What is a Clinical Trial?
Clinical research is an important part of the process of gaining better knowledge and understanding of human health and disease as well as the development of new and effective therapies for treating these diseases. Clinical trials represent an essential component of evidence based medical research.
Clinical trials are research studies involving people (healthy volunteers or patients) that test the safety and efficacy of a new treatment. A ‘treatment’ in this context could mean:
- A medicine.
- A medical device – such as a cardiac stent (used for narrow or weak blood vessels).
- A surgical procedure.
- A test for diagnosing an illness.
Clinical trials are designed by groups of doctors, scientists and other specialists. The trial design is usually based on a thorough analysis of existing research, and the recognition that certain questions about treatment, symptom control or side effects need to be answered. To draw up the best possible trial design, discussions involve medical staff, nurses, patients, statistical experts and support staff, as well as representatives from companies or funding agencies. The background, design and plan for the study are contained in a document known as the protocol.
Types of Trial Design
There are several types of clinical trial design. These can be classified as follows:
- According to the method used to allocate participants into treatment or control groups (non-randomised or randomised controlled trials);
- According to the awareness of either participants or researchers or both of which group participants are allocated into (open label, single or double-blind studies);
- According to the magnitude of difference between treatment and control groups that is expected (superiority or non-inferiority trials).
Principles of New Trial Designs and their Practical Implications
Concept of 'Blinding' in Clinical Trials