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Monitoring once‐weekly recombinant factor IX prophylaxis in hemophilia B with thrombin generation assay and factor IX activity
Author(s) -
Nummi V.,
Jouppila A.,
Lassila R.
Publication year - 2017
Publication title -
international journal of laboratory hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.705
H-Index - 55
eISSN - 1751-553X
pISSN - 1751-5521
DOI - 10.1111/ijlh.12634
Subject(s) - factor ix , chromogenic , medicine , regimen , thrombin , thrombin generation , coagulation , pharmacology , surgery , urology , gastroenterology , platelet , chemistry , chromatography
Summary Introduction Prophylaxis is the recommended treatment mode for severe hemophilia B. However, no single treatment regimen fits for all patients. Once‐weekly prophylaxis with high‐dose recombinant factor IX ( rFIX ) is efficacious, nevertheless, laboratory outcomes following 72 h after administration are lacking. Methods In a prospective open‐label noncomparative study, 10 severe/moderate ( FIX ≤2 IU /dL) adult patients received rFIX dose (60–100 IU/kg) after >72 h washout on two occasions, separated by 7 days. We measured one‐stage and chromogenic FIX , ROTEM , and thrombin generation ( TG ) assay in plasma after washout, 30 min after infusion, and at days 3, 4, and 7. Results Median FIX clotting/chromogenic activity increased from 1.5/2.0 to 87/62 IU/dL following rFIX administration, chromogenic assay resulting in 30% lower recovery. Correspondingly TG was severely reduced at baseline and improved at recovery (peak thrombin 6.0 to 54 n m ). Standard ROTEM failed to detect FIX deficiency. Both FIX activity and TG remained increased from days 3 to 7, with median trough levels of FIX clotting/chromogenic 3.0/3.0 IU/dL (≥1 IU /dL in all severe patients) and peak thrombin 9.1 n m measured on day 7. FIX and TG assays were equally consistent between weeks 1 and 2. Conclusions Once‐weekly rFIX prophylaxis results in favorable laboratory outcome.