Canadian registry reports sustained bleeding reduction with emicizumab in hemophilia A

An observational cohort study in Blood Advances evaluated the long-term safety and effectiveness of emicizumab prophylaxis using routinely collected Canadian Bleeding Disorders Registry data. Researchers included 710 people with congenital hemophilia A who received at least one dose between 2018 and December 31, 2023. Annualized bleeding rates (ABRs) for all reported bleeds were compared within patients before and after treatment using negative binomial regression; 539 participants (75.9%) had more than one year of exposure.

Mean ABR decreased from 1.00 (95% CI, 0.87–1.14) before emicizumab to 0.47 (95% CI, 0.40–0.55) afterward, corresponding to a rate ratio of 0.47 (95% CI, 0.41–0.55; P<.001). Over a median follow-up of 549 days (interquartile range, 374–690), 439 participants (61.8%) had no recorded bleeds. Sustained bleed control was reported for up to five years.

The study recorded 34 adverse events, including two thrombotic events. One was considered unlikely related to emicizumab; the other was associated with a central venous access device and considered probably related to previous eptacog alfa use and/or possibly related to previous emicizumab. These findings support real-world effectiveness, but the observational before-and-after design cannot establish causality, and routinely collected bleeding records may be incomplete. Only the abstract was available for assessment.