Phase 1 trials

The aim of a phase 1 trial is to find out if a new drug or treatment is safe in people and how much of it should be given. It is the first time the treatment is tried out in people. And it is only done if previous laboratory work indicates that the treatment might be good for treating cancer.

At this stage, the researchers see how much of the treatment can be given safely to patients. They don’t focus on how well it kills tumours.

They are also trying to find out how the treatment should best be given to the patients. For example, should it be a tablet that is swallowed, or given as an injection? Should the injection be into the blood stream or directly into the arm or leg muscle?

Researchers test the new treatment in up to 30 patients who may have any type of cancer. The optimum amount, or dose, to give a patient and how the patient copes with the drug is tested.

The first patient to take part is given a very small dose. If all goes well, the next person gets a slightly higher dose. With each patient taking part, the dose is gradually increased (this is called ‘dose-escalation’) and the effect that it has is monitored.

The aim is to find the maximum dose of the treatment that can be given without causing harmful effects.

People who take part in phase 1 trials usually have advanced cancer and have had all the standard treatment available to them. They may benefit from the new treatment in the trial, but many won't.

Phase 1 trials are unpredictable because the effects of the new treatment are not known at this stage. But people often take part because they understand that phase 1 trials are the first step in finding new treatments for the future.

If you want to find out more about phase 1 clinical trials, have a look at the ‘Understanding clinical trials’ section of our CancerHelp UK website.