Clinical Trials

They are usually small trials, recruiting only a few patients. The trial may be open to people with any type of cancer.

When laboratory testing shows that a new treatment might help treat cancer, phase I trials are done to find out

• How much of the drug is safe to give
• What the side effects are
• How the body copes with the drug
• If the treatment shrinks the cancer

Patients are recruited very slowly onto Phase I trials. So although they don’t recruit many patients they can take a long time to complete. The first few patients to take part (called a cohort or group) are given a very small dose of the drug. If all goes well, the next group have a slightly higher dose. The dose is gradually increased with each group. The researchers monitor the effect of the drug until they find the best dose to give. This is called a dose escalation study.

In a Phase I trial you may have lots of blood tests because the researchers look at how the drug affects you. They also look at how your body copes with, and gets rid of the drug. They record any side effects.

People taking part in Phase I trials often have advanced cancer. They have usually had all the treatment available to them. They may benefit from the new treatment in the trial but many won’t. Phase I trials aim to look at doses and side effects. This work has to be done first, before we can test the potential new treatment to see if it works.

Not all treatments tested in a Phase I trial make it to a Phase II trial.  These trials may be for people who all have the same type of cancer or for people who have different types of cancer.

Phase II trials aim to find out

• If the new treatment works well enough to test in a larger Phase III trial
• Which types of cancer the treatment works for
• More about side effects and how to manage them
• More about the best dose to use

Although these treatments have been tested in Phase I trials, you may still have side effects that the doctors don’t know about. Drugs can affect people in different ways.

Phase II trials are often larger than Phase I. There may be up to 100 or so people taking part. 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.

Some Phase II trials are randomised. This means the researchers put the people taking part into treatment groups at random.

These trials compare new treatments with the best currently available treatment (the standard treatment).  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

Phase III trials usually involve many more patients than Phase I or II. This is because differences in success rates may be small. So, the trial needs many patients to be able to show the difference.

One example could be that 6 out of 100 more people (6%) get a remission with a new treatment compared to standard treatment. If there were 50 people in the new treatment group and 50 people in the standard treatment group, there may be 3 more people in remission in the new treatment group. The 2 groups would not look that different. But if the researchers gave each treatment to 5,000 people, there could be 300 more remissions in the new treatment group.

Sometimes Phase III trials involve thousands of patients in many different hospitals and even different countries. Most Phase III trials are randomised. This means the researchers put the people taking part into treatment groups at random.