A Post-Authorization Safety Surveillance Study to Report Clinical Experience with Purified Factor IX Concentrate in Pediatric Patients with Hemophilia B.

Introduction: Purified factor IX (FIX) concentrate (IMMUNINE Aim: Document real-world clinical experience with purified FIX concentrate in routine practice for pediatric patients with hemophilia B. Methods: This prospective post-authorization safety surveillance study enrolled patients ≤6 years old with moderate or severe hemophilia B (baseline FIX ≤5%) who were prescribed purified FIX concentrate, as determined by the treating physician. The planned observation period for each patient was either 12 months or ≥50 exposure days, whichever occurred first. The primary endpoints were the occurrence of treatment-related adverse events (AEs) and serious AEs (SAEs), and inhibitor development. Results: Thirteen male patients (mean ± standard deviation age, 3.80 ± 1.76 years) enrolled and received ≥1 treatment with purified FIX concentrate. Thirty-two AEs were reported in 6 patients; 4 were SAEs. No AEs were considered related to purified FIX concentrate. No patients developed inhibitory antibodies. Inhibitor testing was not conducted in 2 patients. Eighteen bleeding episodes were treated with purified FIX concentrate in 6 patients. Hemostatic efficacy was rated as either "excellent" or "good" in all patients with an available rating. Conclusion: No treatment-related AEs were reported, and purified FIX concentrate was shown to be effective in treating and preventing bleeding episodes in pediatric patients ≤6 years old with hemophilia B.