Substantial Amendments

Applications for a Substantial Amendment must be completed using the NREC Substantial Amendment Form.


  • Proposed change(s) should be clearly described in the NREC form.
  • All changes to documentation should be clearly marked up on the document in question.
  • Changes to the Principal Investigator should be accompanied by a CV.
  • Addition of a new site should be accompanied by a Site Suitability form.
  • Evidence of fee payment should be submitted with each submission.

Substantial amendments to studies approved by local REC

Submission of a Substantial Amendment should be accompanied by the NREC Substantial Amendment form, relevant documentation as designated by the form, and evidence of fee payment.
For trials approved by local REC, previous documents from the trial should also be submitted within one month of submission of the Substantial Amendment. This documentation should include the original REC submission, cover letters and approval letters for any Substantial Amendments, and the most recent version of the documents.

To note

  • It is the responsibility of the Principal Investigator or Sponsor to determine whether an amendment should be considered ‘substantial’ or ‘non-substantial’.
  • Substantial amendments must be reviewed and approved by the relevant NREC prior to any study changes being actioned.
  • Applicants who intend to request a Substantial Amendment to their study must pay the appropriate fee in advance of submitting their application. See Fees for more information.
  • Find further details on substantial amendment classification.
  • See our Operational Framework for more details on the review process of substantial amendments.

Substantial amendments to Clinical Trials of Investigational Medicinal Products should be submitted to

Substantial amendments to Clinical Investigations of Medical Devices should be submitted to

Queries relating to the substantial amendment process can be addressed by the National Office team at for Clinical Trials of Investigational Medicinal Products (NREC-CT), and for Clinical Investigations of Medical Devices (NREC-MD).

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