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The UK’s medicines regulator is backing developers using non‑animal methods, offering early data reviews to help phase out animal testing while keeping medicines safe and effective
The Medicines and Healthcare products Regulatory Agency (MHRA) is taking major steps to accelerate the phasing out of animal testing in drug development and research. With early regulatory reviews and clearer guidance for New Approach Methodologies (NAMs), the agency aims to help developers adopt human-relevant methods while keeping medicines safe and effective, reinforcing the UK government’s commitment to innovative, ethical alternatives.
New regulatory principles for animal testing
As part of the Government’s long-term strategy to reduce the use of animals in drug development, whilst ensuring medicines continue to meet rigorous standards of safety and efficacy.
Each medical application is assessed individually, taking into account the totality of the evidence presented and the proposed clinical use. The guidance sets out general regulatory principles:
Generic/biosimilar products or drugs that are not pharmacologically active in animals should not be tested on animals.
Toxicity testing of biological products in animals should be conducted only in species shown to be pharmacologically relevant.
Products with a well-recognised pharmacological profile may enter UK clinical trials without prior animal testing.
Products with a novel pharmacological action should be tested on animals, in line with international guidelines.
Products that cannot be tested for efficacy in clinical trials, such as vaccines for some emerging pandemic infectious diseases, should be tested on animals.
Julian Beach, Interim Executive Director, Healthcare Quality and Access, said: “A clearer regulatory route for medicines developed without animal testing will help accelerate the transition to modern, predictive science and support the Government’s strategy to reduce and ultimately replace animals in research.
Advances such as AI‑driven analysis and human‑derived cell models mean some medicines no longer require animal studies to demonstrate safety and efficacy.
Our early review of study data, prior to a full marketing application, is designed to assist researchers adopting these approaches in building robust evidence for safety and efficacy.”
Early regulatory review for NAMs
To support the use of New Approach Methodologies (NAMs) and to reduce the perceived risks associated with approaches that do not involve animal testing, the MHRA has committed to reviewing preliminary data from drug trials using non-animal models. By the end of 2026, companies with a product developed without animal testing can have Module 4 of their Marketing Authorisation application reviewed by the MHRA in advance.
NAMs are modern, non-animal scientific methods that assess the safety and efficacy of medicines using human-relevant systems and computational tools, instead of traditional animal studies.
Companies can submit key regulatory documents, including Module 4, the Investigator Brochure and at least one clinical trial report, to the MHRA for an early review. The agency will provide a non-binding opinion on whether the data is sufficient or highlight any gaps. This feedback can then be included in the final Marketing Authorisation application. The MHRA, working with the Commission on Human Medicines, will later carry out a full review and decide whether to approve or reject the application. A fee will apply for early submissions to cover administrative costs and prevent unsuitable applications.