What is a clinical trial?
A clinical trial is a research study/project which investigates whether a treatment, medical strategy or device is safe and effective for humans or to indicate which medical approach works best for certain illnesses and/or groups of people. The data produced by clinical trials helps decision-making in healthcare, advances medical knowledge and helps improve patient care.
There are four different phases of clinical trials.
- Phase 1
- These are trials carried out on small numbers of healthy participants to determine the safety, side effects, how the treatment works in the body and lowest and highest doses.
- Phase 2
- These trials are on larger groups of participants with the particular disease or condition. This phase determines whether the treatment works well enough to be tested in a larger group of participants as well as learning more about side effects and how they can be managed.
- Phase 3
- These trials compare current treatment with new treatments at different doses on several thousands of patients. The results will be used to create patient information and will influence prescribing.
- Phase 4
- These are carried out on licensed treatments which are proven to work and also to determine long term benefits and risks as well as how well the treatment works when used more widely.
Clinical trials FAQs
Participants will receive interventions such as procedures, devices or drugs specific to a research protocol created by investigators. A research protocol details what the trial is going to do, how this will be done and how and when data is collected.
Clinical trials are led by Principal Investigators (PIs) who are often medical doctors. They may be funded by pharmaceutical companies, charities, universities or other organisations to carry out research.
Participants who fit the eligibility criteria listed within the protocol and who have conditions and illnesses being studied can take part in the clinical trial. Other trials seek healthy participants or predetermined groups of people to join. Eligibility factors which allow participants onto clinical trials are known as the inclusion criteria and factors which disqualify participants from taking part in a clinical trial are called exclusion criteria. The inclusion and exclusion criteria are based on factors such as age, gender, disease type or stage, medical history etc.
Clinical trials must be approved by an Ethics Committee, which gives an opinion about the proposed participant involvement on a study and whether the research is ethical. Before taking part in a clinical trial, participants must give consent by signing an Informed Consent Form to indicate that they were given information on the clinical trial and understand the potential benefits, risks, procedures as well as other options to the study.
The informed consent process includes the following steps:
- A consultation with the investigator or member of the research team in which the participant is given the opportunity to understand the objectives, risks and potential benefits of the trial as well as the conditions under which the trial is to be conducted.
- The participant gives their informed consent to take part in the trial.
- The participant is informed of their rights to withdraw from the trial by revoking their informed consent at any time without being subject to any detriment.
