A clinical trial is defined as any experimental study which prospectively allocates humans to a medical intervention. While randomised assignments are considered of highest value for assessing the safety and efficacy of an intervention, the WHO definition of a clinical trial for reporting purposes also includes non-randomised assignments, for example in Phase I trials. As safety problems may occur in Phase I trials, it is critical that the same disclosure mechanisms apply for non-randomised Phase I trials as apply to randomised Phase I, II or III trials. Phase IV or post-licensure trials of health products are considered clinical trials if they involve prospective designs (with or without randomisation). Clinical trials have pre-specified research or product development objectives, and so routine use of health interventions without specified research objectives are not considered to be within the definition of a clinical trial. (please refer to WHO statement on Public Disclosure of Clinical Trial Results)
WHO regards clinical trials registration as the publication of an internationally-agreed set of information about the design, conduct and administration of clinical trials. These details are published on a publicly-accessible website managed by a registry conforming to WHO International Standards for Clinical Trial Registries.
A Primary Registry under the WHO Registry Network is a clinical trials registry with at least a national remit that meets WHO Registry criteria for content, quality and validity, accessibility, unique identification, technical capacity and governance and administration. Primary Registries under WHO Registry Network have fulfilled the requirements of ICMJE.
Clinical trials which meet the definition in question 1 above should be registered. In some countries where regulations apply, observational clinical studies are also eligible for clinical trials registration.
HKUCTR is not a Primary Registry under the WHO ICTRP, investigators and/or sponsors should register their clinical trials prospectively with any of the Primary Registries under the WHO Registry Network or ClinicalTrials.gov in order to compliant with the recommendations and requirements of the ICMJE member journals and WHO ICTRP for the purpose of publications.