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What is a clinical trial

Over the past five years, the FXRFC has reported several significant breakthroughs in Fragile X research and used terms like “therapeutic targets” and “clinical trials”. The Foundation can understand a parent’s frustration with the seemingly slow pace at which these laboratory breakthroughs are translated into something we can actually use to treat children with Fragile X syndrome.

The development of any new drug or treatment starts with years of basic research by scientists in order to gain an understanding of the molecular and cellular basis of the disorder being studied. The goal is to identify “therapeutic targets” so that new chemical substances or treatments that act on these targets can be synthesized and evaluated.

The next step in evaluating potential new treatments is to test them on animals. These are also called “preclinical trials”. Animal testing is an important and necessary step in developing any new treatment. Such tests show whether a potential drug or therapy has toxic side effects and what its safety is at different doses. The results then point the way for human testing.

Most of us understand that drugs or other forms of therapy intended to treat people have to be tested in people. These tests, called “clinical trials”, determine if a drug is safe and effective, at what doses it works best, and what side effects it causes — information that guides health professionals and, for nonprescription drugs, consumers, in the proper use of medicines.

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 “normal” volunteers (20 - 80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects. This usually takes about 2 years to complete.

In Phase II clinical trials, the study drug or treatment is given to a larger group of people (100 - 300) that have the medical condition that you want to treat, to see if the drug is effective and to further evaluate its safety. This also takes about 2 years to complete.

In Phase III studies, the study drug or treatment is given to large groups of people (1,000 - 3,000) 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. This may take 3 ½ to 5 years.

Phase IV studies are done after the drug or treatment has been marketed, and takes an additional 2 years. These studies continue testing the study drug or treatment to collect information about its effect in various populations and any side effects associated with long-term use.

Controlled clinical trials are a type of trial in which results observed in patients getting the drug are compared to the results in similar patients receiving a different treatment. Controlled clinical trials are the best way science has come up with to determine what a new drug really does. That’s why controlled clinical trials are the only legal basis for Health Canada (and the FDA in the U.S.) to conclude that a new drug has shown “substantial evidence of effectiveness.”