On Clinical Trials Day – May 20 2025
May 20th every year marks Clinical Trials Day, to recognise the day in 1747 when James Lind, a ship’s surgeon in the British Royal Navy initiated what is considered to be one of the first ever clinical trials to study the effects of different treatments on scurvy (vitamin C deficiency) using control groups. Lind made the connection between the benefits of citrus fruits and reduction of scurvy after carrying out a clinical trial in 12 people, only two of whom received the citrus fruits. The principle of using human-relevant data to predict and treat human disease is represented in the pioneering work performed by Lind.
Almost 280 years on, where are we now? More human clinical data is generated than ever before. Equally, there is an ever-growing array of cutting-edge technologies to harness it. Yet such data is still not being captured, shared, and used to full effect. Consequently, over 90% of new medications fail somewhere along the clinical trial pipeline, after being approved for testing in humans following preclinical testing in animals. Some human-relevant tests are also employed but the decision to proceed to human clinical trials is mainly based on animal tests, despite their inadequacies in predicting human responses and a lack of ‘bench to bedside’ relevance in translating the results to humans. Some diseases are considered extremely difficult to ‘model’ in animals, for example cancer therapies developed with traditional preclinical rodent models have a 94% failure rate in generating therapeutic benefit in human clinical patients.
Clearly, the focus of preclinical research should be human, taking advantage of the dazzling capabilities now available. Extrapolating from species other than humans is no longer necessary or desirable. Fortunately, progress is underway in some regions as the need for change in biomedical research is increasingly recognised. For example, the FDA recently announced its potentially groundbreaking roadmap to phase out animal testing, initially focused on monoclonal antibody drugs but with the aim of extending to other drugs too. The FDA states that ‘This transition will enhance public health by streamlining drug development and ensuring safer therapies reach patients faster, while positioning FDA as a global leader in modern regulatory science and innovation.’
Collaboration also continues on the EU Roadmap for phasing out animal testing in chemical safety assessments which is due to be published in early 2026.
The UK remains heavily wedded to the use of animals as ‘essential’ and is yet to publish any roadmap or strategy to phase out their use in favour of more modern, fit for purpose science, although the UK Department of Science Innovation and Technology (DSIT) has recently stated that ‘DSIT, Home Office and DEFRA ministers have agreed to publish an alternative methods strategy to support the development, validation and uptake of alternative methods and the phasing out of animal testing. We expect to publish this strategy later this year.’
Such a strategy is long overdue to enable transition towards new approach methodologies which outperform animal tests in relevance, accuracy, speed and cost. Published summaries of UK animal research projects reveal the ongoing repeated use of ‘well established’ animal models, whilst lamenting the unmet needs of patients because so many diseases remain ‘poorly understood’. The irony is that our continued study of other species is one of the main reasons for our ongoing ignorance of human biology.
The UK is rolling out new regulations to accelerate clinical trial approvals and encourage innovation. However, accelerating access to new medicines is not necessarily in the best interests of patients and would appear to be driven by the potential for commercial gains. See our evaluation of the Early Access to Medicines Scheme (EAMS). Furthermore, there is no mention of initiating clinical trials on the basis of human relevant information, rather than animal data, so the translational gap from animals to humans will remain, unless meaningful action is taken.
The UK Government must keep pace with global activities to phase out animal use and phase in more advanced, scientifically relevant research to improve human health and safety. Clinical trials must be based on a firm scientific foundation of human-relevant data, so that participants in clinical trials are no longer used as guinea pigs; being the first to test experimental new medicines based on assurances of safety in animals that we now know cannot be trusted.
It is time to heed the thousand-year old warning of the Persian physician Ibn Sina; to avoid using animals to develop medicines for humans, as quoted in this fascinating paper in The James Lind Library.
