Last updated: 16 April 2026
Below is an attempt to provide information on the new clinical trials regulations. The information is by no means complete or exhaustive. Please use this post as a starting point and take the time to read all of the guidances and other information published on the MHRA website.
Click on the ‘+’ sign to access each section below.
| Date | Update(s) |
|---|---|
| 16 April 2026 | Table in the section Is there new guidance published in addition to the new clinical trials regulations? updated substantially. |
| 15 April 2026 | in the section Is there new guidance published in addition to the new clinical trials regulations?, updates were were added to the following two guidances: i) Declaration of Helsinki and Clinical Trial Regulations alignment ii) Archiving and retention of clinical trial records |
| 28 Mar 2026 | i) In the section Webinars, a link is provided to the MHRA/HRA webinar of 12 March 2026 entitled Clinical trials regulations: Countdown to implementation. ii) In the section Further reading, the following new links are provided: i) To the Health Research Authority (HRA) website page entitled Clinical Trials regulations reform ii) To an HRA post on LinkedIn |
| 27 March 2026 | In the section Is there new guidance published in addition to the new clinical trials regulations? updates were added to to the following two draft guidances: i) Archiving and retention of clinical trial records ii) Clinical trials for medicines: good manufacturing practice and radiopharmaceutical investigational medicinal products A link to the new draft guidance Clinical trials for medicines: guidance on quality and risk proportionality was also added. |
| 13 Mar 2026 | New section New and updated definitions added. |
| 9 Mar 2026 | The following changes were made to the table in the section Is there new guidance published in addition to the new clinical trials regulations? i) Clinical trials for medicines: labelling – Updated date of latest changes. ii) Added link to new draft guidance Clinical trials for medicines: good manufacturing practice and radiopharmaceutical investigational medicinal products iii) Added updates to a) Guidance: UK-specific annotations to ICH E6(R3) b) Guidance: UK-specific annotations to ICH E8 |
| 17 Feb 2026 | The section Is there new guidance published in addition to the new clinical trials regulations? was updated as follows: The following two guidances were updated on 17 Feb 2026: i) Clinical trials regulations: transitional arrangements ii) Clinical trials for medicines: modifying a clinical trial approval The table includes details on the update. |
| 23 January 2026 | In the section Further reading, Items no 4 and 5 were added. |
| 12 January 2026 | Table in the section Is there new guidance published in addition to the new clinical trials regulations? was updated to confirm that the latest update to guidance was on 12 January 2026. Click on each guidance link to see details of the update. Links to the following four new guidances were added. i) Declaration of Helsinki and Clinical Trial Regulations alignment ii) Clinical Trials Regulations enforcement provisions iii) Archiving and retention of clinical trial records iv) International Council for Harmonisation (ICH) E6R3 Annotations |
| 4 Oct 2025 | Post updated and laid out in accordian style for ease of reading. New section Quiz added. |
| 2 Oct 2025 | Table updated further to add information and improve readability. Added new section Types of modification to a clinical trial approval and sub sections. |
| 1 Oct 2025 | Table updated to i) add new column titled Information on latest draft guidance update ii) Add new row with link to guidance on Clinical trials that include an in vitro diagnostic device. |
| 27 Aug 2025 | The following new sections were added: i) Changes to notification of Type A trials ii) Risk proportionate support for reviewing Route B substantial modifications |
| 20 Aug 2025 | New section Route B substantial modification pilot added. |
| 18 Aug 2025 | In the section Clinical trials for medicines: modifying a clinical trial approval, added information on the types of amendments including on Route B which was posted on the MHRA website today. |
| 25 June 2025 | The following two sections were added: i) Guidances published thus far ii) Transitional arrangements. |
| 26 May 2025 | Item no 3 added to the section Further Reading. |
| 1 May 2025 | New link to an article titled Clinical trial reform gets underway added to the section Further Reading. |
| 28 Apr 2025 | The following new sections were added: 1) What reforms proposed in the draft legislation have full implemented been implemented in the final approved regulations? 2) What key elements have also been confirmed in the final approved regulations? A new reference No 7 Reforms to UK clinical trials framework passed into law was added. |
| 25 Apr 2025 | New section Further reading added. |
| 14 Apr 2025 | Post updated substantially. |
| 28 Mar 2025 | Section Webinars updated to add a link to the MHRA webinar of 25 Feb 2025 entitled Guidance accompanying the new clinical trials plus a summary of the webinar. |
| 17 Jan 2025 | 1) Table added to the section Will there also be new guidance published in addition to the new clinical trials legislation? 2) New section When is it anticipated the the new regulation will come into force? added. 3) New reference no 3 added to the References section |
| 19 Dec 2024 | New section References added. |
| 13 Nov 2024 | Added new section Webinar. |
The reforms were developed through a series of stakeholder workshops, seeking the views of a wide range of organisations and individuals from across the clinical research sector, including patient representatives.
