New UK Clinical Trials Regulation 2024: What You Need to Know

The Clinical Trial Regulations in the UK are changing. The government has now signed the new Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2024 into law, and they will come into force following a one-year implementation period on 28 April 2026.

Considered to be one of the most significant overhauls to the UK clinical trials regulatory framework within the last two decades, the Medicines and Healthcare Products Regulatory Agency (MHRA), in collaboration with the Health Research Authority (HRA), have revised the clinical trial regulations, following a consultation period with stakeholders including those in industry, healthcare and the general public. The new regulations underpin the UK Government’s aim to make the UK a world leader in clinical research.

A review of the clinical trials landscape in the UK identified a number of improvements to build and strengthen the sector, leading to the revision of the legislation. The legislation generally aims to increase flexibility and simplify the process to support faster, more streamlined approvals for clinical trials in the UK.

The regulations now incorporate familiar systems such as the Combined Review process, which has been the standard submission process for Clinical Trials of Investigational Medicinal Products (CTIMPs) since 2022, and the streamlined notification scheme for lower-risk trials. Additionally, the regulations introduce some new changes, which will be discussed in further detail below.

During the rollout period, the MHRA and HRA will issue further guidance to support sponsors in implementing the new regulations.

In the meantime, if you are new to the UK clinical trial landscape and/or are planning a new clinical trial, please read on for further information.

Key Aspects of the Clinical Trial Regulations

Combined Review Process

The Combined Review Process has now been formally codified into law. The combined review procedure has replaced previous regulations 14 to 26 of the Medicines for Human Use (Clinical Trials) Regulations 2004, which covered separate ethics committee and regulatory submissions. Specifically, applicants must submit a single application dossier (a request for approval) for both regulatory authorisation under regulation 14 and an ethics committee opinion under regulation 15.

Risk-Proportionate Approach

The risk-proportionate approach, another element previously followed in practice but now formalised in law, introduces the concept of “notifiable trials” for low-risk studies. The new regulations define ‘notifiable trials’ as trials where there are no significant safety concerns with any of the Investigational Medicinal Products (IMPs), do not involve participants who are either under 18 or pregnant or breastfeeding, do not involve ATMPs or IMPs used for the first time in humans (FiH), and meet one of the conditions listed below:

• Condition A: Authorised products used according to their marketing authorisation or established medical practice, i.e. a reduced risk profile compared to novel compounds.
• Condition B: The MHRA has approved trials of the same IMP in the preceding 2 years using the same (or higher) dose, same (or higher) dosing frequency, and the same (or longer) duration. They used the same manufacturing process for the IMP. The approved trial must also have used the same route of administration and investigated the same indication. This leverages existing safety data to streamline approvals.
• Condition C: Trials already approved in the EU, EEA, or US, recognising rigorous regulatory assessments already conducted in trusted jurisdictions.

This represents a major step forward in applying regulatory oversight proportionate to the actual risk presented by different trial types. Trials meeting these criteria benefit from an expedited review process, reducing timelines and, in certain circumstances, documentation requirements. Additionally, the regulations introduce a simplified consent process for authorised products used in routine healthcare settings, striking an appropriate balance between participant protection and practical implementation. These provisions allow sponsors to obtain faster approvals for low-risk trials and reduce regulatory burden where applicable, enabling them to focus resources on areas of potentially higher risk while accelerating patient access to treatments.

Streamlined Timelines

The new regulations establish more predictable and efficient timelines throughout the approval process:

• Validation: 7 days (previously undefined), clarifying when the assessment begins.
• Initial review: 30 days.
• Response period: 60 days (extended from 14 days), allowing sponsors adequate time to prepare comprehensive, high-quality responses.
• Final decision: 10 days after receiving responses, creating a predictable endpoint to the review process, as well as benefiting companies who can respond to any questions quickly, bringing in the timing for the overall decision.

These revised timelines offer several advantages, such as predictable planning and approvals and sufficient time for sponsors to prepare responses to regulatory questions. The extended response window (60 days compared to the EU’s 12 days) acknowledges the practical challenges of addressing complex scientific and technical questions, particularly for some organisations or studies requiring additional data generation.

Amendment Processing

A change in the 2024 regulations is the shift in terminology from ‘amendments’ to ‘modifications’ for changes to approved trials, in alignment with the language introduced under the EU Clinical Trials Regulations. More importantly, the UK regulations introduce a new categorisation framework for modifications, including a new “modification of an important detail” category and sub-categories of substantial modifications, classed as route A or route B. This new framework enables the approval of substantial modifications to be more streamlined.

