New research transparency data on UK clinical trials published

Our data covers the registration status of clinical trials in the UK from 2024, and for the first time, data on whether trials that closed in 2023 have published a summary of results on a public registry within 12 months of the trial ending and shared a lay summary of results with their participants.

Unfortunately, two thirds of studies completed in 2023 have not yet published, or told us that they have published, their study results.

The HRA has a legal duty to promote research transparency, and this includes reporting on how transparent researchers and sponsors are being about their studies.

Registering trials on a public registry is the first step to transparency in research, followed by publishing trial results and sharing a summary of results with participants. Together, they are vital to help build public trust in research and to ethical research practice.

We are publishing this data all together for the first time to give a full picture of research transparency and compliance with HRA policy expectations, as we prepare for the new clinical trials regulations to come into effect next week.

The regulations will make research transparency a legal requirement. Read a blog with more details on the specific requirements.

What does the data tell us?

Registration data

We publish the registration status of clinical trials on an annual basis. This year’s report covers data collected on all clinical trials receiving a favourable opinion from a REC in 2024.

There are 1,346 trials in total, which is a slight increase on the previous year.

Key highlights from the data include:

• 94% of studies told us they are registered or in the process of being registered, which is an increase of 2% on last year’s data and the highest proportion registered since we started recording and reporting this information
• the number of trials providing us with no reason for registration remained the same as last year (4%)
• 2% of studies that received a REC favourable opinion in 2024 were not registered but did provide us with a reason – this was either that the study had not started (63%) or the sponsor no longer considered the study a clinical trial (37%)
• the 2 most used public registries are ClinicalTrials.gov, with 72% of clinical trials registered here, and ISRCTN (26%). Registration on ISRCTN has increased by 1% since last year’s report, and 2% of trials are registered on both registries
• compliance is higher for commercially sponsored clinical trials (94% registered) than non-commercially sponsored trials (84%).
• compliance is higher for Clinical Trials of Investigational Medicinal Products (CTIMPs) with 98% registered, compared to non-CTIMPs (94% registered)

Reporting data

The data on publication of results and results shared with participants is collected from final reports that sponsors are expected to submit to us within 12 months of their study ending. The data covers trials that ended in 2023. Overall, 76% of trials submitted their final report to us within the timeframe.

We found that:

• 52% told us that they have shared their results with participants, or are in the process of sharing their results with participants
• 24% of studies told us they did not share their results with participants and 24% is unknown as we didn't receive a final report
• 32% told us that they published their results on a public registry
• 44% told us that they did not publish their results, and 24% is unknown as they did not submit their final report

We want to increase compliance with our expectation to submit a final report, and are working with sponsors so that we can understand the challenges and support sponsors with both expectations and transparency legal requirements.

“It's really encouraging to see an increase in the total number of trials registered this year. Such high levels of compliance shows sponsors are ready for the new clinical trials regulations, which will make registration a legal requirement.

There is of course room for improvement with the data on publishing and sharing results with participants. Less than half of trials that we have data for have published their findings and 24% did not intend to share their results with the participants.

We must do better - transparency in research is vital and means that other researchers and potential participants can see what research is happening, which helps both avoid duplication and build trust in the research system.

Trust is the golden thread that drives this work. If we build trust, the public will want to take part in research and researchers will choose the UK as a place to invest and innovate. This is crucial now more than ever, as we work to support the government’s ambitions to be a world-leader in clinical trials.

We want to better understand any barriers to meeting these transparency expectations, soon to be requirements for clinical trials of investigational medicinal products (CTIMPs), and a key way of doing this will be for sponsors to share their final reports with us.

Thanks to proactive chasing from our teams, we increased the response rate from 68% to 76%, but we still don’t have the data for almost a quarter of trials that took place in 2023. We will be working hard to increase this number when we report next year to give us a clearer picture of transparency for trials in 2024 onwards.

It’s really important to share this data today, to give a snapshot of where we are now and where we aspire to be. We will be reporting these stats annually going forward and continuing to measure compliance once the new clinical trials regulations come into effect. We will also be sharing further details such as a list of sponsors who haven’t published or who haven’t told us that they have published their trial results.

We are really pleased to see such great results for registration of clinical trials in particular, and are confident that with our processes to gather this data combined with work with partners across the sector, we will see continued positive change in the future."

Clive Collett, Head of Policy and Engagement at the HRA

"The publication and ongoing visibility of this data are incredibly important, and I am pleased we are now seeing the transparency data for publishing results and sharing a summary with participants, even though the data indicates there is a lot of room for improvement. Overall, this work is positive for research participants, patients and the public—especially for those who want to find out what happened in a study they took part in.

The vision of the HRA’s #MakeItPublic group is for trusted information from health and social care research to be publicly available for the benefit of everyone, and this work is fundamental to achieving that. We owe thanks to the many people across the health research community who have worked collaboratively to make information about studies public, and we look forward to continuing to drive our agenda forward.”

Derek Stewart OBE, Chair of the Make it Public group