Biopharmaceuticals such as therapeutic monoclonal antibodies, vaccines, and plasma derivates are produced via complex manufacturing processes. During production, an inherent risk of viral contamination exists, therefore international regulatory agencies require that each biopharmaceutical manufacturing process is assessed for viral clearance efficacy before clinical trials and commercial approval. The logistics and high cost of assessing viral clearance often prohibit studies from being conducted during small-scale process development and optimization; however, delaying viral clearance studies can increase the likelihood of validation failure. The MockV™ MVM Assay Kit is the first in a series of novel kits being developed by Cygnus Technologies and represents an affordable, practical solution for predicting viral clearance at any stage of the biopharmaceutical life cycle.
Whether introduced endogenously from raw materials or exogenously through manufacturing operations, unmitigated viral contaminations can lead to serious health implications and plant shutdowns. For this reason, international regulatory agencies require sponsoring companies to validate their manufacturing process for its ability to clear (remove or inactivate) viral particles. This assessment is achieved through spiking studies, whereby model mammalian viruses are introduced into the load material of a downstream purification technique, processed through, and then evaluated for Log Reduction Value (LRV). Since spiking studies necessitate specialized biological safety level (BSL) laboratories and suitably trained personnel, they incur substantial costs. As such, many companies choose to delay them, instead optimizing purification process steps without knowing their viral clearance efficacy. Although this strategy can provide a cost saving in the short term, it greatly increases the risk of validation failure and can mean additional investment of both time and resources when processes must subsequently be redeveloped.
To address the need for a simpler, more affordable method for predicting viral clearance, Cygnus Technologies is developing a series of novel kits that can be used within a BSL-1 setting. Known as mock virus particle (MVP) kits due to the fact that each product is based on a non-infectious viral surrogate that mimics the physicochemical properties of the corresponding model live virus, these kits enable scientists to quickly and easily assess viral clearance at any stage of a biopharmaceutical’s life cycle. Importantly, by using MVP kits to determine whether process steps and parameters are effective before progressing to live virus studies, biopharmaceutical companies can minimize the risk of validation failure to save both time and money.
The MockV™ MVM Assay Kit, launched in 2020, is the first of Cygnus Technologies’ MVP kits to reach the market. Including a BSL-1 surrogate of Minute Virus of Mice (MVM)—a parvovirus that is used internationally as a model virus for spiking studies—the MockV™ MVM Assay Kit has undergone rigorous testing by regulatory agencies and biopharmaceutical companies. During a collaboration with the FDA, the kit’s “MVM-MVPs” were shown to share a similar particle size, surface-charge, and surface-hydrophobicity profile to live MVM. A study published by researchers from Bristol Myers Squibb has since corroborated the strong physicochemical resemblance. To use the MockV™ MVM Assay Kit, scientists simply spike load material with MVM-MVPs then process it through the chosen purification technique; the collected fractions can then be analyzed for MVP concentration. To enable LRV determination, an immuno-quantitative polymerase chain reaction (Immuno-qPCR) assay enables quantification of MVP concentrations over a 4.0–5.0 log10 dynamic range. A second MVP kit designed for monitoring retrovirus clearance will be available in the near future.
Figure 1. Transmission electron microscopy images of BSL-1 “MVM-MVP” particles (A). Physicochemical comparison of live MVM to surrogate MVM-MVPs (B).
Published studies have demonstrated the utility of the MockV™ MVM Assay Kit to predict the clearance of live MVMs in a variety of applications. These include Protein A affinity chromatography, nanofiltration, anion-exchange chromatography (AEX), and hydrophobic-interaction chromatography (HIC), all of which are widely used purification techniques within the biopharmaceutical manufacturing industry. As just one example, by spiking MVM-MVPs into Protein A columns containing various immobilized monoclonal antibodies (mAbs), researchers observed that interactions with MVPs differed according to the mAb in question. This provided a plausible rationale for the variations in clearance seen across different monoclonal antibody processes operating under the same chromatographic conditions and prompted efforts to find a way of addressing this anomaly. By increasing the pH of one of the wash steps, MVM-MVP clearance was improved—a finding that translated to improved clearance of MVM.
Figure 2. Data from anion exchange chromatography design of experiments performed by GSK with MockV MVM Kit. Interaction plot (left) and response surface plot (bottom) illustrating effects of pH and conductivity on MVM-MVP clearance.
To learn more about the MockV™ MVM assay kit and how you can use it to predict viral clearance, visit cygnustechnologies.com
Figure 3. MVP log reduction value data for a variety of anion exchange resins from a high throughput screening study conducted by the NIH with MockV MVM Kit.