Safety and efficacy of recombinant activated coagulation factor VII in congenital hemophilia with inhibitors in the home treatment setting: A review of clinical studies and registries

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.

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.