November 15, 2011
The U.S. Food and Drug Administration (FDA) held a public meeting (video on YouTube) this past Monday at its Rockville campus to discuss reauthorization of the Animal Drug User Fee Act (ADUFA). The current version of ADUFA includes an important provision that requires drug sponsors to report sales of antimicrobial drugs intended for use in food animals to FDA. The agency compiles these sales data and releases a limited summary to the public each year. The 2009 summary report of ADUFA data allowed CLF researchers to calculate the quantity of antimicrobial drugs sold domestically for use in food animals as a percentage of the total quantity of antimicrobial drugs distributed in the U.S. While useful, these public summaries of ADUFA data are very short, comprising just a few pages that provide the quantities of certain antimicrobial drug classes sold in the previous calendar year (see the reports for 2009 and 2010). The summaries do not currently provide many data that non-governmental public health scientists, state and local public health officials, and veterinarians need to better understand patterns in antimicrobial use and resistance.
FDA organized the Monday meeting to solicit public comments on ADUFA and how the law—and FDA’s implementation of the law—could be strengthened. ADUFA will expire in 2013 without Congressional reauthorization. The meeting on Monday initiated the process by which FDA will revise ADUFA and transmit it to Congress for legislative review and re-approval. Tyler Smith and I attended the meeting on behalf of CLF to present a series of recommendations on how the collection and reporting of data on antimicrobial sales for use in food animals could be improved.
My presentation (ADUFA Comment, Meghan Davis) urged FDA to revise ADUFA and its implementation in several ways. Drug sponsors currently report the quantities of antimicrobial drug classes sold by product, and report the target species, indications for use, and routes of administration for which each product is approved. From ADUFA data, for example, FDA can determine the quantity of an antimicrobial drug class sold in products approved for administration to cattle as medicated feed to increase growth rates and feed efficiency. The agency also already receives monthly—not just annual—sales figures for antimicrobials. None of these data are reported publicly, however. Publishing these data could allow public health scientists to correlate sales data trends—an imperfect but still useful surrogate for trends in antimicrobial use—with trends in resistance data generated by the National Antimicrobial Resistance Monitoring System (NARMS), which are currently reported by month. Improving refinement of the FDA data could further allow independent public health scientists to characterize relationships between antimicrobial use in food animals and patterns of resistance in bacterial isolates from food animals, as well as patterns of resistance in bacterial isolates from food animal products and human consumers.
Additionally, I asked FDA to revise the version of ADUFA it sends to Congress for reauthorization so that the statute allows public reporting of sales figures for all drug classes, regardless of the number of drug sponsors that market a drug in that class. ADUFA currently prohibits FDA from reporting total sales of an antimicrobial drug class when less than three drug sponsors market a product containing an active ingredient in that class. This has kept the public from seeing sales figures for most drug classes—nine of 17 antimicrobial drug classes that are sold in the U.S. have been lumped together in a “not independently reported” category in public summaries. These unreported categories include fluoroquinolones and streptogramins, two drug classes considered “critically important” to human medicine by the World Health Organization.
Furthermore, I urged revision of ADUFA to include collection and reporting of sales data by county or state to allow officials in local and state health departments, as well as independent researchers, to evaluate local and regional impacts of antimicrobial use. Industrial food animal production has become concentrated in certain regions of the country. Antimicrobial-resistant bacteria and the drugs themselves may contaminate soils, water, and air around animal feeding operations. Nearby human populations may be exposed to resistant pathogens through contact with those media. A better understanding of these environmental pathways requires information about how antimicrobials are used in particular areas.
In addition to supporting the efforts of public health researchers and advocates to protect human health, the changes to ADUFA that I recommended on Monday would give veterinarians additional tools for management of diseases in food animals. Most antimicrobial drugs can be purchased for use in food animals without veterinary prescription; hence antimicrobial sales and use can occur without a veterinarian’s knowledge. Understanding patterns of antimicrobial distribution over time and by location will allow veterinarians to perform better surveillance and clinical testing for resistant infections in the herds, flocks, or schools of food animals they manage, improving their ability to prescribe the correct drugs to their patients and recommend tailored strategies for judicious antimicrobial use to their clients.
The meeting at FDA began a process that will culminate in January 2013 when FDA transmits a new version of ADUFA to Congress for reauthorization. Beginning early next year, the agency will enter negotiations with the Animal Health Institute, a lobby group that represents the animal health divisions of large pharmaceutical companies like Pfizer, Bayer, and Merck. Rather than allow the public health and veterinary communities to participate in—or even just observe—these negotiations, FDA instead will publish minutes from the negotiating sessions. When the agency and AHI agree on the next version of ADUFA, a draft will be published and the public will be permitted to submit written comments and to speak at another public meeting. While additional transparency and stakeholder involvement would be ideal, we look forward to working with FDA over the next year to help ensure that a reauthorized ADUFA better serves, not just the industry, but public health practitioners, veterinarians, and food consumers nationwide.
Here is an 8-minute video of my presentation during the meeting: