RESUMEN
Chemistry, manufacturing, and control postapproval changes are an intrinsic part of the life cycle of pharmaceutical products. In this paper, the authors examined the potential impact of such changes on the product quality, safety, and efficacy of biologics. Comparability studies and more specifically analytical comparability are introduced as one of the tools that can support both biomanufacturers and health agencies in ensuring that patient safety and product safety and efficacy is maintained through the proposed changes. Together with a scientific risk-based review approach based on product and process knowledge and the definition of acceptance criteria that will ensure that the product is "essentially similar", what constitutes a holistic comparability study is detailed. ICH Guidelines principles and definitions are used throughout the paper to aid the reader with other appropriate references. Finally, two case studies are presented: change to the manufacturing facility of the drug substance, and change to the manufacturing process of a drug substance intermediate and manufacturing facility.