RE: Comment on Draft Guidance for Industry #273

Tagged cows lined up eating from a trough through a feeding fence

Steve Harvey -

Defining Durations of Use for Approved Medically Important Antimicrobial Drugs Fed to Food-Producing Animals (Docket FDA-2023-D-2925)

The Center for Science in the Public Interest (CSPI) submits these comments on Draft Guidance for Industry (GFI) 273 to the United States Food and Drug Administration (FDA) Center for Veterinary Medicine (CVM). The draft guidance addresses voluntarily establishing durations of use for approved medically important antimicrobial animal drugs with indications that currently lack a defined duration of use.

CSPI supports the CVM objective of defining durations of use for these antimicrobials, as such durations could lead to decreased unnecessary antimicrobial use in food animal production and thus limit the antimicrobial resistance fostered by such use.

We have substantial concerns, however, regarding key aspects of CVM’s proposal. The draft GFI instructs manufacturers to provide an indefinite, unbounded expected duration of use and provides a definite, time-bound duration of use only for the maximum duration of use, a timeframe that is established to accommodate rarer clinical circumstances. This approach will likely nudge veterinarians toward the maximum duration of use, in some cases potentially leading to longer durations of use than is currently the case. Furthermore, CVM does not request any antimicrobial resistance data or analyses drug sponsors may have or ask sponsors to consider resistance risks in establishing the duration of use, even though such information could be critical to understanding whether the benefits of certain durations of use outweigh the associated risk of resistance development.

We expand on these concerns below and urge CVM to adequately address them in the final guidance.