The National Institutes of Health says that well-designed and well-executed clinical trials allow eligible participants to play an active role in their care, gain access to new treatments before they are widely available and obtain expert medical care during the trial. They also allow people to help others by contributing to medical research.

But trials include risks, which may be unpleasant, serious or even life-threatening. Experimental treatments may not be effective, or the protocol may require more of the participant‘s time and attention than would regular treatment.

Answering these questions might help you decide whether to participate:

• What is the purpose of the study?


• Who will be in the study?


• Why do researchers believe the experimental treatment being tested may be effective? Has it been tested before?


• What kinds of tests and treatments are involved?


• How do the possible risks, side effects, and benefits in the study compare with my current treatment?


• How might this trial affect my daily life?


• How long will the trial last?


• Will hospitalization be required?


• Who will pay for the experimental treatment and will I be reimbursed for other expenses?


• What type of long-term follow up care is part of this study?


• How will I know that the experimental treatment is working? Will results of the trials be provided to me?


• Who will be in charge of my care?

About clinical trials

5 types
Treatment trials test experimental treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.

Prevention trials look for better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vaccines, vitamins, minerals, or lifestyle changes.

Diagnostic trials are conducted to find better tests or procedures for diagnosing a particular disease or condition.

Screening trials test the best way to detect certain diseases or health conditions.

Quality of life trials (or supportive care trials) explore ways to improve comfort and the quality of life for individuals with a chronic illness.

4 phases
Clinical trials are conducted in phases, each with a different purpose:

In Phase I trials, researchers test an experimental drug or treatment in a small group of people (20-40) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.

In Phase II trials, the experimental study drug or treatment is given to a slightly larger group of people (20-50 in each arm of the study) with a main goal of determining effectiveness.

In Phase III trials, the experimental 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 experimental drug or treatment to be used safely.

In Phase IV trials, post marketing studies delineate additional information including the drug's risks, benefits, and optimal use.

Source: National Institutes of Health, Stephen Graziano MD