USFDA and China's SFDA Officials argued publicly whether a contaminant from China in Baxter International Inc.'s blood-thinner heparin caused allergic reactions and deaths. 

Chinese officials said on April 21 they had tested batches of heparin used by patient who reported health problems and only some of these batches contained the contaminant.

"The over-sulfated chondroitin can therefore not be the suspected root cause of heparin ADE (adverse events)," said Jin Shaohong, deputy director-general of the China National Institute for the Control of Pharmaceutical and Biological Products. Some other companies' versions of heparin sold overseas included the contaminant and didn't cause side effects, suggesting another ingredient in Baxter's heparin may be to blame for the allergic reactions and deaths, Jin suggested.

Li Xuewang of Huazhong University of Science and Technology's Union Hospital, complained of a lack of details from the USFDA. He said Chinese investigators needed more information on the patients involved.

Speaking to reporters at the Chinese Embassy in Washington, Jin said he and other officials planned to visit Baxter's plant in New Jersey and expected Baxter's cooperation.

USFDA officials said they had tested the heparin in question and did find the contaminant, and that 10 other countries had also detected over-sulfated chondroitin sulfate in samples of heparin made with Chinese ingredients.

"If you look at the supply chain of all the contaminated products found around the world, the one thing they have in common is China," Deborah Autor, head of compliance for the USFDA's drugs division, told a conference call with reporters.

Woodcock, head of the USFDA's drug division, responded that "this contaminant is capable of triggering these types of reactions." The USFDA hopes to have additional discussions with the Chinese over the scientific differences, Woodcock said.

The contaminated heparin has been found in 11 countries, according to the USFDA. People in Germany suffered similar reactions to those in the U.S., Woodcock said. The reactions may be linked to the use of large doses of heparin, a practice that is more common in the U.S. than in some other countries where contamination was found, she said.

Baxter also disputes the Chinese conclusion. Baxter said its own testing also showed over-sulfated chondroitin sulfate could cause the type of reactions reported in heparin patients. Lab tests show no unusual reactions to Baxter's uncontaminated batches of heparin, according to the company.

Meanwhile, the USFDA issued on April 21 a warning letter to the Scientific Protein plant in China, Changzhou SPL. "Your firm failed to establish appropriate specifications for identified and unidentified impurities for the heparin... your firm also failed to perform adequate tested to detect impurities," the USFDA said in a letter to Changzhou SPL Co Ltd.

Changzhou SPL spokesman Alexander Shaine said the FDA's letter did not reflect the company's actual manufacturing processes but said it would cooperate with the agency.

The FDA's letter doesn't reflect the "actual state of compliance" with manufacturing standards, Scientific Protein said in a statement. The contaminant was introduced in China before the raw ingredient reached the Scientific Protein plant, according to the statement.