Issues in clinical trials of prophylaxis of fungal infections.

The validity of the results of a clinical trial is highly dependent upon the design of the trial. The definition of disease, the selection criteria for enrollment in the trial, the selection of the study and control drugs, and the end points all affect whether the information obtained from the trial ultimately is useful in making decisions in clinical practice. These factors all apply to the design of clinical trials of the prophylaxis of infectious diseases. In addition, prophylaxis trials have several important differences from the design of trials of the treatment of those same diseases. The risk-benefit analysis for trials of prophylaxis is different, in that asymptomatic patients are exposed to the drug and more patients will be exposed than will develop the disease under study. Standardization of the design of such clinical trials will allow more efficient development of new drugs and will allow clinicians to compare more accurately the safety and efficacy of prophylactic agents.