Bleeding outcomes and factor utilization after switching to an extended half-life product for prophylaxis in haemophilia A in Austria

Cihan Ay,Anna Vavrovsky,Gerhard Schuster,Ingrid Pabinger,Joachim Rettl,Leonard Perschy,Clemens Feistritzer

doi:10.1038/s41598-021-92245-5

Abstract

To prevent bleeding in severe haemophilia A [SHA, defined as factor VIII (FVIII) activity < 1%] regular prophylactic FVIII replacement therapy is required, and the benefits of factor products with extended half-life (EHL) over traditional standard half-life (SHL) are still being debated. We performed a multi-centre, retrospective cohort study of persons with SHA in Austria aiming to compare clinical outcomes and factor utilization in patients with SHA, who switched from prophylaxis with SHL to an EHL. Data were collected from haemophilia-specific patient diaries and medical records. Twenty male persons with SHA (median age: 32.5 years) were included. The most common reason for switching to the EHL was a high bleeding rate with SHL. Switch to rFVIII-Fc resulted in a significantly decreased annualized bleeding rate (ABR; median difference (IQR): − 0.3 (− 4.5–0); Wilcoxon signed-rank test for matched pairs: Z = − 2.7, p = 0.008) and number of prophylactic infusions per week (− 0.75 (− 1.0–0.0); Z = − 2.7, p = 0.007). Factor utilization was comparable to prior prophylaxis with SHL (0.0 (− 15.8–24.8) IU/kg/week; Z = − 0.4, p = 0.691). In summary, switch to EHL (rFVIII-Fc) was associated with an improved clinical outcome, reflected by ABR reduction, and less frequent infusions, without significantly higher factor usage.

Highlights

Severe haemophilia A (SHA) is a rare, X-linked genetic bleeding disorder, defined by a baseline coagulation factor VIII (FVIII) activity < 1%
Multi-centre cohort study of persons with SHA switching from prophylaxis with standard half-life FVIII concentrates (SHL) to an extended half-life (EHL), we analysed and compared treatment patterns in terms of bleeding outcomes, infusion frequency and factor usage, and costs before and after the switch
While real-world data regarding EHL is becoming increasingly available for other countries, this is the first analysis of its kind in Austria[6,14,15,16,17,18,19,20,22]

Summary

Introduction

Severe haemophilia A (SHA) is a rare, X-linked genetic bleeding disorder, defined by a baseline coagulation factor VIII (FVIII) activity < 1%. To prevent spontaneous bleeding the recommended standard treatment for SHA until recently was regular prophylactic factor replacement therapy via intravenously administered standard half-life FVIII concentrates (SHL) to achieve trough levels > 1%2,3. FVIII products with an extended half-life (EHL), i.e. approximately 1.4–1.6 times greater than SHL, have been approved for use in persons with SHA in Europe, promising lower prophylactic infusion rates and/ or higher trough levels[5,6]. Prophylaxis with EHL holds the potential to improve treatment adherence and/or decrease the annualized bleeding rate (ABR), subsequently raising quality of life, especially for persons with SHA on prophylaxis with difficult venous access or experiencing frequent breakthrough bleeding e vents[5,6,7,8,9]. Guidelines as to which patients should undergo the switch from SHL to EHL, and despite the fact that potentially all patients could benefit from it the question of who would profit most from the switch is still being d ebated[4,5]

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