Start with what CTIS will publish
The first question is not what to redact. It is whether the structured field or document is subject to publication, and when. Trial category, population and the type of submission affect the disclosure timeline.
Confirm the trial category, population, application type and whether the trial is historical, meaning the relevant CTIS application was submitted before 18 June 2024.
Use the current revised transparency guidance and Annex I. Do not assume that every document uploaded to CTIS becomes public.
Structured fields do not have separate public and assessment versions and cannot be redacted after the field is populated.
Remove or redact personal data and CCI that qualify for protection. If redaction was required, provide the corresponding complete version for Member State assessment when the document type requires it.
Verify that redactions are irreversible and unsearchable, metadata are clean, signatures are protected, the document remains meaningful, and the correct CTIS slot is used.
Public, protected and review states
The field or document is in scope for publication under the revised rules and the relevant disclosure timing has been reached.
A publishable document contains personal data or CCI that qualifies for protection, so the public version removes only that protected material.
The document type is outside the publication list. It remains available in the secure domain for the applicable assessment or supervision purpose.
Publication status is document-specific. Under the April 2026 guidance, documents not listed in Annex I Table II are not subject to publication.
Use the correct document versions
| Information type | What to prepare | Main control |
|---|---|---|
| Structured data subject to publication | One CTIS data entry. There is no separate redacted version. | Do not place personal data or CCI in a public structured field unless the rules require that information to be public. |
| Document subject to publication, no protected content | The version for publication may be sufficient where no personal data or CCI require redaction. | Confirm the document type and publication timing before upload. |
| Document subject to publication, protected content present | A version for publication with the protected material removed, plus the corresponding complete version for assessment where required. | The two versions should otherwise contain the same substantive document content. |
| Document not subject to publication | The applicable assessment or secure-domain document. | Still apply data minimisation and include only personal data needed for the regulatory purpose. |
Slot selection matters. The current guidance warns that a document inadvertently uploaded into a publishable slot can be published if it is not corrected before the relevant publication point.
Personal data: anonymise the public version
For people other than trial participants, the guidance permits redaction as the anonymisation technique in the version for publication. The redaction must make the information permanently unreadable and unsearchable. Signatures should never be disclosed in the public version, and author metadata should be removed from the file.
Do not redact names automatically when CTIS requires them to be public. The current guidance identifies principal investigators and certain responsible site persons as examples where names can be disclosed. Participant data require stricter anonymisation because pseudonymised information can still identify a person when combined with additional information.
CCI: use a two-step test and redact narrowly
First ask whether the information is already in the public domain. If it is public, it cannot be treated as CCI. If it is not public, assess whether disclosure would undermine a legitimate economic interest or competitive position. Only information meeting both parts of that test should be considered CCI.
Redact at the smallest useful level. The April 2026 guidance says not to remove entire pages, document subsections or full tables when only particular words, figures or sentences qualify. The public document must remain meaningful to patients, healthcare professionals and other readers.
CCI is time-dependent. Information that justifies redaction early in development may cease to qualify later, so new and modified document versions should be reassessed rather than copying old redactions automatically.
Historical trials need a publication-trigger check
For CTIS applications submitted before 18 June 2024, structured data are published under the revised rules while the historical application documents are not published simply because of the transition. A later substantial modification or non-substantial modification submitted on or after 18 June 2024 can trigger publication of documents that are both in scope of that application and subject to publication under the revised rules. An additional Member State application can trigger publication of applicable Part II documents.
Before filing a lifecycle change on a historical trial, review the publication consequences at the same time as the modification scope. This links directly to the substantial vs non-substantial modification guide.
Final CTIS publication QC
- Confirm the trial category, population and publication timeline.
- Check each structured field and document against the current Annex I publication tables.
- Remove personal data from public structured fields unless publication is specifically required.
- For publishable documents, identify personal data and CCI separately.
- Apply CCI redaction only after the public-domain and economic-interest tests are both met.
- Make redactions irreversible, unreadable and unsearchable. Remove hidden text and author metadata.
- Protect signatures and re-identification risks in small, rare-disease and unusual-event datasets.
- Compare the public and assessment versions to ensure that redaction is the only intended difference.
- Use the CTIS document naming convention to distinguish public, redacted, tracked-change and other document states where applicable.
- Recheck the publication effect of any modification, additional Member State application or historical-trial update before submission.
Official sources and resources
- EMA Clinical Trials Information System: transparency rules and current reference documents.
- Revised CTIS Transparency Rules, EMA/263067/2023, applicable from 18 June 2024.
- ACT EU guidance on personal data and commercially confidential information in CTIS, version 2.2, 30 April 2026.
- Revised CTIS transparency rules and historical trials: quick guide for users, version 2, updated 30 April 2026.
- EMA CTIS training and support, including the current Sponsor Handbook and Sponsor FAQ.
Last reviewed: 18 September 2026