Enhancing aggregate reduction using anion exchange hybrid filter in an immunocytokine diabody fusion protein purification process

Significant aggregation challenges were encountered during the manufacturing processing of an immunocytokine diabody fusion protein. To mitigate this issue and reduce aggregates in the purification process, a variety of depth filters were evaluated for harvest clarification and post-Protein A intermediate filtration. Emphaze™ AEX Hybrid Purifier, a fully synthetic quaternary amine functionalized anion exchange (AEX) nonwoven filter, was found to be particularly effective in removing aggregates during both harvest clarification and post-Protein A intermediate filtration steps. Pre-filters were identified to improve Emphaze filter throughput and further enhance aggregate reduction during the harvest clarification. The effect of operating pH and feed stream aggregate level were evaluated for Emphaze filter for the post-Protein A intermediate filtration, and the aggregate binding capacity of the Emphaze filter was assessed to optimize the aggregate removal. The study also elucidated the aggregate binding mechanism, which was primarily attributed to electrostatic interaction. Overall, the implementation of Emphaze filter resulted in greater than 20 % aggregates reduction, which significantly reduced the impurity clearance workload on the downstream chromatography steps, enabling process simplification while achieving desirable product quality for the diabody fusion protein.