Evidence from rheumatoid arthritis trials for approval: what does it mean? With special reference to using...

Since medicine remains largely empirical, clinical knowledge about therapy is derived primarily from experiments designed to control confounders that use inferential techniques applied to the null hypothesis model. On a public health scale, health agencies need to assess the evidentiary weight supplied for new therapies to make approval decisions. In the field of rheumatoid arthritis (RA), there are additional analytic challenges such as designation of endpoints or missing data. The intellectual architecture that underpins these exercises continues to evolve, and recently the US Food and Drug Administration released an RA Guidance Document to describe some aspects of these exercises. This article focuses on the use of measurements of radiographic endpoints in particular as an element in the evidentiary portrayal of therapeutic efficacy in RA.