In pharmaceutical and biotech development, there exists a regulatory pathway known as the Animal Rule or Animal Efficacy Rule. This pathway becomes essential when traditional human clinical trials are not feasible or ethical, often due to the nature of the disease being studied. In such cases, adequate and well-controlled efficacy studies in animal models play a pivotal role in getting marketing approval for drugs if the results of those studies establish that it is reasonably likely to produce clinical benefit in humans. In all cases, clear communication with the FDA based on their guidance is necessary to choose appropriate animal models and service providers.


The Importance of CRO Experience and Capabilities in Animal Rule Studies

Navigating the landscape of preclinical services for Animal Rule studies can be complex, particularly when considering studies involving highly infectious agents or toxins. This is where experienced CROs with Animal Biosafety Level 3 (ABSL-3) and Select Agent capabilities come into play.

  • Given the potential hazards associated with infectious agents and toxins studied under the Animal Rule, safety and containment are paramount.  Select Agent capabilities ensure compliance with regulations governing the possession, use, and transfer of dangerous biological materials, reducing the risk of intentional misuse.
  • The specific species and number of models to use also differs depending on the nature and clinical significance of any differences between the animal model(s) and humans. If efficacy is demonstrated in a single study conducted in a sufficiently well-characterized animal model, it still may be necessary to conduct a confirmatory efficacy study ideally at a different laboratory. Labs with space for small and large animal species (like dogs and cynos) can be helpful to meet all model needs.
  • The efficacy of drugs developed to treat a pathogen like smallpox, where humans are the only known natural host and no other species has been found to have comparable susceptibility, may need to be tested with similar viruses in relevant animal models. Depending on the strength of that data and other supporting information, the efficacy findings from such studies may be adequate. Having a large library of data from different pathogens in the same families can be an asset.
  • Drugs evaluated for efficacy under the Animal Rule need to also be evaluated for safety under the existing requirements for the safety of new drugs. Full service CROs will be able to run all necessary studies such as PK/PD, DRF, and IND-enabling studies under one roof.

Partnering with a Specialized Preclinical Service Provider like IITRI

For pharmaceutical and biotech companies embarking on Animal Rule studies involving BSL-2 and BSL-3 pathogens, partnering with specialized preclinical service providers is essential. IITRI offers expertise in handling hazardous materials and designing studies that meet regulatory requirements.

  • Experience and track record in conducting studies with relevant pathogens and Select Agents for both commercial and government agencies including for medical countermeasures
  • All studies under one roof including facilities equipped with BSL-2 and BSL-3 containment including the ongoing expansion of NHP ABSL-3 space for larger studies
  • Certifications, accreditations, and licenses from AAALAC, USDA, USDEA, OLAW, CDC, and BSAT.
  • Ability to tailor study designs to meet the specific needs of the drug development program and provide other supporting studies like safety, toxicology, and clinical trial sample analysis.


IITRI is a mid-sized preclinical CRO (100,000 sq./ft. laboratory) that provides full GLP toxicology studies to satisfy IND/NDA submissions.  This include inhalation as a route of exposure. We also provide infectious disease efficacy studies, vaccine studies, bioaerosol challenges (BSL-2/3) and complete analytical/bioanalytical support for all studies and clinical trials. Our smaller size and highly experienced staff (ave. tenure > 10 yrs) enables us to provide a customer-centric experience including guidance throughout the entire non-clinical process.  Reach out to us today to learn how we can best support your program needs.