New Research Demonstrates Usefulness of Western Blot Assay Technique for
Verifying Removal of Infectivity from Biological Products
RESEARCH TRIANGLE PARK, N.C., May 8 /PRNewswire/ -- Building on previous
work from Bayer Corporation, a recent publication by Bayer scientists supports
experimental findings that purification processes used in the manufacture of
human plasma-derived pharmaceutical products have the capacity to remove
pathogenic prion proteins (PrPs) including those associated with CJD
(Creutzfeldt-Jakob disease). In this study (Transfusion, Vol. 41, No. 4,
449-455, April 2001), removal of these proteins was measured using a Western
Blot assay methodology, which recently became commercially available through
BioReliance Corporation (Rockville, Md.). Bayer scientists demonstrated that
results using the Western Blot assay procedure correlated with standard
bioassays for the removal of infectivity. Western Blot is a faster and more
efficient process for assessing removal of these agents and their infectious
potential from biological therapies derived from or utilizing components of
human blood plasma.
"Bayer seeks to further increase its ability to ensure that all our
biological products are safe from any theoretical threat posed by prions,"
said Michael Fournel, vice president of research and technology, Bayer
Biological Products Division. "By developing the Western Blot methodology and
making it commercially available for other manufacturers through our agreement
with BioReliance, Bayer continues to lead the industry in efforts to advance
the safety of life-saving and life-enhancing biological products important to
many people."
Previous studies have demonstrated certain prion proteins capable of
producing transmissible spongiform encephalopathies (TSEs), a class of fatal,
neurodegenerative diseases found in many mammals, can be removed from plasma
products. This study expands on previous work demonstrating that Western Blot
assay methodology was a useful screening tool to assess TSE clearance in these
production processes compared to the longer and more expensive rodent tests,
which demonstrate the removal of infectivity.
Commenting on the impact of this new research, Dr Erwin Gelfand, Chairman,
Department of Pediatrics at National Jewish Medical and Research Center in
Denver, Co. stated, "As physicians make decisions to administer life-saving
blood-based products to patients, they need to feel confident that the
products are safe. Significant strides have been made to assure that these
products are safe from viral contamination. Now, with the potential concerns
over prion-mediated diseases such as Creutzfeldt-Jakob disease, this new
research by Bayer represents a major step forward in alleviating these
concerns."
Pathogenic Role of Prions
The pathogenic form of prion proteins (PrPs) has been associated with
fatal diseases, including mad cow disease in cattle, scrapie in sheep, and the
human disorders Creutzfeldt-Jakob (CJD), Gerstmann-Straussler-Scheinker, Kuru,
and fatal familial insomnia. To date, no clinical evidence exists to support
the transmission of human TSE (CJD) by blood or blood-derived products.
However, recent evidence from experimental animal models suggests that cross-
species transmission can occur and there is a low potential for intravenous
transmission. For these reasons, biopharmaceuticals, including human plasma
derivatives, recombinant proteins grown in media containing fetal calf serum,
and human-derived products containing bovine additives, may have a very low
risk of containing TSEs, increasing the importance of continued advancements
of this assay procedure. To further negate this low potential for
transmission, Bayer scientists are working to lower this potential even
further.
Regulatory agencies require manufacturers demonstrate removal or
inactivation of pathogen impurities, such as viruses, from biological
products. Although agencies do not currently require documentation of prion
protein or TSE removal, they continue to follow the science in this area
closely. Methods that are effective for inactivating the infectious TSE agent
also are destructive to most soluble therapeutic proteins, therefore the
removal of prions remains the most viable strategy to address the hypothetical
risk of TSE transmission. Assessing manufacturing process capacity to remove
prions is an important first approach to addressing this hypothetical risk.
Animal bioassays are conventionally used to detect infectivity, however these
bioassays are extremely expensive and lengthy processes, making a rapid screen
test beneficial. Now, with Western Blot assay methodology, it is possible to
quickly assess if purification methods have the potential to remove TSE
infectivity.
Best known for its flagship product, Bayer Aspirin, Bayer Corporation
produces a broad range of health care, life sciences, and chemical products
that help diagnose and treat diseases, purify water, preserve local landmarks,
protect crops, advance automobile safety and durability, and improve people's
lives.
Headquartered in Pittsburgh, Bayer Corporation had sales of $10.1 billion
in 2000, and is one of Fortune magazine's Most Admired Companies. The company
employs 23,200 people. It is a member of the worldwide Bayer Group, a
$29 billion international life sciences, polymers, and specialty chemicals
group based in Leverkusen, Germany. The Bayer Group (BAYG.DE) stock is a
component of the DAX, and Bayer plans to list its stock on the New York Stock
Exchange Sept. 26, 2001.
SOURCE Bayer Corporation
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Douglas R. Bell, Director, Global Public
Policy and Communications, of Bayer Corporation, 919-316-6316, or
Steve Walker, Vice President of Fleishman-Hillard, 816-512-2270
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