UK Clinical Trials Regulations Transitional Arrangements

Overview

Guidance accompanies the Medicines for Human Use (Clinical Trials) Regulations 2004, as amended by the Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025. The amendments come into force on 28 April 2026. Until this date, the guidance is in draft and should be used only for preparation. Refer to existing guidance for processes before 28 April 2026. Published 25 June 2025; last updated 17 February 2026. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

The Clinical Trials Regulations require investigators and sponsors (and any delegated parties) to consider all relevant guidance for commencing and conducting trials. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

‘Old Rules’ and ‘New Rules’ Clinical Trials

• Old Rules Clinical Trials: Applications submitted before 28 April 2026 (even if outcome pending after); governed by pre-28 April 2026 regulations.
• New Rules Clinical Trials: Applications submitted on or after 28 April 2026; governed by amended regulations.
• Submission route does not affect classification. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

Transitional Arrangements for Applying for Clinical Trial Approval

Old Rules Clinical Trials

Old regulations apply to the entire approval process, even post-28 April 2026 if decisions pending. If non-acceptance issued after 28 April 2026, old rules apply post-response. Lapse provision (approval lapses after 2 years without recruitment) does not apply. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

New Rules Clinical Trials

Amended regulations apply to the entire approval process. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

Transitional Arrangements for Transparency Regulations

Old Rules Clinical Trials

• If trial ends before 28 April 2026: Amended transparency requirements do not apply.
• If trial ends on or after 28 April 2026:
  • Register in public registry: Before first participant consent or within 90 days of 28 April 2026 (or 90 days if first participant recruited pre-28 April 2026).
  • Publish results summary in same registry.
  • Accessible summary for participants not required (encouraged).
  • Automatic deferral for phase I trials applies if minimum information registered by deadline. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

New Rules Clinical Trials

All amended transparency provisions apply. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

Transitional Arrangements for Applying for Approval for Modifications

Determined by modification application submission date:

• Before 28 April 2026: Old regulations apply, even post-28 April 2026 if decisions pending.
• On or after 28 April 2026: Amended regulations apply, even for old rules trials. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

Transitional Arrangements for Good Clinical Practice

Old Rules Clinical Trials

Part 4 of amended regulations applies from 28 April 2026, except regulation 31A(7) (trial master file retention): Retain for at least 5 years post-trial (old rule applies). Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

New Rules Clinical Trials

Part 4 of amended regulations applies. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

Transitional Arrangements for Pharmacovigilance

Old Rules Clinical Trials

Part 5 of amended regulations applies by default from 28 April 2026. Option to continue under old rules: Contact licensing authority within 60 days from 29 April 2026 or when submitting notification/safety report (whichever earlier); applies until first annual safety report post-28 April 2026, then amended rules mandatory. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

New Rules Clinical Trials

Part 5 of amended regulations applies. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

Transitional Arrangements for Manufacture and Importation of Investigational Medicinal Products (IMPs)

IMPs manufactured or imported after 28 April 2026: Subject to Part 6 of amended regulations (for both trial types). Exception: Regulation 37A (exemption for radiopharmaceuticals) does not apply to old rules trials. IMPs manufactured under old rules in approved countries: Import allowed post-28 April 2026 if EU QP certification completed by 28 April 2026. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

Transitional Arrangements for Labelling of IMPs

Part 7 of amended regulations applies to IMPs in both trial types. IMPs manufactured before 28 April 2026: Can continue use with old labelling in original trial. IMPs manufactured after 28 April 2026: Label per amended regulations (date = QP batch certification). New batches post-28 April 2026: Risk assess labelling changes (substantial or minor); substantial requires approval via amendment/modification. Exceptional cases: Submit Route A substantial modification for variations/disapplications with justification. Post-QP certification labelling (e.g., expiry updates) post-28 April 2026: Allowed without full compliance if certified pre-28 April 2026. Importation: QP oversight not required pre-28 April 2026 for pre-certified IMPs with old labelling. Non-IMPs (NIMPs): Must comply with amended regulations from 28 April 2026; submit substantial amendment for approvals/variations by at least 35 days pre-28 April 2026. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

Transitional Arrangements for Enforcement

Depends on breached provision: Amended regulations breach: Part 8 of amended regulations applies. Old regulations breach: Old enforcement applies. Modifications from transitional provisions may be included in infringement notices. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements

Summary Table: Regulations Applicable On and After 28 April 2026

Updates

• 17 February 2026: Clarified pharmacovigilance timelines, labelling approvals, post-QP labelling.
• 12 January 2026: Clarified NIMPs exclusion from labelling transitions.
• 1 October 2025: Summary table edits for labelling accuracy.
• 21 August 2025: Removed feedback link.
• 25 June 2025: First published. Source: https://www.gov.uk/guidance/clinical-trials-regulations-transitional-arrangements