Abstract Number: PB1169
Meeting: ISTH 2020 Congress
Background: Recombinant factor XIII-A2 (rFXIII-A2) is indicated for prophylaxis in patients with congenital FXIII A-subunit deficiency (FXIII-A CD). Real-world evidence on usage of rFXIII-A2 is lacking.
Aims: Investigate the long-term, real-world rFXIII-A2 use on effectiveness and adverse drug reactions from mentor6 (a prospective, multinational, non-interventional, post-authorisation safety study), and effectiveness and safety outcomes from patients in the Prospective Rare Bleeding Disorders Database (PRO-RBDD) registry.
Methods: Both mentor6 and PRO-RBDD prospectively assessed the following endpoints: annualised bleeding rate (ABR), efficacy for minor surgery and bleed treatment, serious adverse events (SAEs), medical events of special interest (MESIs), and specific adverse drug reactions (anti-FXIII antibodies, allergic reactions, embolic/thrombotic events and lack of therapeutic effect).
Results: mentor6 enrolled 30 patients (Table 1, mean [range] age: 25.5 [2-68] years), total exposure time: 75.4 person-years.
No spontaneous treatment-requiring bleeds occurred during mentor6. Six traumatic bleeds required treatment with a FXIII-containing product, thus the mean ABR was 0.066 bleeds/year; 5/6 treatment-requiring bleeds were treated with rFXIII-A2 and all had a successful outcome (Table 2). Of nine minor surgeries performed during rFXIII-A2 prophylaxis, eight reported successful haemostatic outcomes (one missing evaluation).
No neutralising anti-FXIII antibodies (inhibitors), allergic reactions, withdrawals due to AEs, or embolic/thrombotic events with causal relation to rFXIII-A2 were reported. Eighteen patients reported 44 AEs; 30 were mild, 13 moderate and one severe. Eleven AEs were possibly/probably related to rFXIII-A2. Ten AEs were considered SAEs, all were unlikely related to rFXIII-A2; of four MESIs, two were possibly/probably related to rFXIII-A2 (non-neutralising [binding] antibodies and suspected lack of efficacy). All patients with related AEs, MESIs or SAEs recovered.
PRO-RBDD included four patients exposed for ≈9.5 person-years. No AEs, or treatment-requiring or spontaneous bleeds were reported.
Conclusions: These real-world, long-term data confirm the safety and effectiveness of rFXIII-A2 for prophylaxis, treatment of bleeding episodes and minor surgeries in patients with FXIII-A CD.
[Table 1 AEs during mentor6.]
To cite this abstract in AMA style:Hvitfeldt Poulsen L, Kerlin BA, Castaman G, Molinari AC, Menegatti M, Dey S, Garly M-, Carcao M. Results from a Phase 4, Real-World Study Confirm the Safety and Effectiveness of rFXIII-A2 for the Treatment of Congenital FXIII A-Subunit Deficiency [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/results-from-a-phase-4-real-world-study-confirm-the-safety-and-effectiveness-of-rfxiii-a2-for-the-treatment-of-congenital-fxiii-a-subunit-deficiency/. Accessed September 27, 2023.
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