Apart from three biologics, no systemic drugs are approved in Europe for children with moderate-to-severe psoriasis. Retrospective observational studies showed promising results for fumaric acid esters (FAE) in this setting.To show superiority of FAE over placebo in terms of treatment response after 20 weeks in children and adolescents aged 10-17 years.In a multicentre, randomised, double-blind, placebo-controlled phase 3b study patients aged 10-17 years with moderate-to-severe plaque psoriasis requiring systemic therapy were randomised 2:1 to receive FAE (N=91) or placebo (N=43) over 20 weeks, followed by an open-label FAE treatment phase. The co-primary endpoints were Psoriasis Area and Severity Index (PASI) 75 and/or Physician's Global Assessment (PGA) 0,1 (clear or almost clear) responder rate at week 20.At week 20, 55% (95% CI 0.44-0.65) of FAE-treated patients achieved a PASI 75 response vs. 19% (95% CI 0.08-0.33) in the placebo group (absolute difference: 36%; 95% CI 0.20-0.53; p<0.001). 42% (95% CI 0.32-0.53) in the FAE group vs. 7% (95% CI 0.01-0.19) in the placebo group achieved a PGA (0,1) response at week 20 (absolute difference: 35%; 95% CI 0.21-0.49; p<0.001). During the double-blind period, drug-related adverse events occurred more frequently in patients receiving FAE compared to placebo (75.8% vs. 46.5%). Gastro-intestinal disorders were the most common adverse events.FAE administered over a period of 20 weeks demonstrated a response that was statistically significant and clinically meaningful better to placebo. Application up to 40 weeks was generally well tolerated. However, further studies are required.