A public consultation took place in January to March 2022, to which over 2,000 responses were received, and the Government response was published in March 2023.
The New clinical trials draft legislation (Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2024) was laid in Parliament on 12 December 2024 to:
- address the research sector’s need for a more efficient, streamlined and adaptable regulatory framework for clinical trials.
- make the UK a more attractive place for innovators to conduct important research and to help to get potentially life-changing new treatments to patients and the NHS as quickly as possible.
Here is a link to the statement made in parliament by Baroness Merron on 12 Dec 2024 concerning laying of the Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2024 before Parliament.
The New UK clinical trials regulations (The Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025) were signed into law on 11 April 2025.
A 12-month roll-out began on 11 April 2025 to deliver the most significant update to UK clinical trials regulation in two decades – with the aim of:1
- strengthening patient safety,
- accelerating approvals,
- enabling innovation and
- helping more people benefit from taking part in vital research.1
The new legislation will take full effect from 10 April 2026 following a 12-month implementation period to ensure readiness, aims to reduce unnecessary administrative burdens on trial sponsors without compromising patient safety.
The reforms will1:
- Put patients and their safety are at the focus of all clinical trials and bring the benefits of clinical trials to everyone.
- Cut duplication and unnecessary delays, while maintaining robust oversight of the safety of trials.
- Create a proportionate and flexible regulatory environment, reducing bureaucracy for lower-risk trials.
- Cement the UK as a destination for international trials.
- Provide a framework that is streamlined, agile and responsive to innovation.
By reducing red tape and simplifying approvals, the new framework supports the Prime Minister’s target to reduce the time from application to first participant from 250 to 150 days. It will speed up research and reduce the time it takes for promising treatments to reach patients, without compromising on safety.1
The Combined Review – a system that lets researchers apply for ethics and regulatory approval in one go – and notification scheme for some clinical trial initial applications and amendments will now be written into law as part of the changes.1
The key reforms to UK CTR proposed in the December 2024 draft legislation have been fully implemented in the final version of the amendment regulations and include:7
- Risk-proportionate Regulation:
- Regulatory requirements now align with the risk level of clinical trials.
- Low-risk trials can receive faster approval through automatic authorisation without comprising patient safety.7
- Streamlined Approval Process:
- A combined review process integrates regulatory and ethics committee approvals, leading to a single UK decision for decision for clinical trials.
- This aims to reduce duplication and unnecessary delays while maintaining robust oversight of trial safety.7
- Enhanced Transparency Requirements:
- New legal obligations mandate the registration of clinical trials in public registry and the publication of trial results within 12 months of the trail’s conclusion.
- This initiative aims to build public trust in research by improving access to information about ongoing studies.7
The following key elements have also been confirmed in the final amendment regulations:7
- Notification Scheme for Low-Risk Trials:
- A notification scheme has been introduced for lower-risk clinical trials, enabling sponsors to notify the MHRA about eligible trials where the risk to participant is similar to standard medical care.
- This streamlined process facilitates faster initiation of these trials without compromising safety.7
- Extended Archiving Period:
- The regulations now require the archiving of trial master files for 25 years, an extension from the previous 5-year requirement.
- This change ensures long-term accessibility to trial data for future reference and analysis.7
- Sunset Period for Trials Approvals:
- Clinical trial approvals will now lapse after a proposed sunset period of two years if no participants have been enrolled.
- This measure encourages timely initiation of trials and optimises resources allocation.7
On this page from the Health Research Authority, you will find further useful information on the key changes in the legislation.
| Currently used term(s) | New term(s) or definitions as per the new regulations | Notes |
|---|---|---|
| Amendment | Modification From 28 April 2026, modifications will be categorised as: i) ‘substantial modifications’, ii) ‘modification of an important detail’ or iii) ‘minor modifications’. | The term ‘modification’ is already used by the EU countries to describe changes to clinical trials of investigational medicinal products (CTIMPs). This change will make sure there is better alignment between the UK and the international research community. |
| Non-investigational medicinal product Notifiable trial and Public registry. | The new regulations introduce these new definitions | |
| Authorised health care professional | Healthcare professional | The new regulations say that chief investigators and investigators should be a health care professional as defined in the amended legislation. |
| Subject | Participant | Terminology update in line with the new regulations |
| Trial site | Trial location | Terminology update in line with the new regulations |
Yes, alongside the regulations, the MHRA and HRA has published guidance to embed meaningful public involvement in clinical trials and increase the diversity of people taking part in research trials. This will ensure that research findings can improve everyone’s care, helping address health inequalities.
