The staggering reality of drug development is that over 90% of promising treatments fail once they reach human trials, resulting in immense financial losses, delays, and a lack of options for patients. This inefficiency has long been accepted, but a paradigm shift is underway. The future of drug development is here, and it's all about human data trials.
With cutting-edge technologies, researchers are now able to test drugs directly on human biological systems, offering a more accurate, efficient, and ethical approach. But here's where it gets controversial: animal testing, once the cornerstone of drug development, is being challenged.
Animal models have their limitations. Even small variations in how different species process drugs can lead to drastically different outcomes. Recent examples highlight this: Vupanorsen, a potential treatment for cardiovascular disease, appeared safe in animal studies but caused liver issues in humans; Ziritaxestat, for pulmonary fibrosis, showed no toxicity in animals but led to excess deaths in human trials. These cases aren't anomalies; they highlight a persistent gap between preclinical and clinical safety assessments.
Analyses reveal that up to half of drug failures are due to a lack of efficacy in humans, with around 30% attributed to toxicity. Species differences and the inability of animal models to capture the complexity of human disease are at the heart of these issues.
Animal studies will still have a role, particularly for understanding immune responses and behavioural outcomes. However, areas like liver toxicity, pharmacokinetics, and oncology are likely to move away from animal reliance first. The FDA's recent announcement to phase out animal testing for monoclonal antibodies is a significant step forward.
One promising alternative is the use of donated human organs that can't be transplanted. Advances in organ perfusion technology allow researchers to maintain these organs in a living state, creating a platform for testing drug candidates and collecting high-resolution data. Perfused human organs offer physiological responses that are likely to be much closer to those of patients, capturing subtle metabolic and toxicological pathways that animal models miss.
The assumption that research organs are too damaged is often incorrect. Many are declined for transplantation due to factors like donor age, but these organs can provide valuable insights, especially when they reflect common patient conditions. This approach ensures that research reflects the diversity of real patient populations and honors the wishes of donors who want to contribute.
When a donated organ is not suitable for transplantation, it can be used for research with full consent. The organ is prepared and connected to a perfusion machine, keeping it 'alive' with a blood-like fluid. Researchers can then administer drug candidates and monitor responses in real-time, mimicking human physiology with a level of control not possible in living patients.
Ethical safeguards are crucial, with data de-identified to protect confidentiality. The goal is equity, ensuring that the therapies developed benefit everyone. This approach also respects the altruistic wishes of donors and their families.
As with living patients, there are variations between organs, which can initially be challenging to interpret. However, these differences mirror the heterogeneity seen in patients, offering a unique opportunity to understand individual patient biology and treatment responses.
Regulators and industry are embracing this shift. The FDA is phasing out certain animal testing requirements, and Congress has passed the FDA Modernization Act 3.0 to accelerate this transition. The National Institutes of Health is also prioritizing human-based research technologies.
For pharmaceutical companies, integrating human organ data with other streams can provide a more complete understanding of human biology before costly First in Human Trials. This approach doesn't exclude animal data but positions it as one part of a broader, human-centric strategy.
For patients, this means more therapies reaching the market faster, with fewer failed trials. Every averted failure represents not just financial savings but years of potential suffering avoided.
The future of drug development is a convergence of technologies. Perfused human organs, organs-on-chips, 3D bioprinting, and multi-omics data streams, integrated by artificial intelligence, promise to reveal insights into human physiology that were previously inaccessible. For this vision to become standard practice, reproducibility, reliability, and clear advantages over traditional models must be demonstrated through rigorous validation studies. Regulators must also provide transparent pathways for qualification and acceptance.
Looking ahead, animal models will likely continue in a reduced role, used selectively for their specific strengths. Human-relevant technologies are expected to become the foundation of development pipelines. This integrated approach promises to accelerate timelines, improve translational accuracy, and ultimately deliver safer, more effective therapies.
The 90% failure rate in drug development is not an inevitability; it's a call to action. Human organ testing, alongside complementary technologies, offers a way to align drug development more closely with human biology. The shift is happening, supported by regulators, driven by scientific advances, and demanded by patients. What was once unthinkable is now the path forward, and the prospect of safer, faster, and more effective therapies is within reach.
This article was written by members of Revalia Bio's leadership team, who are at the forefront of human data trials, a new category of pre-clinical research that provides drug developers with early, predictive insights from real, functional human organs.
