What is a clinical trial?
Clinical trials are research studies which involve the participation of people. They are conducted after a lot of preliminary work has been done in the research labs. Participants in clinical trials receive specific interventions according to the research plan developed by the investigators. These interventions may be treatment with medications, use of devices or changes to participants’ behavior, such as diet. Clinical trials are used to determine if new treatments are safer and work better than current treatments. They may be conducted in a single hospital/institution only or in multiple hospitals/institutions at the same time.
Types of clinical trials:
There are two types of clinical trials:
Therapeutic or treatment trials are those in which the enrolled participants receive treatments. Usually, the efficacy and safety of different medications or devices are studied in treatment trials.
Non-therapeutic trials are those in which people do not receive treatments but the main goals of the trials are to find diseases early, to look for ways to prevent diseases or improve the quality of life.
Phases of clinical trials:
Clinical trials that test new treatments are developed in several different steps (called “phases”). There are several phases that apply to most types of therapeutic trials:
- Only a small number of participants are enrolled in phase I trials (15- 30 subjects).
- The purpose is to find a safe dose of a medication and to look for the side effects of the treatment.
- A larger number of participants join phase II trials (between 30 and 100 subjects).
- They receive treatment medication doses that are determined from Phase I trials to be tolerable and safe (“maximum tolerated doses” and tolerable side effect profiles).
- The purpose is to look at the effects of the treatment in patients with specific diseases – those who have responded best in Phase I trials.
Phase III / IV:
- A much larger number of participants are enrolled in phase III trials (usually more than 100 to several thousand).
- The purpose is to compare new treatments with current standard treatments.
Clinical trials for children with cancer
Most cancer treatments we use today are results of knowledge acquired from previous clinical trials. You can learn more about past and current clinical trials for children with cancer at the National Institute of Health/National Cancer Institute and Children’s Oncology Group websites.
Dr. Irina Pateva, M.D. Clinical Assistant Professor of Pediatrics, Case Western Reserve University / Rainbow Babies & Children’s Hospital
Dr. Alex Huang, M.D., Ph.D. Associate Professor of Pediatrics, Case Western Reserve University School of Medicine