WASHINGTON – Concerned that the Chinese firms responsible for the contaminated heparin that killed more than 80 people in 2008 are still supplying U.S. drugmakers with crude heparin, a House committee wants to know why the FDA hasn't done anything about it.

The agency has had "credible evidence" over the past few years that at least two Chinese firms supplied lots of heparin contaminated with oversulfated chondroitin sulfate, but "we have seen no indication that the FDA has issued warning letters and/or import alerts to these firms even though FDA has issued warning letters and import alerts to other Chinese heparin firms," the Republican leadership of the House Energy and Commerce Committee said in a letter last week to FDA Commissioner Margaret Hamburg.

The two firms, which allegedly supplied the contaminated heparin to Baxter International Inc. and other companies, are still supplying crude product for use in the U.S., according to the letter signed by committee Chairman Fred Upton (R-Mich.) and four other committee leaders. (See BioWorld Today, April 23, 2008.)

The lawmakers noted that FDA inspections and correspondence with Chinese heparin firms showed that, in some cases, the firms identified specific workshops where the contaminated heparin was produced. Although the agency disqualified the workshops, "we have seen no indication that FDA took any further action to alert heparin companies to avoid these disqualified workshops or to investigate the findings," they said.

The letter demanded to know why the FDA hasn't acted.

This is not the first time the congressional committee has inquired about the agency's heparin investigation. The committee wrote to Hamburg earlier this year, demanding answers about the contamination and the status of the investigation. (See BioWorld Today, Feb. 25, 2011.)

A few months later, Hamburg testified before an Energy and Commerce subcommittee, saying she had raised the issue with Chinese officials. They didn't think there was anything to gain by continuing an investigation into the underlying cause of the contamination, she said. However, they committed to making sure it doesn't happen again. (See BioWorld Today, April 14, 2011.)

In terms of who initiated the contaminated product, "the investigation has come up dry," Hamburg said, "and there are no new leads." She assured the subcommittee that the agency has a strong structure in place to prevent similar incidents.

But Deborah Autor, the FDA's deputy commissioner for global regulatory operations and policy, wasn't so certain when she testified before the Senate Health, Education, Labor and Pensions Committee last month. "It's not a matter of if. It's a matter of when" a similar incident occurs again, she said, adding that virtually all heparin used in the U.S. comes from China. The 2008 contamination was "a crime of opportunity," Autor said. It was fueled by the fact that oversulfated chondroitin sulfate is much cheaper than regular heparin starting materials and is difficult to distinguish by standard tests.

To help protect the drug supply chain, the FDA needs the authority to ban the import of products from facilities that delay or refuse inspections, Autor said. In other countries, companies must demonstrate that their products are safe to gain entry. But in the U.S., the burden is on the FDA to show the products are unsafe. (See BioWorld Today, Sept. 15, 2011.)

New production processes also may be able to help. For instance, scientists have combined chemical and enzymatic synthesis to come up with a much faster and cheaper way to make ultra-low molecular weight heparin. (See the related story on p. 1.)