Clinical Research

A clinical trial is a research study with the goal of answering specific questions about how to better treat a disease.

Clinical trials are used to determine whether new drugs are both safe and effective. Carefully conducted clinical trials are the fastest and safest way to find treatments that work in people

Ideas for clinical trials usually come from researchers. After researchers test new therapies or procedures in the laboratory and in preclinical studies, the treatments with the most promising results are moved into human clinical trials. Clinical trials are broken down into different phases. During each phase, more and more information is gained about the new treatment, its risks and how well it may or may not work.

A regulatory authority such as the US Food and Drug Administration (FDA) must approve a new drug or a new use of an existing drug before it can be made available for prescription to the public. The approval process involves several steps including preclinical studies, clinical trials with people , review of the those findings and finally, approval by the regulatory authority (for example, the FDA).

Why do people volunteer for clinical trials?

Many people volunteer to participate in clinical trials to:

  • have access to new investigational study drugs
  • contribute to medical science

The Four Phases of Clinical Trials


Usually a small number of healthy volunteers
Phase 1 studies are designed to allow scientists and medical doctors to understand what effects an investigational medicine has in human subjects. The goal is to study what happens to the investigational medicine in the body from the time it enters the body until it leaves and how the human body reacts to the new medicine from a safety point of view. Study participants are monitored for any side effects that they may experience.


Phase 2 studies are conducted with individuals who have the condition intended for therapeutic treatment. These studies evaluate the safety and effectiveness of the candidate therapeutic in a group of patients at the same stage of disease to serve as proof of concept for larger Phase 3 trials.

Phase 2a studies examine a range of doses and often use a biomarker for an effect of treatment that does not meet regulatory standards for Phase 3.

Phase 2b study provides a useful step to the larger Phase 3 by use of the Phase 3 protocol and efficacy measures with adjustment in decision making based on sample size.


For drug approval
Phase 3 studies are designed to confirm the safety and effectiveness of an investigational medicine and the dose chosen against a placebo*. These studies are conducted in large numbers of patients with a specific disease or condition. Information obtained from Phase 3 studies is used to determine how the medicine is best prescribed to patients in the future. The complete information available on the new medicine is submitted to health authorities (for example, the FDA).


Once the drug is approved
Phase 4 studies take place after the drug has been approved for marketing and are designed to provide broader experience in evaluating the safety and effectiveness of the new medicine in larger numbers of patients and subpopulations of patients as well as to compare and/or combine the new medicine with other available treatments. These studies are designed to evaluate the long-term effects of the drug. Under these circumstances, less common adverse events may be detected.

* A placebo is used to account for the placebo effect, which are effects from treatment that do not depend on the treatment itself. Such factors include knowing one is receiving a treatment, attention from health care professionals and the expectations of a treatment’s effectiveness by those running the research study. Without a placebo group to compare against, it is not possible to know whether the treatment itself had any effect.