PB0244 - Real world experience using emicizumab in pediatric patients: clinical features and joint health evaluation

Background: Emicizumab is a humanized bispecific recombinant monoclonal antibody that binds to factor IX and factor X and mimics the function of factor VIII (FVIII). This drug solved some major challenges of hemophilia A (HA) treatment such as administration route (subcutaneous), frequency of administration and treatment for FVIII inhibitor.

Aims: To provide real world evidence from the use of emicizumab in a Pediatric Hemophilia Unit in Spain, from January 2017 to December 2023.

Methods: Retrospective study in a tertiary pediatric hospital in children 0-18 years-old diagnosed with severe hemophilia A under treatment with emicizumab. Apart from relevant clinical data, periodical joint evaluation using Hemophilia Joint Health Score (HJHS) and Hemophilia Early Arthropathy Detection with ultrasound (HEAD-US) was collected.

Results: Twenty patients were included into the study and divided in three groups (table 1). Median ABR was 0 (range 0-2). Only 2 bleeding events required replacement therapy or bypassing agents.
Periodical joint health evaluation using HJHS and HEAD-US was performed every 6 months in 13 patients between 3 and 18 years-old. A total of 71 evaluations were collected (figure 1). Nine patients had a HJHS < 4 and HEAD-US < 1 in most of the studies. However, presence of synovitis in ultrasound led us to modify emicizumab treatment in 4 patients (from every 15 days to a every 7 days administration schedule). Two of these patients improved their HJHS and HEAD-US scores after these changes. The other two patients had a long-term FVIII inhibitor and an important articular damage prior to emicizumab initiation.

Conclusion(s): Emicizumab seems to be a safe and useful as prophylactic treatment in pediatric patients with HA, including those under ITI treatment. Periodic joint evaluation with ultrasound appears to be an interesting tool to monitor treatment.