Abstract Number: PB0674
Meeting: ISTH 2022 Congress
Background: Hemophilia A, a bleeding disorder characterized by deficiency of factor (F)VIII, is associated with substantial morbidity. Emicizumab, a bispecific monoclonal antibody that substitutes for deficient activated FVIII, has proven efficacious for bleeding prevention in clinical trials in people with hemophilia A (PwHA) with and without FVIII inhibitors.
Aims: Here, we examine the effectiveness of emicizumab in a real-world setting.
Methods: This analysis utilizes data on all bleeds from Cost of Haemophilia in Europe: a Socioeconomic Survey II (CHESS II), a retrospective, burden-of-illness questionnaire-based study, including the base study and an increased selection (oversample) of patients who initiated emicizumab. Safety data were not captured. Informed consent and ethics approval were obtained.
Results: Overall, 146 PwHA with severe disease (Italy n=81; Germany n=26; Spain n=26; France n=10; UK n=3), 22 from the base study and 124 from the oversample, were included in the analysis. Of these, 78 adults received emicizumab for ≥12 months, including 49 (62.8%) previously treated with FVIII prophylaxis, 28 (35.9%) treated on demand, and 1 who previously received gene therapy; 22/78 (28.2%) had either a history of, or current, FVIII inhibitors (Table 1).
Mean all-bleeds annualized bleed rate (ABR) in the 78 participants decreased from 3.37 at last treatment pre-emicizumab to 1.42 post-emicizumab. Median ABR decreased from 3.00 to 1.19. In the 49 participants previously on prophylaxis, mean ABR decreased from 3.49 to 1.40 after switching to emicizumab (Figure 1). Median ABR decreased from 3.00 to 1.09.
A sensitivity analysis including 123 PwHA who received emicizumab for ≥6 months showed a decrease in mean ABR from 4.33 pre-emicizumab to 1.91 post-emicizumab; median ABR decreased from 3.00 to 1.33 (all p ＜0.001).
Conclusion(s): ABRs decreased in all groups after switching to emicizumab based on physician-reported data from the CHESS II study, both in PwHA previously on FVIII prophylaxis and those previously treated on demand.
To cite this abstract in AMA style:Mancuso M, Nissen F, Zhang H, Ferri-Grazzi E, O’Hara J, Ofori-Asenso R, Moreno K, Burke T. Annualized Bleed Rates in Severe Hemophilia A After Switch to Emicizumab Based on CHESS II Data, Including an Oversample of Emicizumab Patients [abstract]. https://abstracts.isth.org/abstract/annualized-bleed-rates-in-severe-hemophilia-a-after-switch-to-emicizumab-based-on-chess-ii-data-including-an-oversample-of-emicizumab-patients/. Accessed October 1, 2023.
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