How Clinically Relevant Are Treatment Comparisons of Topical Calcineurin Inhibitor Trials for Atopic Eczema?

We sought to explore the architecture of trials of calcineurin inhibitors for atopic eczema to document the extent to which comparisons with active treatments such as topical corticosteroids might have been included or avoided. We identified all eligible randomized controlled trials using the Global Resource for EczemA Trials (GREAT) database. Network plots were produced where the nodes represented a treatment type and the lines between the nodes represented the number of trials or participants involved in the various treatment comparisons. A total of 174 randomized controlled trials for atopic eczema treatments were identified in which pimecrolimus, tacrolimus, or topical corticosteroids were compared with another intervention or a vehicle/emollient. Of 39 trials involving pimecrolimus and 41 trials involving tacrolimus, 8 (20.5%) and 13 (31.7%), respectively, made comparisons with topical corticosteroids, and 25 (64.1%) and 15 (36.6%), respectively, were vehicle-controlled studies. The high rate of comparisons with vehicle controls in randomized controlled trials that assessed the efficacy of pimecrolimus or tacrolimus long after efficacy had been established is a matter of concern. Active comparators (mild topical corticosteroids for pimecrolimus and moderate to potent topical corticosteroids for tacrolimus) are best placed to determine how topical calcineurin inhibitors compare with established clinical practice.