About Clinical Research
Before a pharmaceutical company can initiate testing in humans, it must conduct extensive preclinical or laboratory research. This research typically involves years of experiments. The clinical testing of experimental drugs is normally done in three phases:
Phase I: Phase I studies are primarily concerned with assessing the drug's safety. This initial phase of testing in humans is done in a smaller number of healthy volunteers who are usually paid for participating in the study. The study is designed to determine what happens to the drug in the body, how it is absorbed, metabolized, and excreted. A phase I study will investigate side effects that occur as dosage levels are increased. About 70 percent of experimental drugs pass this initial phase of testing.
Phase II: Once a drug has been shown to be safe, it must be tested for efficiency. The second phase of testing may last for several months to two years and involves up to several hundred patients. Most phase II studies are randomized trials. One group of patients will receive the experimental drug, while a second 'control' group will receive standard treatment, or a placebo. Often these studies are 'blinded'-- neither the patient nor the researchers know who is getting the experimental drug. In this manner, the study can provide the pharmaceutical company and the FDA comparative information about the relative safety of the new drug and its effectiveness.
Phase III: In a phase III study, a drug is tested in several hundred to several thousand patients. This large-scale testing provides the pharmaceutical company and the FDA with a more thorough understanding of the drug's effectiveness, benefits, and the range of possible adverse reactions. Most phase III studies are randomized and blinded trials. Phase III studies typically last several years. Once a phase III study is successfully completed a pharmaceutical company can request FDA approval for marketing the drug.
Late Phase III/Phase IV: In late phase III/phase IV studies, pharmaceutical companies have several objectives: (1) Studies often compare a drug with other drugs already in the market. (2) Studies are often designed to monitor a drug's long-term effectiveness and impact on a patient's quality of life. (3) Many studies are designed to determine the cost-effectiveness of a drug therapy related to other traditional and new therapies.
Who Pays for Clinical Research?
Funding for clinical research comes from both the federal government (through National Institutes of Health) and the private industry (pharmaceutical and biotech companies.) The sponsor of the research hires physicians to conduct the clinical trial. Physicians are typically paid on a per-patient basis. The medical care is often provided free to the patient. Patients may also be paid a small fee to participate in a clinical trial.
Previous | Next