What is a clinical trial?
A clinical trial is a medical research study involving people, who are always volunteers .Trials are done in all areas of medicine, not just cancer. They may involve testing new drugs and combinations of drugs, as well as new technology and procedures. Clinical trials play a very important role in helping to search for new and more effective treatments as well as better ways of diagnosing, screening or preventing a disease. Clinical trials are the best way to find out whether or not a new treatment is better than the current standard treatment. They can also find out if existing drugs work better in new combinations. Some clinical trials find out more about the psychological and social effects of illness and treatment.
What are the main aims of a clinical trial?
Clinical trials aim to answer specific questions about a treatment or procedure
. Researchers want to find out if the treatment they are testing:
• is safe
• has side effects
• Works better than existing standard treatments
• Will improve the standard of care for people with illness.
What are the different types of trial? There are many different types of trial, some of which are more common than others. The following paragraphs describe the main types of trial used in cancer care.
Prevention trials
These use drugs, diet, vitamins or other supplements that doctors believe may help to lower your risk of developing a certain type of cancer. People who take part in prevention trials are often at a higher risk of developing cancer.
Screening trials
Screening trials look at ways of finding a cancer early before symptoms start. Detecting a cancer early means treatment is more likely to be successful. Before you can effectively screen for a cancer you must have an accurate test to diagnose the illness.
Treatment trials
These are the most common type of clinical trial. They look at the best way of treating specific health problems including prostate cancer.
These trials test many different types of treatment such as new drugs, new ways of giving treatment or new combinations of treatments.This fact sheet is for men affected by prostate cancer who would like to know more about clinical trials. It describes the different types of trial and what taking part in one involves. It also tells you where you can find details of trials currently taking place and other sources of support. A guide to prostate cancer clinical trials treatments
For example, a trial may test whether or not combining hormone therapy with chemotherapy is the best way to treat prostate cancer that has spread to other parts of the body. Pilot studies these are small studies designed to test an idea or treatment before doing a larger study. They are sometimes called feasibility studies. If they are successful the research team will go on to do larger studies.
Quality of life studies
These studies look at how an illness or its treatment affects you and your daily life. Many of the large scale treatment trials include a quality of life study. Their aim is to improve the comfort and quality of life for people with cancer. In the case of prostate cancer for example, these studies often look at ways to control the side effects of cancer and its treatment such as incontinence and erectile problems. What are the different phases of a trial?
There are four phases of clinical trial. Doctors call these Phases 1, 2, 3 and 4. You may also see this written with Roman numerals -Phases I, II, III and IV.
Phase 1 trials
This is the earliest stage of testing a new drug or treatment that may be effective against cancer. The main aim of this phase is to find a safe dose and find out about side effects. Phase 1 trials involve a small number of people (often 20 to 30) with different types of cancer. The participants are usually in the advanced stages of cancer and have tried all other treatments available to them. Some may benefit from being on the trial, but some will not. Phase 1 trials are important to find possible future treatments for others with cancer. Some Phase 1 trials are called ‘dose escalations studies.’ In these, doctors begin by giving the first patient a very small dose of the drug. If this does not cause too many unmanageable side effects, they will then slowly increase the dose for each subsequent group of patients in the trial, closely monitoring the side effects on each person. They do this by taking regular blood tests and looking at how the body is coping with and getting rid of the drug. They will also monitor whether or not the drug is helping to shrink the cancer or slow its growth.
Phase 2 trials
This next phase of a trial usually involves around 50 to 100 people. Only about 70 percent of drugs tested in phase 1 trials make it to this next phase. In Phase 2 trials, researchers are still looking at doses and side effects, but they are also looking to see if the treatment is working well enough to take it to a Phase 3 trial. Result sat this phase allow researchers to decide whether a treatment is as good as or better than, the current standard treatment and which types of cancer it is most effective at treating.
Phase 3 trials
Phase 3 trials compare the best existing(standard) treatment with the treatment being tested. Researchers are now trying to find out if the new treatment is better than what is already used. For example, they may test a new type of surgery with the standard approach, or compare a completely new drug with the existing standard one. The trial may also use a different dose of a standard treatment to find out which dose is most effective. Participants are randomly assigned, usually by a computer, to either the standard treatment or the new one. This is called randomisation. There is more information on randomisation further on in this fact sheet. This phase of a trial usually involves many more people than Phases 1 and 2. There may be thousands of people involved from different hospitals in one country or in many different countries. Because the outcomes of new treatments or approaches may arise from other possibly unknown causes, large numbers of participants in trials enables the researchers to draw more confident conclusions about the results they uncover.
Phase 4 trials
Phase 4 trials are done after the new treatment has been given a license. There searchers know the new treatment works and is safe to use but other questions may still need to be answered such as:• Does the treatment have any long term side effects?• Does the treatment have any rare side effects that did not show up in the earlier phase trials?• Will those people who took the treatment live longer than those who did not? It can take many more years to find answers to these questions.