Statistical considerations in clinical field evaluation of drugs.

Statistical problems associated with clinical field evaluation of drugs are many. The Food and Drug Administration requires that the safety and efficacy of a drug must be shown in adequate and well-controlled clinical investigations. From a statistical point of view, safety and efficacy must be precisely defined, and a quantitative method must be developed to measure these properties. It is proposed that efficacy be defined in both the therapeutic and pharmacologic aspects. Further, to measure therapeutic efficacy, it is suggested that an appropriate health index be used. This index would provide information regarding degree of improvement and also the time course of improvement. To measure or evaluate pharmacologic efficacy, it is suggested that kinetic studies be done to compare half-lives, volumes of distribution, and any other relevant kinetic parameter(s).