Assessing the Performance of Extended Half-Life Coagulation Factor VIII, FC Fusion Protein by Using Chromogenic and One-Stage Assays in Saudi Hemophilia A Patients.

Tarek M. Owaidah,Amelita M. Aguilos,Abdulmjeed O. Alnosair,Hazzaa A. Alzahrani,Nouf S. Al-Numair,Mahasen Saleh

doi:10.1155/2020/8768074

Tarek M. Owaidah, Amelita M. Aguilos + Show 4 more

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https://doi.org/10.1155/2020/8768074

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Abstract

Background The one-stage assay is the most common method to measure factor VIII activity (FVIII : C) in hemophilia A patients. The chromogenic assay is another two-stage test involving purified coagulation factors followed by factor Xa-specific chromogenic substrate. Aim This study aimed to assess the discrepancy and correlation between the chromogenic and one-stage assays in measuring FVIII : C levels in hemophilia patients receiving Extended Half-Life Elocta® as a recombinant extended half-life coagulation factor. Methods We performed a study comparing the measurements of FVIII : C levels by the chromogenic versus the one-stage assays at different drug levels. Data of FVIII : C levels, dosage, and the time interval from administration to measurement were retrieved from the hospital records. The correlation, mean differences, and discrepancy between the two assays were calculated. The linear regression analysis was used to predict the time interval till reaching 1% FVIII : C. Results Fourteen patients with 56 samples were included in the study. Of them, 13 patients were receiving Elocta® as a prophylactic, while one was receiving Elocta® on demand. One-third of these samples showed a discrepancy between the chromogenic and one-stage assays. The two assays were well correlated. Mean differences were significant at the individual and the time interval level. The time since the last Elocta® injection could significantly predict FVIII : C levels (β = 0.366, P < 0.001). Conclusion Our findings suggested a significant difference between both methods; the FVIII : C levels measured by the one-stage assay were less than those estimated by the chromogenic assay. However, the measurements of FVIII levels by the two assays were well correlated but discrepant in one-third of the samples. The levels of FVIII : C reach 1% after 5.4 days since the last Elocta® administration.

Highlights

Hemophilia A is an X-linked bleeding disorder caused by mutations in the genes for factor VIII (FVIII), affecting about one case per 5000 living male births [1,2,3]
Patients tend to bleed after minor injuries; incidents of spontaneous bleeding without an apparent cause may occur, while those with severe hemophilia suffer from frequent, excessive, and spontaneous bleeding since birth [1,2,3,4,5]. e diagnosis of hemophilia is usually based on the clinical symptoms and laboratory analysis, confirming the deficiency of one of the coagulation factors. e severity of hemophilia depends on the extent of coagulation factor deficiency [6, 7]
Our study showed that the FVIII : C measured by chromogenic and one-stage assays was discrepant in 35% of the population

Summary

Introduction

Hemophilia A is an X-linked bleeding disorder caused by mutations in the genes for factor VIII (FVIII), affecting about one case per 5000 living male births [1,2,3]. Patients with mild hemophilia suffer from easy bleeding from external orifices and internal organs, especially with trauma or surgery. Patients tend to bleed after minor injuries; incidents of spontaneous bleeding without an apparent cause may occur, while those with severe hemophilia suffer from frequent, excessive, and spontaneous bleeding since birth [1,2,3,4,5]. E severity of hemophilia depends on the extent of coagulation factor deficiency [6, 7]. Depending on the ratio of FVIII clotting protein in the blood, hemophilia had been classified to mild when FVIII is 6–49%, moderate when it is 1–5%, and severe if less than 1% [8, 9]. People with hemophilia A bleed longer than others, internally or externally.

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