WASHINGTON (AP) -- U.S. health officials say testing indicates a solid link between a contaminant in the blood thinner heparin and severe allergic reactions that have killed up to 81 patients. China insists the contaminant could not be the ''root cause'' of the problem.
Chinese officials suggested Monday at a news conference in the Chinese Embassy that the problem with the drug could have occurred in the United States. They plan to visit a Baxter International plant in New Jersey to get a better picture of how the finished product is manufactured.
Raw heparin is derived from pig intestines, often processed by small, unregistered workshops in China. The raw ingredient for Baxter's recalled heparin came from Wisconsin-based Scientific Protein Laboratories, which in turn owns the Chinese factory Changzhou SPL and buys additional raw heparin from other Chinese suppliers.
The Food and Drug Administration warned Changzhou SPL that the company lacks adequate systems for ensuring that the raw materials it uses are safe, with any impurities removed.
Hundreds of patients have suffered severe allergic reactions to large doses of the blood thinner. The FDA said the chief suspect is a contaminant that the agency discovered in China-produced supplies of raw heparin. The contaminant is a compound derived from animal cartilage that so closely mimics heparin that routine purity tests cannot detect it.
Chinese officials claimed that adverse events were reported in patients who got heparin that did not contain the contaminant, over-sulfated chondroitin, but FDA officials said that premise is based on incorrect assumptions.
The Chinese said they hope to get some samples from Baxter for their own investigation.
''When you see it, then you believe it,'' said Jin Shaohong, the deputy director general for the National Institute for the Control of Pharmaceutical and Biological Products in China.
Chinese exports have been under increasing scrutiny since problems have surfaced with pet food, toothpaste and fish. Millions of Chinese toys have been recalled because they contained lead.
FDA officials said new lab tests have reinforced their view that the contaminant is behind the reactions.
''We are aware that our Chinese colleagues are skeptical that such a link has been established,'' said Janet Woodcock, director of the Food and Drug Administration's Center for Drug Evaluation and Research. ''Therefore, we're hoping to have further scientific dialogue with them within the next few weeks to present the data.''
In its warning letter to the Chinese company, FDA said it will recommend disapproval of any new applications listing the company as the manufacturer of any active pharmaceutical ingredient. It cited ''significant deviations'' from good manufacturing processes.
The company said it regretted FDA's decision, and it did not believe the warning letter reflected Changzhou SPL's state of compliance with good manufacturing practices.
The company said the suspect contaminant was not introduced in the manufacturing processes at Changzhou SPL.
''It is now clear that the suspect contaminant was introduced earlier in the supply chain in China and was widespread throughout the unrelated Chinese supply chains of many companies,'' Scientific Protein Laboratories said in a news release.
Germany also discovered the contaminant and recalled batches of heparin after some patient illnesses.
Baxter International officials also took issue with the Chinese claim that the contaminant cannot be a ''suspected root cause of heparin adverse events as reported in U.S. media previously.''
''We have seen adverse event reports on batches where the contaminant has been confirmed to be present,'' said Baxter spokeswoman Erin Gardiner.
Baxter was considering the Chinese officials' request for additional heparin samples for their own further testing, Gardiner said.
The Chinese officials also said that aside from the U.S. and Germany, more than 10 other countries used heparin containing the contaminant but reported no side effects. Also, one batch of heparin injections free of the contaminants has resulted in about a hundred reactions, of which 25 were serious, they said.
