The recent advent of numerous clinical trials for the treatment of moderate-to-severe atopic dermatitis has led to new and emerging therapeutic options for this chronic inflammatory skin disease. With this rapid development has come a lack of consistency in study designs, trial conduct, and statistical analyses. Healthcare providers are challenged to interpret how variations in study parameters may influence clinical trial results. Based on literature review and our experience as clinical trialists, we compiled a list of 22 key study parameters of contemporary clinical trials in moderate-to-severe atopic dermatitis and ranked the top study parameters that may have a significant effect on efficacy results. The top parameters included study comparators, rules for rescue treatment, washout periods for topical and systemic treatments, inclusion criteria such as disease severity by Eczema Area and Severity Index and/or Investigator Global Assessment scores, and the duration of the screening period. We describe considerations for these key parameters, with a focus on between-parameter interactions and effect on efficacy results. This may serve to inform the interpretation of atopic dermatitis clinical trials and raise the profile of the need to harmonize the clinical trial design.
Atopic dermatitis (AD) is a skin disease characterized by red, itchy skin that is highly burdensome for patients. Patients with moderate-to-severe disease have large, inflamed skin areas with frequent itching. Recently, the number of clinical trials for drugs that treat moderate-to-severe AD has rapidly increased, with differences in how these trials are designed. There is a need for healthcare providers examining results from different clinical trials to understand how trial design factors might influence study outcomes. In this article, we identify key trial design factors that impact study outcomes, detail how these factors can impact clinical trial results, and explore how these factors interact with one another to affect study outcomes. The five most important design factors, as determined via author surveys, were study comparators (a placebo and/or another drug to which the drug being studied is compared); the rules for the use of rescue treatment (a form of treatment given if an enrolled participant has uncontrolled AD symptoms); washout periods (the time before the trial when previous treatments are stopped to allow them to be cleared from a patient’s system); inclusion criteria (that determine which participants are included); and the length of the screening period (the time when patients are assessed to determine if they qualify for participation). By understanding how these key trial design factors impact on study outcomes, healthcare providers may be equipped to better interpret different AD clinical trials. This work also emphasizes the value of harmonizing the AD clinical trial design.
© 2021. The Author(s).