Downstream Processing

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

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…

Evaluating Adsorptive Filtration As a Unit Operation for Virus Removal

To date, the majority of recombinant monoclonal antibodies (MAbs) have been produced by mammalian cells. During such production processes, the potential risk of entrained viruses must be critically considered (1). Contamination can arise from animal cell lines or from adventitious viruses introduced during manufacturing. To ensure the viral safety of biotechnology products, companies can take four complementary approaches (2, 3): Using animal-component–free raw materials wherever possible Virus testing of master cell banks Virus testing of unprocessed harvest Performing downscale virus…

Protein A Intermediate Wash Strategies

Protein A affinity chromatography offers efficient monoclonal antibody (MAb) purification and is used extensively in large-scale MAb production. As is the case with most chromatography media, protein A resins often have some degree of nonspecific binding, which causes host-cell proteins (HCPs) to coelute with a MAb. To reduce nonspecific binding interactions, an intermediate wash step can be performed before product elution. Doing so can improve product purity, extend column lifetime, and potentially eliminate a subsequent polishing step. For large- scale…

Fundamental Strategies for Viral Clearance – Part 1: Exploring the Regulatory Implications

Over the past several decades, biologics such as monoclonal antibodies (MAbs) and recombinant proteins have provided therapeutic benefits and efficacy for the treatment of human disease. Completion of the human genome project (launched in 1990) produced a draft of the genome in 2001. A full sequence was published on the 50th anniversary (2003) of the initial publication of Watson and Crick’s papers on the double-helical structure of DNA (1). That large volume of genetic information has been translated into usable…

Advances in Chromatography Automation

Not long ago, chromatography automation meant strip recorders and peristaltic pumps. Today, few people would consider that to be true automation, and even fewer would settle for binders full of strip-recorder paper reels. Automation is becoming intelligent and in the process is making our workflows smarter. But how close is automation to being as smart as an experienced scientist? Bio-Rad Laboratories spoke with academics, biotechnology R&D scientists, and industrial process engineers about the evolution of chromatography automation — where it…

Upstream Efficiencies, Economic Forces, and Changing Technologies Complicate Separation and Purification

When it comes to biotherapeutics manufacturing, downstream processing groups tend to get “dumped on.” Advances in cell lines, bioreactors, and culture media formulations have increased production output, providing both higher expression titers and greater volumes, but the filters and chromatography columns on the downstream side haven’t kept pace. These century-old technologies haven’t evolved as much and are reaching their limits. Regulatory agencies have contributed to innovation stagnation because they are cautious about manufacturing process changes for fear of undermining quality…

Evolving Clarification Strategies to Meet New Challenges

Increasingly efficient bioreactors allow biopharmaceutical manufacturers to achieve higher cell densities. That improved upstream efficiency has led to new purification challenges resulting from high product and contaminant concentrations as well as complex components. Therefore, harvest and clarification techniques are evolving to incorporate feed pretreatment, flocculation, and different filtration technologies such as normal-flow, tangential-flow, and depth filtration. The objective is to increase process capacities and filtrate quality, ultimately reducing biomanufacturing costs. New strategies for clarification of recombinant proteins (in particular, monoclonal…

Cost Estimation for Protein A Chromatography: An In Silico Approach to MAb Purification Strategy

Monoclonal antibody (MAb) production has adopted an accepted technology platform for downstream processing (1). The need for more economic processes has been addressed by increasing MAb titers in fermentation and aiming toward greater bioreactor volumes to increase productivity. Consequently, cost pressures are now passed on to downstream process groups. Membrane and chromatography resin savings are more important for MAb processes than ever before, with highly productive cell cultures generating large volumes of process fluid to purify (2). Traditionally, protein A…

Diatomaceous Earth Filtration: Innovative Single-Use Concepts for Clarification of High-Density Mammalian Cell Cultures

In the past decade, biopharmaceutical manufacturers have demonstrated major improvements in monoclonal antibody (MAb) production, exhibiting product titers frequently in the range of 5–10 g/L using standard fed-batch mammalian cell cultures (1, 2). Increased product yields allow for smaller-scale production vessels. With 2,000-L single-use bioreactors already commercially available, single-use manufacturing of biomolecules becomes more and more an option. Other recent developments in the biopharmaceutical industry — e.g., drugs for smaller indications and more potent drugs allowing for lower dosages —…