Performance of a recombinant fusion protein linking coagulation factor IX with recombinant albumin in one-stage clotting assays. J Thromb Haemost 2019 Jan;17(1):138-148
Date
11/13/2018Pubmed ID
30418692Pubmed Central ID
PMC7379984DOI
10.1111/jth.14332Scopus ID
2-s2.0-85058628400 (requires institutional sign-in at Scopus site) 14 CitationsAbstract
Essentials Performance of the one-stage clotting (OSC) assay varies with the clotting activator used. Recombinant FIX-albumin fusion protein (rIX-FP) was reliably monitored with most OSC reagents. rIX-FP shows comparable reagent-dependent variability to other rFIX products in the OSC assay. Actin® FS and kaolin-based reagents underestimated rIX-FP activity by around 50% in the OSC assay. SUMMARY: Background Measuring factor IX activity (FIX:C) with one-stage clotting (OSC) assays, based on the activated partial thromboplastin time (APTT), is the current mainstay of diagnostic techniques for hemophilia B. Assessing the performance of new recombinant FIX (rFIX) products in OSC assays is essential, as APTT reagents from different manufacturers yield different potency estimates for rFIX. Objectives To evaluate the extent to which choice of reagent composition influences rFIX potency measurements of recombinant FIX-albumin fusion protein (rIX-FP, IDELVION) activity in OSC assays. Methods rIX-FP was added to FIX-deficient plasma, and FIX:C was assessed centrally and locally in a multicenter international field study with a variety of commercial OSC APTT reagents. Paired sample analysis of clinical samples was performed to compare values of FIX:C from local and central laboratories. In-house bioanalytical investigations with spiked samples were conducted to compare the APTT-reagent dependent variability of rIX-FP with unmodified rFIX and rFIX Fc fusion protein (rFIXFc). Results Central and local assessments of FIX:C from 10 countries and 21 participating centers showed comparable results to those from the central laboratory across the majority of 18 different APTT reagents from both clinical and spiked samples. There was a consistent underestimation of rIX-FP activity of ≈ 50% with OSC assays using Actin FS or kaolin-based APTT reagents. In the bioanalytical study, rIX-FP showed comparable variability in OSC assays to unmodified rFIX and rFIXFc. Conclusions rIX-FP activity can be accurately measured by the use of OSC assays with the majority of commercial reagents. Actin FS or kaolin-based reagents will probably lead to a 50% underestimation of activity.
Author List
Horn C, Négrier C, Kalina U, Seifert W, Friedman KDAuthor
Kenneth D. Friedman MD Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Blood CoagulationCalibration
Clinical Trials, Phase I as Topic
Clinical Trials, Phase II as Topic
Clinical Trials, Phase III as Topic
Factor IX
Hemophilia B
Humans
Indicators and Reagents
Partial Thromboplastin Time
Predictive Value of Tests
Recombinant Fusion Proteins
Reference Standards
Reproducibility of Results
Serum Albumin