WASHINGTON - U.S. Rep. Joe Barton, ranking Republican on the House Energy and Commerce Committee, today wrote to Food and Drug Commissioner Andrew von Eschenbach with further questions about FDA’s review process regarding the cause of death in heparin cases.

At issue is FDA’s classification of deaths related to tainted heparin. FDA’s response to Barton on Oct. 23, 2008, linked two “probable” and “possible” deaths to heparin made by American Pharmaceutical Partners. Up to now, APP had not been linked to any known public cases of severe allergic reactions.

APP replied to Barton with a detailed response that contradicts FDA’s classifications; FDA has not yet provided details.

Heparin is a blood thinner that gained widespread notoriety earlier this year when authorities discovered that contaminated supplies from China might have contributed to the deaths of 81 patients in the United States. A recent report published in the New England Journal of Medicine blamed a man-made chemical that was evidently added to batches of the drug.

A copy of the letter can be found here.