BLOG: MHRA Inspectorate – Route B substantial modifications pilot: the results are in

Date: 22 May 2026

As part of the shift towards a risk-proportionate regulatory framework, the MHRA’s Clinical Trials Unit ran a Route B substantial modifications pilot from 1 October 2025 to 31 March 2026 to test a new process to streamline the review of modifications to low-risk approved clinical trials.

Any modification that will be eligible under section 11B of the Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2024 were eligible to join the pilot.

The aim is to cut the time it takes the MHRA to review applications from 35 to 14 days by reducing regulatory hurdles for sponsors of low-risk trials and enabling expert assessors to focus on higher-risk trials.

This will lead to faster initiation of low-risk trials – reducing administrative blocks without compromising participants’ safety.

Read the results here: https://mhrainspectorate.blog.gov.uk/2026/04/27/route-b-substantial-modifications-pilot-the-results-are-in/

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