Draft Guidances published so far
The draft guidances in the table below accompany the Medicines for Human Use (Clinical Trials) Regulations 2004 (“the Clinical Trials Regulations”), as amended by The Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025.
Source: Collection – Medicines: clinical trials hub
| Draft Guidance Title | Information on latest draft guidance update (click on guidance link to view all changes) | What the guidance is about | When the amendment comes into force | Guidance to be followed prior to 28 April 2026 |
|---|---|---|---|---|
| Clinical trials regulations: transitional arrangements | Last updated on 17 February 2026 Clarified timelines for submitting notification of intent to follow old pharmacovigilance rules. Clarified that labelling updates to comply with the new regulations must be approved by the MHRA if they are substantial. Added guidance on post-QP certification labelling on or after 28 April 2026. | Guidance on transitional arrangements for the Clinical Trials Regulations | 28 April 2026 Until this date, this guidance is in draft and should only be used to support sponsors in preparing for the implementation of the new regulations | Please see Clinical trials for medicines: apply for authorisation in the UK and Clinical trials for medicines: manage your authorisation, report safety issues for the guidance that should be followed prior to 28 April 2026. |
Clinical trials for medicines: apply for approval in the UK | Last updated on 9 March 2026 Updated link to guidance for IMP+device trials. | How to apply for a clinical trial from 28 April 2026, including eligibility, documentation and registration in a public registry. | As above | As above |
| Clinical trials that include an in vitro diagnostic device | Last updated on 9 March 2026 Updated wording to align with current guidance on clinical trials that include an IVD. | Guidance on submitting an application for approval of a clinical trial that includes an in vitro diagnostic device | As above | As Above |
| Clinical trials for medicines: expert advice | Last updated on 9 March 2026 Updated figure to clarify that standard RFI timelines apply where the amended application does not require further expert advice. | Clinical trial applications that need expert advice from a specialist group or committee. | As above | As above |
| Clinical trials for medicines: labelling | Last update on 9 March 2026. This is a comprehensive update. You can view all of the changes at the link provided. | Guidance on labelling for medicinal products used in clinical trials | As above | As above |
| Clinical trials for medicines: notifiable trials | Last updated on 12 January 2026. Updated publication ‘Additional criteria for notifiable trials’ to include an introductory sentence. | Guidance on clinical trials that are categorised as ‘notifiable’. To enable a streamlined, risk-proportionate approach to its review of applications, the licensing authority is categorising certain clinical trials as ‘notifiable’. Applications to approve these trials will receive automatic authorisation from the licensing authority. | As above | As above |
Clinical trials for medicines: modifying a clinical trial approval | Last updated on 9 March 2026 Updated substantial modification notification form | Guidance on the various types of modifications that can be made to a clinical trial approval. Further details provided below, after this table. | As above | As above |
| Clinical trials: Non-investigational medicinal products | Last updated on 9 March 2026. Clarified that non-medicinal products should be labelled in the same way as unlicensed NIMPs. Added guidance on determining whether a product is an NIMP or a non-medicinal product. Clarified requirements for including information about non-medicinal products in the clinical trial application. Included additional guidance on providing evidence that NIMPs were manufactured according to GMP principles. Included guidance on providing evidence that non-medicinal products were manufactured according applicable safety standards. Clarified labelling expectations for non-medicinal products | Guidance on using non-investigational medicinal products in a clinical trial. | As above | As above |
Clinical trials for medicines: ending a clinical trial | Last updated on 12 January 2026. Added text stating that all sponsors will need to notify the authorities of the date on which the first participant was recruited through a MOID. | Guidance on the process for ending a clinical trial. | As above | As above |
| Clinical trials for medicines: collection, verification, & reporting of safety events | Last update on 12 January 2026. Added guidance on determining suitability of section 4.8 of the SmPC for use as RSI. | Guidance on the collection, verification, and reporting of safety events in clinical trials of an investigational medicinal product. | As above | As above |
| Declaration of Helsinki and Clinical Trial Regulations alignment | Guidance last updated on 14 April 2026 Updated in response to stakeholder feedback to remove reference to specific versions of declaration of Helsinki in section Use of placebo or no intervention. | Information on the alignment of the amended UK clinical trial legislation with the Declaration of Helsinki, prioritising UK law where conflicts arise. | As above | As above |
Clinical Trials Regulations enforcement provisions | Last updated on 19 March 2026 Updated to remove link to feedback questionnaire as it is now over. | Information about Clinical Trials Regulations outlining expanded enforcement provisions, offences, and compliance requirements for sponsors and investigators. | As above | As above |
