Testing has turned up possible irregularities in some samples of a blood thinner linked to several deaths and hundreds of life-threatening reactions, a spokeswoman for Baxter Healthcare Corp. said Thursday.
The disclosure comes amid mounting questions about the U.S. Food and Drug Administration's oversight of drugs manufactured overseas.
Baxter's testing found "trace differences" in some lots of the blood thinner heparin, including quantities in which the active ingredient came from a supplier's plant in China, said Baxter spokeswoman Erin Gardiner.
Baxter and the FDA said it was too early to say whether the problems were caused by the ingredient made in China. But the disclosure is likely to add to the public's worries about goods from China after product safety scares in the last year involving Chinese-made pet food ingredients and toys.
Several members of Congress said the case underscored a gaping hole in the FDA's inspection program: Although most of the bulk ingredients used by U.S. drug makers are imported, the FDA inspects only about 7% of foreign drug plants a year.
According to a recent congressional report, the chronically underfunded agency does not have an accurate count of foreign drug plants that fall under its jurisdiction. Many -- such as the plant in China -- have never been inspected.
"How do you allow these drugs into this country when you don't even inspect?" asked Rep. Bart Stupak (D-Mich.), a leading FDA critic. "Where is the enforcement to make sure you are doing things right?"
Baxter emphasized that its investigation was continuing and that no conclusions had been reached.
"Baxter has detected differences between lots [of the active ingredient] but it's unclear what the impact of these differences is," Gardiner said. "They are not necessarily the root cause of the increase in adverse reactions, but they are certainly a central part of our investigation."
Some of the samples that were found to have differences "are definitely from China," she added. Earlier testing before the drug was shipped to hospitals and dialysis centers fully complied with industry and regulatory requirements, Gardiner said, but the previous tests were not as sophisticated and failed to detect any possible problems.
Baxter identified the supplier of the heparin as Scientific Protein Laboratories of Waunakee, Wis. The firm's website says it maintains manufacturing facilities for the drug in Waunakee and Changzhou, China, about two hours' drive west of Shanghai. It said that both plants adhere to the same industry and FDA safeguards, adding that SPL provides bulk heparin to Baxter, which further processes and packages the product in Cherry Hill, N.J.
Baxter said Monday that it had suspended manufacturing of multiple-dose vials of heparin after receiving reports of four deaths and 350 bad reactions. The drug helps prevent the formation of blood clots during surgical procedures, and the FDA said doctors continuing to use the Baxter product should carefully monitor patients for signs of allergic reaction.
Heparin is a naturally occurring substance extracted from pig intestines and cow lungs. Some independent experts said contamination could have occurred at any point in the production process, from a problem with raw materials to the wrong kind of solvent being used to clean equipment.
"There are a whole lot of things along the trail that would have to be eliminated," said Larry D. Sasich, a pharmacist and professor at the Lake Erie College of Osteopathic Medicine in Erie, Pa. "It's conceivable that something could have happened here in the United States . . . some change in procedure might have left a residue of some chemical."
Stupak, as well as some consumer, advocates urged a recall, but the FDA said that could do more harm than good by creating an acute shortage, since Deerfield, Ill.-based Baxter accounts for about 50% of the market for this type of heparin.
In a statement, supplier SPL said it was "very concerned" about the problems and is "aggressively taking all necessary steps to investigate the cause and ensure patient safety."
Baxter said it inspected both of its supplier's plants last year and found no problems. FDA spokeswoman Karen Riley said the agency was planning to send inspectors to the plants in China and Wisconsin.
Industry sources in China said the heparin plant was a joint venture between SPL and Techpool Bio-Pharma Co. A representative at the facility's quality-control department confirmed Thursday that it made the ingredient for Baxter and that its production was under scrutiny by U.S. regulators.
"We are taking initiative to cooperate" with the FDA and Baxter, said the representative, who declined to give his name. "We put great emphasis on the investigation. After all, it involves people's lives."
He said the company was expecting FDA inspectors to arrive soon, but he declined to comment further. The plant is not currently making heparin, he said.
Alonso-Zaldivar reported from Washington and Lee from Shanghai.