FDA pinpoints contaminant in Baxter's heparin

By Lisa Richwine

WASHINGTON (Reuters) - U.S. health regulators said on Wednesday they have identified a contaminant found in batches of Baxter International Inc's blood-thinner heparin that were linked to serious reactions and deaths.

Food and Drug Administration officials said they are trying to determine whether the chemical -- over-sulfated chondroitin sulfate -- was purposely or inadvertently added during manufacturing in China.

"We don't know whether the contaminant was introduced intentionally or by accident," said Dr. Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research.

Chondroitin sulfate is widely sold as a dietary supplement to treat joint pain. The over-sulfated version is not known to occur naturally and therefore likely was chemically modified, Woodcock told reporters on a conference call.

It is still unclear whether the contaminant is the cause of up to 19 deaths and hundreds of serious breathing problems and other reactions reported to the FDA, she said.

The substance mimics the blood-thinning actions of heparin but is not FDA-approved for use in medicines, Woodcock said. In some batches, the contaminant accounted for between 2 percent and 50 percent of the samples, she said.

FDA officials said chemically manipulating chondroitin sulfate, which is widely available from animal sources, would be cheaper than getting raw heparin from pig intestines.

Last year, the FDA found pet food ingredients imported from China were tainted, killing more than 200 cats and dogs and causing widespread alarm. The Chinese maker involved was later indicted in the United States for fraud over adding the chemical melamine in an attempt to bolster the value of its ingredient.