The Clinical Trial Process

Clinical trials are designed to advance scientific knowledge while protecting trial subjects. Duke’s researchers must follow specific guidelines to ensure patients’ safety and privacy.

Before a new treatment is tested in patients, investigators conduct studies in research labs, often performing experiments in animal and human cells. This is usually followed by thorough testing in animals. If this research is successful, the FDA can approve the treatment for testing in humans.

Researchers must also design a protocol. This is a study plan that maps out the criteria for participation, schedule of procedures and treatments, and length of the study.

Duke has an independent Institutional Review Board (IRB) that reviews and approves the protocol, consent form, and all other documents for each study. In addition, the IRB reviews each study at least yearly as long as the study is active. To get approval, the study must protect the rights of study participants and ensure that the study does not present undue risks to the participants.

Three Phases

Most clinical research that involves the testing of a new treatment progresses in phases. This allows researchers to ask and answer questions in a way that yields reliable information about the treatment and protects the patients. Clinical trials are usually classified into one of three phases:

  • Phase I trials are the first step in testing a new treatment in humans. In these studies, researchers may evaluate how a new drug should be given (by mouth, injected into the blood, or injected into the muscle), how often, and what dose is safe. A phase I trial usually enrolls only a small number of patients, sometimes as few as a dozen. About 70 percent of experimental drugs pass this initial phase of testing.
  • Phase II trials focus on evaluating how well the new treatment works. They also continue to test the safety of the treatment. This second phase of testing may last from several months to two years, and involves up to several hundred patients. About one-third of experimental drugs successfully complete both phase I and phase II studies.
  • Phase III trials compare the results of people taking the new treatment with results of people taking standard treatment. Investigators usually assign participants to the standard treatment group or the new treatment group at random (called randomization). Phase III trials often enroll large numbers of people and may be conducted at many doctors’ offices, clinics, and health centers nationwide.