he UK has recently undertaken the most significant overhaul of its clinical trials regulations in two decades. Developed by the Medicines and Healthcare Products Regulatory Agency (MHRA) in partnership with the Health Research Authority (HRA), the updated regulations are designed to protect trial participants, reduce unnecessary burdens on researchers, and facilitate the conduct of high-quality, trusted research in the UK. The Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 will come into force on 28 April 2026 across the whole UK.

The new regulations will embed research transparency requirements in UK law for the first time, making trials easier to find and their results easier to use, and helping their participants to feel more valued.

The HRA has published guidance to help researchers and sponsors prepare for the new clinical trials regulations, with a particular focus on ethics review and the new research transparency requirements. The MHRA has also produced guidance to support sponsors in understanding the regulatory changes, covering authorization processes, safety reporting, and other operational aspects.

This article explains the new legal transparency requirements, what will be different in practice, and concrete steps that sponsors and their partners can take to be ready.

Transparency Earns Trust

Trust is a precondition for participation in research, and transparency helps earn that trust. Public Perceptions of Research, a report commissioned by the HRA, revealed that people are more confident in research findings if the research process and its outcomes are made public, such as by registering the research on a public register before it starts (65%) or making the results publicly available as soon as possible afterwards (65%).

Without trust, people won’t want to take part in research or allow their data to be used. Without trust, patients and clinicians won’t want to use the fruits of research, and companies and researchers won’t choose the UK as a place to invest and innovate. Building and maintaining that trust is not optional; it is fundamental.

When clinical research is carried out openly:

• Everyone can see what studies are underway and what past studies found
• Patients, service users, and carers can find opportunities to join
• Researchers can build on earlier findings to develop better treatments and understand how to keep people healthy
• Health professionals, commissioners, policymakers, and funders can use robust results to make informed decisions.

The result is stronger recruitment, greater reproducibility, less research waste, and more social value from every trial.

What are the New Research Transparency Requirements?

The UK’s approach balances firm legal commitments with proportionate implementation, recognition of legitimate commercial interests, and ethical leadership. These changes move long-standing policy expectations into enforceable legal requirements, consolidating the UK offer to global sponsors who need clarity, proportionate regulation, and public trust to deliver high-quality trials. These regulations will embed ethical practice at the heart of clinical trials and make it easy to do research in a way that people can trust, because under the new regulations, sponsors will be legally required to:

• Register each clinical trial in a public registry before the first participant gives their consent to take part or within 90 days of approval to start the trial, whichever comes first. (A “public registry” means a World Health Organization International Clinical Trials Registry Platform primary/partner registry or data provider that enables public access to UK trial information.)
• Publish a summary of results in the same registry (or registries, if more than one) within 12 months of trial conclusion.
• Offer a lay summary of results to “relevant persons” (participants or, where appropriate, the person who provided consent on their behalf, such as a parent on behalf of their child, or someone responsible for their care or welfare, such as a legal representative or next of kin) within the same 12-month timeframe. The requirement to offer lay summaries to those who make research possible properly respects the contribution of participants.

Balancing Public and National Interest with Commercial Interest: Deferrals and Waivers

The new legislation promotes transparency while recognizing legitimate commercial sensitivities, especially in early phase trials. It balances the public interest with the need to stimulate and attract investment into the UK in support of the UK government’s missions in growth and health. Therefore, deferrals to these new requirements will be allowed, where justified, to protect commercial confidentiality.

The updated legislation protects commercial confidentiality, and national interest, through these mechanisms:

• Deferrals for all research transparency requirements can be requested and, where justified, may be granted by the HRA for 30 months following the end of the clinical trial.
• Extensions may be granted up to a total maximum period of 10 years after the global end of the trial.
• Waivers: In exceptional circumstances, such as national defense or security, the requirements may be waived entirely. Waivers will not be given for protection of commercial confidential interests; in such cases, sponsors should request a deferral.

Further deferral of the registration element from 30 months following the end of the study will not normally be granted without strong justification and will generally only be allowed for publishing the summary of results and, where justified and necessary, offering to simultaneously share results with participants.

Certainty for Sponsors: Automatic Deferrals for Phase 1 Trials with Healthy Volunteers

Early phase trials explore novel compounds and/or devices at a very preliminary stage, when commercial sensitivity is greatest. They mainly test safety, pharmacokinetics, and dosing in a small group of participants (often healthy volunteers) and are not designed to establish efficacy. Because these trials aren’t aimed at directly supporting regulatory approvals for broad clinical use, they do not have the same level of public health impact and interest as phase 2 to 4 trials. Full registration might disclose commercially sensitive or proprietary information, such as novel mechanisms, early stage data, or experimental approaches, before these have been sufficiently validated, protected through intellectual property processes, or positioned for further development.

