Abstract Number: PB1004
Meeting: ISTH 2020 Congress
Theme: Hemophilia and Rare Bleeding Disorders » Hemophilia - Clinical
Background: Prophylaxis is the only strategy to prevent the onset/progression of haemophilic arthropathy. The introduction of extended half-life (EHL) concentrates improved personalization and convenience of prophylaxis by reducing infusion frequency, especially in haemophilia B. However, few real-life data are available, particularly on joint assessment. Ultrasound (US) is useful to early detect and monitor arthropathy.
Aims: This study aims to collect data about joint status in patients with haemophila B switching to a EHL concentrate, rIX-FP.
Methods: At annual check-up joints were evaluated by physical examination (Haemophilia Joint Health Score in children; Gilbert score in adults) and by ultrasound scan (Haemophilia Early Arthropathy Detection with UltraSound, HEAD-US). The last available scores before switch and on rIX-FP treatment were compared, together with patients’ data (annualized bleeding rates [ABR], FIX trough levels, concentrate weekly dose) over comparable time periods on standard recombinant FIX (S-rFIX) and rIX-FP prophylaxis. Data mean±1 standard deviation are reported.
Results: Thirthy-six joints in 6 patients (5 severe, 1 moderate, age 31±12yrs) switched to rIX-FP (22±10mo) were evaluated. Results about ABR, FIX through levels, concentrate weekly dose, HEAD-US and orthopedic joint scores are shown in Tab 1.
HEAD-US score was free of abnormalities at both assessments on 22/36 (61%) joints. Six joints (46% of those with HEAD-US ≥1) had improvement on rIX-FP prophylaxis, due to reduction of synovial hypertrophy. Twenty-height joints showed orthopedic score 0 at both assessments. No joint had score improvement, whereas score increased in 2. Nine joints (25%) with HEAD-US ≥1 were negative at physical examination, whereas 2 (6%) had HEAD-US=0 but positive orthopedic scores.
Conclusions: Despite the limited patient sample, this study shows preserved joint status after switch to rIX-FP, associated with reduced rFIX consumption and sustained FIX trough levels. US scan reveals possible improvement of synovial hypertrophy and provides additional information about early abnormalities in joints negative at physical examination.
| rIX-FP | S-rFIX | p | |
| ABR | 0.8±1.6 | 0.1±0.1 | – |
| FIX trough level (%) | 10.8±1.9 | 3.9±1.4 | 0.002 |
| FIX concentrate weekly dose (IU/kg) | 35.6±12.1 | 89.8±22.3 | 0.001 |
| HEAD-US scores | 0.94±1.8 | 0.8±1.6 | – |
| Orthopedic scores | 0.31±0.7 | 0.25±0.6 | – |
[Table 1]
To cite this abstract in AMA style:
Rivolta GF, Coppola A, Quintavalle G, Matichecchia A, Riccardi F, Polo RM, Tagliaferri A. Haemophilia B Patients Switched to Recombinant Factor IX-Albumin Fusion Protein (rIX-FP): Ultrasound and Clinical Joint Assessment [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/haemophilia-b-patients-switched-to-recombinant-factor-ix-albumin-fusion-protein-rix-fp-ultrasound-and-clinical-joint-assessment/. Accessed November 30, 2021.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/haemophilia-b-patients-switched-to-recombinant-factor-ix-albumin-fusion-protein-rix-fp-ultrasound-and-clinical-joint-assessment/