Emicizumab Changes Hemophilia A Spontaneous Bleeding, Bleeding Sites

The findings from a retrospective observational study of the effect of emicizumab in patients with severe hemophilia A were presented at the European Hematology Association 2024 Hybrid Congress in Madrid, Spain. The study was conducted by investigators from the Department of Haematology at Cork University Hospital in Ireland, and its clearest takeaway was that emicizumab reduces spontaneous bleeding in this population.

The team conducted the study at a tertiary care center with a cohort of 16 male patients. The patients’ mean age was 31.1 years, and they received emicizumab for a mean duration of 954 days.

The study primarily sought to compare the patients’ annual bleeding rate (ABR) before and after emicizumab commencement. Researchers found the ABR was lower precommencement compared with postcommencement (0.404 vs 0.559; P=0.459).

The study also looked for changes in bleeding event incidences with commencement of emicizumab, whether events were caused by trauma or spontaneous. Compared with precommencement, patients postcommencement had higher per anum incidence of traumatic bleeds (0.118 vs 0.349; P=0.03) but lower incidence of spontaneous bleeds (0.315 vs 0.153; P=0.137).

The locations of bleeding events in patients also differed before and after commencing emicizumab. The intra-articular knee joint was the most frequent site for precommencement bleeding events, experienced by 25% of the cohort. No patients experienced postcommencement knee bleeds. After intra-articular knee joint bleeding, intramuscular bleeds were the most common type of precommencement bleeding, experienced by 18.8% of the cohort.

The investigators wrote that the findings of their study are limited by its small sample size and follow up, but it “may indicate that emicizumab may be associated with a lower rate of spontaneous bleeds in patients with [hemophilia A] in an Irish context.”

Reference

O’Flynn F, Liston K, Collins N, et al. Bleeding events in patients with haemophilia A pre and post emicizumab prophylaxis. Abstract P1639. Presented at the European Hematology Association 2024 Hybrid Congress; June 13-16, 2024; Madrid, Spain.