Systematic Review of the Published Evidence on the Pharmacokinetic Characteristics of Factor VIII and IX Concentrates
Authors: Xi Menchen , Navarro-Ruan Tamara , Mammen Sunil , Blanchette Victor S. , Hermans Cedric R. , Morfini Massimo , Collins Peter W. , Fischer Kathelijn , Neufeld Ellis J. , Young Guy , Kavakli Kaan , Radossi Paolo , Dunn Amy , Thabane Lehana , Iorio Alfonso 
Published: October 2019

Abstract
Introduction: The efficacy of factor VIII and IX concentrates administered to prevent bleeding episodes in patients with hemophilia A and B is correlated with the plasma levels measured over time after the infusion. The inter-patient variability of pharmacokinetic (PK) parameters is large, and it is difficult to assess individual PK profiles due to the need for multiple time points. This is often not feasible, particularly for pediatric patients. Population PK modeling potentially provides a practical solution to this problem. The successful modelling of PK parameters at the population level requires knowledge of disposal characteristics and relevant covariates. We performed a systematic review of the available evidence in order to identify available PK data for factor VIII and IX concentrates to facilitate the implementation of a population PK approach.
Methods: We conducted a literature search in MEDLINE and EMBASE from January 1997 to May 2014, using the keywords "hemophilia" and "pharmacokinetic". We included only articles that published original PK data for factor VIII and IX concentrates in humans and published in English. Two authors independently screened the studies and extracted the relevant data.
Results: We retrieved 237 unique articles published between 1998 and 2013. We excluded 185 articles that did not meet our research criteria. We included 52 articles, with a total of 1365 patients included in PK analyses. 26 articles reported PK data on factor VIII concentrates, 18 articles report PK data on factor IX concentrates, and one article reported on both factor VIII and IX concentrates. Seven articles reported pharmacokinetic data on both factor VIII and Von Willebrand factor concentrates. We extracted the following data: number of patients, type and severity of hemophilia, patient age, factor concentrate infused, dose infused, sampling data points, half-life, clearance, recovery and the model used for pharmacokinetics, and inclusion of patients undergoing surgery or with inhibitors. The main results are summarized in table 1.
Conclusions: This review provides the first systematic appraisal of the methods and results of published papers in the field. The data gathered confirms the intra-patient variability of factor concentrate PK and provides useful information on which to build population based PK models.
*3 FIX articles and 2 FVIII articles did not report lab test; one article reported PK data for both FIX and FVIII
†11 articles reported FVIII PK data for both one-stage clotting and chromogenic assays
ǂPapers reporting on long-acting FVIII and FIX were included in the review, but not summarized in the table. For this reason, not all 1365 patients are accounted for in the table
§Estimate of the range of the means found in the papers

Disclosures
Xi: Baxter: Research Funding. Navarro-Ruan:Baxter: Research Funding. Mammen:Baxter: Research Funding. Collins:Baxter: Consultancy, Honoraria, Research Funding, Speakers Bureau; CSL: Consultancy, Honoraria, Research Funding, Speakers Bureau; NovoNordisk: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bayer: Consultancy, Honoraria, Research Funding, Speakers Bureau. Neufeld:Baxter: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: data safety monitoring board, data safety monitoring board Other; Biogen IDEC: Membership on an entity's Board of Directors or advisory committees; NovoNordisk: Membership on an entity's Board of Directors or advisory committees; Pfiser: consultancy, data and safety monitoring board Other; Octapharma: Research Funding. Dunn:CSL Behring,: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Baxter: Membership on an entity's Board of Directors or advisory committees; Biogen: Membership on an entity's Board of Directors or advisory committees; Pfiser: Membership on an entity's Board of Directors or advisory committees. Iorio:Baxter: Honoraria, Research Funding; Bayer: Honoraria, Research Funding; NovoNordisk: Honoraria, Research Funding; Biogen: Honoraria, Research Funding; Pfiser: Honoraria, Research Funding.