Clinical trials

The purpose of clinical trials for brain tumour patients is to advance understanding of these tumours and to improve diagnosis and treatment. 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. Trials are vital to establish whether a new approach is better than the old one.

Developing a new treatment

There are normally four phases to developing a new treatment:

Phase 1

After a treatment is tested in the laboratory, it goes into Phase 1 trials. These set out to answer:

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

Initially, the treatment is given at a low dose to a small group of people, who may be health 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 2

In phase 2, the aim is to find out more about the safety and about 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?

This phase uses a larger group 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.

Which treatment patients receive (standard or new) is often decided on a random basis. It is the most successful way of ensuring that the results of the trial are not biased and is known as 'blinding'.

These trials are on larger groups of people (several thousand patients), who are usually ill, and often last a year or more.

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 aim is to assess any long-term risks and benefits of the drug, and any rare side effects.

How do I find a suitable clinical trial?

Every trial has a set of 'entry criteria' that you must fit to be able to enter. The best way 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 Find a clinical trial page.

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


  • The new treatment might benefit you
  • Satisfaction from knowing that you are contributing to advancement of science
  • You are more closely observed for changes in your overall health.


  • They can be inconvenient and time consuming
  • It might be that the experimental treatment is not better, or even not as good as, approved therapies which are already available
  • Unexpected side-effects - the researchers will monitor you closely whilst you are in the trial and make every effort to keep these to a minimum.

How long do I stay on the trial?

The trial will go on until one of the following:

  • You decide to withdraw

It is your right to leave the trial at any time you wish without obligation to give a reason.

  • The trial comes to an end
  • The treatment is clearly failing or there are safety concerns
  • Your doctors believe it is in your best interest to take you off the trial

How can I get onto a trial if it is 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.

Page last reviewed: 01/2018
Next review date: 07/2020

logo for the information standard certification logo for the helplines partnership

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:

Support & Info Line

0808 800 0004 (free from landlines and mobiles)

Research & Clinical Trials Info Line

01252 749 999

Phone lines open Mon-Fri, 09:00-17:00

You can also join our active online community on Facebook - find out more about our groups.