Despite little evidence supporting its superiority to glucocorticoid therapy, use and expenditures for repository corticotropin (rACTH) injection (H.P. Acthar Gel; Mallinckrodt) have increased dramatically in the last 5 years, particularly among a small number of nephrologists, rheumatologists, and neurologists. Recently, the manufacturer justified the extremely high and rapidly increasing cost of rACTH by citing the ongoing need to generate clinical data to support its use. We test this assertion by investigating the quality and provenance of the evidence likely to emerge in the foreseeable future.