Drugs like the blood thinner heparin face a long and winding road as they're transformed from raw ingredients into sophisticated medications.
At its best, it's a global drug market that helps patients in all corners of the world get the medications they need. At worst, it's a supply chain that's exceedingly difficult to unravel when those drugs are associated with making people sick.
But just how difficult it is to ensure the safety of a final product made with ingredients coming from abroad was glaringly apparent this week in Washington.
"The current regulatory system is woefully insufficient, a fact that has been proven by the tragedies caused by unsafe heparin," said Rep. John D. Dingell, D-Mich., in a statement Monday. "It's clear that [the] FDA does not have the ability to protect the American people from unsafe food and drugs."
A hearing on Capitol Hill today will examine the Food and Drug Administration's foreign drug inspection program. The hearing comes just as scientists, drug makers and foreign investigators get closer to figuring out what caused a recent spike in severe allergic reactions and as many as 81 deaths that may be associated with the blood thinner heparin.
After announcing mid-March that it had found a contaminant in heparin, the FDA said Monday that it now believes there's "a very solid mechanistic link" between the contaminated heparin and bad reactions associated with the medication.
The FDA said it has gathered information from 11 other countries that also found a contaminant in their heparin supply and traced the contaminant to just one country.
"The one thing they have in common is China," said Deborah Autor, director of the FDA's Center for Drug Evaluation and Research's office of compliance.
But Chinese scientists and medical experts on Monday disagreed, saying the contaminant is not to blame for the adverse reactions. Chinese officials said some batches that did not contain the contaminant, known as over-sulfated chondroitin sulfate, made people sick. They also said that more than 10 countries used the contaminated ingredient, but have not reported adverse reactions.
Professor Jin Shaohong, deputy director-general of China's National Institute for the Control of Pharmaceutical and Biological Products, instead suggested the problem could have originated at U.S.-based manufacturer Baxter International.
But Autor, as well as Baxter and the plant in China that it receives heparin from, said the presence of the contaminant in the ingredient "would give us reason to believe the contamination occurred before it got to Baxter." Twelve Chinese companies are in the supply chain for contaminated heparin, according to the FDA.
Baxter's tests released Monday evening echoed the findings of the FDA.
"These tests show that significant doses of the over-sulfated chondroitin sulfate do induce a rapid loss of blood pressure," said Norbert Riedel, Baxter's chief scientific officer. "That means that the contaminant, which was introduced at the workshop or consolidator level, before it reached our API supplier and before it reached Baxter, is likely the cause of the increased adverse reactions to the heparin."
To be sure, the problems with heparin have highlighted the importance of ensuring drug safety from the beginning to the end of a complex supply chain.