If it is a drug that is being looked at, then the first thing that happens is that they are tested in the laboratory. If it seems that they may be helpful in the treatment of a particular cancer, they are tested in a phase 1 trial. If this is successful, the drug is entered into a phase 2, and then a phase 3 trial. The most common type of trial for young people with cancer is a phase 3 trial.
Phase 3 trials
The main aim of a phase 3 trial is to compare the effectiveness and safety of the treatment being tested with current standard treatments and to find out more about possible side effects. Phase 3 trials are usually large and often have many hundreds or sometimes thousands of patients from lots of hospitals, often in different countries.
Trial design
You might hear doctors or research nurses talking about things like ‘controlled trials’ and ‘randomisation’. This is what they mean…
Controlled trials
In most studies, one group of people will have the trial treatment, they’ll be known as the trial group. One group, known as the control group, will have the standard treatment. Without the control group, it’s impossible to measure how much of the improvement in patients is due to the new treatment and how much is due to the standard treatment or would have happened by chance.
Randomisation
All phase 3 and some phase 2 studies are randomised. This means that instead of a doctor deciding which treatment you have, a computer decides, so that the doctor has no influence on who goes into which group. If the doctors decided, it could introduce what is known as ‘bias’ and would make the results of the trial unreliable.
The computer allocates the members of each group so that each group has a similar mix of patients of different ages, sex and state of health. This means that if one group does better, it is likely to be because of the treatment, as the two groups are otherwise the same.
The benefit of randomisation is shown in the diagrams below.
Trial groups for which doctors choose patients
Diagram showing how from a mixture of two different types of people, the same type all end up in the same group.
(Diagrams supplied by Lindsay Johnson - Institute of Cancer Research Clinical Trials and Statistics Unit.)
