Overview
Phase I Clinical Trials
Phase II Clinical Trials
Phase III Clinical Trials
Phase IV Clinical Trials
Benefits
Risks
More information
Overview
Clinical trials are the formal testing of new medical treatments for humans and are vital to measure the effects and safety of new medicines and other treatments, such as surgical procedures before they become widely available to the public. The four different types of clinical trials are known as phases. Each phase involves differing observations and periods of time.
Phase I Clinical Trials
This is the first time a new treatment is tested in humans. A small group of healthy volunteers take the medicine (usually a single dose) so that those studying the medicine can observe and record information about how the human body digests and reacts to it. These studies are carried out at specialised research facilities and volunteers are very closely observed in order to confirm that the treatment is not harmful.
Phase II Clinical Trials
During this phase the effectiveness of a new treatment is measured in a moderate number of patients who have the disease or condition in question. Information is collected about how effective the treatment is at different doses and what effects, if any, are observed.
Phase III Clinical Trials
This phase confirms a treatment’s efficacy when compared to current treatments. It involves large numbers (usually thousands) of patients with the disease in question. Phase III clinical trials usually take several years to complete and are carried out internationally at many different hospitals and/or medical clinics. These trials collect large amounts of data to measure how well the new therapy treats the disease. All of this data is usually then provided to governments and other authorities so that they can decide whether the risks and benefits of the treatment justify it becoming available to the general public.
Phase IV Clinical Trials
Further clinical trials are conducted after a treatment has become available to the public. These Phase IV trials allow for the gathering of even more detailed information about the treatment, especially economic and long term safety information. The length of Phase IV trials varies from study to study.
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Benefits of participating in a clinical trial might include:
- playing an active role in your treatment
- accessing expert medical care at leading institutions
- access to new treatments that are not available to the general public
- satisfaction from knowing you are aiding the development of improved medical practice.
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Risks of participating in clinical trials
The risks vary from trial to trial and cannot be easily generalised. Some major risks are:
- possible side effects and
- the possibility that the treatment won’t work as hoped.
All treatments are associated with unwanted side effects and it is important that you develop an appreciation of likely side effects before becoming involved in a trial. This will allow you to consider the likely risks alongside the likely benefits before making your decision to enrol in a trial.
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Where can I go for more information?