prevention in Congenital Hemophilia A and B With Inhibitors: A Review of Clinical Data and Implications for Clinical Practice

OBJECTIVE

To review the pharmacology, dosing and administration, safety, clinical efficacy, and role of eptacog beta in the treatment of congenital hemophilia with inhibitors.

DATA SOURCES

A literature search of PubMed (1966 to August 2021) was conducted using the keywords eptacog beta, recombinant FVII, and hemophilia.

STUDY SELECTION AND DATA EXTRACTION

All relevant published articles and prescribing information on eptacog beta for the treatment of congenital hemophilia with inhibitors were reviewed.

DATA SYNTHESIS

Eptacog beta is a novel recombinant activated factor VII (rVIIa) product that demonstrated efficacy in controlling bleeding and associated pain in patients with hemophilia A or B with inhibitors. Eptacog beta has limited Food and Drug Administration-approved and off-label indications compared with other bypassing agents (BPAs; activated prothrombin complex concentrates [aPCC; eptacog alfa]). Eptacog beta costs less than eptacog alfa, but still more than aPCCs.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review provides insight into the role of eptacog beta for treatment of congenital hemophilia with inhibitors and reviews important health system formulary considerations for available BPAs.

CONCLUSIONS

Eptacog beta is more cost-effective than eptacog alfa and, as such, may become the preferred rVIIa formulary product. However, eptacog alfa availability remains necessary for the treatment of disorders where eptacog beta has limited data. aPCC should remain the first-line BPA for the treatment of bleeding in patients with inhibitors with no contraindications to use because of its equivocal efficacy and safety and in light of the magnitude of cost savings associated with this strategy.

Origins, Development, Current Challenges and Future Directions with Activated Prothrombin Complex Concentrate for the Treatment of Patients with Congenital Haemophilia with Inhibitors

Congenital haemophilia A (HA) is caused by deficiency of coagulation factor VIII (FVIII) activity, leading to spontaneous or traumatic bleeding events. While FVIII replacement therapy can treat and prevent bleeds, approximately 30% of patients with severe HA develop inhibitor antibodies that render FVIII replacement therapy ineffective. The bypassing agents (BPAs), activated prothrombin complex concentrate (aPCC) and recombinant activated FVII, first approved in 1977 and 1996, respectively, act to generate thrombin independent of pathways that involve factors IX and VIII. Both may be used in patients with congenital haemophilia and inhibitors (PwHIs) for the treatment and prevention of acute bleeds and quickly became standard of care. However, individual patients respond differently to different agents. While both agents are approved for on-demand treatment and perioperative management for patients with congenital haemophilia with inhibitors, aPCC is currently the only BPA approved worldwide for prophylaxis in PwHI. Non-factor therapies (NFTs) have a mechanism of action distinct from BPAs and have reported higher efficacy rates as prophylactic regimens. Nonetheless, treatment challenges remain with NFTs, particularly regarding the potential for synergistic action on thrombin generation with concomitant use of other haemostatic agents, such as BPAs, for the treatment of breakthrough bleeds and in perioperative management. Concomitant use of NFTs with other haemostatic agents could increase the risk of adverse events such as thromboembolic events or thrombotic microangiopathy. This review focuses on the origins, development and on-going role of aPCC in the evolving treatment landscape in the management of PwHI.

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.

Comparative evaluation of the safety and efficacy of recombinant FVIII in severe hemophilia A patients

Objective

This study compared the safety and efficacy of Safacto^® versus xyntha^® in patients with severe hemophilia A.

Methods

Thirty-three male patients with severe hemophilia A were randomly divided into two groups. Seventeen patients received Safacto^® and 16 patients received Xyntha^® for four consecutive times. The dosage of FVIII was 40-50 IU/kg for each injection. Plasma level of FVIII activity was evaluated before every injection, 15 minutes after the injection and one month after the start of the trial. The rate of factor VIII activity, pain and joint motion were also assessed before and after the treatment.

