Placebo response in phase 2 and 3 trials of systemic and biological therapies for atopic dermatitis-a systematic review and meta-analysis.

A growing number of clinical trials of biological and systemic therapies have been conducted within adult atopic dermatitis (AD). No study has yet examined and meta-analysed the pooled placebo response in AD. We performed a systematic review and meta-analysis to examine the placebo response in clinical trials evaluating the effect of systemic and biological therapies in adult AD and compared it to results from clinical trials in psoriasis. Two screeners independently searched the databases ClinicalTrials.gov, Embase, Pubmed and Web of Science. A total of 2058 articles were identified, of which 78 were full-text reviewed. Overall, 25 trials were included in the qualitative analysis, of which 24 were further included in the quantitative analysis. At 12-week follow-up, EASI50, EASI75 and EASI90 placebo responses were 39.9% [95% confidence interval (CI), 36.7-43.2], 20.9% (95% CI, 18.2-23.8) and 9.0% (95% CI, 6.7-11.6), respectively. At week 12, the pooled proportion of placebo-treated AD patients that obtained EASI50, EASI75 and EASI90 was significantly higher than the pooled proportion of placebo-treated psoriasis patients obtaining PASI50, PASI75 and PASI90 (P < 0.05). Our findings emphasize the fluctuating nature of AD and show that correct and consistent use of topical treatments strongly reduces disease severity.