Some phase 2 trials are randomised. This means that there are at least two different groups in the trial and the people taking part are selected at random by computer for each of the groups. One group will have the new treatment and the other group will have a comparison treatment. This could be a different dose of the new treatment, a standard treatment or a placebo (see below), depending on the trial.
Sometimes phase 2 trials compare a new treatment to a placebo. A placebo is a ‘dummy’ drug that looks the same as the new treatment. It may be used in clinical trials if there is no standard treatment to compare the new treatment with, or if the new treatment being tested is being added to a standard treatment.
People taking part in a trial using a placebo (a placebo-controlled trial) will not know whether they are receiving the active treatment or the placebo. This is also called a blinded trial. The research team will not know either, but will give them the best level of medical care, whichever treatment they are having. If there are any concerns about patient safety, the researchers can always find out whether someone is having active treatment or the placebo.
The placebo effect
Even though a placebo doesn’t actually treat the cancer, it can affect how some people feel. For example, they might feel better because they think they are getting a treatment for their cancer (even though they aren’t). A change in a person’s symptoms as a result of getting a placebo is called the ‘placebo effect’. The research team will consider the placebo effect when they look at the trial results.