We performed this study as treatment of psoriasis with biologics is often based on short-term response criteria, but patients are often treated long-term, and knowledge about long-term outcome of these response criteria is limited. We found that response early in the treatment predicted risk of drug discontinuation and risk of disease flares, i.e. a low PASI in the first six months is associated with lower risk of disease discontinuation and flares. We feel this paper is important as it provides evidence for guidelines in treatment of psoriasis with biologics.