Harmonizing UK and EU CTA submissions: Practical strategies from EU-CTR experience

Post-Brexit, sponsors face two separate regulatory systems where one once existed. While many view this as a challenge, it actually presents a strategic opportunity for those who know how to leverage it. 

Since January 2020, the UK has operated independently from the EU regulatory framework. While two distinct systems have emerged, many scientific and ethical principles remain aligned, creating a bridge for strategic planning. Based on our experience, a well-designed harmonized approach minimizes redundant work while parallel or coordinated submissions accelerate overall approval timelines. This can deliver first patient enrolled 4-8 weeks faster, and up to 40% reduction in resource costs. 

Understanding the evolving European regulatory landscape 

Under the EU Clinical Trials Regulation (EU-CTR), sponsors now submit through a single portal (CTIS) for all Member States, with assessments divided into Part I (~45 days) and Part II (Member State-dependent timelines). The regulation emphasizes transparency through public trial information access and introduces the innovative FAST-EU pilot program designed to reduce approval timelines to 70 days for trials addressing significant unmet medical needs. 

Following the EU changes, now the landscape of clinical trial regulation in the UK is undergoing significant transformation. With the implementation of new regulations coming into force on April 28, 2026^{1, 2}, sponsors and researchers need to understand the changes and prepare accordingly.  

While overall CTA approval timeline in the UK now extends to up to 107 days (compared to the previous 60 days), it implements framework of regulated timelines:  

1. New 7-day validation period 
2. 30 days for initial outcome 
3. 60 days for sponsor response to requests for further information (RFI) 
4. 10 days for final outcome upon receipt of complete RFI response 

Those changes ultimately provide significant advantages for sponsors to be well informed on expected response timeframe and RFI flexibility, particularly when combined with additional strategic approaches such as:  

• Notifiable trials that can receive automatic authorization in 21 days (7+14 calendar days, including eligibility assessment) 
• MHRA Innovation Office that provides early scientific advice 
• Early Access to Medicines Scheme (EAMS) that addresses unmet needs 

Key updates in the new UK regulatory framework  

The UK's new clinical trial regulations introduce important changes that create strategic opportunities for sponsors planning submissions. 

Risk-proportionate modifications: The UK now categorizes trial modifications into four tiers—Route A (substantial, requiring full approval), Route B (automatic MHRA approval for data-related changes), Modifications of Important Details (administrative, requiring awareness), and Minor Modifications (no notification needed). This tiered approach allows for faster implementation of lower-risk changes. 

Notifiable Trials pathway: Trials with no significant safety concerns meeting specific inclusion and exclusion criteria³ can receive automatic authorization within 14 calendar days, dramatically accelerating timelines for eligible studies with established interventions. 

Accountability measures: Sponsors must notify MHRA of first UK participant recruitment dates. Trial approvals lapse if no recruitment occurs within 24 months, though extensions up to 60 months total are available. Trials submitted before April 28, 2026, are exempt. 

Transparency requirements: Trial registration is now legally mandated before first participant recruitment or within 90 days of approval. Summary results must be published within 12 months of trial end. Phase I healthy volunteer trials receive automatic 30-month deferrals, extendable to 10 years. 

Operational updates: New labeling requirements include safety warnings and contact information. Pharmacovigilance reporting is streamlined—SUSARs reported only to MHRA with extended urgent safety measure notification of timeframes (seven days vs. three). 

In order to keep up with those changes and leverage accelerated pathways, sponsors need to track UK enrollment dates, audit trials for registration compliance, assess labels against new standards, and evaluate notifiable trial eligibility. 

Smart planning to leverage MHRA opportunities 

Sponsors conducting trials in both the UK and EU must now navigate two distinct regulatory systems. The key is developing a comprehensive European clinical development approach that capitalizes the opportunities each system presents while maintaining efficiency. 

Submitting to MHRA first offers a compelling strategic advantage: Initial decisions typically come in approximately 37 days compared to 45 days for EU-CTR Part I and up to 90+ days for Part II. This approach enables powerful cross-learning, where MHRA feedback strengthens EU responses and anticipates potential questions, while EU Part I assessment outcomes can be applied to UK amendments (with significantly shorter review timelines). The result is higher-quality submissions with fewer validation issues across both regions. To maximize these advantages, sponsors should engage early with the MHRA Innovation Office for scientific advice that shapes EU strategy, and/or consider joint scientific advice meetings with both MHRA and EMA to ensure alignment. 

The regulatory landscape will continue to evolve with UK's new regulations (April 2026) and ongoing EU-CTR refinements. There are new functionalities of the portal shared by EMA and CTCG (including the notices and alerts email receipt from CTIS functionality as one of the most expected ones), and initiatives like FAST-EU pilot or the update of the Sponsor handbook expected by end March 2026.   

As the UK and EU regulatory landscapes continue to evolve, those who master harmonized submission plan gain significant advantages with patient access accelerated through efficient regulatory strategies. While EU-CTR experience provides valuable lessons for dual submissions, technology proficiency supported by regulatory expertise, proactive planning, and early alignment are critical. 

At Parexel, we've guided numerous sponsors through the EU-CTR landscape, turning regulatory complexity into competitive gain. Our experience has taught us critical success factors:  

• Expect a learning curve with CTIS management and build in buffer time for technical issues 
• Balance speed with quality in RFI responses, using feedback from one region to strengthen submissions in the other  
• Invest in quality upfront, as validation issues cause the most significant delays 
• Implement formal lessons learned processes to continuously improve future submissions 

Seeking to optimize your UK and EU clinical trial submission strategy? Contact Parexel's regulatory experts to discuss how we can support your development program. 

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References 

1. MHRA Guidance, Clinical trials for medicines: apply for approval in the UK, June 2025 
2. The Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 
3. MHRA, Inclusion and exclusion criteria for Notifiable Trials, January 2026 

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