UK's nonclinical roadmap: MHRA joins global regulatory shift toward NAMs with detailed goals and timelines
Introduction
The UK government recently issued a press release which outlines an ambitious strategy to accelerate the transition away from traditional animal testing toward New Approach Methodologies (NAMs).1,2 This strategy represents a significant evolution in regulatory thinking that could influence global approaches to drug safety and efficacy assessment.
The Medicines and Healthcare products Regulatory Agency (MHRA) is set to play a crucial role in the UK strategy. By outlining specific timelines, the UK, with the MHRA at its center, is moving beyond aspirational goals to actionable regulatory commitments, while providing clarity to the pharmaceutical industry on the path forward for implementing NAMs into their development programs.
Role of the MHRA in advancing NAMs
The MHRA will encourage the use of NAMs by developers of medicinal products; and ensure that NAMs are scientifically valid, reproducible and are predictive for humans. The MHRA will also ensure that its regulatory guidance aligns with advancements in this field. To achieve these aims, in collaboration with key stakeholders, the MHRA will undertake the following activities:
| MHRA focus area | MHRA key actions | Purpose and impact |
| Upskilling of regulatory assessors | Training of assessors on NAMs via existing programs, secondments with method developers/academia/industry, and tailored workshops. Department of Science & Technology (DSIT) has oversight for training information. | Ensure MHRA assessors remain at the forefront of NAMs innovation. |
| Development of digital tools | Collaboration with the UK's first Centre of Excellence on In silico Regulatory Science and Innovation (CEiRSI) to create AI-driven tools for in silico regulatory science. | Leveraging data from various sources can streamline drug development and reduce reliance on in vivo studies.3 |
| Acceleration of alternative methods validation | Actively engage with the planned new UK Centre for the Validation of Alternative Methods (UKCVAM), which will coordinate activities of regulatory bodies and other stakeholders that are developing NAMs and/or validating the methods. Biennial publication of accepted methods and priorities for future NAMs development and validation. |
To increase the coordination of validation efforts at the national level, establish dedicated laboratory capacity for validation testing within the UK, and shorten the validation process. |
| Industry engagement | Establish pathways for early MHRA-company dialogue. Publish case studies and meeting metrics annually. |
Build developers’ confidence in NAMs and their regulatory acceptance. Assess impact on approval timelines. |
| Collaboration with NC3Rs | Continue collaboration with UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs). Annual reporting (from 2026) on impact of the NC3Rs 2 species project on clinical trial submissions containing data from a second species across differing modalities. |
Increase visibility and reduce animal use in toxicity testing. |
| Global Regulatory Influence | By 2026, issue new MHRA guideline endorsing non-animal data in support of a First-Time-in-Human study, when a pharmacologically relevant species has not been identified. By 2026, join the International Medicines Regulators’ Working Group on 3Rs.4 Continue active role in ICH and OECD committees responsible for internationally agreed standards for nonclinical testing. |
Engage with multiple regulatory bodies to drive international alignment and acceptance of NAMs. |
Table 1. MHRA strategic initiatives to advance NAMs
UK timeline for targeted replacement of in vivo studies
The UK government, along with the MHRA and other UK regulatory bodies, have identified an initial list of animal tests or methods which can be progressively phased out. Some of the animal studies targeted for replacement over the next 5 years are outlined below:
| Timeline | Animal test/method | Replacement approach | Notes |
| By 2025 | Rabbit pyrogen test | Validated in vitro Monocyte Activation Test (MAT) | MAT detects endotoxin & non-endotoxin pyrogens for pharmacopoeial testing |
| By 2026 | In vivo irritation & sensitization tests (skin: rabbit; sensitization: mouse/guinea pig; eye: rabbit) | Validated in vitro methods [e.g., as per Organisation for Economic Co-operation and Development (OECD) guidelines] | Applies to skin irritation, skin sensitization, and eye irritation |
| By 2027 | Botulinum toxin batch testing (mice) | Fully validated in vitro potency assays | MHRA already accepts alternative methods for certain botulinum toxin type A strengths |
| By 2027 | Adventitious agent tests (in vivo) | Validated DNA-based methods | To detect the presence of viruses or bacteria and prevent accidental product contamination |
| By 2030 | PK studies using dogs & non-human primates | Computational & AI models | Goal to reduce in vivo animal studies by ≥35% |
| By 2030 | Cardiovascular safety studies using dogs & non-human primates | hERG assay + other in vitro assays | Reduce use by ≥50% |
| By 2030 | Animal-derived polyclonal antibodies | Validated non-animal alternatives | Full replacement targeted |
Table 2. UK plan to phase out select animal tests (2025–2030)
Preparing for transition to NAMs
Although it will take several years to significantly phase out use of animal studies in drug development, the objectives set out in the UK strategy encourage pharmaceutical companies to take proactive and collaborative steps in preparation for this shift.
