Running clinical trials in the UK

Running a clinical trial of an investigational medicinal product (CTIMP) requires MHRA authorisation and Research Ethics Committee (REC) approval. A single application through IRAS covers both: combined MHRA and REC review has operated since January 2022 and is now a statutory requirement under the 2026 framework, with a 30-day review timeline.

Starting a trial without authorisation is illegal. This guide covers the requirements for commercial and academic sponsors.

Understanding CTIMP authorisation

Is your study a CTIMP?

Yes, if:

• Testing a new investigational medicinal product
• Testing a licensed medicine for a new indication
• Comparing licensed medicines in a new way
• Using a placebo as comparator

Probably not a CTIMP:

• Observational studies of routine prescribing
• Non-interventional studies
• Medical device trials (separate regulations)

Trial classification and timelines

Your trial's risk classification determines the approval timeline.

Choosing the right pathway

The Type A/B/C risk classification was the legacy risk-proportionate approach. Since 28 April 2026, the statutory notification scheme replaces it for eligible lower-risk trials: the trial is authorised automatically on notification to the MHRA, though REC approval is still required. The scheme suits:

• Trials of licensed medicines used within licence terms
• Low-risk comparisons of standard treatments
• Studies where IMP risk is no greater than standard care

Full applications (combined MHRA and REC review) are needed for higher-risk trials including first-in-human studies and novel compounds.

Good Clinical Practice

All CTIMPs must comply with GCP principles.

GCP training requirements

• All site staff must complete GCP training before site activation
• Chief Investigator responsible for ensuring training completed
• Refresher training recommended every 2-3 years
• Training must reflect ICH E6(R3), which applies under the 2026 framework

Safety reporting (SUSARs)

Sponsors must report safety events within strict timelines.

Setting up safety reporting

1. Register with MHRA ICSR Submissions platform or MHRA Gateway
2. Establish 24/7 process for identifying urgent safety issues
3. Create templates for SUSAR reports
4. Train investigators on adverse event identification
5. Schedule annual DSUR preparation

Informed consent

Participants must give informed consent before any trial-specific activity.

Trial registration

Trials must be registered on a public registry.

Record retention and archiving

Retention requirements changed significantly for trials applied for on or after 28 April 2026.

The 2026 framework (in force since 28 April 2026)

The Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 came into force on 28 April 2026.

What the framework requires

• Results publication: Publish results within 12 months of trial end
• Participant summaries: Provide lay summaries of results
• Recruitment timelines: First participant within 2 years or approval lapses
• GCP training: Aligned to ICH E6(R3)
• Archiving: 25-year retention for trials applied for on or after 28 April 2026