Types of clinical trials
Clinical trials are sorted in two ways: by what they set out to learn, and by how far a treatment has come. Here is each type in plain words, with what it tends to ask of the people who take part.
Some trials test something, others only watch
An interventional trial gives the people taking part something, such as a medicine, a device, a procedure or a program, and measures what happens. This is what most people mean when they say clinical trial.
An observational study changes nothing about your care. It records what happens over time, through visits, tests or questionnaires, to learn how a condition behaves and who it affects.
What a trial sets out to learn
Treatment trials
Test a new medicine, device, surgery or therapy, or a new way of using one that exists, in people who have the condition.
Prevention trials
Look for ways to stop a condition starting or coming back, through medicines, vaccines or changes in daily habits.
Diagnostic trials
Try out new ways to confirm a condition, such as a scan, a blood test or a device, and check how accurate they are.
Screening trials
Test ways of finding a condition early, before symptoms start, often in people who feel perfectly well.
Quality of life trials
Also called supportive care trials. They look for ways to ease symptoms and side effects and make daily life easier.
Behavioral trials
Study changes in what people do, such as exercise, eating, sleep or talking therapy, and whether they improve health.
How far a treatment has come,
phase by phase
The first time a treatment is given to people. A small group, sometimes healthy volunteers, is watched closely to learn how safe it is and which dose to use.
A larger group who have the condition takes the treatment, to see whether it seems to help while safety is checked all along.
Large groups, often at many sites, compare the treatment with the one doctors already use, with people usually put into groups at random.
Once a treatment is approved, studies keep following people who use it, to learn about long-term safety and how it works in everyday care.
Studies that only observe, and many device and behavioral studies, do not use phases. A listing says when a phase applies.
Other studies you may
come across
Not every study fits neatly into a purpose or a phase. These are the other kinds people often meet when they start looking.
- Registries gather information about people with a condition over many years, without changing their care
- Natural history studies follow how a condition changes over time, with no study treatment at all
- Healthy volunteer studies need people without the condition, most often in the first phase
- Studies from home swap some clinic visits for video calls, kits sent by post or a nurse who visits
- Extension studies let people carry on with a treatment once the main part of a study has ended
Terms you will meet in a trial
People are put into groups by chance, much like a coin toss, so the groups can be compared fairly. Neither you nor the study team picks your group.
A dummy treatment that looks like the real one but has no active ingredient. It shows whether a change comes from the treatment itself, and the consent form always says if a study uses one.
You do not know which group you are in. In a double-blind study the team does not know either until the end, so expectations cannot sway the results.
Everyone, the study team included, knows which treatment is being given. Many extension studies run this way.
The group that gets the usual treatment or a placebo instead of the one being tested. Comparing the groups is how a trial learns anything.
The talk and the form in which the team explains a study, its risks and your rights before you agree. You can ask anything, take the form home and change your mind later.
Stay updated on clinical trials
Orva keeps you updated now and then about research in its six areas, by email or text, from Orva alone.
Go to the sign-upIt is free, the text box is optional, and one reply stops the texts.
