(Article from the NPDG-UK Newsletter - Spring, 2000)
Clinical trials are used to determine whether new drugs or treatments are both safe and effective. Carefully conducted clinical trials are the fastest and safest way to find treatments that work. Many new medicines and treatments are found to be helpful and safe in test tubes and in animals. They must also prove safe and effective in humans before doctors can prescribe them.
Ideas for clinical trials usually come from researchers. Once researchers test new therapies or procedures in the laboratory and get promising results, they begin planning Phase I clinical trials. New therapies are tested on people only after laboratory and animal studies show promising results.
What are clinical trial phases?
Clinical trials of experimental drugs proceed through four phases:
In Phase I clinical trials, researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
In Phase II clinical trials, the study drug or treatment is given to a larger group people to see if it is effective and to further evaluate its safety.
In Phase III studies, the study drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase IV studies are done after the drug or treatment has been marketed. These studies continue testing the study drug or treatment to collect information about their effect in various populations and any side effects associated with long-term use.
What is a protocol?
All clinical trials are based on a set of rules called a protocol. A protocol describes what types of people may participate in the trial; the schedule of tests, procedures, medications, and dosages; and the length of the study. While in a clinical trial, participants are seen regularly by the research staff to monitor their health and to determine the safety and effectiveness of their treatment.
Who can participate in a clinical trial?
All clinical trials have guidelines about who can get into the program. Guidelines are based on such factors as age, type of disease, medical history, and current medical condition. Before you join a clinical trial, you must qualify for the study. Some research studies seek volunteers with illnesses or conditions to be studied in the clinical trial, while others need healthy volunteers.
The factors that allow someone to participate in a clinical trial are called inclusion criteria and
the factors that keep them from participating are called exclusion criteria. It is important to note that inclusion and exclusion criteria are not used to reject people personally. Instead, the criteria are used to identify appropriate participants and keep them safe. The criteria help to ensure that researchers will be able to answer the questions they plan to study.
What is a placebo?
A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials experimental treatments are often compared with placebos to assess the treatment's effectiveness. In some studies, the participants in the control group will receive a placebo instead of an active drug or treatment.
What is a control or control group?
A control is the standard by which experimental observations are evaluated. In many clinical trials, one group of patients will be given an experimental drug or treatment, while the control group is given either a standard treatment for the illness or a placebo.
What is a blinded or masked study?
A blinded or masked study is one in which participants do not know whether they are in the experimental or control group in a research study. Those in the experimental group get the medications or treatments being tested, while those in the control group get a standard treatment or no treatment.
What is a double- blind or double-masked study?
A double-blind or double-masked study is one in which neither the participants nor the study staff know which participants are receiving the experimental treatment and which ones are getting either a standard treatment or a placebo. These studies are performed so neither the patients' nor the doctors' expectations about the experimental drug can influence the outcome.
What protections are there for people who participate in clinical trials?
The government has strict guidelines and safeguards to protect people who choose to participate in clinical trials. Every clinical trial must be approved and monitored by an Ethics Committee in the UK (Institutional Review Board in the USA) to make sure the risks are as low as possible and are worth any potential benefits.
An Ethics Committee is an independent committee of physicians, and lay people that ensures that a clinical trial is ethical and the rights of participants are protected.
All institutions that conduct or support biomedical research involving people must have an Ethics Committee that initially approves and periodically reviews the research.
