UK medicines regulator takes decisive step towards phasing out animal testing
The MHRA has announced new guidance and an advance data review scheme to give drug developers greater confidence in using non-animal methods, as part of the Government's long-term strategy to reduce and ultimately replace animals in research.
Britain's medicines regulator has set out new measures designed to accelerate the move away from animal testing in drug development, offering companies an early review of non-animal data and clearer principles on when animal studies are — and are not — required.
The Medicines and Healthcare products Regulatory Agency (MHRA) announced on 24 March that it will allow developers to submit key sections of their marketing authorisation applications in advance, giving a written opinion on whether the evidence generated without animal testing is adequate. The scheme, expected to be operational by the end of 2026, is intended to reduce uncertainty for researchers adopting so-called New Approach Methodologies (NAMs) — modern techniques such as AI-driven analysis and human-derived cell models that can, in some cases, demonstrate a medicine's safety and efficacy without recourse to animal studies.
Julian Beach, the MHRA's Interim Executive Director for 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."
New regulatory principles
The guidance sets out a series of general principles that will shape how applications are assessed, while stressing that each case will be considered individually on the totality of its evidence. Under the new framework, generic and biosimilar products, as well as drugs that are not pharmacologically active in animals, should not be tested on animals at all. Toxicity testing of biological products on animals should only take place in species shown to be pharmacologically relevant.
Products with a well-recognised pharmacological profile may now enter UK clinical trials without having first been tested on animals — a significant shift in regulatory expectations. However, the MHRA has made clear that products with a novel pharmacological action should continue to undergo animal testing in line with international guidelines, as should products whose efficacy cannot be tested in clinical trials, such as certain vaccines for emerging pandemic diseases.
How the advance review scheme will work
Under the new scheme, companies developing a product without animal testing will be able to submit Module 4 of their marketing authorisation application — the section covering non-clinical study reports — alongside the Investigator Brochure and the final report of at least one clinical trial. The MHRA will then provide a non-binding written opinion, either accepting the adequacy of the data or identifying deficiencies.
This opinion will subsequently be included in the full marketing authorisation application. The MHRA will then conduct a further review in consultation with the Commission on Human Medicines before reaching a final decision. Companies using the advance review will be charged a fee to cover administrative costs and to discourage unsuitable submissions.
The announcement follows the Government's publication in November 2025 of its strategy paper, Replacing animals in science, which outlined plans to support the development, validation and uptake of alternative methods. The MHRA emphasised that while complete elimination of animal testing is not yet feasible across all areas of drug development, advances in technology mean that some medicines no longer require animal studies to meet the rigorous standards demanded by regulators.