no longer falls under EU CTR 536/2014. Instead, it regulates clinical trials independently via MHRA guidance and UK-specific legislation. Although the UK has aligned many processes with ICH E6(R2) and ICH E8(R1), key divergences exist in timelines, submissions, and safety reporting obligations.

Core Clinical Trial Insights: Brexit’s Impact

1. Clinical Trial Applications and Submissions

EU trials now require submission via CTIS, while UK trials must be submitted separately through MHRA’s combined review service. Sponsors planning pan-European studies must navigate dual submissions, doubling administrative and resource burdens.

2. Regulatory Timelines

CTR 536/2014 enforces harmonized timelines for Part I and Part II assessments across Member States. In contrast, MHRA timelines differ, with expedited reviews possible for certain high-priority studies, but without the same coordinated multi-country mechanism available in the EU.

3. Ethics Committee Oversight

In the EU, ethics reviews are governed by Member State frameworks integrated into the CTR process. In the UK, the Health Research Authority (HRA) continues to coordinate ethics reviews, which remain separate from EU systems. This creates duplication for sponsors running joint EU-UK trials.

4. Data Protection and GDPR

The EU’s General Data Protection Regulation (GDPR) applies across Member States, while the UK has adopted its own version (“UK GDPR”). While largely equivalent today, future divergence may complicate cross-border data sharing and trial monitoring.

5. Supply Chain Logistics

Brexit introduced customs barriers and import/export complexities for investigational products. Sponsors now require separate Qualified Person (QP) release in both the EU and UK, creating potential delays and added costs in trial supply chains.

6. Pharmacovigilance and Safety Reporting

EU SUSAR reporting is centralized via EudraVigilance. Post-Brexit, the UK requires safety reports to be submitted to the MHRA separately. Sponsors must maintain parallel safety databases and reporting systems for compliance.

7. Research Collaboration and Site Participation

Many pan-European consortia that previously included UK sites must now treat the UK as a third country, requiring additional agreements and approvals. This has reduced UK participation in some EU-funded Horizon Europe projects, although new association agreements are restoring partial access.

8. Impact on Patients and Recruitment

Brexit has affected patient recruitment by creating uncertainty for multinational trials. However, the UK’s streamlined MHRA pathways aim to attract more early-phase and innovative trials, while EU CTR supports large multi-country Phase III studies.

Best Practices & Preventive Measures

• Develop dual regulatory strategies for EU and UK submissions.
• Engage with both EMA and MHRA for early scientific advice.
• Establish separate QP release processes for EU and UK supply chains.
• Maintain harmonized SOPs for pharmacovigilance covering both jurisdictions.
• Leverage local CROs or affiliates for expertise in both regulatory systems.

Scientific and Regulatory Evidence

• EU Clinical Trial Regulation (CTR) 536/2014
• MHRA Clinical Trials Guidance (UK)
• EMA and HMA Brexit Q&A guidance documents
• ICH E6(R2) – Good Clinical Practice
• GDPR (EU) and UK GDPR frameworks

Special Considerations

Brexit’s impact is particularly significant in:

• Advanced Therapies (ATMPs): Dual oversight from EMA CAT and MHRA.
• Rare Diseases: Cross-border recruitment challenges due to small patient populations.
• Decentralized Trials: Diverging acceptance of telemedicine and direct-to-patient models in the EU and UK.
• Oncology: Parallel submissions complicate large-scale Phase III cancer trials.

When Sponsors Should Seek Regulatory Advice

• When planning multi-country studies involving both EU and UK sites.
• If data transfers between EU and UK are critical for trial endpoints.
• Before sourcing IMPs across borders post-Brexit.
• When implementing hybrid or decentralized trial models in both regions.
• For rare disease or ATMP trials requiring dual oversight.

FAQs

1. Does the UK still follow EU CTR 536/2014?

No. The UK is no longer bound by CTR 536/2014 and has adopted MHRA-specific processes for clinical trial regulation.

2. Are EU and UK GCP requirements aligned?

Yes, both jurisdictions align with ICH E6(R2), but operational processes differ significantly.

3. Can a single submission cover both EU and UK trials?

No. Separate submissions are required via CTIS for the EU and MHRA for the UK.

4. How is pharmacovigilance managed post-Brexit?

Safety reports must be submitted to both EudraVigilance (EU) and MHRA (UK). Parallel systems are mandatory.

5. How does Brexit affect Horizon Europe projects?

UK participation was initially reduced but partial association agreements are restoring some collaborative opportunities.

6. Do QP release requirements differ?

Yes. Separate QP release is required in both the EU and UK for IMPs, increasing operational complexity.

7. Which trials are most affected by Brexit?

Multi-country Phase III studies, ATMP trials, and rare disease studies are particularly impacted due to cross-border dependencies.

Conclusion

Brexit has introduced complexity into the clinical trial landscape by creating parallel regulatory systems in the EU and UK. While the EU continues to advance harmonization through CTR 536/2014, the UK is positioning itself as a flexible hub for innovative and early-phase trials. For sponsors, success now depends on developing dual strategies, ensuring compliance with both EMA and MHRA frameworks, and adopting proactive risk management to navigate cross-border challenges. Although Brexit has created barriers, it also presents opportunities for innovation in clinical research if managed effectively.