FDA releases industry guidance on antibiotics

Cleveland-The Food and Drug Administration (FDA) released its long-anticipated risk-assessment guidance for food animals to help safeguard against the emergence of antibiotic resistance in people.

Dr. Linda Tollefson, deputy director for FDA's Center for Veterinary Medicine (CVM), explains, "What this document represents is a risk-based approach to help prevent antimicrobial resistance that may result from the use of antimicrobial drugs in food producing animals."

This new approach will apply to therapeutic and non-therapeutic antimicrobial drugs intended for food-producing animals. FDA adds that it will lead to a review of all existing approvals.

Tollefson explains that CVM has taken on many initiatives addressing the issue of antimicrobial resistance. There are many sources of the problem, including the inappropriate use of antibiotics in people. However, this document simply represents agriculture's role in preventing the problem, she adds.

Dr. Linda Tollefson

Industry is not disagreeing either.

According to the Animal Health Institute (AHI), a national organization representing animal health manufacturers, it's a better approach to regulating antibiotics.

"The new guidance is a superior approach to regulating antibiotics, compared to the European phase-out of antibiotics for growth promotion or to legislation proposed in the U.S. Congress. The new guidance bases decisions on science and risk assessment, rather than politics, and requires drugs to be looked at individually rather than lumping them all together, AHI says.

Alexander Mathews, AHI president and CEO, says, "This risk-based approach will allow FDA to make sound management decisions that protect public health from the potential transfer of antibiotic resistance bacteria from animals to humans. At the same time, it will preserve the important benefits of using antibiotics to protect animal health, he adds.

Alexander S. Mathews

This new risk-assessment guidance will apply to all antibiotics approved for use in food-producing animals. FDA explains, the guidance provides a scientific process for assessing the likelihood that an antimicrobial drug used to treat an animal may cause an antimicrobial resistance problem in humans consuming meat or other byproducts from that animal.

"This process can help prevent antimicrobial drugs with a high risk of causing such problems from being improperly used in food-producing animals, and thereby potentially leading to antimicrobial resistance in humans," FDA says.

The new guidance encourages drug sponsors to use a risk assessment process to demonstrate that an antimicrobial drug used to treat food-producing animals will not create a risk of antimicrobial resistant bacteria likely to lead to human health problems.

Stephen Sundlof, DVM, MPH, director of CVM, adds, "This guidance uses science to develop a risk-based approach to the issue of antimicrobial resistance. It permits us to help protect human health while giving veterinarians and livestock producers the tools they need to treat animals."

Dr. Stephen Sundlof

Details, details

The agency has devised a three-part system for determining an antimicrobial drug's potential risk to humans if used to treat food-producing animals. The three parts include:

• A "release assessment," which determines the probability that resistant bacteria will be present in an animal as a result of the use of the new antimicrobial drug.

• An "exposure estimate" to gauge the likelihood that humans might ingest resistant bacteria.

• A "consequence assessment," which takes into account the chances human exposure to the resistant bacteria would result in adverse human health consequences.

Once the risk estimation has been completed, it leads to a ranking of drugs: high, medium, low. These risk-based rankings are associated with certain risk management categories.

• Category 1 (high risk estimate): strictly limited use conditions.

• Category 2 (medium risk estimate): intermediate restriction on drug use.

• Category 3 (low risk estimate): least restriction on drug use.

CVM says it also has risk management strategies for drugs that rank high. For example, an application for approval could be flat-out denied, or approved under specific-use conditions. FDA could place limits on marketing, including prescriptions or Veterinary Feed Directive, prohibition on extra-label use or even limits on duration/method of administration.

Included in the new document is a revised ranking system for antimicrobial drugs and their importance to human medicine.

Table 1

Examples include:

• Critically important to human medicine: Third-generation cephalosporins, macrolides, fluoroquinolones.

• Highly important to human medicine: Fourth-generation cephalosporins, aminoglycosides, clindamycin.

• Important to human medicine: First- and second-generation cephalosporins, monobactams, quinolones.

Tollefson adds that FDA consciously decided to release this risk assessment as a guidance document rather than regulation because it is much easier to amend due to changing science.