UK MHRA · August 17, 2025

Clinical Trials Route B Substantial Modifications Pilot

Original title: Guidance: Route B substantial modification pilot

MHRA launches Route B substantial modification pilot from 1 October 2025, with new regulations effective 28 April 2026.

Medium impact Clinical Trials & Research UK clinical-trials

Clinical trials Route B substantial modifications pilot starts on 1 October 2025. Prepare for the implementation of new regulations from 28 April 2026.

Dates and deadlines

Applies from

2025-10-01

Regulatory Deadline

October 01, 2025

Regulatory Deadline

April 28, 2026

Read the official source ↗

Published by UK MHRA. HealthSignal links to the original document; the summary above is extracted from the source text.