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Use of plasma-derived factor X concentrate in neonates and infants with congenital factor X deficiency
Karen L Zimowski1, Catherine E McGuinn2, Yasmina L Abajas3
1Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta and Department of Pediatrics, Emory University, Atlanta, Georgia, USA.
Insights
Plasma-derived factor X concentrate (pdFX) is safe and effective for preventing bleeding in neonates with congenital factor X deficiency (FXD). Prophylactic pdFX at higher doses is feasible and well-tolerated in infants, demonstrating no breakthrough bleeding episodes.
Area of Science:
- Hematology
- Pediatric Medicine
- Rare Diseases
Background:
- Congenital factor X deficiency (FXD) is a rare bleeding disorder.
- Severe bleeding is common in neonates with FXD.
- Plasma-derived factor X concentrate (pdFX) is approved for FXD but has limited data in infants.
Purpose of the Study:
- To evaluate the safety and efficacy of pdFX in neonates with FXD.
- To assess prophylactic pdFX dosing and outcomes in infants.
Main Methods:
- Retrospective case series of four neonates with moderate to severe FXD.
- Prophylactic pdFX initiated in the first week of life.
- Dosing and factor X activity monitored.
Main Results:
- All patients presented with severe bleeding at birth.
- Prophylactic pdFX initiated at ~29 days of life, average dose 69 IU/kg every 48 hours.
- No breakthrough bleeding observed after median 26.5 months follow-up; one patient had thrombotic complications with sepsis.
Conclusions:
- pdFX is a viable prophylactic option for neonates and infants with FXD.
- Higher pdFX doses (70-80 IU/kg every 48 hours) may be feasible.
- Close monitoring of factor X activity is crucial for guiding dosing in this age group.
Background:
Congenital factor X deficiency (FXD) is a rare bleeding disorder that often presents with severe bleeding in the neonatal period. Long-term prophylaxis with infusions of FX-containing products is recommended in patients with FXD and a personal or family history of severe bleeding. A plasma-derived FX concentrate (pdFX) is approved for on-demand and prophylactic therapy in adults and children with FXD. The safety and efficacy of pdFX has been demonstrated in patients <12 years of age, yet limited data exist regarding its use in infants.
Patients/Methods:
This retrospective case series details clinical experience using pdFX in four neonates with moderate and severe FXD across four institutions.
Results And Conclusions:
All four patients presented in the first week of life with severe bleeding. Following treatment of the acute bleed, prophylactic pdFX was initiated at an average of 29 days of life and a dose of 69 IU/kg every 48 hours. Incremental recovery (IR) in three infants averaged 1.42 IU/dL per IU/kg (min-max: 1.06-1.67 IU/dL per IU/kg). One patient experienced thrombotic complications in the setting of sepsis. After a median follow-up of 26.5 months, no patient has experienced breakthrough bleeding episodes. Our study supports the use of pdFX in neonates and infants and suggests that higher pdFX dosing of 70 to 80 IU/kg every 48 hours based on the smallest available vial size is feasible. Because of variability in IR, close monitoring of FX activity should be used to guide dosing in this age group.
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