2D-DIGE As a Tool to Analyze Lot-to-Lot Consistency of Complex Therapeutic Products Such As BAX 855, a PEGylated Recombinant FVIII

Abstract 4360

2-Dimensional difference gel electrophoresis (2-D DIGE) is a method that circumvents the gel-to-gel variability inherent in conventional 2-dimensional gel electrophoresis (2-DE). We developed a 2-D DIGE protocol for recombinant factor VIII (rFVIII), a therapeutic protein used for the treatment of hemophilia A. The FVIII heterodimer is composed of heterogenous, strongly glycosylated heavy and light chains that are held together by a divalent cation. 2-DE of rFVIII led to a separation of the various fragments and their identity could be determined by Western blot. A comparison of two rFVIII batches by 2-D DIGE revealed their identical composition, whereas an rFVIII variant lacking its central B domain was congruent with the smallest heavy and light chain fragments of rFVIII only. A simpler pattern was obtained upon removal of the terminal sialic acids of rFVIII’s glycans due to a better focusing in the first dimension. 2-D DIGE was also well suited to structurally evaluate BAX 855, a PEGylated longer-acting variant of recombinant FVIII. 2-D DIGE thus proved an excellent and straightforward method for structural analysis of rFVIII. Our data suggest that the method could serve as a tool to characterize and control quality of very complex pharmaceutically active ingredients such as PEGylated proteins.