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Guidance for completing the application form and updating the record

What are clinical trials?

Guidelines for study registration and reporting

Other public registries and portals

Legislation around clinical trials


ISRCTN works with a number of stakeholders to improve the information publicly available about clinical trials.

ISRCTN supports open access to clinical trial data information in line with:

  • World Health Organization guidelines - registration of all interventional trials is considered to be a scientific, ethical and moral responsibility.
  • ICMJE statements - for a manuscript to be considered, trial details should be deposited before recruitment starts.
  • Industry recommendations - trial information should be deposited within 21 days of recruitment starting and results be made available within one year of market authorisation.

ISRCTN helps ensure that a number of organisations meet their trial registration objectives:

ISRCTN works to streamline trial registration processes with the following organisations:

  • The National Institute for Health Research through the NIHR Central Portfolio Management System (CPMS) - adoption by the Portfolio ensures that trials can benefit from NHS support and the Portfolio sends trial data batches on behalf of researchers who have opted for ISRCTN registration.
  • The Health Research Authority and its partners through the Integrated Research Application System - IRAS is a centralised system that helps researchers apply for permissions and approvals for health and social care research in the UK. Please see the section below for more information.

ISRCTN engages with the following organisations to make sure that current and future participants are better informed about relevant trials:

  • INVOLVE - advised on how to increase participants' involvement in research.
  • Association of Medical Research Charities - has reported on challenges to communicating the existence and results of research in plain English.
  • NIHR Be Part of Research volunteer registry - available to NIHR-funded or -supported studies. More than 250,000 research-ready participants are signed up to take part in health and social care research. This free service can identify volunteers for your study through the wide range of data it collects including age, ethnic group, sex, location and condition.

ISRCTN maximises the visibility of its clinical trial data by feeding it to other web platforms:

  • WHO clinical trial search portal - ISRCTN data uploaded weekly.
  • Be Part of Research - ISRCTN data uploaded weekly. Be Part of Research aims to list trials that have recruited and are recruiting in the UK and help the UK Government meet its commitment in the NHS Constitution that patients should be made aware of research relevant to them.

ISRCTN follows the development of all publicly available trial registries through its participation in the WHO registry network, in particular:


HRA-ISRCTN Registry partnership

From 1 January 2022 the HRA will automatically register clinical trials with the ISRCTN registry as one of the steps to ensure research transparency. This will start with clinical trials of investigational medicinal products (CTIMPs) that are submitted through combined review in the new part of IRAS.


Deferred publication of full details in registration of applicable UK phase I clinical trials

The EU Clinical Trials Regulation (CTR) states that any trial approved anywhere in the world from 31 January 2022 must be publicly registered before it starts, if data from the trial may later be included in an application made to an EU authority under the EU CTR. The HRA, MHRA and ISRCTN have been working with the UK phase I community to develop a process to ensure that UK phase I data meet the EU’s new transparency requirements without premature disclosure of commercially sensitive information. The process allows phase I trials with an HRA deferral to be registered with initial disclosure of only a minimal dataset. The full trial details and a summary of the results need not be published until up to 30 months after the end of the trial. That process is in line with EU transparency rules for phase I trials.


The new EU transparency rules apply to data included in applications made to EU authorities under the CTR. They do not apply to submissions made under the EU Clinical Trials Directive or to applications made in the UK. However, if data from a UK phase I trial approved on or after 31 January 2022 might be included in a future application made under the CTR, the sponsor must register the trial before it starts. ISRCTN’s deferral procedure for phase I trials allows sponsors to do that while protecting their commercially sensitive information.

  • Note: In order to use the deferral process, the trial must have requested HRA approval of deferral of publication of full details in the trial registration
  • Summary guidance on uploading minimum fields for deferred trials (guidance PDF)
  • Detailed guidance for applicants on uploading minimum fields for deferred trials (detailed guidance PDF)