Genetic Engineering & Biotechnology News

DEC 2017

Genetic Engineering & Biotechnology News (GEN) is the world's most widely read biotech publication. It provides the R&D community with critical information on the tools, technologies, and trends that drive the biotech industry.

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Genetic Engineering & Biotechnology News | GENengnews.com | DECEMBER 2017 | 21 Another strategy involves the judicious use of helper viruses—tools that facilitate the propagation of recombinant virus prepara- tions that will, in the absence of helper vi- ruses, reflect how they have been engineered to lack the ability to proliferate. In nature, the hepatitis B virus "helps" the replication- defective hepatitis D virus replicate by pro- viding envelope proteins. "Many helper viruses—a good example is adeno-associated virus—are larger than their counterpart therapeutic viruses, and can often be separated by filtration employ- ing appropriately-sized membranes," stated Dr. Cunningham. In instances where helper viruses are more susceptible to chemical or pH inactivation than their corresponding therapeutic viruses, virus inactivation may facilitate their removal. In instances where helper viruses are of simi- lar size to the therapeutic virus, chromato- graphic separation of these two virus popula- tions may be a consideration, assuming that the virus preparations are well characterized. Viral Safety in Continuous Processing Continuous bioprocessing, which is slow- ly gaining on batch processing, raises new is- sues in viral safety. Morven McAlister, Ph.D., senior director, Pall Life Sciences, made the case in her talk for better understanding of the "virus filter design space" during con- tinuous processing. She explained how with first-generation virus filters, virus retention was affected by factors such as low-pressure conditions and process interruptions. "The newer genera- tion filters have been designed to overcome these problems, such that they show consis- tent virus retention at both upper and lower operating ranges." An example of a newer generation filter is Pall's Pegasus Prime. It can be used for batch processes at higher system pressures, but it shows equivalence at low flow or system pressures, which is more representative of a continuous process. "A filter that shows equivalence in perfor- mance over upper and lower process parame- ters is what we define as having a robust virus filter design space," Dr. McAlister explained. "The idea behind continuous processing is that processing occurs in real time, so the filter must be capable of operating under very low flow conditions, which is a very different filter design space than batch filtration." One could, theoretically, achieve some level of process continuity by expressing, harvesting, and holding process fluid for batch virus filtration, but that scenario does not fully exploit the value of continuous pro- cessing, Dr. McAlister continued. "One of the main advantages of continu- ous processing is the ability to reduce the size of the manufacturing environment re- duced by eliminating the need for large hold tanks," she noted. "By fully understanding the design space for each process step, there is constant control over production which can reduce the time for a monoclonal anti- body to be completely processed." There are various models that could be followed and still allow a batch to be defined. For example, one option may be to use mul- tiple filters in a parallel configuration. When a defined throughput is met, that filter can be taken offline and the flow diverted to a sec- ond filter. In this way, the fluid that is filtered with the first virus filter could be viewed as a batch. However, with this model, consider- ation has to be given to process interruptions and flushes. References: 1. International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH). Q11 Development and Manufacture of Drug Substances (Chemical Entities and Biotechnological/Biological Entities), (November 2012). https://www.fda.gov/ downloads/drugs/guidances/ucm261078.pdf, accessed November 10, 2017. 2. D. Strauss et al., "Characterizing the Impact of Pressure on Virus Filtration Processes and Establishing Design Spaces to Ensure Effective Parvovirus Removal," Biotechnol. Prog. 33(5), 1294–1302 (September 2017). Leading the Data Enabled World The leading peer-reviewed journal covering the challenges and opportunities in collecting, analyzing, and disseminating vast amounts of data. Big Data coverage includes: Big data industry standards New technologies being developed specifi cally for big data Data acquisition, cleaning, distribution, and best practices Data protection, privacy, and policy Business interests from research to product The changing role of business intelligence Visualization and design principles of big data infrastructures Physical interfaces and robotics Social networking advantages for Facebook, Twitter, Amazon, Google, etc. Opportunities around big data and how companies can harness it to their advantage www.liebertpub.com/big Leading the Data Enabled Wo The leading peer-reviewed journal covering the challenges and opportunities in collecting, analyzing, and disseminating vast amounts of data. Big Data coverage includes: Big data industry standards New technologies being developed specifi cally for big data Data acquisition, cleaning, distribution, and best practices Data protection, privacy, and policy Business interests from research to product The changing role of business intelligence Visualization and design principles of big data infrastructures Physical interfaces and robotics Social networking advantages for Facebook, Twitter, Amazon, Google, etc. Opportunities around big data and how companies can harness it to their advantage www.liebertpub.com/big Leading the Data Enabled Wo The leading peer-reviewed journal covering the challenges and opportunities in collecting, analyzing, and disseminating vast amounts of data. Big Data coverage includes: www.liebertpub.com/big Editor-in-Chief: Vasant Dhar Bioprocessing

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