Clinical Trials

What is a clinical trial?

During various stages of the patient treatment pathway, patients or parents/carers may be asked to take part in a form of medical research called a clinical trial.

Clinical trials are tests where patients are given a newly developed drug or treatment in order to find our whether it works better than the existing treatment. Clinical trials help doctors to improve existing treatments or to find new methods to prevent, diagnose and treat diseases.

How are new drugs and treatments made?

Medical research usually starts in the laboratory where scientists study individual cells to see how they respond to a treatment, or to find out more about how diseases such as cancer work. If the results of these laboratory studies look promising there comes a point where the treatment needs to be tested in humans to discover what effects it has on patients. The process of testing a new drug or treatment on people is called a clinical trial.

Clinical trials are used to test a range of different factors such as how well a new drug works, whether changes to existing treatments can improve how they work, how combinations of treatments work together, how radiotherapy treatment or surgical techniques can be improved, or whether totally new treatments, such as gene therapy or immunotherapy, work in people. There are also types of trials that look at quality of life or supportive care issues.

In order to be certain that a new treatment or drug is both safe for patients to take and effective against the disease, it has to go through a lot of testing to discover:

  • what is the safest and most effective dose (safety)
  • whether there are any side effects (toxicity)
  • whether the drug/ treatment works better than existing treatments (efficacy)
  • how much the new treatment benefits the patient (outcome)

The testing is carried out in three (or sometimes four) stages which are called phases. Each phase is very strictly regulated and patients are closely monitored to make sure that they are not being put in any risk. Each successive phase of the trial allows the new treatment to be tested on more patients. Also as the scientists running the trial get a better idea of exactly which patients will benefit from the new treatment they can ask the appropriate group of patients to take part in the next phase of the trial.

Phases of clinical trials

Phase 1

If a drug looks promising in laboratory studies, a phase 1 trial may be carried out. This is usually the first time a new drug is tried in people. These types of trials do not usually look at the effect on specific types of cancer but look at things such as side effects and the safest and most effective dose. These types of trials are usually done with a small number of people, usually 10-30.

Phase 2

This type of trial may be open to people with specific types of cancer or a number of different cancers. Phase 2 trials are usually carried out on more patients than phase I trials, usually around 100 patients. In this phase the researchers and doctors look at which type of cancer the drug works best against, the best dose to use and what kind of side effects the patients experience. If the new drug or treatment shows promising results then it is moved onto a much larger phase 3 trial.

Phase 3

If a drug in a phase 2 trial looks as if it works as well or better than an existing treatment, a phase 3 trial is carried out. These trials are usually only open to people with a specific type of cancer. Many more people are included in these trials (hundreds or even thousands of patients) and by being able to measure the effect of the treatment in more patients, the doctors and researchers can be more certain about the drug's effectiveness and safety.

A single phase 3 trial can be carried out in hospitals in many different countries at the same time, and this is known as an International clinical trial.

How does a new treatment move from clinical trial to being prescribed to patients?

The new treatment being tested in the trial must be proven to be both safe and effective. If the clinical trial proves that the new treatment achieves these goals then the final stage is for the treatment to be licenced for doctors to be able to prescribe it to patients.

In the UK drug licencing is carried out by the Medicines and Healthcare Regulatory Authority (MHRA), who look at all the evidence from the laboratory experiments right through to the clinical trials to decide whether the new treatment is safe. The equivalent organisation in Ireland is the Irish Medicines Board (IMB). If the MHRA or IMB licence a new treatment then doctors are legally permitted to prescribe it in the UK or Ireland. Alternatively, a European licence can be granted by the European Medicines Agency (EMA) followed by a marketing licence, which is granted by the MHRA or IMB.

A second regulatory body then decides whether the newly licenced treatment will be freely available to patients through the National Health Service. In England, Wales and Northern Ireland drug access is controlled by the National Institute of Clinical Excellence (NICE). The equivalent organisation in Scotland is the Scottish Medicines Consortium, and in The Republic of Ireland is the Irish Medicines Board. The purpose of these organisations is to make sure that patients get access to the best quality treatments and to ensure value for money for the NHS.

Many new drugs or treatments are developed by pharmaceutical companies but may not make it past phase 1 and some may make it to phase 3 but the benefit to the patient may not be as much as first thought.

How do trials examine whether the new treatment is better than the existing one?

The new drug or treatment is usually compared to an existing treatment. Patients who enrol in the clinical trial are assigned to different groups. This process of assigning patients is done randomly by a computer, in a process known as randomisation.

