Defining Small Number of Animals for Minor Use Determination; Periodic Reassessment

The Food and Drug Administration (FDA, the Agency, or we) is proposing to revise the "small number of animals" definition for dogs and cats in our existing regulation for new animal drugs for minor use or minor species. The Minor Use and Minor Species Animal Health Act of 2004 (MUMS Act) provides incentives to encourage animal drug sponsors to develop and seek FDA approval of drugs intended for use in minor animal species or for minor uses in major animal species. Congress provided a statutory definition of "minor use" that relies on the phrase "small number of animals" to characterize such use. We are proposing certain revisions to the definition of "small number of animals" based on our most recent reassessment of the small numbers, which we conducted from 2018 to 2019.