Clinical Trial Applications in the UK

Our UK team prepares, submits, and manages clinical trial applications through the MHRA and the UK’s Integrated Research Application System (IRAS). The UK now operates independently from the EU clinical trials framework, with its own legislation, submission platform, timelines, and assessment process. For the full description of our clinical development methodology and EU support, see Clinical Development.

UK Regulatory Landscape

The UK clinical trials framework has diverged from the EU since Brexit. Trials in the UK are regulated by the MHRA, not through the EU Clinical Trials Information System (CTIS).

Current Framework

Clinical trials in the UK are currently regulated under the Medicines for Human Use (Clinical Trials) Regulations 2004 (as amended), with submissions made via IRAS. The UK operates a combined review process in which the MHRA and a Research Ethics Committee (REC) assess the application in parallel.

New UK Clinical Trials Regulation (SI 2025 No. 538)

The Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 (SI 2025 No. 538) came into force in April 2026. This regulation formalises the combined review submission process and introduces several changes to timelines and procedures:

The combined review becomes the standard pathway, with MHRA and REC assessments running in parallel from a single submission.

The sponsor response period for Requests for Further Information (RFIs) extends to 60 days (from the current shorter window), giving sponsors more time to prepare substantive responses.

The overall target for a final decision is Day 100 from validated submission, compared to the current Day 60 framework.

UK transparency requirements for trial registration are strengthened. Support extends through the full lifecycle of the trial, including results reporting.

For trials running in both the UK and EU, separate applications are required: IRAS for the UK, CTIS for the EU. We coordinate dual submissions to align clinical and regulatory planning across jurisdictions.

What We Handle Locally

Our UK team delivers the following within the UK clinical trials framework. For clinical programme design, protocol authoring, EU CTA/CTIS submission, and sponsor/legal representative services, see the central Clinical Development page.

  • Prepare and review UK CTA submission documentation, including the cover letter, IRAS application form, protocol, and Investigator’s Brochure. We conduct targeted review of these documents against UK regulatory expectations, identifying issues that could trigger RFIs or delay approval.
  • Submit UK CTAs via IRAS on behalf of sponsors. We manage the application from submission through validation, track the combined review timeline, handle RFIs from the MHRA and REC, and coordinate through to approval.
  • Support the transition to the new UK CTR (SI 2025 No. 538) for trials initiated around the April 2026 changeover. We advise on which framework applies, manage submission timing, and ensure documentation meets the new requirements.
  • Coordinate UK CTA submissions alongside EU CTIS submissions for multi-jurisdictional trials. We align documentation, manage timeline differences between the two systems, and ensure consistent regulatory positioning across both applications.
  • Manage substantial amendments to approved UK CTAs, including protocol amendments, IB updates, and changes to trial conduct. We prepare amendment documentation and submit through IRAS.
  • Support UK trial registration to meet transparency requirements, and provide ongoing regulatory support throughout the trial lifecycle through to results reporting.
  • Prepare for and manage MHRA interactions during the trial, including responses to safety-related queries, annual safety reporting, and end-of-trial notifications.

Our UK Team

Clinical trial application work in the UK is delivered by our regenold UK regulatory team, who have direct experience with MHRA submissions across Phase I to Phase III programmes. The team works closely with our central clinical development specialists on protocol strategy, clinical programme design, and cross-jurisdictional coordination.

For the full team, see Our Teams.

Key UK Regulations

Planning a clinical trial in the UK?

Tell us about the trial, your timeline, and whether you are filing in the UK only or in parallel with the EU. We will outline the submission strategy.

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Frequently Asked Questions (FAQ)

What is the main difference between UK and EU clinical trial submissions?

The UK uses IRAS as its submission platform; the EU uses CTIS. The UK operates a combined review with MHRA and REC assessing in parallel from a single submission. The EU CTR uses a Part I (scientific) and Part II (national/ethics) structure assessed across member states. Timelines differ, and the new UK CTR introduces a Day 100 decision target compared to the EU’s 60-day standard assessment. Separate applications are required for each jurisdiction.

When does the new UK Clinical Trials Regulation take effect?

SI 2025 No. 538 comes into force on 28 April 2026. It formalises the combined review process, extends the sponsor RFI response period to 60 days, and sets an overall Day 100 decision timeline. Trials submitted before the changeover date may follow the existing framework; we advise on transition timing.

Can the same documentation be used for both UK and EU submissions?

Core clinical documents (protocol, IB) can be shared, but the submission packages differ. IRAS requires UK-specific forms, cover letters, and formatting. CTIS requires Part I and Part II documentation structured per EU CTR requirements. We prepare both packages from the same source documents, adapting for each platform’s requirements.

Does regenold UK act as sponsor for UK trials?

Our central clinical development team can provide EU sponsor and EU legal representative services under the EU CTR. For UK-specific sponsor obligations, contact us to discuss your requirements. We support all aspects of UK CTA preparation, submission, and lifecycle management regardless of sponsor structure.

Do you run clinical trials directly, or do you manage CROs?

We do not operate our own trial sites or in-house labs. When a trial needs operational execution (site monitoring, data management, biostatistics, central lab services), we select, qualify, and manage CROs and service providers. We write the RFPs, evaluate bids, negotiate contracts, and provide oversight. What we do directly: programme design, protocol authoring, regulatory submissions, sponsor representation, authority interactions, and clinical dossier compilation.