Disease activity assessment in SLE: do we have the right instruments?

No new therapy has been approved for systemic lupus erythematosus (SLE) in decades. Interest in SLE by pharmaceutical and biotechnology companies has increased, leading to multiple clinical trials. Unfortunately, we have now compiled quite a long list of "failed" trials. If this was due to the fact that the studied therapy did not work in SLE, we could accept it and move on. Of concern, however, is that many of the "failed" treatments had a strong "signal" of efficacy, often in subgroup analyses that made logical sense, given what was known about the mechanism of action of the treatment. This has led, understandably, to concern that there is something wrong with SLE trial designs, particularly with SLE disease activity indices.