Improved clearance of host cell protein impurities at the polishing purification step using multimodal chromatography.

In biotherapeutic protein production, host cell proteins (HCPs) are one of the main process related impurities which must be cleared and controlled through downstream processing. In this paper, we studied a novel therapeutic protein molecule which had a high level of HCP co-purification throughout the downstream process. Here, we focused on the polishing purification step and developed an effective strategy for improving HCP clearance using multimodal chromatography (MMC) resin, Nuvia cPrime. A high throughput process development (HTPD) workflow was used to identify the resin and process conditions which could enable significant HCP clearance while maintaining acceptable product quality and process performance. HCP analysis of gradient elution fractions on multimodal chromatography found that HCPs eluted at the beginning of the gradient, at a lower salt concentration than the therapeutic protein. Based on these findings, a step elution process involving an intermediate low salt wash was developed to clear weak-binding HCPs, while retaining the therapeutic protein on the column. This strategy was highly effective and enabled 80 % reduction in total HCP content, including some problematic and difficult to remove candidates such as Peroxiredoxin-1, Serine protease HTRA1, Clusterin and Lipoprotein lipase.