Various acidic and basic charge variants of monoclonal antibodies persist through purification and drug product formulation. Traditionally, these variants have been controlled primarily through cumbersome elution peak fractionation and pooling during cation-exchange chromatography (CEX), which often results in a reduced product yield. Here we present an approach for the separation and enrichment of the native form of a mAb and of basic and acidic variants using self-displacement chromatography in a multi-column continuous chromatography set-up. Owing to their higher charge, basic mAb variants are preferentially retained in CEX and displace the variants with a relatively smaller charge such as the native and the acidic variants, when the amount loaded exceeds the resin capacity. To this end, we utilized a three-column continuous system to consecutively displace acidic, main and basic charge variants of a mAb in the order of increasing binding strength during product loading. Optimal operating parameters were found using a model utilizing a multi-component colloidal isotherm and the general rate model. The process was simulated for various numbers of cycles, column bed height, and mAb residence time for feeds with different charge variant profiles. The process was then designed and validated with an experimental run for a feed with 65 % native variant over five continuous cycles. This resulted in the enrichment of the native variant to 90% with an overall yield above 90%. Our method and approach can control and reduce in particular the charged variant heterogeneity, and in general, aid in the separation of charged proteins at preparative scale in continuous chromatography.

Continuous multi-column displacement chromatography for separation of charge variants of monoclonal antibodies

2019 Spring National Meeting

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