Results

Plasma level of FVIII clotting activity in Safacto^® and Xyntha^® were 1.96±0.5 IU/dl and 1.63±0.5 IU/dl and increased to 88.84±25.2 IU/dl and 100.09±17.8 IU/dl, respectively (P<0.001). Pain score and range of motion improvement were 9.3±0.9 and 8.7±0.1 in Safacto^® (P=0.17); and 9.4±0.8 and 8.8±0.3 in Xyntha^® (P=0.35), respectively. No allergic or other unfavorable reactions was observed with either of the preparations.

Conclusion

This study showed that Safacto^® has a favorable efficacy and safety profile.

Methodologies for data collection in congenital haemophilia with inhibitors (CHwI): critical assessment of the literature and lessons learned from recombinant factor VIIa

AIMS

To systematically review the effectiveness of on-demand treatment with recombinant coagulation factor VIIa (rFVIIa) in congenital haemophilia with inhibitors and, if feasible, perform a meta-analysis of the data.

MATERIALS AND METHODS

Publications from Embase^® , MEDLINE^® , MEDLINE^® In-Process and the Cochrane Central Register of Controlled Trials were searched. Selected publications were reviewed for inclusion by two independent expert reviewers. Discrepancies were reconciled by a third independent reviewer. Data from selected studies were extracted using a predefined grid to ensure uniform and comparable results were captured.

RESULTS

A systematic search (cut-off date of 2 May 2016) identified 20 studies (13 observational; seven randomized controlled trials). All studies were of sufficient quality to include in this analysis and comprised 1221 participants, with 5981 bleeds in 746 individuals treated with rFVIIa. Haemostatic overall effectiveness of the individual studies identified ranged from 68% to 100% at ≤12 hours, 86% to 96% at 13-24 hours and 76% to 99% at 24-48 hours with rFVIIa <100 μg/kg, with similar rates reported for the ≥250 μg/kg dose. However, heterogeneity between the studies precluded pooling of results.

CONCLUSIONS

Data from the individual studies confirmed that rFVIIa is an effective therapy for the on-demand treatment of bleeds in congenital haemophilia with inhibitors. However, the high levels of heterogeneity between studies precluded pooling of results for a valid, reliable or precise summary measure. There remains a need to implement standardized clinical definitions and measurements for the effectiveness and safety of haemophilia therapies in future clinical trials.

Bioengineering of rFVIIa Biopharmaceutical and Structure Characterization for Biosimilarity Assessment

Eptacog alfa (NovoSeven^®) is a vitamin K-dependent recombinant Factor VIIa produced by genetic engineering from baby hamster kidney (BHK) cells as a single peptide chain of 406 residues. After activation, it consists of a light chain (LC) of 152 amino and a heavy chain (HC) of 254 amino acids. Recombinant FVIIa undergoes many post-translational modifications (PTMs). The first ten glutamic acids of the N-terminal moiety are γ-carboxylated, Asn145 and Asn322 are N-glycosylated, and Ser52 and Ser60 are O-glycosylated. A head-to-head biosimilarity study was conducted for the originator and the first biosimilar AryoSeven™ to evaluate comparable bioengineering. Physicochemical properties were analyzed based on mass spectrometry, including intact mass, PTMs and higher-order structure. Both biotherapeutics exhibit a batch-to-batch variability in their N-glycan profiles. N-Glycopeptide analysis with UHPLC-QTOF-MS^E confirmed N-glycosylation sites as well as two different O-glycopeptide sites. Ser60 was found to be O-fucosylated and Ser52 had O-glucose or O-glucose-(xylose)_1,2 motifs as glycan variants. Ion mobility spectrometry (TWIMS) and NMR spectroscopy data affirm close similarity of the higher-order structure of both biologicals. Potency of the biodrugs was analyzed by a coagulation assay demonstrating comparable bioactivity. Consequently, careful process optimization led to a stable production process of the biopharmaceuticals.

Successful Control of Massive Bleeding in a Child with Burkitt's Lymphoma via a Biosimilar Recombinant Activated Factor VII (AryoSeven™)

We describe a case of a 4-year-old girl with Burkitt's lymphoma, who suffered from a massive gastrointestinal hemorrhage 3 days after chemotherapy. In spite of applying the common practice in correction of coagulopathy, thrombocytopenia persisted and bleeding became life-threatening. In the present case report, we report a successful control of bleeding with a single-dose administration of a biosimilar recombinant activated human factor VII (AryoSeven).