Understanding clinical trials

Treatment for cancer can be confusing and difficult to understand. There can be a lot of information to get your head around.

When diagnosed with cancer, a team of experts will carefully plan out your treatment.¹ They will do their best to make sure you receive the necessary care and support. But that doesn’t mean you can’t have some say in the treatment or care you receive.

Clinical trials are a type of medical research where scientists look to test new treatments for people like yourself. You might be interested in joining a clinical trial, and your doctor can help you to find out if there are any that are suitable for you.²

We understand that clinical trials might be new to you, so we have created this article to share some information about them.

What is a clinical trial?

Every day, scientists are looking to discover new treatments for cancer. When a potential new treatment is found, a clinical trial helps them to see how well the drug works.²

Clinical trials follow very carefully planned steps, called phases, to see:³

• Whether a potential new treatment works
• What the side effects are and how to manage them
• How the potential new treatment works compared to treatments that we already have
• The best dose of the treatment and how often it can be given

The different phases are:

Phase 0

Sometimes, Phase 0 trials are used to find out if a new treatment behaves the way the scientists expect it to. It usually involves around 10–20 people and only a very small dose of the treatment.³

It aims to find out:³ 

• Whether the treatment reached the cancer cells
• How the body responds to treatment
• How the cancer cells respond to treatment

Phase 1

This is usually the first step of a clinical trial. It tends to involve 20–50 people that have different types of cancer.³

Phase 1 trials aim to find out:³

• How much of the drug should be given to patients
• If the drug has any side effects
• What the body does to the drug
• How the cancer responds to the drug

Phase 2

If a drug passes through Phase 1, it typically moves on to Phase 2. This may include people with different types of cancer or a group of people with the same cancer. As many as 100 people may be included in a Phase 2 trial.³

Phase 2 trials aim to find more about:³

• How well the drug works, including which types of cancer the drug acts on
• Any side effects caused by the drug
• How much of the drug should be given to patients

Phase 3

Phase 3 is often the largest phase in the clinical trial process. It will include a group of around 1000 or more people. Usually, the people in the trial all have the same type of cancer, but sometimes people with different types of cancer are included.³

Most Phase 3 trials will have at least two different treatment groups. Usually, one group will receive a treatment they would have received as normal care if they were not taking part in the trial. Another group will receive the study treatment.⁴

Phase 3 trials aim to find out:³ 

• Which group responds best to the treatment
• More about any side effects caused by the drug
• How the drug affects the people’s quality of life

Phase 4

This step is usually done after a new treatment has been shown to work and is now approved to be used outside of clinical trial settings.³

Phase 4 trials aim to find out:³ 

• How the treatment works over a longer period of time
• If any new side effects begin to happen after more time on the treatment
• How well the treatment works in people that weren’t included in the Phase 3 trial

Why would I think about joining a clinical trial?

When thinking about clinical trials, it is important to consider what you will get out of the experience. Often, clinical trials offer:⁵

• Personalised care – When you take part in a clinical trial, you will be monitored by experts and are likely to have more tests and check-ups than if you were not taking part. Some people find this reassuring because if they experience a side effect, their doctors are likely to spot it sooner
• New treatments – Before a new treatment is approved to be used, it can only be used in a clinical trial. This might mean that you have access to the treatments that are not currently available to everyone
• Contributing to medical progress – Clinical trials aim to keep finding better treatments. By joining a clinical trial, you will be directly helping the future of treatment for people with cancer

However, it’s also important to consider:⁵ 

• It’s a big commitment – Clinical trials may be carried out at a different hospital and this can involve travel that can be tiring and take up a lot of time. You may need to visit the hospital a few times a week.
• The side effects are not known – Because a clinical trial is looking at a potential new treatment, there may be side effects that the healthcare team don’t know about yet. But if there are any, the clinical trial doctors will do their best to help manage them and support you.

Joining a clinical trial is not a small decision and your doctor will be able to support you in making that decision. They will be able to give you some more information about what to expect if you do want to join and more information about specific clinical trials. Remember you’re not alone in making these decisions.