Pharmacokinetic variability of factor VIII concentrates in Chinese pediatric patients with moderate or severe hemophilia A

Pharmacokinetic profile of children with haemophilia A receiving low-dose FVIII prophylaxis in Indonesia: A single centre experience

BACKGROUND

Pharmacokinetic (PK) studies of low-dose prophylaxis (LDP) of coagulation factor VIII (FVIII) in children with severe haemophilia A (SHA) are scarce.

OBJECTIVE

This study aims to investigate the PK profile of children with SHA receiving LDP of FVIII.

METHODS

Paediatric patients receiving FVIII infusions (10 IU/kg twice weekly) were included. PK profiles were estimated using the Web Accessible Population Pharmacokinetic Service for Haemophilia (WAPPS-Haemo). The primary outcomes were the terminal half-life (t_1/2 ), concentration-time profile, and time to reach an FVIII level of < 1%. The secondary outcome was the suggested dosing interval of FVIII prophylaxis based on the individual PK profile.

RESULTS

Twenty-five patients were recruited; their mean age was 12.3 ± 3.0 years. The t_1/2 differed among patients receiving LDP of FVIII twice weekly, with a median of t_1/2 was 14.8 h (IQR 12.6-16). The median time to reach an FVIII level of < 1% was 73.8 h (IQR 58.8-80.3). Most patients could maintain a trough level of FVIII > 1% longer than 48 h. At 72-96 h, patients needed a second dose of FVIII infusion because the FVIII level was < 1%. The suggested dosing interval of FVIII prophylaxis ranged from daily to every 96 h, depending on the individual PK profile.

CONCLUSION

Our study identified inter-individual differences in the PK parameters using LDP of FVIII twice weekly. The inter-individual results in different dosing intervals advise the timing of LDP. Estimating individual PK parameters enables the identification of the optimal prophylaxis frequency to prevent bleedings.

Enhanced pharmacokinetics and reduced bleeds in boys with hemophilia A after switching to Kovaltry from other standard half-life factor VIII concentrates

Background

BAY81-8973 (Kovaltry; Bayer, Berkeley, CA, USA) was reported with enhanced pharmacokinetic (PK) profiles compared with some other standard half-life (SHL) factor VIII (FVIII) concentrates. Limited head-to-head comparative studies were conducted in a real-world setting.

Objective

To make head-to-head comparisons of PK and clinical outcomes between Kovaltry and three other SHL FVIII concentrates.

Methods

Forty-seven boys with severe hemophilia A were enrolled and divided into three groups according to their previously used FVIII concentrates (Kogenate FS, N = 22; Advate, N = 14; GreenMono, N = 11). Two separate PK tests were conducted in each participant with a five-point assay during the study period from 6 months before switching to 6 months after switching. FVIII levels were detected by one-stage assay, and PK profiles were calculated by noncompartmental assay. Annualized bleeding rates were collected through participant' bleed logs.

Results

Longer half-life time (Kogenate FS group: 14.4 vs 11.9 hours, P < .0001; Advate group: 13.4 vs 9.7 hours, P < .0001; GreenMono group: 15.1 vs 10.7 hours, P < .001]) and lower clearance (Kogenate FS group: 3.3 vs 3.9 mL/kg/h, P < .01; Advate group: 3.7 vs 5.9 mL/kg/h, P < .01; GreenMono group: 3.0 vs 5.1 mL/kg/h, P < .01) were observed with Kovaltry. In addition, longer mean residential time (P < .01) and higher area under the curve (P < .01) were demonstrated. No statistical difference was found in in vivo recovery between Kovaltry and the other FVIII products. Participants who switched to Kovaltry from three other FVIII concentrates with the same dosing regimens obtained higher trough FVIII levels and better protection with reduced annualized bleeding rates.

Conclusion

Compared with Kogenate FS, Advate, and GreenMono, Kovaltry showed enhanced PK profiles, which contributed to reduced bleeding rates.

Pharmacokinetic study of Kovaltry in thirty-five pediatric patients aged <12 years with severe hemophilia A

BACKGROUND

Kovaltry (BAY81-8973) is an unmodified full-length factor VIII (FVIII) concentrate that enhances the pharmacokinetic (PK) profiles as compared to some other standard half-life time FVIII concentrates. However, the PK of Kovaltry in haemophiliac patients aged <12 years has not been reported previously.

AIM

To investigate the pharmacokinetics and clinical outcomes of Kovaltry in 35 paediatric patients aged <12 years.

METHODS

A total of 35 boys with severe haemophilia A were enrolled from August 2019 to May 2020 in Beijing Children's Hospital. After 72-hour washout, PK tests were performed post-infusion of 50 IU/kg Kovaltry in a five-timepoint assay. WinNonlin software was used to generate individual PK parameters. The dose, frequency and bleeding details were collected within the first 6 months after switching to Kovaltry from other FVIII concentrates.

RESULTS

Compared to the blood group O, patients with blood group non-O showed longer mean half-life (t_1/2 ) (p < .01), lower mean clearance (CL) (p = .01) and similar in vivo recovery (IVR) (p = .51). Higher von Willebrand factor antigen (VWF:Ag) level was correlated to longer t_1/2 (p < .0001) and lower CL (p < .01). IVR was correlated to body mass index (BMI) (p < .0001). Patients with trough level >3 IU/dL demonstrated lower annual bleeding rate (ABR) (p < .01), annual joint bleeding rate (AJBR) (p < .01) and annual spontaneous bleeding rate (ASBR) (p < .01).

CONCLUSION

This study firstly reported the PK profiles of Kovaltry in 35 paediatric patients <12 years old. The great inter-individual variability of PK parameters was also confirmed in these patients. VWF:Ag and blood group were major influencing factors of t_1/2 and CL of Kovaltry, while BMI was a vital predictor for IVR. Patients with high trough FVIII level in routine prophylaxis had reduced bleeding rates.