There is a possibility that viruses could be present in animal-derived starting materials used in biopharmaceutical production
and, therefore, potentially contaminate the final product. Because of the potential risk to the end user, it is crucial to
approach the safety of these therapeutic products through a rigorous and systematic testing strategy. Kate Smith, principal
scientist, development services at BioReliance offers insights on the tests required to check for the presence of these contaminants
and how to remove the contaminants that are present in final products using chemical inactivation or processes such as chromatography
Biopharmaceutical manufacturing processes frequently rely on starting materials derived from mammalian sources. The level
of risks that these materials present are contingent upon the nature of the starting material, mainly, whether they come from
human or animal sources.
One example of human-derived material is plasma. Despite the screening of blood donations, when a product is being manufactured
from human plasma, there is potential for contamination by pathogens such as hepatitis and human immunodeficiency virus (HIV).
Additionally, many biological drugs are manufactured in Chinese hamster ovary (CHO) or murine cell lines. With these cell
lines, it is rare for viruses to be absent. While these materials are well characterized and screened for viruses in advance,
the cells commonly contain endogenous viral contamination, typically in the form of a retrovirus. This virus is detected and
quantified using transmission electron microscopy as part of the bulk-harvest testing.
This risk is not limited to biopharmaceutical materials. Even products falling into the medical-device category can be affected,
such as collagen preparations. Collagen is derived from animal tissues; therefore, there is a high probability that a viral
pathogen may be present.
Viruses may also enter the process or product by adventitious means. For instance, a contaminated raw material may be introduced
into the process, or viral contamination could have entered the cell culture from a human operator.