Abstract Number: PB0506
Meeting: ISTH 2021 Congress
Theme: Hemophilia and Rare Bleeding Disorders » Hemophilia - Clinical
Background: Safety and efficacy of rFVIIIFc and rFIXFc were established in phase 3 trials. The PREVENT study prospectively evaluates real-world usage and effectiveness of rFVIIIFc and rFIXFc in Germany over 24-months in patients with haemophilia A (PwHA) or B (PwHB).
Aims: Providing first interim analysis of the paediatric population (<18 years) with at least 9 months of prospective observation.
Methods: PREVENT (NCT03055611) was approved by medical ethics committees. Informed consent was obtained from all patients/caregivers. Primary endpoints are annualised bleeding rate (ABR), injection frequency and factor consumption. Secondary endpoints include reason for initiating rFVIIIFc or rFIXFc treatment. The interim analysis (data cut September 24, 2020) used descriptive statistics.
Results: The analysis included 55 PwHA and 10 PwHB, with median (range) age of 8.0 (0-17) and 11.5 (3-15) years, respectively. Forty-nine (89%) PwHA and 6 (60%) PwHB were severe. Inhibitor history prior to rFVIIIFc/rFIXFc initiation was reported in 12 (21.8%) severe PwHA and none among PwHB. No inhibitors had been detected at time of data cut.
Median ABR and joint ABR were low for PwHA and PwHB (table 1), during a median (range) follow-up of 18.9 (9.3-23.3) and 20.1 (10.5-23.7) months, respectively. For this follow-up period, the proportion of zero joint bleeds were 63.6 % in PwHA and 40.0 % in PwHB.
Median injection frequency and factor consumption are shown in table 1.
Most patients and physicians were satisfied or highly satisfied with the treatment (table 1).
Main reason for initiating rFVIIIFc or rFIXFc treatment was to reduce injection frequency while maintaining protection from bleeds (table 2).
| Haemophilia A (N=55)a | Haemophilia B (N=10)a | |||
| n | n | |||
| ABR, median (Q1;Q3) | 55 | 0.6 (0.0;1.8) | 10 | 1.9 (0.6;4.6) |
| Joint ABR, median (Q1;Q3) | 55 | 0.0 (0.0;0.6) | 10 | 0.6 (0.0;1.0) |
| Weekly injection frequency, median (Q1;Q3) | 55 | 2.3 (2.0;3.0) | 10 | 1.0 (1.0;1.0) |
| Weekly consumption (IU/kg/week), median (Q1;Q3) | 53 | 102.0 (86.9;126.6) | 10 | 55.0 (44.3;73.9) |
| Physicians satisfied or highly satisfied with treatment after 1 year, n (%) | 42 | 39 (93) | 8 | 8 (100) |
| Patients satisfied or highly satisfied with treatment after 1 year, n (%)b | 13 | 11 (85) | 6 | 6 (100) |
| aFor some of the outcomes data were not available for all patients at the interim data cut. bCompletion of all patient-reported outcomes was optional. |
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Clinical outcomes and treatment of paediatric patients on prophylaxis with rFVIIIFc or rFIXFc
| Haemophilia A (N=55) | Haemophilia B (N=10) | |
| Improve protection from bleeds | 12 (21.8%) | 1 (10.0%) |
| Improve protection to increase physical activity level | 1 (1.8%) | 0 (0.0%) |
| Reduce injection frequency while maintaining protection from bleeds | 42 (76.4%) | 9 (90.0%) |
Reason for treatment initiation with rFVIIIFc or rFIXFc
Conclusions: Treatment with rFVIIIFc or rFIXFc in children and adolescents provided a high level of protection from bleeds with low injection frequency. This interim analysis of the real-world use of rFVIIIFc and rFIXFc for up to 2 years reinforces the results of the pivotal trials.
To cite this abstract in AMA style:
Heller C, Bidlingmaier C, Escuriola C, Hagedorn N, Oldenburg J, van den Boom J, Malmström H, Santagostino E, Tiede A. Interim Analysis of the PREVENT Study: Real World Prospective Data from Children and Adolescents with Haemophilia A or B Treated with Recombinant Factor VIII Fc (rFVIIIFc) or Recombinant Factor IX Fc (rFIXFc) [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/interim-analysis-of-the-prevent-study-real-world-prospective-data-from-children-and-adolescents-with-haemophilia-a-or-b-treated-with-recombinant-factor-viii-fc-rfviiifc-or-recombinant-factor-ix-fc/. Accessed August 15, 2022.« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/interim-analysis-of-the-prevent-study-real-world-prospective-data-from-children-and-adolescents-with-haemophilia-a-or-b-treated-with-recombinant-factor-viii-fc-rfviiifc-or-recombinant-factor-ix-fc/