Viral Clearance

Predicting Viral Clearance in Downstream Process Development

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As viruses can arise during the manufacture of biopharmaceuticals, regulatory agencies require viral clearance validation studies for each biopharmaceutical prior to approval. These studies are typically conducted in biosafety level (BSL)-2 facilities and require large capital and human resources. The use of an accurate, economical, and quantifiable noninfectious viral surrogate would enable downstream purification scientists to study viral clearance throughout process development. This report explores the use of a BSL-1 compatible, noninfectious MVM particles to predict viral clearance results over…

May 27, 2021

Virus Assay Variation Is the Main Source of Variation in Viral Clearance Studies: Retrospective Analysis of a Large Data Set

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Biopharmaceuticals produced from mammalian cell cultures are susceptible to viral contamination. That risk is mitigated by applying complementary approaches. Those include extensive testing of cell banks, selecting low-risk raw materials, testing cultivations for viruses, and documenting the capacity of a purification process to inactivate and remove viral contaminants. The latter commonly is referred to as viral clearance and usually expressed as a log reduction value (LRV). Novo Nordisk has performed several viral clearance studies for different processes and process steps.…

April 16, 2021

Viral Clearance in a Downstream AAV Process: Case Study Using a Model Virus Panel and a Noninfectious Surrogate

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Over the past decade, adenoassociated virus (AAV) vectors have become established as leading gene-delivery vehicles. In 2017, the pipeline for gene therapies included 351 drugs in clinical trials and 316 in preclinical development (1–4). As those candidates advance, significant efforts are being made in process development and manufacturing for viral vectors, with the overall goal of reducing process impurities while maintaining the highest possible process yield. To address that goal, industry suppliers have developed innovative AAV-specific separation technologies. Thermo Fisher…

April 16, 2021

Customized Yeast HCP Quantification with Biolayer Interferometry Using a Horseradish Peroxidase Substrate

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Biopharmaceuticals are the largest group of drugs under development (1), and the demand for new and safe drug products is high. The most common bacterial and mammalian cell lines for production are Escherichia coli, Chinese hamster ovary (CHO) cells, and yeast. During a production bioprocess, a cell line expresses not only the molecule of interest, but also host-cell proteins (HCPs). They are considered to be impurities in a final drug product because they can affect the efficacy and safety of…

March 9, 2021

Ask the Expert: Predicting Viral Clearance During Downstream Development

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Until recently, downstream process development (PD) teams have lacked methods for easy, effective, and economical estimation of a process’s viral clearance capability. David Cetlin (senior director of R&D at Cygnus Technologies) delivered an “Ask the Expert” presentation on 13 October 2020 describing how MockV kits containing noninfectious mock-virus particles (MVPs) could fill that gap. Cetlin’s Presentation Viral clearance studies tend to be outsourced to contract research organizations (CROs) because they require biosafety level (BSL)-2 and -3 facilities for working with…

December 17, 2020

How Much Harm Can a Single Droplet Do? Considerations for a Viral Inactivation Step

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Viral clearance is a fundamental aspect of viral safety for biopharmaceutical products. Regulatory agencies around the world require biomanufacturers to segregate their operations appropriately to mitigate the risks of carryover contamination from previous process steps or product batches and of crossover contamination between product(s) made in the same facility. Guidelines are vague in defining “appropriate,” leaving biomanufacturers to interpret regulatory expectations and define their own virus reduction and segregation strategies. Given the differences among manufacturing processes and facilities housing such…

October 29, 2020

Streamlined Polishing and Viral Clearance Using a New Hybrid, Biomimetic, Single-Use Anion Exchanger

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Flow-through anion-exchange (AEX) chromatography is used frequently in biopharmaceutical purification processes for reduction of net–negatively charged host-cell proteins (HCPs) and viruses as part of a validated viral clearance strategy (1, 2). AEX column chromatography is the technology most often used for electrostatic viral clearance, particularly in commercial-scale biopharmaceutical manufacturing, for which columns have a long-established history of reliable and well-understood performance (3). Still, validation of HCP and viral clearance by AEX columns in biopharmaceutical processes involves complexities that contribute significantly…

October 29, 2020

A Challenge in Viral Clearance Determination: Estimation of Fifty-Percent Tissue Culture Infective Dose (TCID50) for Low Virus Concentrations

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Performing viral clearance studies is an important safety element of manufacturing all biopharmaceuticals expressed from mammalian cells (1). Typically, viral clearance is described as a log reduction value (LRV) and calculated as the log10 of the ratio of input to output virus load. Amounts of virus load are calculated from the volume and concentration of input and output fractions. Virus concentration is often calculated as 50% of tissue-culture infective dose (TCID50) using the Spearman–Kärber (SK) equation (2, 3). In this…

May 24, 2020

A Response Plan for Viral Contamination in Bioproduction Facilities

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The biopharmaceutical industry uses living biological systems as a platform for manufacturing of protein-based drugs, vaccines, and other therapies derived from or consisting of different cell types. On one hand, living systems are inherently susceptible to viral infection and may harbor endogenous viruses, so the potential for such contamination cannot be eliminated. On the other hand, the industry has an excellent patient-safety record. Viral safety is achieved through three fundamental measures: prevention (e.g., by selection), removal (by clearance and/or reduction),…

March 3, 2020

Detection and Clearance of Viruses in the Biopharmaceutical Industry

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Viral contamination is a common threat to all animal- and human-derived biopharmaceuticals. This type of contamination can affect any part of a bioproduction process, so biomanufacturers need to perform viral testing studies and incorporate viral clearance methods into their processes. Viral contaminants can come from cell lines (e.g., endogenous retroviruses) or from adventitious (e.g., mycoplasma) introduction during drug manufacturing. Virus testing of master cell banks (MCBs), working cell banks (WCBs), end-of-production cell banks, and bulk unprocessed harvest material is called…

December 17, 2019