Flowthrough anion exchange chromatography is commonly used as a polishing step in downstream processing of monoclonal antibodies and other therapeutic proteins to remove process‐related impurities and contaminants such as host cell DNA, host cell proteins, endotoxin, and viruses. DNA with a wide range of molecular weight distributions derived from Chinese Hamster Ovary cells was used to advance the understanding of DNA binding behavior in selected anion exchange media using the resin (Toyopearl SuperQ‐650M) and membranes (Mustang® Q and Sartobind® Q) through DNA spiking studies. The impacts of the process parameters pH (6–8), conductivity (2–15 mS/cm), and the potential binding competition between host cell proteins and host cell DNA were studied. Studies were conducted at the least and most favorable experimental conditions for DNA binding based on the anticipated electrostatic interactions between the host cell DNA and the resin ligand. The resin showed 50% higher DNA binding capacity compared to the membrane media. Spiking host cell proteins in the load material showed no impact on the DNA clearance capability of the anion exchange media. DNA size distributions were characterized based on a “size exclusion qPCR assay.” Results showed preferential binding of larger DNA fragments (>409 base pairs). © 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 34:141–149, 2018

Viral contamination is an inherent risk during the manufacture of biopharmaceuticals.As such, biopharmaceutical companies must demonstrate the viral clearance efficacy of their downstream process steps prior to clinical trials and commercial approval. This is accomplished through expensive and logistically challenging spiking studies, which utilize live mammalian viruses. These hurdles deter companies from analyzing viral clearance during process development and characterization. We utilized a noninfectious minute virus of mice-mock virus particle (MVM-MVP) as a surrogate spiking agent during small scale viral filtration (VF) and anion exchange chromatography (AEX) studies. For VF experiments, in-process mAb material was spiked and processed through Asahi Kasei P15, P20, P35, and BioEX nanofilters. Across each filter type, flux decay profiles and log reduction values (LRVs) were nearly identical for either particle. For AEX experiments, loads were conditioned with various amounts of sodium chloride (9, 20, 23, and 41 mS/cm), spiked with either particle and processed through a Q-SFF packed column. LRV results met our expectations of predicting MVM removal.