| Archiving and retention of clinical trial records | Guidance last updated on 14 April 2026 Changes were made for clarity and readability based on stakeholder feedback, and terminology between guidance and legislation was aligned. | Information on clinical trial record retention and archiving requirements including requirements for ownership, data integrity, and transitional provisions. | As above | As above |
International Council for Harmonisation (ICH) E6R3 Annotations | Last updated on 9 March 2026. On the document ‘UK-specific annotations to ICH E6(R3)’: added reference to ICH E8. Added annotation to Annex 1 2.6.4; updated annotation to Annex 1 2.13 and Annex 3.17.2 (c)(iii) to include reference to HRA guidance on research transparency; updated annotation to Annex 3.17.2 (c)(ii) to clarify that action should be taken in accordance with the protocol. Added document ‘UK-specific annotations to ICH E8’. | Information to help comply with ICH E6(R3), if you are running clinical trials in the UK. | As above | As above |
| Clinical trials for medicines: good manufacturing practice and radiopharmaceutical investigational medicinal products | Guidance last updated on 26 March 2026. CTA at the top of the page removed as now expired | Guidance on good manufacturing practice and the use of radiopharmaceutical investigational medicinal products in clinical trials. | As above | As above |
UK-specific annotations to ICH E8 | Guidance last updated on 9 March 2026 ICH E8) is an international guideline that provides an overall introduction to clinical development, designing quality into clinical studies and focusing on those factors critical to the quality of the studies. | |||
| Clinical trials for medicines: guidance on quality and risk proportionality | Last updated on 16 April 2026. Updated to remove questionnaire feedback panel as it has now expired. | This guidance should be read in conjunction with ICH E8 (R1) General Considerations for Clinical Studies. ICH E8 (R1) establishes the overarching scientific and quality principles for clinical study design and conduct, including the application of quality by design approaches. | As above | As above |
| Clinical trials for medicines: guidance on compliance with ICH E6 good clinical practice (GCP) in the United Kingdom | Last updated on 16 April 2026. Updated to remove questionnaire feedback panel as it has now expired. | Information on how ICH E6(R3) good clinical practice (GCP) principles are implemented and enforced in UK clinical trial legislation. |
As per regulation 20 of the Clinical Trials Regulations, a clinical trial approval may be modified by:
- the trial’s sponsor,
- the licensing authority, or the ethics committee.
Source: MHRA
What are the categories of modifications to a clinical trials authorisation approval
Modifications to a clinical trial approval can be categorised into:
Substantial modifications categorised as Route A or Route B
i) Route A substantial modifications
- These are likely to have a substantial impact on the safety or rights of the participants or on the reliability or robustness of the data generated in the trial
- Approval to make substantial modifications must be received from the licensing authority and ethics committee before implementation.
- The exception to this is for substantial modifications that relate to urgent safety measures.
- When considering implementing substantial modifications, sponsors should assess whether such modifications alter the original clinical trial approval to the extent that it should be considered a new clinical trial.
- If this is the case, a new application for clinical trial approval should be submitted.
ii) Route B substantial modifications
- These are defined in regulation 11B of the Clinical Trial Regulations and the examples section of this guidance.
- Note that the ethics committee does not provide automatic approval for Route B substantial modifications
Modifications of an important detail
- These do not significantly impact the safety or rights of the participants but the authorities need to be aware of them for administrative or oversight purposes.
- Instructions for notifying the authorities about a modification of an important detail are provided on completion of the modification tool.
Minor modifications
- These may be implemented at any time and without informing the licensing authority or ethics committee at the point of implementation (however, other approvals may be required, which can be determined using the modification tool).
- The sponsor must keep records of any modifications implemented and, if requested, make them available to the licensing authority or ethics committee.
Source: MHRA
It is the sponsor’s responsibility to determine the modification type, using a risk-based approach, whether a modification is substantial, minor or a modification of an important detail.
Source: MHRA
The MHRA is also expanding its current risk proportionate approach to include the review of modifications to approved clinical trial applications.
- Once implemented under the new regulations, substantial modifications which meet pre-defined criteria will be eligible for automatic approval from the MHRA through the Route B substantial modification process.
- This process will need to be followed by everyone submitting an eligible modification to a clinical trial.
- Draft guidance supporting the Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 is available in this post and in more detail on the Clinical Trials Hub.
