Use of TNF blockers and other targeted therapies in rare refractory immune-mediated inflammatory diseases: evidence-based or rational?

Evidence-based medicine implies that clinical decision making should be based on external research evidence when available. This external evidence includes, but is certainly not restricted to, randomised controlled trials (RCTs). The development of powerful but often expensive targeted therapies for immune-mediated inflammatory diseases (IMIDs) is one of the major successes of evidence-based medicine but, paradoxically, also threatens the traditional RCT-based approach. Indeed, the increasing availability of these drugs decreases the number of patients available for RCTs, questions the ethical basis for the use of placebo groups and raises the issue of cost-efficacy. These considerations become even more important in rare phenotypically diverse and potentially life-or organ-threatening IMIDs such as sarcoidosis, Behcet's disease and uveitis. Using the successful application of tumour necrosis factor blockade in these diseases as an example, this review defends the concept that pathophysiological insights in cellular and molecular disease pathways as well as limited case series are valid sources of external evidence for the rational use of targeted therapies in these rare refractory conditions. If authors fail to redefine their concept of rational therapy along the lines of not only evidence-based but also pathophysiology-based and practice-based medicine, they may underestimate the potential of novel drugs in rare refractory IMIDs and thereby jeopardise the health of their patients.