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Contaminant Found in Suspect Heparin

Mysterious Compound May Be Culprit in Deaths Linked to Blood Thinner

By Daniel J. DeNoon
WebMD Health News

Reviewed by Louise Chang, MD

March 5, 2008 -- A mysterious heparin "contaminant" may be behind the deaths and serious injuries in gravely ill patients who received the blood thinner, the FDA said today.

"At this point we do not know whether the introduction of this contaminant was accidental or deliberate," FDA Commissioner Andrew C. von Eschenbach, MD, said in a news conference.

Over the last 14 months, the FDA says, 19 patients died with severe allergic reactions after receiving heparin produced by Baxter International Inc.

It's not yet known whether heparin was directly responsible for these fatal allergic reactions, or for the 785 reports of serious adverse events in patients who received heparin. Most of these patients had grave medical conditions and had undergone risky surgery.

Baxter, which made about half of all the heparin used in the U.S., last week recalled all of its heparin products. There is no supply shortage, however, as heparin maker APP has increased production. No adverse events have been definitively linked to APP's heparin products.

Janet Woodcock, MD, the FDA's chief medical officer and acting director of the FDA's Center for Drug Evaluation and Research, said the "contaminant was present in significant quantities" in lots of heparin associated with these allergic reactions.

The contaminant made up between 5% and 20% of the heparin in these suspect lots, Woodcock said. All of the lots passed quality control tests because the contaminant, like heparin itself, is a complex molecule derived from pig intestines. It was detected only after sophisticated chemical tests, although the FDA says it will soon offer laboratories a simpler test for detecting the substance.

"We do not know how this heparin-like compound got into the active ingredient," Woodcock said. "We don't yet have direct causal link between the contaminant and adverse events. Some of the batches of heparin causing the effect have this contaminant in them. So there is an association between the heparin-like compound and adverse events, but no causal relation yet."

Heparin "Contaminant" Traced to China

In a separate news conference, Baxter officials said they had traced the contaminant to crude materials that its supplier, Scientific Protein Laboratories (SPL), obtained in China.

"It is premature to conclude that the heparin active pharmaceutical ingredient sourced from China and provided by SPL to Baxter is responsible for these adverse events," an SPL news release notes.

Peter J. Arduini, president of Baxter's medication delivery business, noted that for more than a decade China has been supplying heparin raw materials to the U.S.

"Before physically opening a plant in China, SPL sourced heparin's active pharmaceutical ingredient from China for years," Arduini said. "This resulted in more than a half billion doses made from Chinese-sourced heparin over the last 12 years."

Arduini said Baxter is devoting all of its resources to finding the source of the problem. He said the company has ruled out problems with product packaging and inactive ingredients and is now focused on the crude heparin it receives from SPL.

"Either the problem is further back in supply the chain, before it gets to the SPL processing plants, or it is something in the processing before it gets to Baxter," Arduini said.

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