Abstract Number: PB0879
Meeting: ISTH 2020 Congress
Theme: Hemophilia and Rare Bleeding Disorders » Hemophilia - Clinical
Background: The Phase 3 A-LONG/Kids A-LONG and ASPIRE extension studies evaluated the efficacy and safety of the extended half-life recombinant factor VIII Fc fusion protein (rFVIIIFc); however, no patients in Japan were enrolled in Kids A-LONG or the study assessing rFVIIIFc in previously untreated patients (PUP). The prospective, multicenter, observational FACTs study is designed to evaluate the effectiveness of rFVIIIFc in adolescents and children with hemophilia A (HA) in Japan (Part 1) and summarize the experience of immune tolerance induction (ITI; Part 2).
Aims: To present the first real-world interim data from Part 1 of the FACTs study.
Methods: Study participants provided written informed consent, and local Research Ethics Committees provided study approval for all study sites. Data from patients < 18 years of age with HA treated with rFVIIIFc were collected at baseline and every 6 months up to 2 years, including pre-study treatment data. The regimen was at the investigator's discretion.
Results: As of August 2019, 64 PUPs and minimally treated patients (MTP) were enrolled in the study (Table 1).
| All patients (N=64) |
|
| Median (min‒max) age at rFVIIIFc start, years | 7 (0‒17) |
| Hemophilia severity, n (%) Severe Moderate Mild |
43 (67.2) 17 (26.6) 2 (3.1) |
| FVIII exposure prior to rFVIIIFc treatment, n (%) 0‒3 days 4‒20 days 21‒100 days 101‒150 days ≥151 Not available |
9 (14.1) 6 (9.4) 3 (4.7) 5 (7.8) 29 (45.3) 12 (18.8) |
| FVIII, factor VIII; max, maximum; min, minimum; rFVIIIFc, recombinant factor VIII Fc fusion protein. | |
[Table 1. Patient treatment and disease history]
Prior to the study, 3 out of 6 patients with a history of high-titer inhibitors underwent ITI with factor VIII (FVIII) and 39 (61%) patients received prophylactic treatment with FVIII (21 [54%] received FVIII treatment ≥3 times/week). During the study, 28 (54%) patients received rFVIIIFc prophylaxis two times/week; 12 (50%) patients < 6 years of age received weekly rFVIIIFc (Figure 1). Forty-five (70%) patients had no bleed events during the first 6 months of treatment. The median annual spontaneous bleed rate was zero during the study. Three patients developed inhibitors to rFVIIIFc during the study
(PUPs, n=2; MTP, n=1) and shifted to ITI with rFVIIIFc.
Conclusions: These interim data in Japanese pediatric patients are consistent with previously reported clinical efficacy and safety data from patients with HA treated with rFVIIIFc.
[Figure 1. Injection frequency in patients receiving prophylactic treatment prior to and during study]
To cite this abstract in AMA style:
Kobayashi M, Matsushita T, Nogami K, Usami I, Shiraishi M, Takatoku M. Real-World Effectiveness Evaluation of the Recombinant Factor VIII Fc Fusion Protein in Adolescents and Children with Hemophilia A in Japan: “Fc Adolescent and Children Treatment” Study (FACTs) Part 1 Interim Analysis [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/real-world-effectiveness-evaluation-of-the-recombinant-factor-viii-fc-fusion-protein-in-adolescents-and-children-with-hemophilia-a-in-japan-fc-adolescent-and-children-treatment-stud/. Accessed September 27, 2023.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/real-world-effectiveness-evaluation-of-the-recombinant-factor-viii-fc-fusion-protein-in-adolescents-and-children-with-hemophilia-a-in-japan-fc-adolescent-and-children-treatment-stud/