PB0216 - Hemoglobin improvement among patients with hemophilia A treated with emicizumab prophylaxis: post hoc analysis of the HAVEN 1, 3, 4 and STASEY trials

Background: Recurrent bleeding in people with hemophilia A (PwHA) can cause iron deficiency and/or chronic inflammation anemia, reflecting a poorly controlled bleeding state. Data on the impact of anemia and screening recommendations in PwHA are limited. Having previously been shown to improve bleed control, the effect of emicizumab on hemoglobin in PwHA is of interest.

Aims: To assess change from baseline in hemoglobin and associated red blood cell (RBC) indices in participants (≥12 years) receiving emicizumab prophylaxis for severe hemophilia A during long-term follow-up of the HAVEN 1, 3, 4, and STASEY trials (sponsored by Roche).

Methods: Ethics approval and consent were obtained. Hemoglobin change from baseline was evaluated in the pooled population (N=497) and in subgroups, including baseline hemoglobin level (80< hemoglobin < 100, 100≤hemoglobin < 120, 120≤hemoglobin < 140, 140≤hemoglobin < 180; g/L), prior treatment regimen, and inhibitor status. Change from baseline in associated RBC indices was assessed. Laboratory data on iron status were unavailable.

Results: In the pooled population, mean hemoglobin (standard deviation [SD], g/L) was 145.3 (15.8) at baseline and 151.3 (13.2) at Weeks 73–78 (Table 1). Mean hemoglobin increased from baseline to Weeks 73–78 for all subgroups (baseline hemoglobin level, prior treatment regimen, and baseline inhibitor status; Table 1). These improvements were continually observed over time, especially for those with low baseline hemoglobin (Figure 1). Annualized bleed rate (ABR; at Weeks 27–52) and hemoglobin (at Week 52) were negatively correlated (r=−0.48) among participants with low baseline hemoglobin ( < 120g/L). Participants with inhibitors had lower baseline hemoglobin than those without inhibitors yet experienced a greater increase in hemoglobin (mean [SD], g/L) by Weeks 73–78 (8.1 [15.9] vs. 2.9 [10.9]). Additional laboratory measurements are presented (Table 1).

Conclusion(s): These data complement the previously observed reduction in ABR for PwHA receiving emicizumab; all subgroups studied experienced hemoglobin increases. Routine anemia screening in PwHA may aid early identification.