MilliporeSigma - Viral Safety - 21

Viral Safety

Keeping Up with Viral Safety Trends in Bioprocessing
of critical drugs which, in turn, affected
patient access," says Dr. Raghunath.
Several reports detailed the incidence
of this contamination.
Raw materials have often been implicated in viral contamination incidents
and there is a general acceptance of their
vulnerability to virus contamination.
Testing cell culture media for the presence of virus is inherently constrained
by assay sensitivity and an inability to
detect low levels of virus contaminants.
As a consequence, manufacturers are
considering adding steps to inactivate
or remove potential virus contaminants
from cell culture medium and other raw
materials used in upstream manufacturing processes.
"Some companies have evaluated high
temperature short time (HTST) pasteurization methods to kill pathogens in
cell culture media," says Dr. Raghunath.
"However, not all media components
are stable at high temperatures. Further,
HTST requires some significant initial investment and equipment, so only a few
companies have taken that approach.
More recently, companies have developed novel filters designed for cell culture-media treatment. Cell culture media
is at risk for introducing viral contamination into a bioreactor, so having that viral
filtration step is considered a good way
to enhance viral safety assurance in the
manufacturing process."
21

| October 1, 2017

In addition to cell culture media, cell
banks used for manufacturing biotherapeutics are also considered high risk for
introducing contamination and need
to be well characterized before starting
manufacturing.
"There is extensive characterization of
the master, working, and end of production cell banks before bioprocessing,"
said Kathryn Remington, Ph.D., principal
scientist focusing on the BioReliance®
portfolio of MilliporeSigma. "Companies
need to verify that the cells are the type
that they think they are and also look for
purity of the cells. They'll then need to
be screened for bacteria, fungi, mycoplasma, and viruses."
Martin Wisher Ph.D., global head of
regulatory affairs focusing on the BioReliance® portfolio of MilliporeSigma
added that "in vivo studies need to be
completed in the master cell bank and
end of production cell line. You want to
be sure that your cell banks are free of
viral contamination. Testing the bulk harvest with in vitro assays gives you further
evidence that the cell banks were clear
and gives you assurance that there is no
other contamination coming in through
the process."
Regulatory testing standards for cell
banks and bulk harvest are outlined in
the International Council for Harmonization of Technical Requirements for

Scientists involved in performing cell line characterization testing.

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