Are there special considerations relevant to trials of biologic agents?

Although biologic agents have been developed to effect change in observed or hypothesized pathogenic pathways, discrepancies between biological and clinical effects are well recognized. In trials of these agents, biological and clinical effects need to be evaluated. While the biological effects require assessment to test the proposed primary effect and significant influences, clinical evaluation should use the same set of assessment procedures as pharmacological agents. The disease controlling antirheumatic therapy (DC-ART) classification with its requirement for longterm efficacy poses problems for the biological agents, which, in general, have demonstrated short term benefit. They may be best accommodated in a new "remission induction" category or, alternatively, as part of longterm combination therapy either with pharmaceuticals or with other biologicals to fulfill DC-ART requirements.