Heparin Contaminant Probably Counterfeit

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Main Category: Blood / Hematology
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Article Date: 19 Mar 2008 - 10:00 PDT

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Following interviews with scientists in the US and China, the New York Times has reported that the heparin contaminant found in products linked to 19 deaths and hundreds of serious cases of severe allergic reaction throughout the US is probably a counterfeit product made to act like heparin.

The Times said the suspected contaminant is most likely a substance similar to chondroitin sulfate, a widely used dietary supplement for easing the joint pain of osteoarthritis. It is derived from animal cartilage and can be chemically altered to act like heparin. The substance that appears to be the focus of the investigation is called over-sulfated chondroitin sulfate, which like heparin is an anticoagulant.

While there is no evidence that the contaminant was deliberately introduced as a counterfeit, there are scientists, according to the New York Times, who are leaning toward this conclusion.

Professor of pathology and pharmacology at Loyola University Chicago, Dr Jawed Fareed, who is already carrying out his own investigation of the contaminant, said in an interview with the Times that:

"A child could tell you it's counterfeiting."

Fareed said this was a "deliberate act" of introducing a heparin-like substance to increase the yield of the active ingredient. Over-sulfated chondroitin sulfate can be made more cheaply than heparin, which is derived from pig intestines.

The Times also interviewed a retired professor from the Shandong University School of Pharmaceutical Sciences, 80-year old Dr Zhang Tianmin, who told the paper that counterfeiters could derive chondroitin sulfate either from animal cartilage or shellfish, to make a heparin-like molecule quite cheaply.

The FDA declined to comment on whether they had found the contaminant or not, but the Times interviewed one FDA investigator who said that the agency had been looking at chondroitin sulfate.

Even if they track down the contaminant, scientists cannot be certain that it caused the allergic reactions and deaths. There remain too many unanswered questions, such as when was the contaminant introduced into the process, how was it introduced, and why has it only affected some patients and not others? This message has been echoed several times by Baxter, the manufacturer of the heparin products at the centre of the investigation.

Heparin (administered as heparin sodium) is a blood thinner used in operating rooms, dialysis and critical care centres to stop surgery and dialysis patients getting potentially fatal blood clots.

To date, the FDA has received over 700 reports of severe allergic reactions, including 19 deaths, following use of heparin products.

Earlier this month, FDA investigators found batches of Baxter's heparin products contained a contaminant. The batches all used an active ingredient sourced from one plant in China. It was later discovered that this plant was supposed to have been checked by the FDA but it was not because its name was confused with another plant on the FDA database.

Baxter maintain that only 4 of the deaths can be linked to their heparin products.

Until its voluntary recall, Baxter was supplying half of the US demand for heparin, which is injected into millions of Americans every year.

Contaminated heparin products have also been found in Germany and Japan.

The allergic reactions to the contaminated heparin included symptoms like difficulty breathing, excessive sweating, nausea, vomiting, and abrupt fall in blood pressure that can lead to life-threatening shock.

The contaminant cannot be differentiated from real heparin using standard tests, said the FDA in an earlier communication. The agency has plans to offer laboratories simpler methods to test for the contaminant, which at present can only be detected using specialized nuclear magnetic resonance spectroscopes.

Late last week, the FDA announced that all heparin imports would be tested at their points of entry into the US.

Click here to go to the full New York Times report.

Sources: New York Times, MNT archives.

Written by: Catharine Paddock, PhD
Copyright: Medical News Today
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