One of the main goals in downstream processing of recombinant monoclonal antibodies is the reduction of impurities present in the cell culture material, including genomic DNA, host cell proteins, aggregates, endotoxin, and potential virus. Genomic DNA, in particular, exists as chromatin complexes associated with various host cell proteins. Current harvest filtration steps do not effectively remove chromatin, which can non-specifically associate with the protein of interest and Protein A chromatography resin. These associations can result in variable levels of HCP and DNA in the Protein A eluate leading to further variability in precipitation and impurity levels upon pH adjustment. Optimized pH adjustment and depth filtration steps are required to ensure robust impurity clearance. To mitigate these risks and to streamline harvest and downstream operations across production scales, a positively charged 3M Emphaze™ AEX hybrid purifier was tested during harvest of a CHO-expressed mAb to evaluate the benefits of chromatin removal. Performance of the purifier was studied by monitoring filtration pressure, turbidity, residual HCP, DNA, and chromatin complex. Scalable process conditions for harvest filtration operations using the 3M Emphaze™ AEX hybrid purifier resulted in complete removal of genomic DNA prior to the Protein A chromatography step.

Downstream process impact of reducing impurities during harvest operations using charged hybrid filters

255th National Meeting (2018)

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