FDA Can’t Keep a Secret—Agency Accidently Reveals Arsenical Drug Sales

For years, the drug and food animal industries have refused to reveal the extent of their arsenical sales and use. Since 2009, the Food and Drug Administration (FDA) has collected this information, but the agency has refused to release it despite its public health implications. Now, after careful review of FDA reports and correspondence, I can publish a number that neither FDA nor these industries want you to know: 706,530 kilograms (kg) of arsenicals were sold for use in food animals in 2010, the most recent year for which we can determine arsenical sales.

How do we know? The Animal Drug User Fee Act (ADUFA) requires drug companies to report sales of antimicrobial drugs to FDA each year. (Antimicrobials include antibiotics such as penicillin and tetracycline, as well as drugs like arsenicals, used against pathogens in the intestines.) The agency releases a brief annual summary of these data to the public but withholds the rest. Last year, FDA published its summary of 2010 antimicrobial sales, but then quietly revised the numbers several days after the initial release. Without any explanation at first, the quantity of antimicrobials sold in the U.S. dropped by more than 700,000 kg and an increase in sales of almost 7 percent compared to 2009 became just a 1.3-percent uptick.

FDA acted as if nothing had happened: the same link that brought users of the FDA website to the initial report now took them to the revised report, which was identical to the initial report but for the new numbers, and which did not acknowledge that any changes had been made. Finally, after CLF and other organizations demanded an explanation, FDA gave a terse response: “We were still adjusting classifications and numbers including a late submission from a drug sponsor.”

This explanation was hardly adequate. If the revision was due to an additional submission by a drug company, the total quantity of antimicrobials sold should have increased, not dropped. Rep. Louise Slaughter, who has long championed legislation to end the misuse of antimicrobials in food animal production, put this question to FDA in a letter sent last November. She waited almost an entire year for a response (2012-10-03_FDA-Letter-to-Slaughter), which arrived earlier this month. According to the agency, “the [2010 summary] was updated to not only include a late data submission, but to also remove sales data for a class of drug (arsenicals) that was inappropriately included in the report.”

This explanation makes more sense, as it accounts for the reduction in total sales of more than 700,000 kg. Indeed, when one compares the initial and revised reports, one sees that the net decrease of 705,476 kg in total antimicrobial sales resulted from a 1,054-kg increase in cephalosporin sales (the “late data submission”) and a 706,530-kg decrease in sales of drugs grouped together in the “not independently reported” (NIR) category—the “sales data for a class of drug (arsenicals) that was inappropriately included.”  (The NIR category includes all drug classes manufactured by fewer than three companies.) No other changes occurred. The late submission explains the increase in cephalosporin sales; the removal of arsenicals, an NIR drug class, explains the large drop in NIR sales. FDA has not reported any other changes. Accordingly, the change in NIR drug sales (706,530 kg) should be the quantity of arsenicals sold in 2010.

It is possible that the late submission included additional sales of NIR drugs. In this case, 2010 sales of arsenicals would be even higher, as the reduction in arsenical sales needed to achieve a net decrease of 706,530 kg in sales of NIR drugs despite an increase in sales of other NIR drugs would be higher. In other words, drug companies sold at least 706,530 kg of arsenicals in 2010; the actual quantity could be higher, but we cannot be sure. Assuming that 706,530 is the correct number, arsenicals were the fourth-bestselling antimicrobial drug class sold for use in food animals in 2010, after tetracyclines, ionophores, and penicillins.

In June 2011, the manufacturer of Roxarsone, a leading arsenical drug approved for use in poultry and swine, announced that it was voluntarily suspending sale of the drug in response to an FDA study that associated Roxarsone use in chickens with increased concentrations of inorganic arsenic in chicken liver. As a result, sales of arsenicals in 2011 and this year are almost certainly down from 2010. FDA never withdrew Roxarsone’s approval, however, and the drug could be returned to the market at any time. In that event, more than 700,000 kg of arsenicals may once again be sold for use in producing our food, with a known carcinogen ending up on our dinner plates and in the environment.

Initial and Revised Summaries of 2010 ADUFA Data