How clinical trials get approval

All trials go through an approval process. A trial can't begin to recruit until all stages are complete.

Peer review

A protocol is the detailed plan of a trial. It outlines how the trial will be run. A group of people who are not involved with the trial should review and approve the protocol. When research teams ask another organisation for funding, peer review is often part of the funding approval process.

The peer review group includes:

doctors
other healthcare professionals
non medical (lay) members of the public

They look at:

the aim of the trial and how important the issue is
the design of the trial
the patients the research team would like to recruit
whether people are likely to want to take part
how they plan to analyse the results
whether the research team have thought about all the possible issues

Ethical approval

A Research Ethics Committee (REC) also review the trial protocol. There are over 80 RECs across the UK. The Health Research Authority (HRA) organises them.

Each committee has up to 15 members who are not involved with the trial in any way. At least 1 in 3 of these people are members of the public who are not researchers or health professionals.

RECs look after the rights, safety, dignity and wellbeing of people taking part in research in the NHS. They assess each trial protocol against a set of standards.

They look at:

the aim of the trial and how important the issue is for patients
how the research team plan to recruit people
whether the likely benefits are greater than the possible risks
the qualifications and experience of the team running the trial
whether the trial has been peer reviewed
if the patient information sheet (PIS) is complete and easy to understand
if other information such as GP letters, patient questionnaires or forms are well written

The committee then decides if the trial is safe and ethical to do, and whether it can go ahead or not.

The committee can ask the research team to make changes to the protocol or the patient information sheet before they give the final go ahead.

During the trial

The researchers are not allowed to change the protocol without telling the ethics committee. They must also tell the committee if patients have any serious unexpected side effects.

The committee can stop the trial at any time if they have any concerns about the welfare of the people taking part.

At the end of the trial, the ethics committee gets a copy of the results.

Other checks

The research team may also need to get approval from other groups as well as an ethics committee. This depends on the type of trial.

For example, a trial may use scans or treatment that would expose people to more radiation than normal. In this case, the team must get a certificate from a specialist committee to give them permission to do this.

Trial authorisation

All clinical trials involving medicines and medical devices need approval from the Medicines and Healthcare Products Regulatory Agency (MHRA). This is called Clinical Trial Authorisation (CTA).

Hospital approval

Each hospital that wants to take part in the trial needs approval from its NHS Research and Development (R and D) department. You may hear this called site specific assessment (SSA).

This assessment makes sure that the hospital has the staff, time, equipment and expertise to carry out the trial safely. The R and D department also look at other trials already running at the hospital. They may not want to run two trials recruiting similar patients, for example.

Once approved, the trial team will arrange training for the hospital staff. This could be online or in person and should include anyone involved with the trial. This includes doctors, research nurses, pharmacists and radiographers.

Once everyone is familiar with the trial and all the approvals are in place, they can start recruiting patients.

References

Clinical trials for medicines: apply for authorisation in the UK
Medicines and Healthcare products Regulatory Agency
GOV.UK website, last updated 27 August 2024
Accessed July 2025