Skip Navigation
 
 
 
 xxx
 
Print This Page
Share this page: More
 

Clinical Trial Phases

Clinical trials are an important form of clinical research. They are designed to test new therapies or diagnostic techniques in patients. In general, clinical trials address whether a new treatment or technique is safe and more effective than existing therapies. Clinical trails are an enormously important weapon in our arsenal against malignant brain tumors.

There are four stages to clinical trials:

Phase I Clinical Trials

Phase I trials test a new treatment in a small number of patients to evaluate its safety. They are used to determine things like the safest dose of a drug, identify side effects or determine if a diagnostic test is safe. These trials are a required first step for any new therapy.

Phase II Clinical Trials

Phase II trials study if the intervention is effective. In other words, does the drug or test work as intended. Phase II trials include a larger group of patients than phase I trials. Data about safety is collected throughout a phase II trial to ensure there are no previously unrecognized side effects or toxicities.

Phase III Clinical Trials

Phase III trials require a much large number of participants and are designed to test whether the new therapy works as intended and how it compares to existing therapies. Information gathering about side effects and safety is continued throughout this phase. These are typically large studies that involve several medical institutions. Only the most promising therapies progress to a phase III trial due to the intense effort, time, expense and patient involvement they require. If a phase III trial is positive, the drug or therapy is submitted to the Food and Drug Administration for approval and the drug is marketed.

Phase IV Clinical Trials

Phase IV trials are designed to monitor the effectiveness of a drug after it has been approved and marketed to ensure it continues to have the effects intended and to monitor for any previously unrecognized side effects.

 
 
 
 
 
 

© The Johns Hopkins University, The Johns Hopkins Hospital, and Johns Hopkins Health System. All rights reserved.