Randomised Controlled Trials
This page tells you about randomised clinical trials. You can scroll down the page to read all the information here.- What is randomisation?
- Why randomise?
What is randomisation?
Phase 3 trials compare one treatment with another, to find out which is better. Most phase 3 trials are randomised. This means that there are at least 2 different groups in the trial and those taking part are put into one or other group at random. This 'randomisation' is usually done by a computer.
Each group in the trial will receive a different treatment. If there are 2 groups, one group will have the new treatment being tested and the other the standard treatment that they would have to treat their cancer if not in the trial. Those having the standard treatment are called the 'control group'. A randomised trial that has a control group is called a 'randomised controlled trial'.
There may be more than 2 groups. Some trials test more than one new treatment or they may test variations in one particular new treatment - for example different doses of a drug. There will still be a control group, who have the standard treatment that they would have if not in the trial.
Sometimes control groups are given a dummy treatment, called a placebo. This is only done if there is no standard treatment available.
Why randomise?
Randomisation is done because researchers need to be sure that the results they get are correct and not biased for any reason.
Of course, researchers are unlikely to be deliberately biased. But it is possible to be biased without realising it. Supposing a new treatment is being tested that has quite bad side effects. The doctors running the trial might subconsciously avoid putting sicker patients into the new treatment group. So as the trial went on, the control group would have more and more of the sickest patients in it. The less sick people in the new treatment group might do better than the control group. So, when the trial results come out, the new treatment looks as if it works better than the standard treatment. But really it doesn't.