For a treatment to enter everyday use – it must pass through different types of clinical trial.

These are the first time the treatment is tested in people. They are usually small trials recruiting only a few patients and may be open to people with any type of cancer. The first few patients are given a very small dose and then providing there are not too many side effects the next group are given a slightly higher dose. These studies usually have a complex design and include lots of blood tests and clinical measurements.
People taking part in Phase I trials often have advanced cancer and have usually had all the treatment available to them. They may benefit from the new treatment but many won’t.

They aim to find out:

  • The safe dose range
  • What type of side effects
  • How the body copes with the drug
  • Does the treatment shrink the cancer

Phase I trials at UCLH are usually conducted at the NIHR/Wellcome UCLH Clinical Research Facility, although some may be conducted on the inpatient wards or in the Macmillan cancer centre and coordinated by the CCTU team. 

These are usually larger than Phase I trials with up to 100 people taking part.

Phase II studies aim to find out:

  • How effective the drug or treatment is in certain tumour groups
  • More about side effects and how to manage them
  • More about the best dose
  • If the new treatment works well enough to test in a larger Phase III trial

Sometimes in a phase II trial, a new treatment is compared with another treatment already in use, or with a dummy drug (placebo).

If the results of phase II trials show that a new treatment may be as good as existing treatment, or better, it then moves into phase III (3).

These trials compare new treatments with the best currently available treatment (the standard treatment). Phase 3 is sometimes written as phase III. These trials may compare:

  • A completely new treatment with the standard treatment
  • Different doses or ways of giving a standard treatment
  • A new way of giving radiotherapy with the standard way

If the differences between the new treatment and the existing treatment are small, hundreds of patients may need to take part before one is identified as better than the other. Studies may take place in several different hospitals at the same time, including hospitals in other countries.

These trials are carried out once a drug has been licensed and are looking to find out more about the rarer side effects of the drug and how well the drug works when it’s used in the wider population.