The introduction of the Quality by Design concept in the early 2000’s has changed the
paradigm of product and process development for recombinant biotherapeutics, switching from the process makes the product to the product makes the /> The Quality by Design approach starts by the understanding of the impact of changes in quality attributes on product clinical efficacy and safety. Without understanding it, it is difficult to develop a manufacturing process that would have to consistently deliver a product of the desired quality. Therefore, it is important to understand the quality attributes possibly generated by the manufacturing process (process-related impurities), the intrinsic heterogeneity of recombinant proteins, the post-translational physical and chemical modifications, and their risks for the /> The Master Class on critical quality attributes of recombinant proteins for therapeutic use will address the understanding of quality attributes, the purpose of assessing their criticality and how to select critical quality attributes. The Master Class will be illustrated by a review of physico-chemical variants, process- and product-related impurities and their impact on the product efficacy and safety.