mAb Aggregate Polish And Viral Clearance Using Hydrophobic Interaction Chromatography

By John J. Li, Moira Lynch, and David Cetlin

Republished with permission BioProcess International vol 17 (11-12)si 2019

Therapeutic monoclonal antibodies (MAbs) have revolutionized personalized medicine, significantly impacting fields like oncology, immunology, neurology, and infectious diseases. Resin manufacturers have invested heavily in developing better polishing chromatography solutions to eliminate residual impurities, ensure virus clearance, and ultimately meet the critical quality attributes (CQAs) required for safe antibody drugs.

MAb purification processes typically involve at least one anion-exchange (AEX) polishing step. Depending on the specific impurities and challenges, this AEX step might be followed by a second polishing step using either cation-exchange (CEX) or hydrophobic interaction chromatography (HIC).

The ultimate goal of this downstream purification process is to consistently produce safe and effective drugs for human use. This requires removing various impurities like host cell proteins (HCPs), residual DNA, protein A from the affinity step, process contaminants, viruses, endotoxins, antibody aggregates, and other antibody variants to meet regulatory guidelines. Among these impurities, aggregate removal can be particularly challenging, especially for MAbs with high aggregate levels. The FDA recommends reducing MAb aggregates to less than 1% for later clinical trials. A typical MAb process can start with 1-5% aggregates after protein A capture, but this percentage can be much higher (>10%) for some MAbs.

To address this challenge, Thermo Fisher Scientific offers a range of purification tools based on POROS through-pore resin technology. POROS HQ and XQ are AEX resins, while POROS HS and XS are CEX resins, each with unique properties and selectivity suitable for removing low-to-moderate levels of MAb aggregates (1, 2).

This application note explores a new family of POROS HIC resins with innovative ethyl and benzyl chemistries for successfully polishing two “challenging” drug products - MAbs A and B - both with high aggregate levels exceeding 10%. It also covers viral clearance strategies for MAb A and B processes using POROS HIC, including a novel prediction technique that utilizes parvovirus surrogate mock virus particles (MVPs) from MockV Solutions alongside live viral clearance data with xenotropic murine leukemia virus (XmuLV) and minute virus of mice (MVM).