Clinical Trials of Veterinary Medications Differ From Drugs for Human Use

New drug development is commonly regarded as being for human use. However, veterinary pharmaceutical development and production can be profitable. Zoetis is a booming company that creates and manufactures diagnostic products, medications, and vaccines for animal use. The company posted $6.3 billion in annual revenue in 2019.¹

How does a company like Zoetis go about developing new medications for animal use? A review of 21 CFR §514.117 shows the legislation behind clinical trials for medications intended for animal use.²

FDA regulations 21 CFR §514.117, as authorized by the Food, Drug, and Cosmetic Act’s 21 U.S.C. §360(b) provision, defines adequate and well-controlled studies for medications intended for animal use. This section goes into detail regarding the characteristics that the FDA’s Center for Veterinary Medicine (CVM) looks for when approving veterinary drugs.

This is because the CVM must see that a veterinary drug is safe and that there is substantial evidence for the drug’s effectiveness before approving it. For substantial evidence to be displayed, 1 or more adequate and well-controlled studies must be executed.²

However, knowing how to conduct a study is only a small part of the process. To begin developing a new drug for veterinary use, the drug sponsor must contact the CVM’s Office of New Animal Drug Evaluation, which facilitates preapproval steps. It is important for the sponsor to create an investigational new animal drug file, which is the main form of communication between the CVM and the sponsor. The sponsor must also pay Animal Drug User Fee Act fees, which fund the CVM in reviewing drugs intended for veterinary use.³

So, how do veterinary medication clinical trials differ from human ones? One key point is that veterinary medication clinical trials focus on a target animal when analyzing the drug, or on the type of animal at which the drug is aimed. Human medication clinical trials commonly begin with studies in laboratory animals and then move to humans. Lab animals may be used in veterinary medication clinical trials, but the most important aspect is the studies done in the target animal.⁴

Additionally, veterinary medication clinical trials are not labelled as phase 1, 2, 3, or 4 as in human clinical trials. Veterinary medication clinical trials are referred to as target animal effectiveness studies and target animal safety studies.⁴

Safety is investigated by examining possible adverse effects and the margin of safety, which evaluates what would happen if the drug were given at a higher dose or for a longer duration than originally intended. Once safety is evaluated in the target species, the effectiveness of the drug must be evaluated. Effectiveness ensures that the drug can perform as advertised. Additional considerations must be evaluated for certain species. If the target species produces food for human consumption, it must be proved that the drug will not harm humans who later consume products from that animal.³

When trials are conducted for new veterinary drugs, the medication may end up in an OTC, prescription, or veterinary feed category. An OTC drug would need to be effective and safe to use by someone who is not a veterinarian by reading the directions for use on the label. If this is not possible, then the drug would be prescription or a veterinary feed directive. The difference between these 2 categories is that a veterinary feed directive is used in or on animal feed, and a prescription drug is not.³

Conclusion

Overall, conducting a clinical trial for a drug intended for veterinary use has some key legislative and terminology differences from those for human use. Moreover, 21 CFR §514.117 is a key piece of legal framework that can be used when planning to conduct a veterinary clinical trial.² Analysis of the target animal and conducting target animal effectiveness studies and target animal safety studies are the main factors considered when approving a new animal drug.⁴ It is also important to decide whether the drug will end up classified as an OTC, prescription, or veterinary feed product.³

About The Authors

Danielle K. Moorman is a PharmD candidate at the University of Kentucky College of Pharmacy and an MBA candidate at the University of Kentucky Gatton College of Business and Economics, both in Lexington.

Joseph L. Fink III, JD, DSC (Hon), BSPharm, FAPhA, is a professor of pharmacy law and policy and the Kentucky Pharmacists Association Professor of Leadership at the University of Kentucky College of Pharmacy in Lexington.

References

1. Zoetis. Accessed July 15, 2022. https://www2.zoetisus.com/about-us

2. CVM GFI #106 the use of published literature in support of new animal drug approvals. FDA. April 2022. Accessed July 15, 2022. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/ cvm-gfi-106-published-literature-support-new-animal-drug-approval

3. From an idea to the marketplace: the journey of an animal drug through the approval process. FDA. August 14, 2020. Accessed July 15, 2022. https://www.fda.gov/animal-veterinary/animal-health-literacy/idea-marketplace-journey-animal-drug-through-approval-process

4. Veterinary clinical studies. Veterinary Consultants. Accessed July 15, 2022. https://animalhealthconsultants.com/veterinary-clinical-trials/