Run a clinical trial under the 2026 UK regime

If you are testing an investigational medicinal product, testing a licensed medicine for a new indication, comparing licensed medicines in a new way, or using a placebo as a comparator, you are almost certainly running a CTIMP and the regime applies to you. Observational studies, non-interventional studies, and medical device trials sit outside it.

The old Type A/B/C risk classification has been replaced for eligible lower-risk trials by a statutory notification scheme: your trial is authorised automatically once you notify the MHRA, though you still need Research Ethics Committee (REC) approval. Higher-risk trials - first-in-human studies and novel compounds - still need a full application through combined MHRA and REC review.

If you submitted your application to approve a trial before 28 April 2026, that trial is treated as an "old rules clinical trial" even if you had not received an outcome by that date. Applications submitted on or after 28 April 2026 are "new rules clinical trials". This distinction matters less than it sounds: most of the new duties - including the transparency and registration obligations below - apply to all CTIMPs from 28 April 2026, regardless of which rules classification your trial carries.

Manufacturing and importing investigational medicinal products (IMPs) is a good example of where the date, not the trial's rules classification, controls the outcome: any IMP manufactured or imported into the UK after 28 April 2026 is subject to the amended manufacturing requirements, whichever type of trial it is destined for. Labelling rules apply to both old and new rules trials too, though IMP stock manufactured under the old rules before 28 April 2026 can still be used in the trial it was made for.

A single application through the Integrated Research Application System (IRAS) covers both MHRA authorisation and REC approval. Combined review has operated since January 2022 and is now a statutory requirement, with a 30-day review timeline once your application is validated - in practice the process is averaging around 41 days from submission to decision. If your trial qualifies for the notification scheme, submit your notification to the MHRA alongside your REC application; authorisation follows automatically and you do not wait for a separate MHRA decision.

As sponsor, you are responsible for Good Clinical Practice (GCP) compliance, safety reporting, and informed consent at every site running your trial. None of these duties are new in principle, but the standards behind them have moved.

For the first time, UK law requires you to register your trial in a public registry and publish a results summary. You must register on a WHO-recognised public registry by the earlier of the date your first participant gives consent or 90 days after your trial is approved. You must then publish a summary of results on the same registry within 12 months of the global end of the trial, and offer a lay summary of those results to participants (or the person who consented on their behalf).

Failing to register or to publish a results summary is an offence under the regulations. The MHRA takes a graduated approach to enforcement, escalating from advice through to infringement notices and, ultimately, prosecution.

Retention requirements changed significantly for trials applied for on or after 28 April 2026. Check your trial master file and participant record retention arrangements can meet the new period, and that your archive contracts and storage budget account for it.