November 3, 2011
Last Friday, the U.S. Food and Drug Administration (FDA) posted data on antimicrobial drug sales collected under the Animal Drug User Fee Act (ADUFA). ADUFA requires drug companies to report information on sales of antimicrobial drugs intended for use in animals, including food animals. These data provide the most reliable information we have on the use of antimicrobials in animal agriculture. CLF’s Ralph Loglisci and David Love, PhD, used 2009 ADUFA data to calculate the quantity of antimicrobial drugs used in food animal production in that year as a percentage of the total amount of antimicrobial drugs used in the U.S. over the same period—the number, they determined, was almost 80 percent!
The data that FDA posted on its website (October 28) was a PDF that contained sales data for 2010. These data showed a significant increase in antimicrobial drug sales—almost 7 percent. But a funny thing must have happened over the weekend. On Monday, the numbers changed. And the new numbers were significantly different—the total quantity of drugs distributed in the U.S. dropped more than 1.5 million pounds, and a 6.7-percent increase compared with 2009 became just a 1.3-percent increase. FDA neither announced this change nor made it obvious in any way. The same link that had brought users of the FDA website to the PDF posted on Friday now brought visitors to a second, nearly-identical PDF with different numbers. If not alert, one could easily have mistaken the second document for the first.
As word spread amongst researchers and public health advocates, FDA remained silent. The agency did not even acknowledge the change until today, when it posted a terse, one-paragraph explanation that included the following: “An earlier draft of the summary report was posted erroneously on 10/28/11. It did not contain the final results. We were still adjusting classifications and numbers including a late submission from a drug sponsor.”
This explanation is unsatisfactory for several reasons. The most important question is this: if the numbers were revised following the inclusion of “a late submission from a drug sponsor,” why was the revised total number lower than the first? The incorporation of sales figures from an additional drug company should make the total number higher, not lower. The paragraph published by FDA after three days of silence does not provide an adequate explanation. It cannot give researchers the confidence they should be able to have in numbers reported by a federal agency. CLF hopes that FDA will provide more robust explanations—indeed, more believable explanations—for why the revision occurred, why FDA attempted to hide the revision, and why FDA did not acknowledge the revision until three days after it occurred. Public confidence in FDA data requires nothing less than transparency in, and full explanations of, these significant revisions.