Safety and efficacy of nonacog alfa for the treatment of haemophilia B in children younger than 6 years of age in a routine clinical care setting: the EUREKIX registry study

Abstract

European regulatory authorities request postmarketing safety and efficacy data for factor IX (FIX) products. Collect additional clinical data from routine nonacog alfa use in children aged <6years with haemophilia B. The EUREKIX registry included retrospective and prospective data collection phases. Safety was assessed via adverse drug reactions (ADRs)/adverse events (AEs) and events of special interest (ESIs) as the primary objective; efficacy was evaluated via annualised bleeding rates (ABRs). The retrospective phase comprised 37 subjects. Of these, 25 had severe haemophilia B. One subject experienced 2 ADRs; another experienced 4 ESIs of hypersensitivity. Median ABR in subjects receiving a predominantly on-demand regimen (prophylaxis <50% of time; n=11) was 2.0; median ABR was 3.8 in those receiving predominantly prophylactic treatment (prophylaxis ≥50% of time; n=24). Joint bleeding was infrequent (median ABR, 0.4; n=35). The prospective phase included 26 subjects, with 17 continuing from the retrospective phase. A total of 20 subjects had severe haemophilia B. Three subjects experienced 7 treatment-related AEs; 3 experienced 4 ESIs. Median ABR was 4.5 and 1.1 in subjects who received predominantly on-demand (n=5) or prophylactic treatment (n=19), respectively; the overall median ABR for joint bleeding events was 0.0. Overall, nonacog alfa treatment effectively controlled bleeding events, with no new safety signals identified. These data support the safety and efficacy of nonacog alfa in routine clinical settings in children aged <6years.