UK clinical trial regulation: what changed on 28 April 2026
Since 28 April 2026, UK clinical trials run under the 2004 Regulations as amended by SI 2025/538. Combined review and transparency are now legal duties, approvals lapse if no one is recruited within two years, safety reports go to the MHRA only, the trial master file must be kept for 25 years, and GCP means the ICH principles.
SI 2025/538 is the biggest change to UK clinical trial law since 2004. This first update covers what changed for sponsors on 28 April 2026, and what to do about each change. From now on, each update covers one month.
- UKApplies from 28 April 2026
One application, one decision, now set in law
Source: MHRA →Combined review by the MHRA and a research ethics committee was already standard practice. It is now a legal requirement. Sponsors submit one application through IRAS, the authorities confirm it is valid within 7 days, and they must take all reasonable steps to issue a single combined decision within 30 days of validation. Applying to the ethics committee is now the sponsor's job, not the chief investigator's.
What it means for sponsors
Submit one complete package and plan around the timelines. If the authorities ask for more information, you have 60 days to respond, which can be extended. If the amended application is refused again, it is treated as rejected, so use the first request for information to fix everything. The 30 days is a target, not a guarantee.
- UKApplies from 28 April 2026
A lighter route for lower-risk trials
Source: MHRA →Lower-risk trials can now be flagged as notifiable. Broadly, that covers trials of UK-authorised medicines used within their authorisation or established clinical practice, trials closely matching a UK trial approved in the last 2 years, and trials already approved in the EU, EEA or USA, where there are no significant safety concerns. Trials involving under-18s, pregnant or breastfeeding participants, advanced therapies or first-in-human products are excluded.
What it means for sponsors
Check each new trial against the MHRA criteria and record your reasoning. The MHRA aims to authorise notifiable trials within 14 days, but the ethics review still runs as normal, so the trial cannot start until the combined decision arrives. An eligible trial submitted for full review may be invalidated.
- UKApplies from 28 April 2026
Approval lapses if no one is recruited within 2 years
Source: MHRA →Approval now lapses 24 months after it is granted if no participant has been recruited. Sponsors can apply for an extension before the period runs out. If approval lapses, the sponsor must notify the end of the trial.
What it means for sponsors
Report the date the first UK participant is recruited, as a modification of an important detail. Track the 24-month date for any trial that is slow to open and apply for an extension in good time. This rule does not apply to trials whose application was received before 28 April 2026.
- UKApplies from 28 April 2026
Registration and results are now legal duties
Source: HRA →Sponsors must register the trial in a public registry by whichever comes first: the first participant being recruited, or 90 days after approval. Within 12 months of the trial ending, they must publish a results summary in the same registry and offer participants a summary in plain language. Failing to register or to publish results is an offence.
What it means for sponsors
Build registration into start-up, and plan the plain-language summary in the ethics application and participant information. Deferrals are possible, for example to protect commercially confidential information, but must be agreed with the HRA in advance. The MHRA can take unresolved transparency failures into account when it assesses your future applications.
- UKApplies from 28 April 2026
Safety reports go to the MHRA only
Source: MHRA →SUSARs and annual safety reports now go to the MHRA only, not to the ethics committee. SUSAR timelines are unchanged. Written notice of an urgent safety measure is extended from 3 to 7 days. Sponsors must also keep and evaluate records of serious adverse events and reactions, including those in their trials of the same product outside the UK.
What it means for sponsors
Update your safety reporting SOP, and any CRO or vendor agreements that still send reports to the ethics committee. The MHRA still expects a phone call about an urgent safety measure, ideally within 24 hours. The annual safety report is due within 60 days of the end of each reporting year.
- UKApplies from 28 April 2026
Amendments become modifications, with clearer routes
Source: MHRA →Changes to an approved trial now fall into three groups. Minor modifications need no submission, only a record. Modifications of an important detail are notified through the portal. Substantial modifications are reviewed, and the authorities aim to decide within 35 days. A faster route, Route B, covers certain lower-risk substantial changes.
What it means for sponsors
Classify every change and record why. The MHRA expects Route B to be used wherever a change is eligible, and an eligible change submitted the long way may be invalidated. Any change submitted on or after 28 April 2026 follows the new rules, even for trials approved before then.
- UKApplies from 28 April 2026
Keep the trial master file for 25 years
Source: MHRA →The trial master file, including electronic records, must now be kept for 25 years from the day after the trial ends, up from 5. Participants' medical files must also be kept for 25 years.
What it means for sponsors
Review archiving contracts, storage costs and eTMF vendor terms, and make sure a named archivist is in place. Trials whose application was received before 28 April 2026 keep the 5-year rule for the trial master file.
- UKApplies from 28 April 2026
GCP now means the ICH principles
Source: MHRA →The old UK GCP principles are replaced by the principles of the ICH GCP guideline, as amended from time to time. The MHRA applies ICH E6(R3) in the UK from 28 April 2026. Only the principles are law; the rest of the guideline is guidance that sponsors must have regard to.
What it means for sponsors
For trials already running, the MHRA expects a documented impact assessment and a gap assessment of your quality management system, and inspectors may ask to see both. Retraining can be risk-based rather than everyone at once. Any departure from the guidance needs a documented rationale.
- UKApplies from 28 April 2026
New labelling rules, including for non-investigational products
Source: MHRA →Labelling requirements for investigational medicinal products are rewritten. Non-investigational medicinal products used in a trial now have their own labelling requirements and must be made to GMP.
What it means for sponsors
Products certified before 28 April 2026 can keep their old labels within their trial; later batches need labels that meet the new rules. Non-investigational products get no transitional relief, so non-compliant labels need a substantial modification. Labels do not need changing just to say "participant".
- UKApplies from 28 April 2026
Insurance or indemnity is still required
Source: MHRA →This did not change. The amended Regulations still require insurance or indemnity to cover the liabilities of the investigator and sponsor, and the application must include proof of it or an explanation.
What it means for sponsors
Keep insurance on your start-up checklist. It is one of the UK-specific requirements the MHRA kept alongside ICH E6(R3).
- UKApplies from 28 April 2026
What applies to trials submitted before 28 April
Source: MHRA →A trial whose application was received before 28 April 2026 is an old rules trial. The old approval process and the 5-year trial master file rule still apply to it, and the 2-year lapse rule does not. Most other rules, including GCP, safety reporting and any modification submitted from 28 April, apply to every trial.
What it means for sponsors
Old rules trials that had not ended by 28 April 2026 had to be registered within 90 days of that date, and must publish results within 12 months of ending. Check each trial in your portfolio against the MHRA transitional guidance and record which rules apply to it.
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