Open research > Registering and reporting clinical research

Clinical trial registries are a public record of all planned clinical trials and what they intend to do e.g. what they will be testing, what they will compare it with and what measure or outcome they will use to assess this. Following registration, trials are updated throughout their lifespan, with any changes to the initial plan and further details such as the number of patients recruited and the trial protocol.

There are many clinical trial registries. Two of the registries most commonly used in the UK are ISRCTN and, but many types of UK trials may be registered in any International Committee of Medical Journal Editors (ICMJE) registry or WHO primary registry.

UK Clinical Research Collaboration Tissue Directory (UKCRC) is the primary registry for research tissue banks.

Registries for clinical studies beyond clinical trials are limited. Some formal registries allow registration of a broader range of studies; for example, Prospero is a register for systematic, rapid and umbrella reviews and Research Registry register all types of research studies, from case reports to observational studies, systematic reviews and meta-analyses.

Where studies are approved by the Health Research Authority (HRA), their information is published on the HRA’s website through their research summaries tool.  

What is required for registration?

Clinical Trials of Investigational Medicinal Products (CTIMPS) and Combined Trials of an Investigational Medicinal Product (IMP) and an Investigational Medicinal Device (IMD), once approved, have been automatically registered at the ISRCTN registry by HRA since January 2022, unless the trial has been, or will be, registered by the sponsor at The government announced in March 2023 that new legislation is being drafted which will make it a legal requirement for all CTIMPS to be registered in a WHO public register. 

For all clinical trials beyond CTIMPS and IMP/IMD trials, it is a condition of a favourable HRA ethics opinion that they are registered in a publicly accessible database, on the WHO list of primary registries, or the ICMJE list of registries, by the trial sponsor, before the first patient is recruited.

HRA approved trials should also update the registry record as the study progresses as a condition of favourable ethics approval. Updates would include final enrolment numbers, the date of primary study completion (the last data collection timepoint for the last subject) and any changes to the trial protocol. If a trial finishes early, its status should be updated in the registry to note this and to report the numbers enrolled up to the end date.

All HRA approved research tissue banks must be registered on the UKCRC Tissue Directory as a condition of favourable ethics opinion. The research tissue bank should be registered no later than six weeks after favourable opinion, or six weeks after the bank holds tissue with the intention to use it for research purposes. 

Registration is not required where:

  • a trial is abandoned before it commences 

  • a deferral for the trial has been agreed by or on behalf of the research ethics committee 

In these instances, a minimal record of the study is still expected to be published. Please see the HRA webpage for full details. 


Clinical Trial: A clinical trial compares the effects of one treatment, preventative intervention or diagnostic test with either another, or a control (no treatment/test). According to the HRA, clinical trials include: a clinical trial of an investigational medicinal product, a clinical investigation or other study of a medical device, a combined trial of an investigational medicinal product and investigational medical device, any other trial to study a novel intervention of randomised clinical trial to compare interventions in clinical practice e.g. trials of surgical interventions, radiotherapy, imaging, mental health investigations/therapies, physiological investigations, trials of non-medicinal products or devices or complimentary/alternative therapies.

Clinical Trials of Investigational Medicinal Products (CTIMPS): Investigational Medicinal Products (IMP) are any medicine that is being tested in a clinical trial for its effectiveness as a treatment or being used as a reference point for the effectiveness of another treatment. They include newly developed drugs and licensed drugs that are being tested against a new condition or in a new formulation. A clinical trial of an investigational medicinal product compares the effects of an IMP against another treatment, or a control.

Combined trials of an investigational medicinal product and an investigational medical device (IMP/IMD trials): An Investigational Medical Device is any instrument/implement (other than a medicine) used to diagnose, monitor, treat or manage a medical condition, whose effectiveness and/or safety is being studied. Examples include syringes, surgical tools, some medical apps, and soft and hardware e.g. continuous glucose monitors/pacemakers. A combined trial of an IMP and an IMD is trial that investigates these two things in parallel.

The Health Research Authority (HRA): Is a ‘non-departmental’ public body, sponsored by the Department of Health. It protects and promotes the interests of the public and participants in health or social care research by ensuring research is safe, ethical, and transparent. The HRA co-ordinates and standardises health and social care research regulatory practice, research ethics committees and approvals for processing confidential patient information. The HRA’s function and scope is laid out in the Care Act 2014 with some functions relating to the Medicines for Human Use (Clinical Trials) Regulations 2004.

Sponsor: In non-commercial research (including charity funded), the sponsor is normally expected to be the employer (which may or may not be the funder) of the chief investigator and in commercial research, it is the funder. A sponsor takes overall responsibility for the effective and proportionate set up, running and reporting of a research project.

Read the full list on our definitions page.

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Registering and reporting clinical research