We recognize that sponsors of phase 1 trials with healthy volunteers, and the Contract Research Organizations (CROs) they work with, value certainty in applicability of research transparency requirements and compliance timelines so that they can be confident their commercial interests will be appropriately protected when placing their trials in the UK.

For these reasons, sponsors of phase 1 trials with healthy volunteers will be granted an automatic deferral of registration and result-sharing up to 30 months from the end of the trial, provided that sponsors register a minimal record up front. This includes the registry number, IRAS ID, investigator and sponsor contact details, ethics committee decision, nature of clinical trial (for example, “bioequivalence in 24 healthy volunteers”), key dates (start/end of trial and recruitment), and the justification for the deferral.

Full registration is required when the deferral (including any extensions) ends, or if the trial is terminated early for safety reasons.

This balances public interest with innovation incentives. It protects early stage intellectual property while guaranteeing that, even during a deferral, the public is aware that a trial exists, with full transparency delivered later.

In addition, sponsors can ask for two additional 30-month deferrals at time of application to cover publishing the summary of results and sharing results with participants. These will be granted on grounds of commercial confidentiality where justified.

With the automatic deferral plus these additional requested extensions, sponsors may not need to publish or offer a summary of results for 90 months (7.5 years) after the end of the trial. Further requests may be made, but the total deferral period cannot exceed 10 years from the end of the trial. After that, sponsors must meet the transparency requirements.

Enforcement of New Requirements

The amended enforcement provisions within the clinical trials regulations also bring the new transparency requirements (except for the requirement to offer a lay summary to “relevant persons”) into scope for infringement notices and offenses.

Failure to register a trial or publish a summary of results (excluding the requirement to offer a lay summary) without an approved deferral or waiver will be an offense under the new legislation. If the offense is uncorrected, the MHRA may take enforcement action. The MHRA uses a graduated compliance approach, utilizing a range of compliance measures up to and including the use of infringement notices and potential prosecution. This enables proportionate enforcement, with criminal prosecution reserved as a last resort.

The revised regulations also give the MHRA the ability to not approve trials where the sponsor has not complied with the registration and publication of results requirements in their other trials and have failed to rectify this. The HRA and MHRA will work together to effectively support and facilitate compliance with the new regulations.

Which Trials Must Meet These New Regulations?

The following transitional arrangements set out which trials must comply with the new regulations:

• The new research transparency rules will apply to all clinical trials of medicines approved on or after 28 April 2026 (“new rules clinical trials”).
• They will not apply to trials ended before 28 April 2026 (“old rules clinical trials”).
• Ongoing trials (on or after 28 April 2026) that have not yet recruited must register before first participant recruited or within 90 days of the “in force” date (by 27 July 2026) (whichever comes first).
• Ongoing trials that have already recruited first participant, if not already registered, must be registered within 90 days of the “in force” date.
• Ongoing trials will not need to offer a lay summary of the results to all relevant persons.
• If a trial has an existing deferral in place for registration and is ongoing on 28 April 2026, the deferral end date will be automatically extended to 30 months after the end of the trial and will apply to both registration and publication of the summary of results.

Four Actions Sponsors Can Take Now to Prepare

1. Audit UK trial portfolio and transparency compliance

• Identify “old rules” UK clinical trials and expected end date and ensure all are appropriately registered.
• Ensure registration by the legal deadline where necessary and start the 12-month results clock from end of trial for “old rules” trials that will end on or after 28 April 2026.
• Identify any ongoing phase 1 healthy volunteer studies with existing deferrals that will receive automatic deferral and note new end date.

2. Build registry readiness into start-up

• Update standard operating procedures, start-up checklists, and contracts so that registry selection, required data fields, user permissions, and lay summary of results plans are all agreed upon before the first participant is recruited.
• Confirm procedures to ensure registration before first participant or within 90 days of approval (whichever is sooner) are in place; registration should become part of routine study activation instead of a late task.

3. Design around the 12-month results deadline

• Assign clear owners and timelines for both the scientific results summary and the lay summary.
• Document the justification and set reminders well ahead of each 30-month decision point where you seek a deferral, keeping the 10-year total deferral limit in mind.

4. Prepare for offering lay summaries of results to participants

• Plan how and when the offer will be made and recorded.
• Treat lay summaries as plain-language communication, not marketing, and plan for any translation or accessibility needs early.
• Co-design the summaries with patient partners and test for clarity (refer to existing HRA guidance on Informing participants).

Transparency and Trust Make the UK a Great Place for Research

These reforms are not an administrative burden; they are an opportunity. Transparency enhances scientific integrity, supports public engagement, and accelerates the translation of research into health benefit.

Sponsors who embed research transparency into everyday practice will reduce their compliance risk, properly respect participants’ contribution, help patients and earn their trust, and sustain the UK’s reputation as a world-class place to conduct high-quality clinical trials that improve global health and grow the economy.