The Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 came into force on 28 April 2026.
The regulations apply across all 4 nations of the UK (England, Wales, Scotland and Northern Ireland).
All clinical trials of investigational medicinal products (CTIMPs) taking place in the UK are required to comply with the updated regulations.
We have developed guidance that outlines the following changes:
- definitions and terminology
- research transparency requirements for clinical trials
- the approvals process for clinical trials
- Research Ethics Committees that review clinical trials
- simplified arrangements for consent in clinical trials
- pharmacovigilance
This guidance sets out the changes to the REC and MHRA review process for CTIMPs in line with the new clinical trials regulations.
It does not detail any other review processes CTIMPs may need, such as HRA and Health and Care Research Wales (HCRW) Approval. This is because only the REC and MHRA review process for CTIMPs is within the remit of the clinical trials regulations and is directly impacted by the updated legislation.
There are some changes to how non-CTIMP applications are processed and managed based on the changes brought in by the updated regulations. This will help make sure there's better process alignment between CTIMPs and non-CTIMPs. Read our guidance on changes to non-CTIMP clinical trials and other research.
MHRA guidance
We also recommend you read the guidance produced by the Medicines and Healthcare products Regulatory Agency (MHRA) to help you understand the changes.
Good clinical practice (GCP) for clinical trials
The updates to the clinical trials regulations include changes to GCP and the conduct of clinical trials.
This includes a legislative requirement for CTIMPs to comply with the conditions and principles in the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use Guideline for Good Clinical Practice.
Most of these changes apply to all CTIMPs from 28 April 2026, regardless of whether they were submitted before or from this date. For further information, read the MHRA's transitional arrangements guidance.
The MHRA has produced guidance explaining the changes relating to GCP conduct for clinical trials.