Find your care
What is a clinical trial?
A clinical trial is a carefully designed research study that uses volunteers to answer specific health questions, such as whether a medication, device or other intervention can improve health outcomes. The study protocol states the study’s purpose, goals of discovery and exactly how the research process must be implemented in each center where the clinical trial is taking place. To ensure that information gained from the study is reliable and valid, the protocol outlines how the= research is conducted safely and consistently.
There are three main types of clinical research studies: prevention trials, interventional trials and observational trials. Each type of study operates according to a protocol and requires informed consent from study participants – whether or not the research involves treatment of a diagnosed disease.
For information about clinical trials offered at UCLA Health, please visit clinicaltrials.ucla.edu.
What is informed consent?
Informed consent is the process by which potential study participants are given all of the information they need to determine whether or not they wish to voluntarily participate in a clinical trial. Informed consent is an ongoing and dynamic process that keeps participants informed of all study-related information throughout the research process. Potential study participants are educated about the purpose and duration of the study; required procedures; potential risks and benefits; and known side effects of intended treatment (if applicable). All consent-related information will be provided to potential participants in an informed consent form, which participants are given to sign if they so decide. A person is never obligated to participate in clinical research. The informed consent form is not a contract, and the participant may withdraw from the trial at any time – before or during the clinical trial.
What are the different types of clinical trials?
There are many different kinds of clinical trials, each with a different design and purpose.
Screening trials may include new techniques for diagnosis, such as new types of diagnostic imaging or lab work that may identify certain genetic markers in people with a particular health issue. Screening trials may also look for ways to identify potential risks people may have for developing a particular health issue, such as brain cancer.
Observational clinical trials
Observational clinical trials address health issues in large groups of people or populations in natural settings and do not involve assigned treatments or interventions. Observational clinical trials may investigate certain genetic factors, symptoms or quality of life for people who are affected by a specific health issues, like brain tumors.
Interventional clinical trials
Interventional clinical trials consist of treatment trials and prevention trials. Under strictly controlled circumstances, interventional clinical trials test whether experimental therapies or new formulations of already-approved treatments are safe and effective. They may also examine whether a drug or device is effective at preventing a specific illness or health issue.
Interventional clinical trials are divided into phases in order to extract safety information, determine efficacy and delineate whether or not a new treatment is as good as or better than the currently recognized standard of care. There are several phases of clinical trials.
Phases of Clinical Trials
Clinical trials are separated into four distinct phases.
Phase I clinical trials involving a potential new drug are designed to investigate the safety, side effects and appropriate dosage of a new investigational drug. Participants in phase 1 trials are carefully monitored through lab work, physical exams and imaging tests. If the initial cohort of study participants does not experience any dose-limiting toxicity (serious effects from the drug), the next group of participants then begins a higher dose, predetermined by the study protocol. This process continues until the maximum tolerated dose is identified.
Phase II clinical trials test drug effectiveness. During this phase, the drug or treatment is exposed to a larger number of participants – up to 100 people in some trials. In phase II trials, it is also possible to compare the new drug with another drug already in use, or with a placebo. Most importantly, phase II trials screen out ineffective treatments. If the results of a phase II trial indicate that a new drug is as effective as or more effective than an existing treatment, the new treatment proceeds to phase III.
Phase III clinical trials are large-scale studies that aim to prove that the new drug under investigation is safe, effective and non-inferior to the current standard of care. To do this, the drug is evaluated across a variety of factors, including drug tolerance, effectiveness and side effects, and compared against the same measures in the current standard of care. A secondary objective in a phase III trial is proving that the trial treatment is superior to the standard of care. Examples of treatment superiority include fewer side effects, better quality of life, improved survival, or even decreased need for monitoring. In a phase III trial, several hundred patients may be enrolled over several years and may sometimes involve thousands of patients across many different hospitals and even countries.
Phase IV clinical trials monitor for increased incidence of adverse events associated with a newly approved drug or device. This process is called pharmacovigilance. After a drug is found to be safe, effective and at least as good as the current standard of care, it then goes through a stringent approval process by the Food and Drug Administration (FDA). When the drug comes to market, there are additional observations made for safety reasons. These observations may include whether or not a drug is safe for use in children, pregnant women or nursing mothers, or in individuals with certain health concerns or who are taking other medications. Pharmacovigilance may also identify optimal use or additional uses of an FDA-approved drug.