On April 10th, the U.S. Food and Drug Administration announced an ambitious plan to phase out animal testing requirements for monoclonal antibodies and other therapies, replacing it with potentially more effective, human-relevant methods. Using a range of approaches, including AI-based computational models of toxicity and cell lines and organoid toxicity testing in a laboratory setting, the new approach aims to improve drug safety and accelerate the evaluation process, while reducing animal experimentation and lowering R&D costs.

Contract Pharma gains insight from CEOs at the forefront of building biotech companies that don’t rely on animal models and what this change might mean for the future of drug development. In the first of this two-part series, Wyatt McDonnell, Ph.D., CEO & Co-Founder, Infinimmune, shares insight on human-first models and what the FDA’s policy shift means for biotech R&D.

Contract Pharma: What are human-first models and how do they compare to animal studies?

Wyatt McDonnell: Human-first models are technologies that derive insights directly from human biology—whether through stem-cell-derived organoids, immune cell profiling, or patient-derived data—rather than inferring responses from other species. At Infinimmune, we apply this principle to antibody discovery. We identify fully human, in vivo–evolved antibodies from B cells that have already encountered and responded to actual disease conditions.

Our approach comes with inherent and significant advantages in relevance to patients and precision. Animal studies can miss important nuances in human immune responses, especially for complex conditions like cancer or autoimmunity. Our platform further enhances these naturally optimized molecules using AI systems trained exclusively on human antibody data by human scientists—creating a virtuous cycle where human biology informs both our starting materials and our engineering process. By beginning with molecules, the human body has already refined, we’re working with biology’s proven solutions rather than approximations.

Contract Pharma: What does the FDA’s policy shift mean for biotech R&D timelines and regulatory approval?

Wyatt McDonnell: By encouraging non-animal testing methodologies for biologics like monoclonal antibodies, the FDA is acknowledging what many in the field have observed: approaches centered on human biology may offer more predictive and efficient development paths. This initiative supports innovative platforms built around human-relevant data from the earliest stages.

For Infinimmune, it aligns with our foundational approach. Our antibodies originate from authentic human immune responses, and we refine them using AI that’s trained exclusively on human antibody data. This human-to-human pipeline may help de-risk programs earlier, potentially shortening development timelines. When you’re working with molecules already shaped by the human immune system and optimized through human-trained AI systems, you’re building on biology that’s already demonstrated functionality in its intended context.

Contract Pharma: What potential drug products would this impact?

Wyatt McDonnell: This shift could benefit numerous biologic modalities, with monoclonal antibodies and cell-based therapies likely seeing the most immediate impact, as these areas often face challenges with cross-species translation. We’re particularly optimistic about the implications for immunology and inflammation and oncology.

At Infinimmune, we focus on discovering antibodies with native human functionality—not just target binding but comprehensive effector potential and immune synergy. Our human-first discovery platform, enhanced by AI trained exclusively on human antibody data, allows us to consider challenging targets where animal data may not translate effectively. This approach eases the difficulty of lead selection and optimization because we’re refining what human biology has already initiated rather than engineering from scratch.

Contract Pharma: How is the industry moving toward more ethical, efficient, and scalable preclinical innovation?

Wyatt McDonnell: The industry is embracing platforms that combine biological relevance with throughput capabilities. Technologies like single-cell sequencing, advanced computation, and immune profiling are converging to make human-centered discovery both possible and scalable—precisely where Infinimmune operates.

We’ve developed our discovery engine, Anthrobody, to identify and functionally screen millions of naturally paired human antibodies simultaneously, directly from blood. Our process eliminates species translation challenges and library biases while providing a direct path from human biology to therapeutic candidates. This approach is further enhanced by our AI systems, which are trained exclusively on human antibody data by scientists who understand the nuances of human immunology. As regulators and industry partners continue to prioritize relevance and efficiency, human-first platforms that integrate technologies like these are positioned to establish new standards for therapeutic discovery.

Wyatt McDonnell, Ph.D., is CEO and co-founder of Infinimmune, an antibody discovery company using AI and single-cell immune profiling to develop human-derived antibodies. Their discovery engine is animal-free by design, enabling faster and more precise development of next-gen immunotherapies.