StrokeSurvivorBlog

Researchers conduct clinical studies to evaluate the safety and effectiveness of investigational (experimental) drugs. Investigational drugs that are found to be safe and effective may then become available for doctors to prescribe. If an investigational drug is determined to be unsafe or ineffective, the study results may still be useful for scientists and for the advancement of medical research.

Objectives

In clinical studies, investigational drugs are often compared with approved drugs or placebo (inactive pill, liquid, or powder) to assess safety and effectiveness. Clinical study participants may be assigned to take:

• Investigational drugs
• Approved drugs
• Placebo
• A combination of these drugs

Phases of Clinical Research Studies

Clinical studies are divided into 4 phases:

• Phase 1: Researchers test an investigational drug for the first time in humans by giving it to a small number of healthy people to evaluate its safety, determine a safe dosage range, and identify side effects.
• Phase 2: The investigational drug is given to a larger number of people who have a particular disease or condition, to determine its effectiveness and to further evaluate its safety.
• Phase 3: Several hundred to several thousand people with the appropriate disease or condition participate in these studies. The investigational drug undergoes additional testing to further determine its safety and effectiveness, monitor side effects, and compare it to commonly used treatments.
• Phase 4: After a drug is available by prescription, additional information is gathered to assess the drug’s risks, benefits, and use.