The portal provides access to 20 clinical trial registries (20 October 2024).
There is a standard and an advanced search with different facilities - these are described below.
Research has been conducted on approaches to searching this resource.
4 May 2017: The WHO Network of Clinical Trial Registries agreed that 'results availability' will be added to the core data elements of the ICTRP record, along with details of ethics committee approving the trial and trial completion date.
A record of changes to the ICTRP up to 2018 is provided.
Recent publications about the development and content of ICTRP:
Chan A-W, Karam G, Pymento J et al. Reporting summary results in clinical trial registries: updated guidance from WHO. Lancet Glob Health. 2025;13:e759-e768.
Fernandez-Gonzalez L. Registering transparency: the making of the international clinical trial registry platform by the world health organization (2004-2006). Global Health 2023; 19(1):71.
Namiot ED, Smirnovova D, Sokolov AV, Chubarev VN, Tarasov VV, Schioth HB. The international clinical trials registry platform (ICTRP): data integrity and the trends in clinical trials, diseases, and drugs. Front Pharmacol 2023; 14:1228148
Default operator AND; breast cancer = breast AND cancer (i.e. NOT the phrase ‘breast cancer’)
Terms are mapped to synonyms using the UMLS metathesaurus
Boolean operators NOT, AND, OR
Phrase searching "breast cancer"
Nesting Parentheses can be used to nest search terms e.g.
((“colon* cancer*” and neoplasms) or (“Incision AND liver” not malignant)) and hospital
Boolean operators, if not nested, are applied automatically in the following order: NOT, AND, OR'
Truncation * but only at the end of a word, not in the middle. Note that truncation disables synonym searching.
Individual words within phrases may be truncated e.g. “colon* canc*”
Truncated words must have at least three characters.
Field tags It is possible to limit searches by several options on the standard interface.
Hyphens Both hyphenated and unhyphenated terms should be searched
Help pages Yes
Example (cancer* OR neoplasms) AND pain*
Saved searches No
Export tagged Yes (CSV or XML)
Default operator AND; breast cancer = breast AND cancer (i.e. NOT the phrase ‘breast cancer’)
Terms are mapped to synonyms using the UMLS metathesaurus
Boolean operators NOT, AND, OR
Phrase searching "breast cancer"
Nesting Parentheses can be used to nest search terms within the fields e.g.
((“liv* cancer*” and neoplasms)
Boolean operators, if not nested, are applied automatically in the following order: NOT, AND, OR'
Truncation * but only at the end of a word, not in the middle. Note that truncation disables synonym searching.
Individual words within phrases may be truncated e.g. “colon* canc*”
Truncated words must have at least three characters.
Field tags This interface offers a fielded search
Hyphens Hyphenated and unhyphenated terms should be searched
Help pages Yes
Saved searches No
Export tagged Yes (XML only)
Updated 6 Oct 2025