Factor XI (FXI) is the zymogen of a serine protease, Factor XIa (FXIa). It is a 160 kDa protein, with an average plasma concentration of 3 to 7 µg/ml. Its presence in IgG preparations is associated with the risk of thromboembolic events in patients. FXI poses challenges due to its (auto) activation during the fractionation process under certain conditions. Intravenous administration of the IgG-containing FXIa has been shown to induce activation of the intrinsic coagulation pathway and cause blood clot formation, posing a life-threatening risk to patients. During the cold ethanol plasma fractionation process, some of the coagulation factors, for example, factors II, IX, and X are removed from IgG, but FXI remains a challenge because of its co-precipitations with IgG. The aim of this study was to evaluate the removal of FXIa from Fraction II paste (containing mainly IgG) using a chromatographic monolithic column, modified with a novel multimodal ligand, as an alternative to affinity-based resin chromatography. The multimodal chromatographic purification approach was proven to selectively bind FXIa. In addition, the process parameters, such as temperature and flow rates, were optimized for FXIa removal to define the process parameters for scaling up.
