On April 10, 2025, the U.S. Food and Drug Administration (FDA) announced a landmark policy shift: it plans to gradually phase out animal testing requirements for the development of monoclonal antibody therapies and other drugs, replacing them with more advanced, human-relevant testing methods. This move has sparked widespread discussion in the pharmaceutical industry—proponents argue it will usher in a new era for drug development, while skeptics express concerns about potential safety risks.

01Core Content of the Policy

According to the roadmap released by the FDA, animal testing requirements will be gradually reduced, refined, or replaced through the following innovative approaches:

1. AI-based toxicity prediction models: Using computational modeling and machine learning algorithms to predict drug behavior and potential side effects.
2. Human organoids and organ-on-a-chip systems: Cultivating microtissues that simulate human organ functions in laboratories for drug testing.
3. Application of real-world data (RWD): Referencing existing human use data from other countries to avoid redundant trials.
4. Regulatory incentives: Offering streamlined review processes to R&D companies that adopt new methods.

The plan will first apply to Investigational New Drug (IND) applications. The FDA intends to launch pilot programs within the next year, selecting some monoclonal antibody developers to test non-animal experimental strategies under regulatory guidance.

02Supporting Views: A Paradigm Shift in Drug R&D

• Enhanced R&D Efficiency: Shortening drug development cycles and accelerating the launch of innovative therapies.
• Reduced Costs: Cutting expenses related to animal testing, which may ultimately lower drug prices.
• Improved Safety: Human models can more accurately predict drug responses than animal models.
• Ethical Progress: Thousands of laboratory animals will be spared from testing each year.
• Scientific Leadership: Establishing the U.S.’s global leadership in regulatory science innovation.

03Skeptical Voices: Radical Does Not Equal Correct

However, industry experts have also raised cautious objections:“Monoclonal antibodies like PD-1 antibodies have indeed shown good safety, but this cannot be generalized to all antibody drugs,” an anonymous expert noted. “Particularly for innovative therapies such as agonist antibodies, antibody-drug conjugates (ADCs), and T-cell engagers (TCEs), completely eliminating animal testing poses significant risks.”

Major concerns include:

• Technological Maturity: AI models and organoid technology are not yet sufficient to fully replace complex biological systems.
• Risks for Specialized Drugs: For highly toxic drugs (e.g., agonists, ADCs), the lack of animal testing may increase clinical risks.
• Challenges for Oral Drugs: The bioavailability of small-molecule drugs cannot be accurately evaluated by existing alternative methods.
• Historical Lessons: For example, CD28 superagonists were safe in animal tests but triggered severe reactions in humans; completely abolishing animal testing may increase similar incidents.
• Regulatory Challenges: It may increase the workload and decision-making pressure on reviewers.

04Future Path for Balanced Development

Industry experts suggest adopting a more prudent transition plan:“The appeal of drug R&D lies in exploring the unknown, and the greatest respect [for this process] is to ‘boldly hypothesize, cautiously verify’,” a senior R&D professional said. “Policies should not be categorized by technology type but should be tailored based on drug mechanisms. For drugs with highly toxic mechanisms, necessary animal testing should be retained.”

The FDA stated that it will collaborate with institutions such as the National Institutes of Health (NIH) to accelerate the validation of new methods through interagency coordination, and will host public workshops to gather industry opinions. The policy will be implemented in phases, with pilot results guiding subsequent adjustments.

05Global Impact and Outlook for China

Relevant experts pointed out: “As the world’s most comprehensive antibody drug database, we observe that this policy may reshape the global landscape of drug R&D. However, in China, considering differences in technological reserves and regulatory systems, the likelihood of following suit in the short term is low.”

As the industry explores a balance between scientific progress and ethical considerations, the FDA’s groundbreaking decision will have far-reaching implications for global drug R&D, and its implementation effects will continue to attract sustained attention from the industry.