About Clinical Trials

What is a clinical trial? 

Clinical trials are research studies involving patients or volunteers, which compare a new or different type of treatment with the best treatment currently available. No matter how promising a new drug or treatment may appear during tests in a laboratory, it must go through clinical trials before its benefits and risks can really be known. Before starting clinical trials the study sponsor must receive approval from the government regulatory authority (this is the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK) and an ethics committee. 

Why are clinical trials important? 

Trials are essential to find out whether one treatment is safer and more effective than another. A new treatment is not always better, and can sometimes be worse than existing treatments. Health professionals and patients need the evidence from trials to know which treatment will work best for them. Many of the treatments now commonly used in the National Health Service have been tested through clinical trials.

Different types of trial 

There are many different types of trials and designs of studies. More information can be found here. All new drugs have to go through a series of phases; firstly to test if they are safe and secondly to test if they are effective. 

Phase I trials aim to test the safety of a new treatment. This includes looking at the side effects of a treatment, for example, does it make people sick, raise their blood pressure? Phase I trials involve only a small number of people, who may be healthy volunteers.

Phase II trials test the new treatment in a larger group of people who have an illness, to see whether the new treatment is effective, at least in the short term. Usually a few hundred people are involved at this stage. Phase II trials also look at safety.

Treatments only move into a phase III clinical trial if phases I and II have been successful.

Phase III trials test the new treatment in a larger group of people with the illness. Phase III trials compare the new treatment with the treatment currently in use, or occasionally with a placebo. These trials look at how well the new treatment works, and at any side effects. They usually last longer than phase II trials, typically a year or more, and are larger, often involving several thousand patients from different countries.

After successfully completing this phase of testing, an application to government regulatory groups can be made to market and make available for sale the drug. After reviewing all the data from the clinical trials and other information a decision will be taken.

Phase IV: This phase usually involves further evaluation of the study drug in a variety of ways once the drug has been approved for use by a government. This could include the ongoing safety and efficacy in a larger patient population, compare the drug to other, similar drugs already in the marketplace for cost effectiveness and similar benefits, and the overall long term effect of a patient's condition and quality of life.