What should I know before choosing to join a clinical trial?

Remember, you can leave a trial at any time

If you’re thinking of leaving a trial, you can do so at any time and do not have to give a reason. If you leave, you can have the standard treatment available for your condition, and your decision will not be held against you.

Questions to ask your doctor

The first thing to do is to find out as much as you can about the trial, by asking lots of questions of the doctor or researcher who is running it.

Questions might fall into the following areas:

Basic questions about the trial

The doctor organising your treatment will give you basic information about the trial. Things you might want to know include:

  • What is the aim of the trial?

  • Who is funding it?

  • How will the trial differ from my normal care?

Questions about your treatment

Every clinical trial has its own risks and benefits, and it’s vital to understand these before you give your consent. Your questions might include:

  • What treatment will I get if I don’t take part in the trial?

  • What are the possible side effects of my treatment?

  • How may the treatment affect me physically and emotionally?

  • Who can I contact if I have a problem? Will someone be available 24 hours a day?

  • What extra tests or appointments will I have?

See below for more on assessing the risks and benefits of a clinical trial.

Questions about the commitment you make

It’s worth asking questions about how long a trial might take and where it is – so you can work out how convenient the trial might be for you.

Questions you should ask include:

  • How long is the trial expected to last? And for how long will I need to take part? (Some trials may just involve filling out a survey; others might last for years in multiple phases.)

  • What will happen if I stop the trial treatment or leave the trial before it ends?

  • How much of my time will be needed – including travel time?

  • Will I need to take time off work?

  • If the trial is testing a drug, will I have to collect it from the hospital, will it be sent to me by post or will I get it through my doctor?

  • Will I need extra help from family and friends?

  • Will the costs of my travel to the trial be reimbursed?

  • Will I have to fill in questionnaires or keep a diary?

Questions about what happens after the trial

If you’re volunteering for a trial, you may wish to know what happens after it ends. So, you might want to ask:

  • How long will it be before the results of the trial are known?

  • How will the results be made available at the end of the trial?

Taking advice from other people

Once you’ve had a conversation about the trial with your doctor, it may be a good idea to take some time to talk it over with family or friends – unless a decision is needed urgently because of your medical condition.

It might also be a good idea to talk to people who have experience of clinical trials.

You can also find stories from people who have taken part in clinical trials from our microsite, Research Changed My Life; or you might want to see the videos of patientsparents and young people on healthtalk.org.

Assessing the risks and benefits

Clinical trials are carefully designed to minimise the risks and maximise the benefits to all who take part, whatever treatment they receive.

But assessing the risks and benefits of a trial can be difficult, especially when you’re not a health professional yourself.

Some trials will have very little risk. But the risks of a trial may be greater when less is known about the treatment being tested.

In all trials the treatment may cause side effects that doctors cannot predict and that you may not be expecting. These may be unpleasant and, very rarely, can be life-threatening.

So you should be told everything that the researchers know about any possible risks and side effects and why the trial is necessary, so that you can make an informed choice about whether to take part.

If you take part in a trial you will be monitored regularly during and after the study. See our section on what happens during the trial for more information on this.

Early stage versus later stage trials

New treatments, or new uses for existing treatments, are tested in various stages – or phases – of clinical trials. Early stage trials (phases 1 & 2) involve a relatively small number of people and may be designed to test, for example, a drug’s safety or look for side effects. Phases 3 & 4 involve larger numbers of people and are designed to assess how the treatment works, compared with existing treatments, while continuing to assess side effects and risks.

Before being given to people for the first time, all drugs are checked for safety in animals.

New treatments versus standard treatments

Not everyone receives a new treatment in a clinical trial. Trials need to compare a new treatment with the standard treatment already in use, if there is one. So some people in a trial will receive the standard treatment but, until the results of the trial are analysed, no one will know which treatment is better.

New does not always mean better and you may not be worse off if you do not receive a new treatment.

See our page on what happens on a clinical trial for more information on ‘control groups’ in trials.

What happens if something goes wrong

It’s rare for patients to be seriously harmed by trial treatments. But before any trial can start, arrangements have to be put in place in case something goes wrong and people are harmed.

Research ethics committees can refuse approval for trials where there is no insurance or other provision for compensation; for more information on these committees, see our page on how trials are regulated, approved and funded.

Drug companies are insured so that, if a patient suffers because of a trial, compensation can be paid.

Trials funded by other organisations may not have this kind of insurance, but a payment may be made if something does go wrong. Individual NHS trusts are responsible for insuring themselves against damage caused by their own studies.

Before giving your consent to take part in a clinical trial, you may want to find out exactly what arrangements have been made for compensation.

How will my information be used?

Information you supply as part of the trial

If you register for a clinical trial, the research team will collect information as part of that particular trial. This information is held by the research team, not the UKCTG. All your trial records and any information that is collected about you will be kept confidential, in the same way as your medical records.

The researchers cannot tell anyone that you are in the trial without asking you first. If your doctor or consultant is not the person who recruited you to the trial, it can be helpful for them to be told you are in a trial as they will be responsible for your day-to-day healthcare; but they can only be told with your permission.

Once the trial has finished the results are usually published, and often presented at conferences. No name or any information that can identify you will be used in any reports about the trial.