Chinese Still Deny Role in Heparin Problems, Say Baxter is Blocking InvestigationMay 6, 2008 | Parker Waichman LLP
The Chinese State Food and Drug Administration has alleged that Baxter International has refused to cooperate with its investigation into tainted heparin. The Chinese are also insisting that a counterfeit chemical found in batches of a heparin ingredient sourced from China had nothing to do with the hundreds of adverse reactions and scores of deaths linked to heparin in the US. However, last week a US research team published a study that showed how that fake chemical - oversulfated chondroitin sulfate - could cause the very type of reactions seen here.
The US Food & Drug Administration (FDA) has linked tainted heparin with 81 deaths in the US, and hundreds of adverse reactions. Baxter International recalled nearly all its heparin injections in the U.S. after some patients experienced extreme - and in some cases fatal - allergic reactions, including difficulty breathing, nausea, vomiting, excessive sweating, and rapidly falling blood pressure that was life threatening after being administered the products.
In March, the FDA confirmed that it had found oversulfated chondroitin sulfate in samples of the active ingredient used in Baxter heparin. The FDA said the chondroitin sulfate was molecularly changed to mimic heparin’s blood-clotting properties. That ingredient was supplied to Baxter by Changzhou SPL, a Chinese plant partially owned by Wisconsin-based Scientific Protein Laboratories LLC. Last month, FDA Commissioner Andrew von Eschenbach said that while the FDA has no specific evidence that the chondroitin sulfate contamination was intentional, “the concern is that it had to be by design.”
In a written statement, China's State Food and Drug Administration insisted that the chondroitin sulfate had nothing to do with the adverse heparin reactions. The Chinese assert that since contaminated heparin has been found in 12 countries, and reactions have only been seen in the US and Germany, the chemical is not to blame. The statement also claims reactions have also been reported in people who received untainted heparin.
The statement also claimed that "Baxter failed to provide necessary cooperation in the process of the investigation, which is not conducive to further identifying the reasons for the adverse reactions to heparin." Baxter is denying these allegations, and says it is cooperating with all parties in the heparin investigation. Last month, Chinese regulators were even given access to Baxter's New Jersey plant where it finishes processing raw heparin.
The Chinese assertion that chondroitin sulfate was not behind the heparin reactions is questionable. Late last month, a research team, led by scientists at MIT, found that the chondroitin sulfate activates two inflammatory pathways: one that initiates blood clotting and dilation of the blood vessels, and one that produces anaphylactic toxins. The first leads to a dangerous decrease in blood pressure, the second a serious allergic reaction. In blinded laboratory tests, the contaminated heparin activated the biological pathways, while normal heparin did not. In the study, pigs treated with tainted heparin exhibited side effects similar to those seen in humans.