Abstract
Objective
To assess real-world treatment patterns and outcomes in previously treated patients
≥12 years old with severe haemophilia A treated with marketed factor VIII (FVIII)
replacement products.
Methods
Data were collected prospectively between 25 January 2019 and 30 November 2020 across
45 sites in 17 countries. Primary endpoint was annualized bleed rate (ABR). Secondary
endpoints included factor consumption, bleed treatment, joint health, and safety.
Exploratory endpoints included pain and quality of life outcomes.
Results
A total of 157 patients received ≥1 FVIII injection (prophylaxis n = 139, on-demand n = 19). Mean (standard deviation; SD) observation period was 43.1 (13.3) weeks. Median
(quarter [Q]1, Q3) ABR was 2.0 (0.0, 5.7) for those on prophylaxis. Those receiving
standard half-life FVIII products or extended half-life FVIII products had a median
(IQR) ABR of 2.2 (0.0, 6.1) and 1.3 (0.0, 5.0), respectively. Still, only 35% of patients
on prophylaxis experienced zero bleeds and 18% had more than five bleeds in a year.
Approximately 23% of bleeding episodes required >1 FVIII dose for resolution. The
mean (SD) number of routine prophylaxis injections/week was 2.2 (1.1). Median (Q1,
Q3) annualized factor consumption for patients on prophylaxis was 4,106.4 (3,151.6,
5,291.2) IU/kg/year. No changes in Haemophilia Joint Health Score (mean [SD] of 16.1
[19.3] versus 15.7 [17.7]), PROMIS pain intensity 3a T-score (mean [SD] 41.6 [8.2]
versus 40.9 [9.1]), or Haem-A-QoL (mean [SD] 30.6 [17.3] versus 29.5 [17.4]) were
observed between baseline and the end of the observation period for those using prophylaxis.
Conclusions
Prophylaxis using standard or extended half-life FVIII replacement therapies achieves
adequate haemostatic control in only about half of patients, with some experiencing
very poor outcomes. Real-world data highlight the urgent need to optimize prophylaxis
to enhance haemostatic control, ideally achieving a zero ABR and its associated benefits.
Keywords
observational study - clinical study - haemophilia a - factor VIII - prospective studies
Bibliographical Record
Pratima Chowdary, Liane Khoo, Michael Wang, Hervé Chambost, Anthony K.C. Chan, Annemieke
Willemze, Johannes Oldenburg. Prospective, Observational Study of the Clinical Outcomes
of FVIII Treatment in Adults and Adolescents with Severe Haemophilia A. TH Open 2025;
09: a26219749.
DOI: 10.1055/a-2621-9749