FDA Announces What's Contaminating Heparin

March 19, 2008 — -- Investigators believe they have discovered what's contaminating the blood-thinning medication heparin and are trying to determine whether it was put in the drug intentionally, the Food and Drug Administration announced today.

An altered version of a dietary supplement made from animal cartilage is now at the center of the worldwide drug safety investigation.

FDA officials said the man-made chemical compound known as over-sulfated chondroitin sulfate is cheap and abundant. It mimics heparin when tested, but is not naturally occurring and not something that would be part of the normal production chain for heparin.

Heparin's raw ingredients come from pig intestines, but today, Dr. Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research, said the contaminant "didn't come straight from the pig."

Still, investigators "cannot rule in or out" whether the contaminant was accidentally or deliberately put into the product, Woodcock said.

The FDA also emphasized it is not yet certain whether the contaminant is the root cause of the recent spike in severe allergic reactions and as many as 19 deaths that may have been associated with the blood thinner.

"Right now, people should not be alarmed," Woodcock said. "We have not received any more reports of fatalities of this type since the recall on Feb. 28."

Today's announcement is the latest in a heparin scare that has prompted the FDA, overseas officials and heparin maker Baxter Healthcare Corp. to take action. After Baxter issued a massive heparin recall, FDA regulators traveled to China to inspect a plant from which the manufacturer receives the drug. Investigators then announced they'd found a contaminant in heparin whose ingredients came from China.

Germany also recently informed the FDA that people were getting sick from heparin there as well, but from a different brand of the medication.

On Wednesday, Baxter's corporate vice president and chief scientific officer, Norbert Riedel, said in a statement that the contamination likely happened early on in the supply chain, before the heparin reached the active pharmaceutical ingredient supplier and before it reached Baxter.

"We're at a critical juncture in the investigation and further progress can be accelerated with the cooperation of the consolidators and workshops," Riedel said.

To determine the scope of the problem and head off more bad reactions, FDA investigators have partnered with universities to study the contaminant and have ramped up their efforts to test heparin shipments coming from overseas to find out whether they're safe.