The emergence of generic drugs, meaning pharmaceutical drugs that are equivalent to innovative drugs, resulted in numerous points of view in the case of biological drugs regarding their use in the therapy of many diseases, including psoriasis. Considering the definition given by WHO and EMA for biological drugs and their bioequivalents, the authors express their views on the concept of biosimilarity, compatibility and immunogenicity of a biosimilar product. The possibility of extrapolating the indications for a biosimilar drug when there are no clinical studies for it, is also discussed by the authors. The working group expresses its adherence to EMA’s point of view on the use of drugs and their interchangeability, stating that a switch is not allowed between a biosimilar drug and its reference product.