FDA says new evidence links heparin problems to China

WASHINGTON — Food and Drug Administration officials said Monday they have new evidence that links hundreds of serious adverse reactions and scores of deaths among patients given the blood thinner heparin to a man-made contaminant introduced during production in China.

Janet Woodcock, director of the agency's Center for Drug Evaluation and Research, said the contaminant has been traced to 12 different Chinese companies and has been found in heparin batches shipped to 11 nations, all of it from China.

Chinese officials, however, disputed the finding and said the compound — over-sulfated chondroitin sulfate — could not be "the root cause" of the adverse reactions.

Speaking Monday at the Chinese Embassy here, Jin Shaohong, a top official with the Chinese National Institute for the Control of Pharmaceutical and Biological Products, said some of the batches of heparin associated with severe allergic reactions and distributed by Baxter International did not have the synthetic chondroitin in them. He also said that heparin with the contaminant has been found in many nations, but that none has reported a similar spike in harmful reactions as in the United States.

Jin said the Chinese government was conducting its own investigation of the heparin issue, which would include a visit today to Baxter's New Jersey processing plant, where officials hoped to collect additional samples of the tainted drug.

He said the allergic reactions could have been created by impurities introduced when the imported raw heparin was refined by Scientific Protein Laboratories of Wisconsin and then prepared for distribution in New Jersey.

The FDA disputed that claim.

Jin said that "the results of our recent investigation and other available evidence do not support the theory that the root cause" of the adverse reactions to heparin was the over-sulfated chondroitin that the FDA identified as the likely culprit.

FDA officials have raised the possibility that the contaminant was intentionally added to the heparin, but have said they still don't know for sure how it got into the supply.

Baxter spokeswoman Erin Gardiner said her company disagreed with the Chinese conclusions, adding that the evidence is now strong that the over-sulfated chondroitin caused the problem.

She also said the Chinese were incorrect when they said some batches of heparin that caused severe reactions did not contain chondroitin.

Woodcock said that Chinese officials had tested batches of heparin with methods less sensitive than those used in the United States and elsewhere and had missed the presence of the contaminant.

She said FDA scientists now believe the adverse reactions were most pronounced when large doses of the drug were administered quickly, and the contaminant acted as a "mediator" that caused a response similar to an allergic reaction.