Will Bovine Serum Be Next On The List For Drug Regulators?; Mad Cow Raises Concerns; Cow serum, used to produce most drugs, carries minimal risk, experts say.(HEALTH & MEDICINE)

Byline: GLORIA LAU

Aside from steaks and stews, where do you find cow blood?

In drug production. It turns out that cow serum -- a purified derivative of cow blood -- is commonly used to produce many of the new biologic drugs on the market.

These drugs can do everything from fight cancer to help rheumatoid arthritis patients walk again. Many are proteins or other cell-based products that can't be otherwise mass-produced.

Regulators worldwide require that the drugs be tested for safety and effectiveness on animals and people before they grant marketing approval.

But the serum producers say they can't guarantee that the serum is free of all viruses and bacteria. Because of that, regulators are concerned about cow serum safety.

Japanese and European authorities have urged drug makers to start using more synthetic serums. The Food and Drug Administration started encouraging the same, but hasn't issued a hard deadline. A spokesman for the agency didn't return phone calls seeking comment.