Prions Come Under Closer Scrutiny

Agnes Shanley, Editor in Chief

Drugmakers Are Taking Steps To Ensure Removal of Abnormal Prions, Rogue Proteins Implicated in Mad Cow, Scrapie and variant Creutzfeldt-Jakob Disease

 

In July, the U.S. Food and Drug Administration issued a final interim rule limiting the types of animal-derived materials that can be used to manufacture animal feed, cosmetics, and food supplements. The rule aims to protect humans and livestock from abnormal prions (Graphics), proteins that are found in many animal species, but which, in abnormal form, have been associated with fatal neurological conditions.

 

Materials including gelatin, keratin and tallow, whose derivatives include fatty acids and glycerin, come from cattle and other livestock. The new rule, which will be finalized in October, would forbid manufacturers from using raw materials made from brain, skull, spinal cord, and other designated parts of cattle 30 months of age and older, and would set an impurity ceiling of 0.15% for tallow.

 

The rule does not explicitly cover pharmaceuticals or set any validation requirements for biopharmaceutical manufacturing. Currently, the Atlanta-based biotech firm Serologicals Corp.estimates that over  $20 billion worth of biotech products, representing over 60% of pharmaceuticals now on the market, use bovine derivatives at some point in their development or production. They include:  

 

?         Monoclonal antibodies, which use bovine serum as a nutrient

?         Human plasma derivatives such as gamma globulin

?         Insulin, heparin, and  bovine pituitary hormones. A 1996 study by the U.K. government indicated that all these products could be vulnerable to prion contamination (For more information on this and other studies, see http://www.priondata.org/data/A_drugs.html).

 

Even if the ruling doesn't discuss biotech manufacturing specifically, the Agency has, clearly, been paying more attention to potential risks from prions since the first case of Mad Cow, or bovine spongiform encephalopathy ( BSE) was reported in the U.S. last December, in a cow that had been imported from Canada. In the UK and Europe, where over 150 cases of BSE have been documented, regulatory agencies have mandated removal of prions from blood products, via white blood cell filtration, and manufacturers can make the claim that their products are "prion-free" on their labels. The European Union has codified standards for use of animal derivative materials, as has Japan's Ministry of Health, Labor and Welfare.