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Clinical trials

The purpose of clinical trials for brain tumour patients is to gain a better understanding of these tumours and improve diagnosis and treatment. Some trials also seek to control symptoms more effectively and improve quality of life. 

By their definition, clinical trials are experimental, and while the hope is that they will be beneficial, there is no guarantee.

What is a clinical trial?

A clinical trial is an experiment that involves patients in a new way of managing a condition. It aims to find out if the new way works, if it's safe, what the best way of giving it is and, vitally, to establish whether the new approach is better than the old one.

Developing a new treatment

There are up to 5 phases to developing a new treatment, each of which can take some time. As a result, it can take 10-15 years or more for a treatment to go from initial design to becoming standard treatment in the clinic.

Phase 0

A phase 0 trial uses small, therapeutic doses of a drug or treatment to see what it does in people. The dose is too small to treat your tumour, but this does mean you're less likely to have side-effects.

It's aim is to speed up the development of promising drugs by testing them in people rather than animals.

Not all treatments go through a phase 0.

Phase 1

A phase 1 trial is usually the earliest trial of a treatment in people, after testing in the laboratory. It aims to find out:

  • whether the treatment is safe
  • what's the right dose to use
  • whether it has any side-effects.

Initially, the treatment is given at a low dose to a small group of people, who may be healthy volunteers. If the group experiences no serious side-effects, another group is given the drug at a higher dose. This process is repeated until the 'maximum tolerated dose' or MTD is determined.

Phase 1 trials tend to be carried out in specialised clinical research units rather than hospitals; recruit only a few people; and last several months.

Patients receive optimum care and attention while in the unit.

Phase 2

Not all treatments tested in phase 1 will make it to phase 2.

In phase 2, the aim is to find out more about the safety and side-effects, and whether the new treatment does what is hoped (referred to as its efficacy):

  • Is it any good?
  • Does it shrink the tumour?
  • Does it keep the tumour away for longer? (progression-free survival)
  • Does it make the patient feel better?
  • Is the treatment safe and well-tolerated?

The new treatment is often compared to an existing treatment or to a dummy drug (placebo).

It may be a randomised trial. This means people are put into the different treatment groups at random.

Phase 2 trials use larger groups of patients (up to about 100) and can last for a couple of years.

Phase 3

Phase 3 looks at whether the new treatment works better than the existing, 'standard' treatment or whether it produces fewer side-effects.

This is done by comparing two groups of patients with similar characteristics. Some of the patients receive the standard treatment and some receive the new treatment. The outcome of the two groups is compared to see whether the new treatment is better.

These trials are often 'randomised, blind trials', which are the most successful way of making sure the results of the trial are not biased and can be trusted.

(Randomised means patients are put into the different treatment groups at random. Blind means the patient doesn't know which treatment they are receiving [single blind], or that both the patient AND the researcher don't know which treatment the patient is receiving [double blind].)

These trials are on larger groups (several thousand patients), who are usually ill, and often last for several years. They often take place in many hospitals across different countries.

Phase 4

Phase 4 trials are conducted when a drug has been shown to be effective and has been licensed to treat an illness.

This phase aims to find out what happens when the drug is given to thousands of people in the general community. The purpose is to assess any long-term risks and benefits of the drug, and any rare side-effects.

What is an adaptive clinical trial?

Traditional clinical trials test only one drug or aspect of treatment at a time and take several years to produce results - positive or negative.

In an adaptive clinical trial, researchers can add in new drugs or combinations of therapies in response to a patient's improved or deteriorating condition, thereby speeding up the research.

This is particularly useful for fast growing tumours.

Find out more

How do I find a suitable clinical trial?

Every trial has a set of entry criteria that you must fit to be able to take part in the trial. The best way to find a trial is to speak to your clinician about trials that may be suitable for you.

You can also search for a clinical trial matching your criteria on our Take part in a clinical trial page. 

What are the advantages and disadvantages of taking part in a clinical trial?


  • The new treatment might be better.
  • If the treatment is an improvement, you may be one of the first patients to benefit from it.
  • Satisfaction from knowing that you're contributing to advancement of science.
  • You're more closely observed for changes in your overall health - so these may be picked up and dealt with more quickly.


  • They can be inconvenient, time consuming and costly - as they may require additional trips to hospital, or treatment centres in other parts of the country or even abroad. It may affect your insurance - seek advice before you take part.
  • It might be that the experimental treatment isn't better, or even not as good as, approved therapies which are already available.
  • Unexpected side-effects - the researchers will monitor you closely whilst you're in the trial and make every effort to keep these to a minimum.
  • You might not be receiving the new treatment.

How long do I stay on the trial?

The trial will go on until one of the following:

  • You decide to withdraw - it's your right to leave the trial at any time, without having to give a reason
  • The trial comes to an end
  • The treatment is clearly failing or there are safety concerns
  • Your doctors believe it's in your best interest to take you off the trial.

How can I get onto a trial if it's not offered by my hospital?

This may not be easy. It can mean travelling and staying near the site of the clinical trial. Sometimes a trial is geared to taking patients from other regions. The best thing is to discuss your wishes with your health team to see if particular arrangements can be made.

If you have further questions, need to clarify any of the information on this page, or want to find out more about research and clinical trials, please contact our team:

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