Characterization and implications of host-cell protein aggregates in biopharmaceutical processing

Area of Science:

• Biopharmaceutical Manufacturing
• Protein Chemistry
• Analytical Biochemistry

Background:

• Residual host-cell proteins (HCPs) are critical quality attributes in biopharmaceutical production, including monoclonal antibodies (mAbs) and vaccines.
• Individual HCPs can persist through purification, potentially impacting product stability and patient safety due to interactions with product, media, or chromatin.
• Current understanding attributes HCP persistence primarily to biophysical interactions with product, resin, or chromatin.

Purpose of the Study:

• To investigate the role of HCP aggregates in HCP persistence during biopharmaceutical manufacturing.
• To explore how HCP aggregation affects the detection and removal of HCPs.
• To identify specific HCPs or protein families that contribute to aggregation and persistence.

Main Methods:

• Analysis of process streams from seven monoclonal antibody (mAb) production processes.
• Measurement of HCP levels and characterization of HCP aggregates.
• Proteomic analysis to identify proteins within aggregates and assess their interactions.

Main Results:

• HCPs found in aggregates, independent of chromatin, play a significant role in the persistence of many HCPs.
• HCP aggregates can interfere with the accurate detection of HCPs using standard proteomics methods.
• Proteins involved in the unfolded protein response (UPR), such as chaperones, were disproportionately present in aggregates due to functional complementarity with the product.

Conclusions:

• HCP aggregates are a major factor in HCP persistence during biopharmaceutical production.
• Existing HCP detection methods may be compromised by the presence of HCP aggregates.
• Understanding HCP aggregation is crucial for improving HCP clearance strategies and ensuring biopharmaceutical product quality and safety.