Types of clinical trials

In most trials patients are split into two groups. One group will have the standard treatment for their cancer type. The other group will have the trial treatment which is being tested. The results are then compared to see if the new treatment works and if it is better than the standard treatment. Researchers also look at the side effects and compare if they are different, or worse or better.

When there is no standard treatment to compare with, one of the groups is given a placebo treatment instead. This is an inactive treatment which looks like a real one

To decide who goes into each group in a fair way, a computer places patients into treatment groups. This is called randomisation.

You may not be told which treatment group you are in. In some trials, neither the patient nor the doctor will know which treatment they are receiving.

Clinical trials

If you are asked to take part in a phase 2 or phase 3 trial, you may hear terms such as controlled trials, placebo, randomisation, blind trials and double-blind trials.


Controlled trials

In most trials, one group of patients will have the trial treatment and one group will have the standard treatment. Groups are randomly selected (see ‘randomised trials’ below).

Sometimes, the standard treatment is to ‘watch and wait’. This is when you do not need to have any treatment, unless the cancer starts to develop or cause symptoms.

The people with cancer who are having the trial treatment are called the trial group. The people having the standard treatment are called the control group. The researchers will compare the results of the trial group against the control group.

Researchers compare the results of both groups to find out if:

  • there is any benefit from the new treatment
  • the side effects are better, worse or different.

If the trial group shows any improvement, the researchers also measure:

  • how much of the improvement is due to the new treatment
  • how much would have happened by chance.


Placebo and blind trials

A placebo is an inactive treatment that looks the same as the drug or treatment that is being tested. But it does not act on the cancer.

It may be used when a new drug is added to a standard treatment. One group will get the standard treatment plus the new drug. The other group will get the standard treatment plus a placebo. If you are in this group, it does not mean you will not receive any treatment. The placebo is given along with the standard treatment.

You will not know if you are getting the trial treatment or a placebo. This is called a blind trial. Researchers compare the responses to the placebo and the treatment being tested to find out if it has any benefit.

In many trials, doctors do not know whether you are getting the placebo or the treatment being tested. These are called double-blind trials.

In an emergency, your doctor can find out this information from the trial co-ordinators or the pharmacy department at the hospital.

Blind trials or double-blind trials aim to reduce any bias. For example, knowing you are having a new treatment might make you feel more positive or negative. This could influence what you report to the researchers. Also, your doctor may judge your response differently if they know you are having a treatment that they feel positive about.


Randomised trials

Some phase 2 and phase 3 trials are randomised, controlled trials. This means that a computer programme randomly (by chance) chooses the groups for each treatment.

The computer matches the different groups to make sure they are as similar as possible. For example, this means they will have a mix of people with similar ages, gender or state of health.

Everyone taking part will get a code number and will be put into to the different treatment groups randomly. They may get:

  • the new treatment
  • the standard treatment, and sometimes an inactive treatment (a placebo) with it.

When people are put into treatment groups by a computer, it avoids any bias. If doctors or researchers decide who should get which treatment, they could be influenced by what they already know. Without realising it, they may put people more likely to respond to a new treatment into that particular group. This would affect the results of the trial and make a treatment look better than it is.

Randomisation
Randomisation

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Blind trials and double-blind trials

If you take part in a trial of a new drug, you may not be told which treatment group you are in. This is called a blind trial. The medicine used will look the same, whether it’s the new treatment, standard treatment or a placebo.

Some randomised trials are called double-blind trials. This means that neither you nor the doctor treating you will know which treatment you’re getting. Your doctor opens a specially coded treatment pack and only the trial organisers know which drug it contains. In an emergency, your doctor can find out from the trial co-ordinators which treatment you’re having. Or the pharmacy department at the hospital will be able to break the code.

Blind trials or double-blind trials aim to reduce any bias. For example, knowing you’re having a new treatment might make you feel more positive or negative. This could influence what you report to the researchers. Similarly, if your medical team knew that you were having a new treatment for which they had high hopes, this might affect how they judged your response to it.


Who can take part in a clinical trial?

All trials have guidelines about who can take part. These are sometimes called eligibility or inclusion criteria. For example, a trial may only include people with a certain type or stage of cancer. The stage of a cancer is its size and whether it has spread.

Trials also have guidelines about who cannot take part. These are called exclusion criteria. This is to make sure it would be safe for you to take part and that results are as accurate as possible.

Some possible reasons why you may not be able to take part in a trial are:

  • you have another health condition
  • you take certain medicines
  • you have had certain treatments in the past.

Your cancer doctor or nurse can tell you if a certain trial is suitable for you.


Current research into stomach cancer

The STO3 trial is trying to find out whether adding a targeted therapy drug called bevacizumab (Avastin®) to chemotherapy before and after surgery will improve the results of treatment.

Another trial is trying to find out if giving a targeted therapy drug called onartuzumab with chemotherapy is more effective for people with stomach cancer that has spread.

There are many different trials going on and your doctor or nurse can give you more information.

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