Pharmacokinetic characteristics of the triple inactivated plasma-derived Kedrion FIX concentrate: data from the KB037 clinical trial

The pharmacokinetics data of phase I/II clinical trials (EudraCT Number: 2005-006186-14) of the new, triple inactivated plasma-derived Kedrion FIX concentrate was designed according to the recommendations of SSC-ISTH [1,2]: 11 post-infusion FIX/time points samples during the first 72 h. The PK data were also analysed by a modified, less dense, 9 FIX/time points, sample design. The outcomes of the safety and efficacy study and the pharmacokinetics' results have been previously and partially described [3,4]. The single-dose PK at enrolment (PK I) and the end of the trial (PK II) were analyzed by WinNonlin 7.0 (Pharsight) and according to three different methods: Non-Compartment Analysis (NCA), One Compartment Method (OCM), and Two-Compartment Method (TCM). The outcomes of PK parameters by TCM show that a higher number of FIX/time concentration points may not always give a better definition of the decay curve. On the other hand, the Terminal HL of NCA is deeply affected by the goodness of the last two-three points. The quite long Kedrion FIX HL may allow for a cost/effective tailoring of prophylaxis in haemophilia B patients.