Viral Clearance

Introduction: Viral Clearance and Inactivation in Downstream Processing

Viral safety in the biopharmaceutical industry is both an upstream-production and downstream-processing concern. Companies must take a multipronged approach using orthogonal methods that are validated to prevent viral contamination or to remove it from biologic drug products. On the upstream side, the focus is on prevention through risk assessment and mitigation. That begins with environmental control of facilities and includes both careful selection of raw materials and cell lines and preparatory filtration of culture media components. In downstream processing of…

Triton X-100 Elimination: The Road Ahead for Viral Inactivation

The nonionic surfactant Triton X-100 (C14H22O(C2H4O)n) is a key chemical used in ensuring the viral safety of biological medicinal products. Two pharmaceutical sectors share an extensive historical background with it: biopharmaceuticals and plasma-derived products, for which it is used to inactivate lipid-enveloped viruses. Recently, environmental regulations in the European Union have encouraged or mandated a phase-out of this surfactant (1). The goal of the ruling is to protect aquatic ecosystems from potential Triton X-100 degradation products that can function as…

Worst-Case Conditions for Viral Clearance

As described in ICH Q5A on virus safety of biotechnological products (1) and the European guideline on virus safety of biotechnological products, EMEA 398498 (2), viral clearance studies are mandated as part of the viral safety evaluation of products derived from human or other mammalian cell lines. When acceptable ranges of process parameters are known, both guidelines recommend that scale-down models be evaluated under worst-case conditions for viral clearance. The BioPhorum Development Group’s viral clearance workstream performed a benchmarking survey…

Hollow-Fiber Nanofiltration for Robust Viral Clearance of Non-MAb Biologics

Monoclonal antibody (MAb) and other therapeutic biologics produced by mammalian cells have the potential to introduce endogenous retroviruses and can be infected with adventitious viruses through raw materials or other parts of the biomanufacturing process (1–3). Based on regulatory guidelines, products derived from mammalian cells must contain less than one virus particle per million doses, which requires purification processes to demonstrate virus removal capabilities of about 12–18 log10 clearance of endogenous retroviruses and 6 log10 clearance for adventitious viruses (4).…

Comprehensive Virus Clearance Evaluation Using Microscale Membrane Adsorbers

Membrane adsorbers can be a simple and effective choice for anion-exchange (AEX) purification of biopharmaceuticals. However, as Sherri Dolan (global technology consultant for virus clearance at Sartorius) explained during a May 2022 presentation, biomanufacturers generally do not leverage their membranes’ full loading capacities. Doing so could improve process economics and decrease costs for several downstream applications. Dolan’s Presentation Membrane adsorbers are ideal for flow-through AEX applications (e.g., secondary purification and polishing) because they can be used at high flow rates…

The Impact of Protein Stability on Virus Filtration

Filtration of protein-based biologics is essential for minimizing viral contamination and ensuring product safety and high quality. The tendency of therapeutic monoclonal antibodies (MAbs) and recombinant proteins to aggregate under a number of conditions can complicate selection of a virus filter. An increasing demand for high concentration formulations creates additional challenges. When performing filterability studies and to ensure meaningful virus filter evaluations, downstream process scientists must address factors that can lead to aggregation. This special report on virus filtration by…

Viral Safety of Viral Vectors:
Special Concerns Arise When the Virus Is the Product

As anyone who has focused on host-cell proteins as process contaminants can tell you, trying to purify a specific type of molecule from a large mixture of many similar molecules is like trying to find a few particular needles in a huge pile of varied needles. The same could be said for purifying viral vectors from cell culture fluids. When viruses are the products, unwanted viruses are contaminants that must be separated away — or better yet, prevented from being…

MAb Viral Clearance Studies:
A Substantiated Platform Approach for the IND Stage

Virus removal/inactivation is a major concern in the safety of monoclonal antibodies (MAbs) and other recombinant-protein drugs. Some methods (such as nanofiltration and low-pH inactivation) have been demonstrated repeatedly by the industry to be reliable for most viruses, with >4 log10 removal. Based on my company’s virus-removal experiences with its MAb downstream-process platform, we propose a “bracketing method” — testing only samples that lie at the extremes of a design space — to prove proactively that small differences in operating…

Predicting Viral Clearance in Downstream Process Development

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…

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

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.…