Immediate actions drug developers can take include:
Conduct a comprehensive audit of your current nonclinical development plan to identify areas where NAMs could be implemented in lieu of or in addition to in vivo studies, and whether such changes align with the UK timelines for phasing out of animal testing.1,2
Gain expertise in the types, development and validation of NAMs; or collaborate with experts in CROs and/or academic institutions.
Engage early with the MHRA to understand qualification of a NAM for a given context of use, the agreed routes for method validation via the UKCAM or other organization, and the Scientific Advice procedures to gain MHRA feedback for NAMs during product development.
In the longer term, as the MHRA and other regulators formally transition to specific NAMs, drug developers may need to develop a transition plan for their nonclinical programs that aligns with the UK/MHRA timeline for phasing out specific animal tests and accommodates the differing rates of NAMs adoption across global authorities.
Conclusion
The UK strategy for replacing animal studies with alternative methods is a bold advancement in drug development that is anticipated to provide better predictive value for drug safety and efficacy, while reducing animal testing. The UK strategy and MHRA initiatives represent both a challenge and an opportunity for pharmaceutical companies. Early engagement and collaboration with regulators will be crucial for success. Companies that seek regulators’ advice early on how to integrate NAMs into their development programs will be better positioned to navigate the evolving global requirements.5,6,7,8,9,10
For drug developers that are considering designing their nonclinical programs within the UK timeline, Parexel's regulatory experts offer valuable support. Our team, which includes former FDA, UK and EMA nonclinical assessors, has extensive experience in nonclinical development and a deep understanding of the progressive policies of regulatory agencies.
Would you like to discuss how your organization can prepare for upcoming changes or explore specific NAMs that might be relevant to your development programs? We are always ready for a conversation.
References
- Press release: Animal testing to be phased out faster as UK unveils roadmap for alternative methods, November 2025
- Policy paper: Replacing animals in science: A strategy to support the development, validation and uptake of alternative methods, November 2025
- Medicines & Healthcare products Regulatory Agency. Impact of AI on the regulation of medical products - Implementing the AI White Paper principles, April 2024
- EMA, EMA/27380/2024: Terms of Reference (ToR) for the International Medicines Regulators’ Working Group on 3Rs, October 2024
- FDA, FDA Announces Plan to Phase Out Animal Testing Requirement for Monoclonal Antibodies and Other Drugs, April 2025
- FDA, FDA Releases Draft Guidance on Reducing Testing on Non-Human Primates for Monoclonal Antibodies, December 2025
- FDA, Guidance for Industry: Monoclonal Antibodies: Streamlined Nonclinical Safety Studies, December 2025
- EMA, Reflection paper on the current regulatory testing requirements for medicinal products for human use and opportunities for implementation of the 3Rs, December 2024
- EMA, Reflection paper on non-human primates in safety testing of human medicinal products and opportunities for 3Rs implementation, October 2025
- EMA, The European medicines agencies network strategy 2028, March 2025
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