Drugs in Development*

Terms

Clinical trials are scientific investigations carried out on human subjects to define the safety, efficacy and effects (toxicity, side effects and interactions) of a drug. The FDA requires strict testing of all new drugs prior to their approval for use as therapeutic agents.

Phase I trials involve the first introduction of an experimental drug to patients or healthy volunteers, normally less than 100 enrollees. They are closely monitored to determine the interaction of the drug, including the side effects associated with different doses. Sufficient information and signs of effectiveness are necessary to permit design of well-controlled Phase II studies.

Phase II trials are well controlled, closely monitored clinical studies, usually with no more than several hundred human subjects. They test the effectiveness of a drug against a particular indication(s) in patients with the disease or condition in question and measure common, short-term side effects and risks associated with the drug.

Phase III trials are expanded controlled and uncontrolled studies, including several hundred to several thousand participants, initiated after preliminary data of drug effectiveness are obtained. These trials seek to gather additional effectiveness and safety information about safety and evaluate the overall benefit-risk relationship of the drug and to provide competent basis for dosing.

Adapted from the HIV/AIDS Treatment Information Service (www.hivatis.org).