Baxter International Inc., the world's largest maker of blood-disease treatments, didn't fully cooperate with China's probe into a blood thinner linked to 81 deaths in the U.S., the nation's drug regulator said.

Baxter didn't give requested samples and information on the manufacturing of suspect heparin batches to Chinese investigators when they visited the company's production facility in New Jersey on April 22, China's State Food and Drug Administration said in a statement distributed in Beijing today. Baxter, in a statement, said it had cooperated with the probe.

Chinese experts ``expressed deep regret'' that Baxter ``failed to provide necessary cooperation in the investigation,'' the three-page statement in English and Chinese said.

Allergic reactions to Baxter's heparin led to a U.S. recall in January and February and an investigation by regulators in both the U.S. and China, where the drug's main ingredient was made. Officials of the two nations clashed over the cause of the reactions, with the U.S. blaming a substance known as over- sulfated chondroitin sulfate in samples of the drug made in China.

Deerfield-based Baxter and Scientific Protein Laboratories Inc., the supplier of the tainted ingredient, said April 29 that the problem stems from Scientific Protein's suppliers. The contamination occurred before reaching Scientific Protein's laboratory in China and was ``deliberate and widespread,'' according to Scientific Protein.

Cause Unproven

In today's statement, China reiterated its earlier assessment that the cause of the U.S. deaths can't be proven to be over-sulfated chondroitin sulfate, and said it needs more information from Baxter to identify the cause of the problems.

``It is essential to conduct a thorough analysis on raw materials, excipients, manufacturing process, clinical use and patient status to further identify the reasons,'' the statement said. ``Baxter's response is not conducive to further identifying the reasons for the adverse reactions.''

In an e-mailed response to the Chinese drug regulator's comments, Seok Lin Hong, Baxter's Singapore-based communications director for Asia Pacific, said the company had cooperated with the administration.

``Baxter agreed to provide samples to the SFDA in response to their request,'' the statement said. ``We have been cooperating with all parties involved in the heparin situation and we will seek to understand any concerns to the contrary.''

Tainted Heparin

Heparin is a blood thinner made from pig intestines and used during kidney dialysis, heart surgery and other situations when doctors need to prevent blood clots. Baxter sold about half of the heparin used in the U.S. until the recall earlier this year.

Since January 2007, 81 people have died after allergic reactions, the U.S. Food and Drug Administration said on April 21. Tainted heparin made by other drugmakers has been found in more than a dozen countries since Baxter's recall, and regulators have said they don't know how it was introduced.

Chinese officials on April 21 said the contaminant over- sulfated chondroitin sulfate in Baxter's heparin wasn't the ``root cause'' of the cause of allergic reactions and deaths. They said heparin sold by other companies overseas also contained the substance without causing side effects.

China's government is still investigating how over-sulfated chondroitin sulfate was added to the heparin, Yan Jiangying, spokeswoman for the State Food and Drug Administration, told today's briefing in Beijing.

More Information

U.S. regulators suspect the drug was intentionally contaminated to increase profit, FDA Commissioner Andrew von Eschenbach told lawmakers at an April 15 hearing. He later told reporters the agency didn't have evidence the contamination was intentional.

Once the cause of the contamination is identified, China ``will handle the issue in accordance with laws'' if domestic companies caused the problems, the administration's statement today said.

It also called on U.S. authorities and companies involved to ``provide more necessary information for the investigation.''

The Chinese investigation team that visited Baxter's production facility included Professor Jin Shaohong, deputy director general of China's National Institute for the Control of Pharmaceutical and Biological Products, and Fan Huihong, deputy director of the biochemical drugs division of the institute.

Jin said today that when asked to provide samples to help the Chinese investigation, Baxter said it had destroyed recalled drugs, and that samples of ingredients were taken by the FDA.