The Food and Drug Administration (FDA) approves labeling

claims of clinical benefit following from treatment with drugs and biologics on the basis of substantial evidence demonstrated in ade-quate and well-controlled investigations. Section 505(d) of the Act establishes substantial evidence as the evidence standard for making conclusions that a drug will have a claimed effect. Reports of adequate and well-controlled investigations are to provide the basis for determining whether there is substantial evidence to support claims of effectiveness for new drugs. These requirements are specified in the Federal Food, Drug, and Cosmetic Act (the Act). Following from the Act, the Code of Federal Regulations (CFR) further clarifies acceptable measurement standards for performance of clinical trials intended to support product labeling claims. 21 CFR 314.126 describes characteristics of an adequate and well-controlled investigation. The guidance for industry entitled Providing Clinical Evidence of Effectiveness for Human Drug and Biological Products reviews the nature and quantity of evidence necessary to meet FDA ’ s substantial evidence standar