For companies developing new animal health products in the United States, understanding the transition from Investigational New Animal Drug (INAD) to New Animal Drug Application (NADA) is key to regulatory success. While these acronyms may seem similar, they represent two distinct phases in the veterinary drug development process—one focused on preparation, the other on approval.
This article provides a step-by-step overview of how the INAD-to-NADA lifecycle works, what’s required at each stage, and how sponsors can position themselves for a smooth approval process with the FDA’s Center for Veterinary Medicine (CVM).
What Is an INAD?
An INAD file is opened early in development and serves as the regulatory home base for a product before approval. It allows a sponsor to:
- Legally ship investigational drugs across state lines
- Conduct clinical field studies
- Submit protocols, safety data, and manufacturing updates to CVM
- Receive feedback on proposed studies and CMC approaches
Although an INAD is not technically required by regulation, it is critical for any product that will undergo field trials or be submitted for FDA approval.
What Is a NADA?
The New Animal Drug Application (NADA) is the formal marketing application submitted to CVM once all required data is complete. The NADA must demonstrate:
- Substantial evidence of effectiveness
- Safety to the target animal, humans (in the case of food animals), and the environment
- Manufacturing quality and consistency
- Proper labeling, dosage, and intended use
The data compiled within the INAD directly informs the content of the NADA. A well-maintained INAD file often leads to fewer review cycles and a quicker path to approval.
Key Milestones in the Veterinary Drug Lifecycle
Below is a high-level roadmap from INAD to NADA:
1. Pre-INAD Consultation (Optional)
Sponsors may begin with informal discussions with CVM to explore the regulatory pathway and target species considerations.
2. INAD File Opened
The INAD file is initiated. Sponsors can submit protocols for target animal safety, effectiveness, and manufacturing data. CVM feedback helps refine development strategy.
3. Pivotal Studies Conducted
Clinical trials are executed under the INAD. These include effectiveness trials, safety margin studies, and possibly user and environmental safety evaluations.
4. CMC and Manufacturing Data Compiled
As development progresses, the sponsor provides detailed Chemistry, Manufacturing, and Controls (CMC) information, including stability data, specifications, and manufacturing site information.
5. Presubmission Conference
This is a formal meeting with CVM to confirm that the sponsor has addressed all necessary technical sections. CVM provides feedback to ensure the NADA will be complete.
6. NADA Submission
The complete NADA is submitted, with technical sections that include safety, effectiveness, CMC, and labeling. Each section can be submitted as a “Phased Review” or as part of a traditional, full submission.
7. CVM Review & Approval
CVM reviews the application, may request clarifications or additional information, and—if all requirements are met—approves the product for market.
Conditional Approval: A Unique Veterinary Pathway
In some cases, especially with minor species or innovative therapies, sponsors may pursue Conditional Approval, which allows for earlier market access after proving reasonable expectation of effectiveness. The INAD still plays a central role in compiling data to eventually meet full approval standards.
Strategic Tips for Sponsors
- Plan Early: Open your INAD before pivotal studies begin to ensure study designs align with CVM expectations.
- Leverage CVM Feedback: Use protocol reviews and presubmission conferences to de-risk your NADA.
- Track Changes: Document manufacturing changes carefully—any shift may trigger the need for bridging studies or new data.
- Avoid Silos: Make sure your regulatory, CMC, and clinical teams are aligned throughout the lifecycle.
How DSI Supports the INAD to NADA Process
At DS Inpharmatics, we guide veterinary sponsors through every phase of drug development—from INAD setup and protocol design to full NADA submissions and post-approval strategies. Our subject matter experts offer:
- Regulatory pathway planning
- CMC data development and gap analysis
- CVM meeting support
- eCTD publishing and submission management
- Quality and audit readiness
Whether you’re developing a product for livestock, companion animals, or wildlife, DSI helps ensure your product moves from idea to approval with confidence.
Final Thoughts
The transition from INAD to NADA is not just a regulatory formality—it’s the framework for developing safe, effective, and compliant veterinary drugs. By understanding each phase and taking a proactive approach to communication and data planning, sponsors can reduce delays and set their products up for long-term success.
Need guidance on your INAD or planning your NADA strategy?
DS Inpharmatics is here to help. Contact us to learn how our experts support veterinary product development from start to finish.
