Background:
Congenital FXD is a rare bleeding disorder characterized by spontaneous joint and mucocutaneous bleeding and gastrointestinal or intracranial hemorrhage. pdFX is a US- and EU-approved treatment for congenital FXD, but data in children <12 years have been unavailable.
Aims:
To investigate pdFX efficacy, safety, and pharmacokinetics in children <12 years with moderate to severe congenital FXD.
Methods:
In this 6-month, open-label, multicenter, phase 3, prospective study in children <12 years, all subjects had a confirmed diagnosis of moderate to severe congenital FXD (basal FX:C <5%), severe bleeding history, or an F10 gene mutation causing a documented severe bleeding type. Subjects received routine prophylaxis at recommended 40–50 IU/kg twice weekly to maintain trough FX:C levels ≥5%. Each investigator assessed efficacy based on standardized criteria and presence of breakthrough bleeding. All subjects provided informed consent and the protocol was approved by appropriate independent ethics committees.
Results:
Mean age of the 9 trial completers was 6.8 years. Eight subjects had severe and 1 had moderate FXD. Overall, 537 prophylactic infusions were administered; mean dose/child was 38.6 IU/kg. Ten bleeds in 3 of 9 children were reported: 6 minor, 3 major, 1 unassessed. Investigators rated overall pdFX efficacy as excellent in all subjects. Overall mean incremental recovery was 1.74 IU/dL per IU/kg. FX trough levels were maintained >5% after visit 4 (days 29–42) in all subjects.
A total of 28 treatment-emergent adverse events (TEAEs) were reported in 8 children; none were considered pdFX related. No significant changes were noted in vital signs, physical exams, or laboratory measurements. No evidence of inhibitor development was seen.
Conclusion:
pdFX is efficacious in the prophylaxis of bleeding episodes in subjects <12 years with moderate to severe FXD. Safety profile in this population is consistent with previous results in subjects ≥12 years.
Funding: Bio Products Laboratory