Amendments process flow chart

This flow chart documents the process for submission of clinical trial amendments to the Competent Authority (CA), Research Ethics Committee (REC), and relevant host organisation.


(1) Examples of substantial and non-substantial amendments are available on the HRA website. The decision as to whether an amendment is substantial or non-substantial is ultimately the sponsor’s.

(2) Non-substantial amendment form. For studies that received their initial approval before the HRA process change on 31 March 2016, new sites will need to be added using the new HRA process. See the HRA website or contact CTRG for further guidance.

(3) Consider whether the amendment requires MHRA approval even if it does not require NHS REC approval.

(4) Information on HRA categorisation of amendments

(5) Details on where to submit your amendments to, can be found in the IRAS help section.

Substantial amendments

If the University is the research sponsor, CTRG reviews and approves all amendments to protocols before submission to regulatory bodies. This is essential in order for the University to fulfil its sponsorship role and to ensure that indemnity is not affected by the changes.

A substantial amendment is defined as change to the terms of the protocol or any other supporting documentation that is likely to affect to a significant degree:

  1. the safety or physical or mental integrity of participants
  2. the scientific value of the research
  3. the conduct or management of the research
  4. the quality or safety of any investigational medicinal product used

Addition of new sites, or appointment of a new principal investigator at an existing trial site (for CTIMPs only), are substantial amendments since they change the conduct or management of the research.

If the amendment requires immediate implementation due to safety concerns (urgent safety measures) this must be discussed with the MHRA as soon as possible and a formal amendment submitted within three days.

In all other cases the REC, MHRA (trials only), sponsor and HRA or relevant NHS trusts (where required) must approve substantial amendments before they are implemented.

In order for CTRG and the relevant parties to review and approve amendments all documents must be provided in two formats: the original showing the amended text as tracked changes, and a clean version of the amended document.

Non-substantial amendments

For all non-substantial amendments, please submit using this using this template. Details on where to submit your amendments to can be found in the IRAS help section

You will not get a validation email but you will receive a categorisation email. There are two possible outcomes: 

  • HRA Approval for the amendment confirmed
  • HRA Approval for the amendment pending

In both cases, applicants should communicate this outcome to sites, along with the amendment application that was submitted. This should be sent to both the site research team and the R&D office, and the local CRN. If any amendments are category A or B, sites have 35 days to raise any objections, after which if no objections have been raised, the amendment can be implemented. Category C amendments can be implemented immediately.

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