Randomisation reduces bias because it rules out the chance that the doctors could put the healthiest patients in the 'new treatment' group, which could give misleading results. Also randomisation helps doctors to be certain that the treatment is effective and any positive outcomes did not just happen by chance.

You may see the terms 'blind' or 'double blind' randomised clinical trial. A blind trial means the patient does not know if they are receiving the existing treatment or the new one. In a double blind trial neither the doctors nor the patients know which treatment they have received because the labels are coded. The code is only deciphered at the end of the trial, when the patients and doctors can discover who had which treatment.

How can you find out more about clinical trials?

Each patient's consultant oncologist or surgeon will be aware of national or international trials that are suitable for the patient and may tell the patient or their parent/ carer about any clinical trials that are recruiting patients.

It is important to remember that not all patients may be suitable for particular trials. Clinical trials may not always be available, and the patient may not meet some of the requirements to be treated on trials that are available.

If a patient's medical team know of a clinical trial that the patient is eligible for, the doctor will describe what taking part in the trial will mean for the patient, what happens before and during the trial and about any possible risks. Patients will be given time to think about whether they wish to take part in the trial.

If a patient or their parent/carer hears about a clinical trial that they would like to take part in, they should discuss it with the patient's consultant. There are lots of things that need to be considered before a patient can take part in a trial. Some of these considerations or 'eligibility criteria' are known as 'inclusion' and 'exclusion' criteria and they will be fully explained to patients. These criteria are like guidelines detailing exactly which patients can take part in the trial. For example, inclusion and exclusion criteria may depend on:

  • age
  • gender
  • medical history
  • current health of the patient
  • types of treatments previously given to the patient
  • the exact type of cancer
  • whether it is newly diagnosed or recurrent cancer
  • stage of cancer

These strict criteria are put in place so that patients who are in a very similar position can be tested. If the group of people taking part in a clinical trial have too many differences between them, it may be difficult to obtain clear results about whether the treatment was effective or not.

Deciding whether to take part in a clinical trial

In order for a doctor to register a patient onto a clinical trial, the patient or their carer must sign a form to give 'informed consent'. This means that the patient or their parent/carer has been told all about the trial and any risks and benefits to taking part, and that they understand this properly and are giving permission for the patient to start on the trial.

Whether a patient decides to take part in a clinical trial or not is entirely their choice. Nobody can be forced to take part in a clinical trial, and a patient's future treatment won't suffer if they decide not to take part in any trial. There are very strict rules to govern this.

As part of deciding whether to take part in a clinical trial, patients or parents/carers may want to think about the benefits and risks involved in taking part in a clinical trial. Benefits may be that parents and patients will have an active role in his or her health care, may have access to new treatments before they become generally available, and helping others by contributing to medical research.

Risks could include side effects of the drug, which may be unpleasant, or the treatment may not be safe or effective for the patient. The trial may involve frequent stays in hospital and extra cost.

If you are considering enrolling on a clinical trial, it is fine to ask lots of questions - don't feel that any question is too trivial or silly to ask. It is very important that the patient and parents/carers understand what will happen during the trial and why it is running. Doctors will be happy to answer any questions patients or their parents/carers may have about clinical trials.

You could try writing a list of questions for the doctor. If you'd like to consider the answers later, you could write down the answers or ask the doctor whether you can record the answers on a voice recording device. That way you can listen to or read the answers to questions at a time when there may not be so much information to take in all at once. Having a family member there may also help.

Finding clinical trials that are right for you

There are several different web-based search tools that let you look for clinical trials for bone cancers.

It is important to remember that if you search for 'bone cancer' lots of the trials that come up are for breast cancer or prostate cancer patients whose cancer has spread to their bones, this is called secondary bone cancer and these trials are not relevant to primary bone cancer patients. It is better to search for your type of bone cancer, e.g. osteosarcoma, Ewing's sarcoma or chondrosarcoma, as this should give more relevant results.

Macmillan Cancer Care has a page that has information about clinical trials for primary bone cancer patients:

Cancer Research UK has a search tool to find clinical trials in the UK. You can select 'bone cancer' and then enter the type of bone cancer in the search box:

The Irish Cancer Society has more information on clinical trials, plus contact details to ask for information about Irish clinical trials here:

For a really comprehensive list of clinical trials you could try the American site,, which lists trials around the world. This site is very technical and can be difficult to interpret and so it is not the easiest site to use. As with the other sites it helps to narrow the search by selecting which country you would like to find trials in (United Kingdom, Ireland, etc.), and searching for the appropriate type of bone cancer.

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