FDA Issues Final Guidance to Assist Sponsors of Animal Drugs for Minor Uses and Minor Species (MUMS)

December 21, 2023

The U.S. Food and Drug Administration has released updated information to help animal drug researchers and sponsors navigate the pathway to approval for animal drugs intended for minor uses and minor species (MUMS).

The final guidance, entitled, “Special Considerations, Incentives, and Programs to Support the Approval of New Animal Drugs for Minor Uses and for Minor Species,” was released as a draft guidance in July 2020 for public comment. The comment period was extended to 180 days in order to hear from all interested parties. The agency received many comments on the proposed Aquaculture Species Grouping section of the draft guidance; the agency intends to address aquaculture species grouping in greater detail in the future.  Other revisions were made in response to public comments and to improve clarity.

The FDA’s mission is to protect and promote the health of both humans and animals, including those animals that are considered “minor species” – animals other than those typically thought of as livestock (cattle, pigs, chickens, turkeys) or companion animals (dogs, cats, horses). Minor species are animals that may not be quite so common – such as sheep, goats, and ferrets, but also zoo animals and wildlife. Minor species include fish and insects like honeybees. 

Similarly, the FDA has a responsibility to facilitate approval of treatments for conditions that are relatively rare in the major species, or which occur in small numbers or in limited geographic areas. Such treatments are referred to as minor uses in major species, or simply minor uses. Some examples of minor uses in major species include various cancers in dogs or regional occurrences of diseases, such as outbreaks of blackhead in turkey flocks in the Southern U.S. 

Because MUMS drugs, by definition, are for use in relatively small markets, there is less economic incentive for a drug company to invest in the research and development necessary to bring a product to market via the traditional new animal drug approval process. Congress took action to try and address the disparity of products available to treat these animals by passing the Minor Use and Minor Species Animal Health Act of 2004 (the MUMS Act). This act allows for alternative legal pathways to the marketplace for MUMS drugs (indexing and conditional approval) and also provides incentives, such as exclusive marketing rights and grant eligibility (via designation), for researchers and companies to overcome the financial roadblocks they face in producing animal drugs for limited markets.

In certain cases, a minor species drug is intended for use in species that are too rare or too varied to be the subject of adequate and well-controlled studies in support of a drug approval. The Index of Legally-Marketed Unapproved New Animal Drugs for Minor Species (the Index) provides an alternative FDA review process to affirm the safety and effectiveness of unapproved new animal drugs for use in non food-producing minor species. Minor use drugs are not eligible for the Index. There are currently 16 entries listed on the Index, for use in animals such as elephants, raptors, ferrets and ornamental finfish. 

Sponsors of MUMS drugs may pursue conditional approval of their products, which allows the marketing of a MUMS drug when all requirements for its approval have been met except the “substantial evidence” standard for effectiveness. Instead, conditional approval requires these drugs to meet a “reasonable expectation of effectiveness” standard and to be marketed for up to five years (through annual renewals) while the drug’s sponsor continues to collect the effectiveness data needed to support a full approval.  Conditional approval allows MUMS drugs to reach the market sooner, but the drug sponsor still has the responsibility to demonstrate progress toward meeting the full effectiveness requirement within five years. 

The MUMS Designation program provides incentives similar to those available for orphan medical products for use in people. Sponsors who are granted MUMS designation status are eligible to apply for grants to defray the costs of safety and effectiveness studies in support of the drug approval. They are also given 7 years of exclusive marketing rights beginning on the day of approval or conditional approval. 

Many of those seeking approval for MUMS drugs are new to the new animal drug approval process. The final guidance released today describes the new animal drug approval process for MUMS drugs and explains the various scenarios that might arise along the way. This guidance also explains how to navigate the various components of the MUMS program so that sponsors can use them to their benefit when pursuing drug approval. For sponsors of products intended for use in aquaculture, the guidance describes special considerations that apply.

Issued by FDA Center for Veterinary Medicine.
For questions, Contact CVM.