A comparative in vitro study of the coagulation effects of branded vs generic preparations of the oral anticoagulant apixaban

Abstract

The introduction of the direct oral anticoagulants (DOACs) represents a major advancement in the field of anticoagulant therapy. However, scant research has been conducted to study the effects of generic versions of DOACs on in vitro coagulation tests. The aims of this study were: 1) to determine the anticoagulant effects of the branded version of apixaban (Eliquis®) on a panel of coagulation assays, including Prothrombin time (PT), activated Partial Thromboplastin time (aPTT), PT-derived Fibrinogen, Clauss Fibrinogen, Thrombin time (TT), Diluted Russell’s Viper Venom Test (dRVVT), One-stage Factor VII, One-stage and chromogenic Factors VIII and Factor IX, and Thromboelastography (TEG); 2) to compare the effect of the branded version with those of three generic versions of apixaban (MAR- apixaban®, Apigat®, and Apismart®). Plasma from six healthy first-time donors was collected and pooled to produce platelet-poor plasma (PPP) which was spiked with five different concentrations (50 - 750 ng/ml) of each of the four apixaban versions. Each concentration was tested using apixaban-calibrated anti-Xa assay and further confirmed using Ultra-High-Performance Liquid Chromatography-Mass Spectrometry coupled with tandem mass spectrometry (UHPLC-MS/MS). Each assay was then performed in duplicate on each concentration of each version of apixaban. Correlation testing and One-way ANOVA/Kruskal-Wallis tests were used to identify significant correlations between increasing apixaban concentrations and assay results, and any differences in mean results between the apixaban versions, respectively. A positive correlation was identified with increasing concentrations of apixaban and PT, APTT, PT-derived fibrinogen, and dRVVT assays; a negative correlation was observed with all factor assays; and no correlation was observed with Clauss Fibrinogen and TT assays. Inconsistent results were obtained for all Thromboelastography (TEG) parameters due to the high intra-assay variability. This study concluded that branded and generic versions of apixaban exerted identical in vitro effects on the different coagulation assays tested.