Pharmacokinetics, thrombogenicity and safety of a double viral inactivated factor IX concentrate compared with a prothrombin complex concentrate

A quantitative systems pharmacology model of blood coagulation network describes in vivo biomarker changes in non-bleeding subjects

Essentials Baseline coagulation activity can be detected in non-bleeding state by in vivo biomarker levels. A detailed mathematical model of coagulation was developed to describe the non-bleeding state. Optimized model described in vivo biomarkers with recombinant activated factor VII treatment. Sensitivity analysis predicted prothrombin fragment 1 + 2 and D-dimer are regulated differently.

SUMMARY

Background Prothrombin fragment 1 + 2 (F1 + 2 ), thrombin-antithrombin III complex (TAT) and D-dimer can be detected in plasma from non-bleeding hemostatically normal subjects or hemophilic patients. They are often used as safety or pharmacodynamic biomarkers for hemostatis-modulating therapies in the clinic, and provide insights into in vivo coagulation activity. Objectives To develop a quantitative systems pharmacology (QSP) model of the blood coagulation network to describe in vivo biomarkers, including F1 + 2 , TAT, and D-dimer, under non-bleeding conditions. Methods The QSP model included intrinsic and extrinsic coagulation pathways, platelet activation state-dependent kinetics, and a two-compartment pharmacokinetics model for recombinant activated factor VII (rFVIIa). Literature data on F1 + 2 and D-dimer at baseline and changes with rFVIIa treatment were used for parameter optimization. Multiparametric sensitivity analysis (MPSA) was used to understand key proteins that regulate F1 + 2 , TAT and D-dimer levels. Results The model was able to describe tissue factor (TF)-dependent baseline levels of F1 + 2 , TAT and D-dimer in a non-bleeding state, and their increases in hemostatically normal subjects and hemophilic patients treated with different doses of rFVIIa. The amount of TF required is predicted to be very low in a non-bleeding state. The model also predicts that these biomarker levels will be similar in hemostatically normal subjects and hemophilic patients. MPSA revealed that F1 + 2 and TAT levels are highly correlated, and that D-dimer is more sensitive to the perturbation of coagulation protein concentrations. Conclusions A QSP model for non-bleeding baseline coagulation activity was established with data from clinically relevant in vivo biomarkers at baseline and changes in response to rFVIIa treatment. This model will provide future mechanistic insights into this system.

The impact of a three-factor prothrombin complex concentrate on the anticoagulatory effects of the factor Xa inhibitor edoxaban

BACKGROUND

Edoxaban, a direct factor Xa inhibitor, is a once-daily, non-vitamin K antagonist oral anticoagulant. There is no established method to reverse the activity of non-vitamin K oral anticoagulants in cases of hemorrhage or urgent surgery. This study evaluated the ability of a 3-factor prothrombin complex concentrate (3F-PCC) to reverse the anticoagulatory effects of edoxaban.

METHODS

In this phase 1 study, 24 healthy subjects were randomly assigned to receive a single dose of 60 or 180mg edoxaban, followed by placebo, 25IU/kg 3F-PCC, or 50IU/kg 3F-PCC. Edoxaban pharmacokinetics and pharmacodynamics, including the primary endpoint of prothrombin time (PT) and endogenous thrombin potential (ETP), were assessed. D-dimer and prothrombin fragment 1 and 2 (F1+2) were also measured.

RESULTS

Overall, there were no apparent consistent effects of 3F-PCC on edoxaban pharmacokinetics. Administration of 3F-PCC 25 or 50IU/kg with edoxaban 60 or 180mg did not substantially accelerate the return of PT to baseline levels. However, infusion of 3F-PCC 25 and 50IU/kg did substantially accelerate return to baseline of ETP compared with placebo. D-dimer and F1+2 data did not indicate any lasting procoagulant effects of 3F-PCC infusion, although a transient increase in F1+2 was noted during and after 3F-PCC infusion. Edoxaban and 3F-PCC co-administration was well tolerated in normal healthy subjects.

CONCLUSIONS

There was no apparent reversal of PT prolongation with 3F-PCC following edoxaban infusion, but ETP was completely reversed. Co-administration of 3F-PCC was well tolerated, but a dose-dependent increase in F1+2 may reflect a procoagulant risk.