Trial design
The design of a clinical trial is very important as it ensures that the trial is given approval to proceed from the ethics committee and, in the case of a drug trial, the regulatory agencies. Doctors, nurses, patients and researchers work together with statisticians, trial managers and in the case of drug trials, representatives from pharmaceutical companies, to design the best possible trial.
The trial design forms the basis of the trial protocol which is a blue print for how a trial will be carried out.
The protocol will contain the following information:
- The question the trial is asking
- The number of people that will be involved and for how long
- Which treatments will be compared and how
- Which tests participants will undergo and when they must have them
- Details about how and when data will be collected
- Who can and can not take part – the inclusion and exclusion criteria.
All clinical trials have strict guidelines as to who may participate. These are known as inclusion and exclusion criteria. The inclusion criteria may include things like age, type of MS and degree of disability. The exclusion criteria might rule out people who have taken certain drugs, pregnant or nursing mothers etc. The purpose of the inclusion and exclusion criteria is to ensure that the appropriate trial participants are identified, to enhance safety and to ensure that the researchers are able to provide answers to the questions being studied. The doctor who is responsible for the trial is ultimately responsible for which patients are included or excluded.
The trials carried out in the development of a drug can be split into four phases and each phase requires a different approach to trial design. It should also be noted that the phases may overlap.
Phase 1
This is the first time the drug is given to man, usually involving 20-30 normal healthy male volunteers. The initial aim is to determine the safety and tolerance.
Phase 2
This is the first time the drug is given to patient's usually small numbers of hospitalised patients so they can be monitored closely. The aim of the study is to confirm that the drug has a therapeutic effect and to determine the optimal dose ranges and frequency.
Phase 3
These are large multi centre comparative studies designed to show the safety and efficacy of the new drug compared to a standard drug or placebo and involve large numbers of patients. These studies are required for submission to the regulatory authorities.
Phase 4
These are large trials that are conducted in patients with a drug after it has received a product license and focus on the safety of the drug in the long term.
More about the drug development process.
More about clinical trials and some of the key terms.
UK Clinical Research Collaboration (UKCRC) booklet "Understanding Clinical Trials".
The more you understand about clinical trials and the research process the better equipped you will be to have an informed discussion if the opportunity for involvement presents itself.