Safety in clinical trials

If you decide to take part in a clinical trial, you are protected in lots of ways:

  • All clinical trials have to be approved by a research ethics committee. These are independent groups made up of a mixture of health professionals and non-medical people. They make sure your right’s and well-being are a priority and that the likely benefits of the trial are greater than the possible risks.
  • Patients are often involved with research teams to help them understand the patient’s point of view.
  • Data monitoring committees monitor the safety of a clinical trial and how well a treatment is working. They can stop a trial if it is causing harm to a person.
  • The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) makes sure clinical trials meet high standards of practice and that all serious side effects are reported.
  • All clinical trials need to have insurance to protect the people taking part. But it is rare for a drug or treatment to seriously harm anyone in a trial.

Making sure a clinical trial is safe

Understandably, anyone who joins a clinical trial wants to know it is safe for them. There are different ways that people are protected before and during a trial.

Ethics committees

All research in the UK involving people must be approved by an ethics committee who review the trial plan (protocol).

An ethics committee is a group that protects the rights, interests and well-being of the people taking part in the trial. They put this at the centre of their decision-making. The ethics committee is independent of the trial sponsors, funders and investigators.

They look at each research suggestion (proposal). Then they give an opinion about the trial and whether the research is ethical.

An ethics committee makes sure that:

  • the trial is well planned
  • the likely benefits are greater than the possible risks
  • people are recruited to the trial correctly
  • information about the trial is clear and accurate.

An ethics committee includes a mix of health professionals and non-medical people. This can include patients, lawyers and members of the public. Having non-medical people is important, as they can look at the trial from a different point of view.

Patient involvement

Patients and members of the public are becoming more involved with trial research teams. They bring the patient’s point of view of the illness and treatment. This helps researchers understand why people might want to take part in a trial and what might put them off.

Patients and members of the public can also suggest new areas for research. And they can help write information about clinical trials for the public.

Data monitoring committees (DMCs)

Before a trial starts, a data monitoring committee is usually set up. The DMC:

  • oversee how the trial is designed
  • monitor people’s safety
  • monitor the effectiveness of the treatment during the trial.

If the DMC are concerned that a new drug or treatment is causing harm, they can work with the research ethics committee to stop a trial. For example, they could stop a trial if people are having severe side effects. This is unlikely to happen in phase 3 or 4 trials, because researchers test new drugs or treatments well during phases 1 and 2.

The DMC will also stop trials early if the results from the new treatment are looking much better than standard treatment. This means doctors can start using the new treatment instead of the standard treatment. People sometimes move from the control group to the new treatment group, so everyone in the trial can benefit from it.

Medicines and Healthcare products Regulatory Agency (MHRA)

The MHRA is a government body that makes sure trials meet standards of good practice to protect the people taking part. The MHRA must give approval for all trials before they can start. It continues to monitor trials for as long as they last.

It can also make changes to the trial plan (protocol) and interrupt or end the trial in some circumstances. Researchers must report all serious side effects from a trial treatment to the MHRA. Then this is reviewed.

If they see that it’s having serious effects and negative effects, they’ll pull you out of it. So you always have the option of stepping back from it.

Tom, clinical trial participant


All trials must have insurance. There are different arrangements for this, depending on who is running the trial. Research ethics committees will not approve trials where there is no insurance or compensation, if it is needed. All trials have a legal sponsor to make sure there are arrangements (such as insurance) to protect people taking part.

Drug companies who are funding trials are insured. If a drug harms someone taking part in the trial, compensation can be paid. Some drugs may cause unpleasant side effects, but it is rare for a drug to seriously harm anyone in a trial.

Trials that are funded by other organisations (not by drug companies) will pay compensation for any serious injury caused. This follows guidelines set by the Association of the British Pharmaceutical Industry (ABPI).

Individual NHS trusts are responsible for insuring themselves against any possible harm that local trials cause.

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