On Friday, leaders of the House Energy and Commerce Committee sent a letter to US Food and Drug Administration (FDA) Commissioner Scott Gottlieb calling on the agency to look into conflicting data on the nation's supply of the lifesaving drug, heparin.
The letter, signed by Republican Reps. Greg Walden (R-OR), Joe Barton (R-TX), Michael Burgess (R-TX) and Gregg Harper (R-MS), raises concerns that fluctuations in the heparin market could lead to a shortage or prompt economically motivated adulteration of the drug.
Heparin is a medically necessary anticoagulant derived from pig intestine and used during open heart surgeries and kidney dialysis. In many situations, there is no suitable medical alternative to heparin.
In 2007 and 2008, adulterated heparin sourced from China led to the deaths of more than 100 Americans and prompted an investigation by FDA that led to dozens of Chinese heparin suppliers being placed on import alert.
Since then, FDA has finalized guidance on monitoring the quality of crude heparin and the US Pharmacopoeia (USP) has released new quality standards for the drug.
However, concerns over the quality of Chinese heparin have continued, with FDA warning a China-based heparin testing lab as recently as July 2017 and a Chinese heparin manufacturer in late 2016.
Out of concern that disease outbreaks could threaten the supply of heparin, which may only be sourced from pig intestine in the US, FDA has proposed to re-introduce heparin sourced from bovine lung, though it may be years before a proposal is finalized.
FDA also recently allowed Baxter Healthcare to import Heparin intravenous (IV) infusion bags to the US to address a shortage of the drug caused by Hurricane Maria.
In the letter, the congressmen ask FDA to look into whether the US supply of Chinese heparin is increasing or decreasing, and whether the fluctuation could raise the risk of adulterated heparin making it onto the US market. They also ask the agency to review whether the recent increase in US heparin exports to China could endanger the nation's supply and to come up with a contingency plan in the event of a heparin shortage.
"Given the United States' continued reliance on heparin sourced from China, recent trends and interpretation of Chinese customs data for Chinese heparin exports and imports raise troubling concerns," the congressmen write.
Based on Chinese customs data from three different sources, committee staff said that while Chinese heparin exports have risen since the crisis in 2007 and 2008, there is conflicting data on whether those exports are increasing or declining.
"Starting in 2015, Chinese heparin exports surged about 32 to 40 percent above the volume of 2014 Chinese heparin exports. However, for 2016, the data sets conflict over whether Chinese heparin exports were surging or declining," the congressmen write.
While two of the data sources show a 13% increase in Chinese heparin exports from 2015 to 2016, the third data source showed a 26% decline in exports over the same period. Around the same time, Chinese heparin exports to Thailand and Hong Kong also shot up to 40,000 kilograms and 28,000 kilograms, respectively, in 2016.
On top of their concerns over fluctuations in Chinese heparin exports, the congressmen also note that China has been importing much greater quantities of heparin, including heparin sourced from the US, in recent years.
"In 2016, the US exported 17,050 kilograms of heparin to China, by far the leading exporter of heparin that did not originate in China and with the greatest value of imports at $11,634,209," the congressmen write, noting that this was the first time US heparin exports to China exceeded direct imports of heparin from China.
House E&C Statement, Letter