Single-Study Approvals: Quantum of Evidence Required.

When does a single positive adequate and well-controlled study of a new drug meet the statutory requirement to demonstrate substantial evidence of effectiveness? The answer to this question, particularly with respect to new molecular entities, has been of considerable debate since 1962 when the requirement that new drugs prove their benefit to patients became law. A 1997 revision to the statute provided one pathway to a single-study approval (a single adequate and well-controlled study plus confirmatory evidence), while a 1998 guidance issued by FDA provided additional pathways, one of which is the one that is most frequently cited by FDA (a single statistically very persuasive study). This paper explains these 2 distinct pathways and provides illustrative examples of how FDA uses each of these 2 pathways.

Single-Study Approvals: Quantum of Evidence Required.

When does a single positive adequate and well-controlled study of a new drug meet the statutory requirement to demonstrate substantial evidence of effectiveness? The answer to this question, particularly with respect to new molecular entities, has been of considerable debate since 1962 when the requirement that new drugs prove their benefit to patients became law. A 1997 revision to the statute provided one pathway to a single-study approval (a single adequate and well-controlled study plus confirmatory evidence), while a 1998 guidance issued by FDA provided additional pathways, one of which is the one that is most frequently cited by FDA (a single statistically very persuasive study). This paper explains these 2 distinct pathways and provides illustrative examples of how FDA uses each of these 2 pathways.

FDA's Flexibility in Subpart H Approvals: Assessing Quantum of Effectiveness Evidence.

This article examines the strength of scientific and clinical evidence for FDA's nineteen non-AIDS, non-cancer Subpart H approval determinations over the Accelerated Approval program's twenty-four year existence. The authors researched the bases for FDA's determinations when an unvalidated surrogate or intermediate clinical endpoint is "reasonably likely to predict clinical benefit." The four key factors set forth in FDA's "Guidance for Industry, Expedited Programs for Serious Conditions - Drugs and Biologics" were applied to past Subpart H approvals.

Quantum of Effectiveness Evidence in FDA's Approval of Orphan Drugs: Update, July 2010 to June 2014.

Background: This study serves as a follow-up to a March 2012 analysis conducted by Frank Sasinowski that reviewed the quantum of effectiveness evidence that is required to secure FDA approval of therapies for rare diseases, or orphan drugs, from the 1983 enactment of the Orphan Drug Act through June 30, 2010. The current study was designed to determine, over the 4 years since the original study, how frequently FDA has required marketing applications of drugs for rare diseases to provide the conventional level of proof of effectiveness that is ordinarily expected for most drugs for prevalent diseases.

Methods: This study employed methods similar to the original analysis, identifying the noncancer orphan drugs approved as new chemical entities by relying on FDA's publicly available documents for drugs approved by FDA from July 1, 2010, to June 30, 2014.