Ending a trial



Why a trial may end

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Changing your mind

You can change your mind at any time

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Reasons why a trial may end

A clinical trial can end for a number of reasons:
  • Your treatment on the trial is complete, i.e. the set number of weeks/ months/years that you are allowed to have the treatment or the set amount of treatment you are allowed to have has been reached
  • Your doctor does not believe the treatment is working for you, or that it does not have any advantages over standard treatment
  • You experience serious side effects whilst on the trial
  • The trial is stopped early because the treatment has proven to work, has proven to not work as well as the standard treatment, or it’s been found to be too harmful
  • You decide to leave the trial

Once a trial has ended, a trial can be un-blinded and it is then possible to identify who has benefited from the treatment. If this happens, you are sometimes allowed to remain on the study treatment if you are responding well to it. However, this is not always the case. In general, your participation in a trial ends when the trial ends. This is because it might not be safe or effective to continue the treatment based on knowledge at the time.

Follow up

If you decide to leave the trial, if you have been asked to stop your study treatment, or the trial has officially ended, you may be asked to attend a number of follow-up appointments. Follow-up appointments are very important as they allow the researchers to monitor how you are doing and assess how safe and effective the treatment has been.

Trial results

After a clinical trial is completed, the researchers will carefully examine and analyse all of the information gathered during the trial. This can take quite a while, as no analysis can be carried out until the last participant has left the trial. After a thorough examination of all the results, the researchers will determine whether they have medical importance. In most cases, the results of these trials are published in scientific or medical journals.

In the UK the Health Research Authority (HRA), the part of the NHS that regulates health research, has recently issued guidelines to researchers on the need to inform participants of their findings. Researchers in the UK now have to share a summary of their findings with you and also tell you how to access the trial results.

In 2016, the EU Clinical Trial Regulations came into force, this means that summary results of all clinical trials of medicinal products in the EU have to be published on the EU portal.

If you do want to find out the results from a trial you have taken part in, you could also ask the doctor or nurse who is in charge of your treatment, or find out the official name of your trial and search for the trial in the PubMed database of medical publications (this will open a new tab).

Changing your mind

You can change your mind at any time

Taking part in a clinical trial is completely voluntary. You can stop at any time, whatever the reason.
However, if you do want to stop, you need to let your doctor know before stopping so that they can discuss next steps with you.

Withdrawal from a trial
Finding out which treatment you were on

If you withdraw from a clinical trial, you may not find out which treatment you have been taking, as it depends on the type of trial you have been on. For example most randomised clinical trials will only release this kind of information when the trial has been completely finalised. If you have been on a double-blind trial, even your doctor will not know which treatment you have been given. However, whilst designing a trial, the researchers will have included a stage where a trial is un-blinded. Ask your trial nurse or one of the researchers to find out what a trial’s policy is with regards to this issue before you agree to participate.