- The section on modifying a clinical trial covers the Route B substantial modifications criteria.
Source: MHRA
To ensure a smooth transition into the new Clinical Trials Regulations, the MHRA will be testing the Route B substantial modification process over the coming months and invite you to get involved.
The MHRA is opening a pilot for Route B substantial modifications from 1 October 2025 until 31 March 2026, and encourages you to sign up to take part. More information is available on this MHRA page.
By joining the pilot, you will gain early insight into how the new process works and help the MHRA shape it, so it’s ready to support the new regulations from 28 April 2026.
Click on this link for information on the transitional arrangements concerning the topics listed below or for a summary of the arrangements, click here.
Transitional arrangements for:
- applying for clinical trial approval
- transparency regulations
- approval for modifications
- Good Clinical Practice
- pharmacovigilance
- manufacture and importation of investigational medicinal products
- labelling of investigational medicinal products
- enforcement
Source: MHRA
Webinars
- Here is a link to the MHRA webinar of 15 October 2024 entitled Implementing the new UK Clinical Trials Regulations and a link to a blog post on the webinar.
- Here is a link to the MHRA webinar of 25 February 2025 entitled Guidance accompanying the new clinical trials regulations.
- Here is a link to the MHRA webinar of 12 March 2026 entitled Clinical Trials Regulations: Countdown to Implementation
1. New Clinical Trials Regulations will bring UK closer to EU regime, Rory Trust, Burges Salmon, 22 April 2025
2. Clinical trial reform gets underway, Charlotte Radcliffe et al, 1 May 2025, DAC BeachCroft
3. New Measures to Encourage Clinical Trials in the United Kingdom, Paul Ransom, 22 May 2025, Morgan Lewis.
4. UK Clinical Trials Reform: Early Growth Indicators and Key MHRA Guidance, Libby Amos-Stone et al, 19 January 2026, BioSlice Blog, Arnold & Porter.
5. MRHA publishes raft of guidance on new UK Clinical Trial Regulations, Ishbel McCormack et al, 21 January 2026, Burges Salmon LLP
6. Clinical Trials Regulations Reform, Health Research Authority
7. LinkedIn post from the Health Research Authority, 28 March 2026
Find below, a link to a quiz on the New Clinical Trials Regulations.
Results
#1. The New Clinical Trials Regulations were signed into law on which date?
#2. On what date will the New Clinical Trials Regulations come into force?
#3. Which of the following are included in the New clinical trials regulations? There may be more than one correct answer.
Select all that apply:
#4. All clinical trials can start once they have received a joint ‘clinical trial approval’ consisting of both, a favourable opinion from an ethics committee and an authorisation from the licensing authority, the UK MHRA. Is this true of false?
#5. A sponsor disagrees with the conditions attached to the approval by the licensing authority and wishes to appeal a licensing authority decision. How many days do they have to send written notice of their intention to appeal?
#6. A sponsor submits a CTA application. Within how many days of submission will the outcome of the validation checks be communicated by email and through IRAS?
#7. If the licensing authority does not approve a CTA application or the applicant disagrees with the conditions attached to the approval by the licensing authority, which of the following statements is FALSE?
#8. Valid CTA applications are reviewed by the licensing authority and ethics committee. A combined decision will be issued to the applicant:
#9. If a CTA application is not approved and the applicant needs more than 60 calendar days from the date on which the decision letter was issued, to provide the requested further information in order for the application to be reconsidered, which of the following are false?
Select all that apply:
#10. When must a clinical trial be registered in a public registry according to regulation 25(1)?
Once you complete the quiz and click Finish, You will see:
- The questions that you have answered correctly with a Green band around the answers
- The questions that you have answered incorrectly with a red dotted line around them and a Green band around the correct answers for these questions.
Source: Health Research Authority
References
1. Clinical Trials regulations signed into law, 11 April 2025, MHRA
2. New Year Update: incoming changes to UK regulation of clinical trials, Jackie Mulryne et al, 13 January 2025, Arnold & Porter.
3. Framework amending the UK clinical trial regulations laid before Parliament, Jane Summerfield et al, 17 December 2024, Hogan Lovells
4. Patients, the NHS and the Life Sciences sector set to benefit from new clinical trials framework being laid in parliament today, Press release, 12 December 2024, MHRA
5. New clinical trials regulations laid in parliament today, Health Research Authority, 12 December 2024
6. MHRA webinar of 15 October 2024 entitled Implementing the new UK Clinical Trials Regulations
7. Reforms to UK clinical trials framework passed into law, Jane Summerfield et al, 24 April 2025, Hogan Lovells