By Craig Jackson and Michael Cunningham
When it comes to viral safety, biopharma companies have historically focused on their downstream processes, but recently there is increased awareness of the potential disruption viral contamination can bring, and a move towards mitigating the risk in upstream cell culture processes. The key driver for all aspects of viral safety is, of course, patient safety, and there are few regulatory pressures pushing companies to incorporate viral risk mitigation technologies upstream. Regulatory guidance focuses on ensuring cell lines and raw materials are well-characterized and free from detectable adventitious agents. However, there is a good business case to implement measures that minimize the risk of viral contamination and the potential disruption to manufacturing operations.
Where can contaminants enter the upstream process? Chinese hamster ovary (CHO) cells are especially susceptible to contamination with rodent viruses; minute virus of mice (MVM), in particular, has led to problems at a number of biopharma plants. Contamination often originates from raw materials and animal-derived components such as bovine serum or trypsin, which are regarded as particularly high-risk. Contamination can also originate from other cell culture components such as glucose – which attract rodents – or from equipment or facility operators, who can introduce human virus contaminants (such as adenovirus) into a process.