Downstream Processing

The Secret Life of Protein A

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Affinity chromatography with protein A has become the foundation for purification of nearly every therapeutic IgG in commercial production. One of the features most responsible for its success has been its compelling simplicity. IgG binds. Contaminants do not. Load, wash, and elute pure IgG. In the real world, however, protein A does not elute pure IgG. It typically contains several hundred to a few thousand parts per million (ppm) contamination by host-cell proteins (HCPs) and other contaminants. Numerous studies demonstrate…

October 15, 2015

Identification and Quantification of Heat-Shock Protein 70: A Major Host-Cell Protein Contaminant from HEK Host Cells

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Recombinant therapeutic proteins are commonly produced by cell lines such as Chinese hamster ovary (CHO), human embryonic kidney (HEK) 293, murine myeloma (NS0), and Escherichia coli bacterial cells. Host-cell proteins (HCPs) are indigenous proteins produced by those expression hosts and considered to be process-related impurities generated from the cell culture process (1). HCPs are potentially harmful and immunogenic to patients, and they can compromise the stability of protein drugs (2–4). For those reasons, HCPs must be consistently removed or reduced…

October 15, 2015

Optimization and Scale-Up of HCIC-Based MAb Purification Processes, Part 2

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In multistep schemes, hydrophobic charge-induction chromatography (HCIC) has been shown to contribute effectively to clearance of Chinese hamster ovary (CHO) host-cell proteins (CHOPs), DNA, and viruses. When used for capture chromatography, HCIC can provide better aggregate clearance than protein A sorbents can. Chen et al. enhanced clearance of aggregates, CHOPs, and product- related impurities by controlling HCIC based on both pH and the presence of binding-promoting salt in the wash and elution buffers used (1). Taken together with our findings…

June 16, 2015

Anion-Exchange Chromatographic Clarification: Bringing Simplification, Robustness, and Savings to MAb Purification

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Monoclonal antibodies (MAbs) are the most prominent and successful therapeutic proteins in the pharmaceutical industry. More than 35 MAbs have been approved to treat a range of conditions, and hundreds more are in development (1, 2). Once, the upstream cell culture process was considered the bottleneck to producing high antibody doses required for treatment, but recent advances in cell culture technology have boosted antibody titers to the range of 5–10 g/L (3). That increase in productivity has shifted focus onto…

June 16, 2015

An Industrial Platform Solution for Antibody Fragment Purification

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Compared with traditional approaches such as chemotherapy and radiotherapy, monoclonal antibodies (MAbs) have become the most successful cancer treatments in the past 20 years (1). With great clinical success in many therapeutic areas, MAbs now account for >40% of the entire biotechnology drug market, and sales are projected to be >US$160 billion over the next few years in the United States alone (2). More than 35 MAbs have been approved for clinical use, and hundreds more are filling industry development…

June 16, 2015

Fundamental Strategies for Viral Clearance Part 2: Technical Approaches

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Viral safety is required for biologics manufactured to treat human diseases. Although significant improvements in ensuring viral safety have been made over the past few decades, “zero risk†of viral contamination is a myth. Viral contamination risk can be carefully managed by screening raw materials, testing process intermediates, and evaluating how effectively manufacturing processes remove and inactivate viruses. Viral clearance studies verify virus removal or inactivation by a manufacturing process. Although regulatory agencies have expectations for the designs of those…

May 12, 2015

Reagent Clearance Capability of Protein A Chromatography: A Platform Strategy for Elimination of Process Reagent Clearance Testing

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During the manufacturing of monoclonal antibody (MAb) products, many process reagents are used for cell culture and MAb purification to facilitate and control process performance. Process reagents are considered to be process-related impurities, so demonstration of their clearance is required for the chemistry, manufacturing, and controls (CMC) information submission of an investigational new drug (IND) application (1, 2). These reagents may be classified into two categories: generally recognized as safe (GRAS) reagents and potential safety concern (PSC) reagents (3). GRAS…

May 12, 2015

Optimization and Scale-Up of HCIC-Based MAb Purification Processes, Part 1

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Monoclonal antibodies (MAbs) serve important medical needs in cancer treatment as well as that of autoimmune and infectious diseases (1). Antibodies are also widely used in clinical diagnostic assays. They can be coated on solid surfaces to bind specific analytes, conjugated to reporter molecules (either as whole antibodies or fragments) for analyte detection, used in sensitivity panels for lot-release testing, and supplied as positive controls in diagnostic kits (2). Our study evaluates the use of hydrophobic charge-induction chromatography (HCIC) for…

May 12, 2015

Characterization of Postcapture Impurity Removal Across an Adsorptive Depth Filter

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In the manufacture of monoclonal antibodies (MAbs), the first purification step following harvest clarification is normally protein A affinity chromatography because of its high selectivity for IgG and high process yield (1, 2). At this stage, a MAb is eluted from a protein A ligand at low pH and then held or adjusted to a low pH (pH ≤ 3.8) for a given amount of time before pH adjustment, usually ≥30 minutes, in a virus inactivation (VI) step targeted at…

March 10, 2015

Affinity Capture of F(ab’)2 Fragments: Using Twin-Column Countercurrent Chromatography

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Antibody fragments are potent active drug substances (1–4). Because they lack glycosylation, they can be produced using different biological expression systems, including yeast and microbial systems as well as mammalian cells. These molecules are interesting as biopharmaceuticals because they are smaller than full-size antibodies and therefore may penetrate better into different tissues. Antibody fragments are cleared faster in biological systems because they lack the Fc antibody structural region (4). However, fragments may be conjugated to increase their size for improved…

February 6, 2015