What is a clinical trial?
A clinical trial is a carefully controlled study designed to examine the safety and/or effectiveness of drugs, devices, treatments or preventive measures in humans. Clinical trials follow a strict protocol to ensure that the testing is completed as quickly and safely as possible and accurately answers the questions being asked.
Although the start of a clinical trial is cause for optimism it must be remembered that on average only one in five drugs that enter clinical trial will prove safe and effective enough to receive approval by regulatory bodies for distribution to the wider population.
What are the phases of a clinical trial?
Phase 1 is usually quite small and almost always designed purely to assess the safety of the new treatment and how well it's tolerated. Often phase I studies recruit healthy volunteers to take part rather than patients. Approximately 70 percent of new medical treatments pass Phase 1 testing stage.
Phase 2 tests the effectiveness of a treatment on a larger number of patients. Participants are typically divided into groups and the benefit of the drug compared to a placebo. Usually the patients don't know whether they have been given the real drug or the placebo. The trial is then known as a ‘blinded study'. One-third of drugs that enter clinical testing successfully complete phase II and progress to larger-scale phase III studies. Phase 2 trials are sometimes divided into phase 2a and phase 2b.
Phase 2a is specifically designed to determine the best dose of the drug.
Phase 2b is specifically designed to study how well the drug works at the dose determined in the phase 2a study.
Phase 3 involves extensive testing to assess safety, efficacy and dosage levels in a large group of patients. This step can take two to five years. About 80 percent of drugs that enter Phase 3 will successfully complete this stage.
Phase 4 evaluates the long term risks and benefits of the drug once it's available on the market.
Why participate in a clinical trial?
One common reason is to benefit from new research developments before they become more widely available. You should keep in mind that although the start of a clinical trial is a very promising sign, it isn't a guarantee for a treatment and during the trial you may receive a placebo rather than the new drug or treatment.
Another advantage is that people taking part in clinical trials are followed up even more carefully than usual, even after the trial has finished. This close attention could result in better management of the condition.
What are the risks of taking part in a trial?
Procedures could be painful, for example injections and biopsies and, of course, there is always the risk of an unwanted or unexpected negative reaction to the treatment. Therefore, it is very important that you discuss what is involved in detail with the trial nurse or doctor before giving consent to take part.
Trials also often involve multiple and frequent visits to hospital. This is obviously not always easy or practical. Participants in a trial also have to keep in mind that the treatment they receive might not provide any direct benefit for them - there is a chance they might be given a very low dose of the drug, or even a placebo.
Some questions you might like to ask before taking part in a trial can be found here.
Who can participate in a clinical trial?
All clinical trials have guidelines about who can take part. The factors that allow someone to participate in a clinical trial are called ‘inclusion criteria' and those that disallow someone from participating are called ‘exclusion criteria'. These criteria are based on such factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions.
Inclusion and exclusion criteria are not used to reject people personally, instead they:
- Keep the participants safe, for example another underlying condition could make participation in the trial dangerous.
- Increase the reliability of the results and therefore get the treatment to market as quickly as possible so that the wider population can benefit. If the trial participants are very different at the beginning of a trial it is difficult for the researchers to interpret the results because they don’t know if the reason one patient responded to treatment and another didn't is due to the drug or differences in their condition to begin with. This is especially helpful in the early phases of a clinical trial when there are only few participants.
In most circumstances, people who wish to participate in a clinical trial will find it easier if they live relatively near the team of people who are conducting the research, because they need to be monitored frequently. The clinical trial organisers will usually reimburse travel costs (within reason).
What do I do if I want to participate in a clinical trial?
Join patient registries if they are available for your condition. Patient registries are databases that contain information about patients with a particular condition. The registries are then used by clinical trial organisers to contact suitable trial participants and invite them to take part. Find out more here: Registries
Talk to your doctor, he or she might know of trials that may be of interest to you.
Finally, you can also directly contact the centre involved in the clinical study. They will get in touch with your local doctor whose involvement is essential. Please see the links below to find the details of trials currently recruiting participants.
Where can I find out about trials for my condition?
The U.S. National Institutes of Health has a website that lists most of the clinical trials happening around the world. You can search for trials for your condition and narrow this list down to a particular location. However the information provided in these trial summaries is not always easy to understand so you may wish to discuss it with a health professional. Also be aware that observational clinical studies are included in this database. No new treatments or drugs are given in these studies, instead a group of patients is observed to learn more about the condition.
The Muscular Dystrophy Campaign in the UK has translated many of the trial summaries on clinicaltrials.gov into lay language - Trials
Placebo: An inactive substance, for example a sugar pill, designed to resemble the drug being tested. It is used to rule out any benefits a drug might exhibit because the recipients believe they are taking it.
Clinical trial protocol: A set of instructions that describes the types of people who may participate in the trial; the schedule of tests, procedures, medications, and dosages; and the length of the study. The protocol is carefully designed to safeguard the health of the participants as well as answer specific research questions.
If you have any questions about clinical trials please contact us:
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