PB1228 - Pharmacokinetic study of nonacog beta pegol with differents models

Background: The half-life recombinant factor IX concentrates (rFIX EHL) exhibit a half-life that is 3 to 5 times longer than that of standard FIX concentrates. Theoretically, there can be pharmacokinetic differences between them.

Aims: The aim of this study is to analyze pharmacokinetic parameters using two different models in patients with hemophilia B who are undergoing treatment with Nonacog beta pegol.

Methods: Observational, multicenter and prospective study which included patients with severe hemophilia B receiving prophylactic treatment with Nonacog beta pegol between August 2023 and January 2024.
The assessment of pharmacokinetic (PK) parameters—such as the elimination rate constant (Ke; h-1), volume of distribution (Vd (dL/kg)), clearance (Cl (dL/h/kg)), and half-life time (t½)—was conducted using the pharmacokinetic population software online WAPPS-HEMO and a monocompartmental model.
The PK parameters were compared between both models. A one-stage assay for FIX activity was employed, with a minimum of two samples per patient.
The Student’s t-Fisher test was used to compare medians, utilizing SPSS software

Results: 4 patients treated with Nonacog beta pegol from 2 Spanish hospitals were recruited. Median age was 40,7 years, median weight 83Kg.
The mean activity-time points per patient were 3,2.
The assessment of the PK parameters was performed by using the pharmacokinetic poblacional software online WAPPS-HEMO and using a monocompartmental model.
Using the WAPPS-HEMO population model, the PK parameters obtained for Nonacog beta pegol were: Ke (h-1)= 0.00355; Vd (mL/kg) =76.725; Cl (mL/h/Kg)= 0.036 and t 1/2 (h)= 157.19 Using the monocompartmental model, the PK parameters of Nonacog beta pegol were: Ke (h-1)= 0.006; Vd (mL/kg) =93; Cl (mL/h/Kg)= 0.57 (p < 0,001 vs WAPPS-HEMO) and t 1/2 (h)= 118,6 (p < 0,001 vs WAPPS-HEMO).

Conclusion(s): There are differences between Cl and t ½ parameters when there were evaluated using the monocompartmental model and software online WAPPS-HEMO .