From the Executive Director

Balancing act

The activities of an association like the AASV often resemble a balanc-ing act. For an association, many issues need to be studied, positions taken, and advocacy efforts activated. All this is done with the goal of looking after the best interests of the members of the organization while balancing the best interests of society as a whole. The difficulty arises when the issue is not scientifically "black and white." Scientific uncertainty creates areas of dispute and concern for the adversarial stakeholders of an issue.

The AASV frequently interacts with a number of organizations on issues of importance to our members. One governmental organization that requires this interaction is the US Food and Drug Administration (FDA). The FDA has been striving to overhaul the drug approval process, specifically for antimicrobials for use in food animals. The controversy over antimicrobial resistance has been driving the FDA to make changes in the approval process for the last several years.

Recently, the FDA Center for Veterinary Medicine released a draft guidance document entitled "Evaluating the Safety of Antimicrobial New Animal Drugs with Regard to Their Microbiological Effects on Bacteria of Human Health Concern."¹ This document outlines a recommended approach that pharmaceutical companies might use to address safety concerns on a drug's effect on the development of resistance in bacteria of importance to humans. The document also outlines possible mitigation strategies that will have a direct effect on how veterinarians and producers use antimicrobials.

A public meeting was held in early October to introduce this document and hear public comment. The swine industry was well represented at this meeting. The National Pork Board and the National Pork Producers Council provided comments. John Waddell, AASV Vice President, provided comment on behalf of the American Veterinary Medical Association. I offered public comment for AASV. All four of these groups will also be providing the FDA with more extensive, formal written comments. The FDA will consider all comments and then will issue a final guidance document.

Without going into great detail about this guidance document, I want to provide an overview that demonstrates a bit of the balancing act by the AASV as well as the FDA. Upon review of the document, you could arrive at either of two completely opposite views. The two extremes are the following:

• This document portends that no new antimicrobials will be approved in the future, the FDA will be prohibiting routes of administration for mass medication of animals, and the FDA will be removing some antimicrobials from the market.
• This document means that the companies will now have guidelines to follow which will open the pipeline to allow new antimicrobial approvals to flow to the market.

How can two such polar views surface from the same document? It is because the document is so subjective that it allows both views. Much is left up to the regulators and the companies to interpret and implement. In the end, the only true test will be the implementation of the guidance. The proof of which view is accurate will be whether new antimicrobials are approved and whether currently approved antimicrobials will be removed from the market. I suspect, as with most balancing acts, the results of the guidance document will be somewhere between the polar views.

The degree of subjectivity in this document causes a great deal of concern among most food animal organizations, including the AASV. Several consumer activist groups are calling for the use of the precautionary principle when approving antimicrobials. The basic premise behind the precautionary principle is that if you cannot prove that there is zero risk, you do not approve the drug. The problem with this is the challenge of proving a negative, ie, no risk of harm. Application of this principle would no doubt prove to be an insurmountable barrier to any further research and development of new antimicrobials for use in food animals. As written, the guidance document could allow this principle to come into effect.

Other potential effects concern the AASV. The first concern is the probability that the distribution of antimicrobials will be restricted. Most, if not all, antimicrobials in the future will only be available either by prescription or veterinary feed directive (VFD). Over-the-counter distribution will be limited to a very small number of products. These restrictions are also likely to eventually apply to currently approved drugs.

Secondly, the routes of administration for a number of antimicrobials may be reduced by the prohibition of feed and water medication to large groups of animals. Some antimicrobials may be limited to individual animal treatment. Related to this concern is the possibility that many antimicrobials will be limited to short duration of treatment: less than 6 days in some cases and no more than 21 days in others. This restriction on duration may effectively eliminate most prevention and growth promotant uses of antimicrobials.

Last of all, this guidance document contains language that would allow the FDA to further restrict the extra-label drug use (ELDU) in food animals. This could be construed as a "back-door" way to regulate the practice of veterinary medicine, a regulatory responsibility that Congress has clearly not given to the FDA. Additional limitations on ELDU might compromise a number of clinical treatment decisions made by practitioners.

The balancing act comes into play as AASV formulates a response to this document. As veterinarians, we desire an adequate armamentarium of effective antimicrobials in the appropriate dosage forms for the efficient treatment of food animals. On the other hand, however, we also want to act responsibly when the risk of harm to human health is raised as an issue. One of the common comments is that science or science-based decision making must take precedence in this kind of dialogue. Unfortunately, we do not know all there is to know about the use of antimicrobials in food animals, the development of antimicrobial resistance, and possible effects on human health. Science can only take us so far. After that, we have to count on common sense, deductive reasoning, and credibility to strike a balance in the decision making.

Reference

1. Food and Drug Administration, Center for Veterinary Medicine. Draft Guideline for Industry: Evaluating the Safety of Antimicrobial Drugs with Regard to Their Microbiological Effects on Bacteria of Human Health Concern. Rockville, Maryland: National Press Office; September 6, 2002. Draft Guidance for Industry #152.