The regulations have established clear provisions for handling amendments during the transition period to the new regulations. The previous/current process will be followed for amendments submitted before the implementation date, while the new modifications procedure will apply to changes requested after implementation. This approach ensures the regulatory transition does not disrupt amendments already in process. By maintaining continuity for ongoing regulatory interactions, this implementation strategy prevents unnecessary complications for trials already underway. Sponsors can progress current amendments without adapting to new requirements mid-process, while planning future modifications according to the new framework.

Improved Safety Reporting Framework

The safety reporting framework has been refined to maintain robust oversight while reducing unnecessary administrative burden. The new regulations streamline the reporting of Suspected Unexpected Serious Adverse Reactions (SUSARs) to only the MHRA and provide options to specify certain SUSARs that don’t require immediate reporting based on protocol-defined criteria. The UK legislation now includes the ICH-based provision that requires submission of annual safety reports within 60 days of the data lock point. These changes ensure comprehensive safety monitoring while eliminating duplicative reporting requirements. The flexibility to define protocol-specific reporting requirements for certain SUSARs allows for a more tailored approach focusing on meaningful safety signals, rather than on known or expected events that don’t alter the overall risk profile.

It is also important to note that the timelines for reporting urgent safety measures have been extended (to 7 days).

Extended Document Retention Requirements

Document retention requirements have been revised, with appropriate grandfathering provisions:

• ‘Old rules’ trials (i.e. trials approved under the previous/current legislation) maintain the 5-year retention period for trial master files.
• New trials (i.e. trials approved under the new UK clinical trials regulations) require a 25-year retention period (plus an additional 2 years if used for a marketing authorisation).

Transparency and Other Requirements

Whilst many sponsors may already be performing activities to promote research transparency as best practice, the regulations now make the following principles mandatory for all trials:

• Trial registration before recruitment of the first participant or within 90 days of trial approval, whichever occurs first (the current recommendation is within 6 weeks of the first participant recruited).
• Publication of summary results within 12 months of trial conclusion.
• Lay summary of results to be offered to participants within 12 months of trial conclusion.

Sponsors still have the ability to request a deferral to these requirements in certain cases, for example, to protect commercially confidential information.

Finally, sponsors should be aware that if recruitment has not started within 24 months of the clinical trial approval, the approval will lapse, although they can request an extension of this timeframe.

Benefits for New Clinical Trials

The new regulations’ streamlined approval process directly translates to more efficient study initiation with clearly defined timelines.

The risk-proportionate approach should help reduce the administrative requirements for low-risk “notifiable trials” for both sponsors and authorities. This practical flexibility particularly benefits studies of already-authorised products, which can now progress with reduced regulatory assessment while maintaining appropriate safety standards.

It is worth highlighting that gene therapy products are no longer treated separately (with the exception of xenogenic cell therapy), which we assume reflects the progression in the development of these types of therapies and is good news for companies developing products in this area.

Benefits for UK Clinical Research

The efficiency improvements in the new regulations aim to substantially reduce the time from application to first participant. This acceleration directly enhances the UK’s competitive position in the global clinical research landscape. By eliminating unnecessary delays without compromising rigorous scientific and ethical review, the UK offers a compelling research destination.

Patient-centred improvements, including enhanced research transparency, ensure that the regulations serve operational efficiency and broader public health objectives. The regulatory predictability established by the new framework positions the UK as a premier research destination capable of attracting increased investment, complementing its existing strengths in research infrastructure, investigator expertise, and diverse patient populations.

The new regulatory framework shows that the MHRA is taking a pragmatic approach to clinical research. It enables appropriate focus to be given to higher-risk products while allowing well-established products a smoother review, reflecting their well-established safety profile.

Transition Phase and Implementation

The 12-month implementation period from April 2025 to April 2026 provides a critical window for sponsors to prepare for the new regulatory requirements. During this transition phase, the MHRA and HRA will release additional guidance documents, webinars, and consultation opportunities to support industry adaptation. Organisations should prioritise key preparation activities during this period, including reviewing and updating SOPs and templates, training staff on regulatory changes, and assessing the impact on ongoing and planned trials.

Early understanding of the new requirements will help ensure a smooth adaptation. Strategic timing of submissions near implementation dates may also be advantageous, particularly for studies that could benefit from the new framework’s more flexible approaches.

The UK Clinical Trials Regulations 2024 represent a significant evolution in the UK’s approach to clinical research oversight and bring best practice into the legislation. The streamlined processes, proportionate approaches tailored to risk levels, and predictable timelines position the UK as an attractive destination for clinical trials, offering potential competitive advantages in reducing the time from application to first participant.

DLRC’s regulatory experts have been closely monitoring the development of these regulations and are ready to assist sponsors in navigating this new landscape. Our team can help optimise trial strategies to leverage the full benefits of the UK system while ensuring full compliance with all requirements. Contact us today to discuss how we can support your clinical development programmes in this evolving regulatory environment by emailing hello@dlrcgroup.com.