Abstract Number: PB0935
Meeting: ISTH 2020 Congress
Theme: Hemophilia and Rare Bleeding Disorders » Hemophilia - Clinical
Background: Emicizumab was introduced in the UK for haemophilia A with inhibitors (HA-I) in February 2018. Although clinical trials demonstrate significant reduction in bleeding rates, real-world studies are limited.
Aims: To describe and compare the use and efficacy of Emicizumab with prior treatment modalities in UK HA-I patients.
Methods: Haemtrack (HT) and National Haemophilia Database (NHD) treatment data provided demographics, ABR, AJBR and inhibitor titres for descriptive comparison between switchers with non-switchers, (01/02/2018-30/09/19). A within-patient before and after switching comparison was conducted in the subset with ≥6 months pre and post-switching HT data, analysed using Wilcoxon signed-rank testing. Bleed-free proportion was analysed using the Χ2 McNemar test.
Results: Of 172 patients with HA-I, 81 (47%) switched to Emicizumab, median (IQR) age 26 (11-51) years. Dosing schedules, available for 75/81 patients, showed weekly dosing in 53/75, fortnightly in 19/75 and variable in 3/75. Immune tolerance induction (ITI) occurred concomitantly in three. Emicizumab uptake increased steadily across the follow-up period and was associated with an overall reduction of 92% and 68.5% in the use of FEIBA and rFVIIa for HA-I, respectively. The 61/81 patients with ≥6 months HT compliant Emicizumab treatment data had a median (IQR) follow-up 57 (42;78) weeks, ABR 0 (0;0) and AJBR 0 (0;0) and 89% (n=54) were bleed-free. Within-patient comparison of 30 patients with ≥6 months pre-switch data showed a fall in ABR and AJBR (p< 0.001) (Table). The 58/172 patients not switched to Emicizumab (with ≥6 months HT compliant data) were generally younger and with lower inhibitor titres, bleed rates and use of bypassing agents (Table). Emicizumab was discontinued in two mild haemophilia patients whose inhibitors remitted and in one patient with recurrent reactions.
Conclusions: Emicizumab prophylaxis in HA-I is associated with dramatic reduction in bleeding rates in the real-world. Further data are required to determine long-term clinical outcomes.
| Non-switchers, n=67 | Pre-switch, n=30 | Post-switch, n=30 | Within-patient comparison p value | |
| Severity | severe 58, moderate 9 | severe 29, moderate 1 | – | |
| Inhibitor titre at presentation (BU) med. (IQR) | 5.25$(1.33-14.28), n=52 | 9.04$(3.95-45.6), n=13 | – | |
| Age med. (IQR) | 6 (2;15.5) | 30 (12;47) | – | |
| Follow-up (weeks) med. (IQR) | 78 (59;78) | 48 (41;71) | 49 (39;80) | – |
| ABR med. (IQR)[range] | 0.7 (0;1.9) [0;18] | 12 (2.5;16.8)[0;61.2] | 0 (0;0) [0;41.1] | p<0.001 |
| AJBR med. (IQR) [range] | 0 (0;0.7) [0;18] | 4.4 (1.3;10.0) [0;23.8] | 0 (0;0) [0;32.8] | p<0.001 |
| Bleed-free number (%) | 32 (48%) | 3 (10%) | 26 (87%) | p<0.001# |
| $p=0.11 # Χ 2 goodness-of-fit test | ||||
[Comparison of patient characteristics and within-patient analysis of Emicizumab treated patients]
To cite this abstract in AMA style:
Wall C, Xiang H, Palmer B, Collins P, Hart D, Hall G, Chalmers E, Benson G, Evans G, Liesner R, Makris M, Harrison C, Mangles S, Maclean R, Shapiro S, Stephensen D, Sartain P, Hay C. Real World Efficacy of Emicizumab in Haemophilia A with Inhibitors: A Report from the UK National Haemophilia Database [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/real-world-efficacy-of-emicizumab-in-haemophilia-a-with-inhibitors-a-report-from-the-uk-national-haemophilia-database/. Accessed September 29, 2023.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/real-world-efficacy-of-emicizumab-in-haemophilia-a-with-inhibitors-a-report-from-the-uk-national-haemophilia-database/