Medicines: clinical trials hub
Legal framework, regulatory requirements, and supporting guidance needed to design, apply for, conduct, modify, close, and comply with UK legislation for clinical trials for medicines in the UK.
UK Legislation
The Medicines for Human Use (Clinical Trials)(Amendment) Regulations 2025 came into force 28 April 2026.
The Medicines for Human Use (Clinical Trials)Regulations 2004
The Medicines for Human Use (Clinical Trials)(Amendment) Regulations 2025
The Human Medicines Regulations 2012
Regulatory Framework
Important Note: This guidance is designed to assist sponsors and investigators in complying with their duties in relation to clinical trials. This page includes links to pages containing general guidance only. It must not be regarded as a definitive interpretation of the Regulations or a substitute for the regulations.
The MHRA cannot provide a definitive interpretation of the law; only the courts can do this. If in doubt you should seek your own legal advice.
International guidance
Other relevant guidance
MHRA guidance
The amended Clinical Trials Regulations took full effect on 28 April 2026. As such, this guidance should now be considered effective and is no longer in draft.
Applying for clinical trial approval
IMPs & NIMPs
During the clinical trial
Making changes to trials
Ending a trial
Compliance
News and blogs
Payments and fees
Payments for DSUR submissions by credit or debit cards can be made via our payment centre.
Archived guidance
Access previous versions of MHRA Guidance from the UK Government Web Archive
Guidance - before 28 April 2026
Clinical Trials guidance that should be followed prior to 28 April 2026.
Updates to this page
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This page has been updated to streamline and clarify information in light of recent changes to clinical trials legislation. Content has been reorganised, references updated, and links improved to direct users to current online guidance.
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Notification published of system updates and downtime, in preparation for the transition to the new Clinical Trials Regulations that are mandated on 28 April 2026.
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Added 'Clinical trials for medicines: guidance on quality and risk proportionality' and 'Clinical trials for medicines: guidance on compliance with ICH E6 good clinical practice (GCP) in the United Kingdom'.
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Added guidance document 'Clinical trials for medicines: good manufacturing practice and radiopharmaceutical investigational medicinal products'.
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Added 'International Council for Harmonisation (ICH) E6R3 Annotations'
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Added the following guidance pages to the collection: - Declaration of Helsinki and Clinical Trial Regulations alignment - Clinical Trials Regulations enforcement provisions - Archiving and retention of clinical trial records
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Added 'Common issues identified during clinical trial applications' to the group 'Guidance - before 28 April 2026'.
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Added link to payment DSU Payment centre to Pay an fees section of the collection.
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Added new page to collection: Route B substantial modification pilot
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Links added for draft guidance, to support amendments that come into force 28 April 2026.
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First published.