Monoclonal antibody (mAb) charge variants are critical quality attributes that contribute to the production of high-quality, safe and efficacious drug product. During commercial process development, shifts in charge variant profiles are observed when processing conditions change - especially in cell culture. It is highly desirable to improve drug substance quality by identifying root causes of charge variant changes, and, subsequently, controlling relevant process parameters. Traditionally, charge variants are quantified by isoelectric focusing (iCEF) or analytical ion exchange (HPLC), in which resolution is high, but throughput is low. The development and implementation of an automated enrichment method has allowed for enhanced charge variant characterization by increasing purity and quantity of individual charge variants. The enrichment method is based on the technology of Multicolumn Countercurrent Solvent Gradient Purification (MC-SGP) and utilizes two ion exchange columns to enrich the target species, deplete species that are not of interest, and enhance separation during a fractionated elution from the column. The enriched samples that result from this method can achieve &gt; 90% purity, and adequate amount generated allow for further characterization (mass spectrometry, bioassays, etc.) to perform root-cause analysis of charge variant changes, and the impact on potency or activity. Furthermore, proposed process parameters (e.g. bioreactor media components and feed strategy, etc.) impact on charge variants were investigated. By achieving these goals, charge variant profiles in the drug substance can be characterized and controlled, leading to a higher quality drug product.

Novel semi-preparative chromatographic method to enrich charge-variant species for extended characterization

2019 Spring National Meeting

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