[Interchangeability of biological products in the Brazilian Unified National Health System (SUS): the main regulatory challenges].

Biological products have sparked a worldwide therapeutic revolution. However, the high cost of these products threatens health systems' sustainability. The development of copies is considered an economic alternative, but due to the products' complexity, many concepts used in generic drugs do not apply. Interchangeability between biologicals poses a regulatory challenge. This essay discusses the main regulatory challenges for establishing criteria for interchangeability between new biologicals and their copies in the scope of the Brazilian Unified National Health System (SUS), considering the guidelines adopted by the world's main drug regulatory agencies concerning interchangeability and the prevailing Brazilian regulatory framework on this issue. Concerns related to the interchangeability of biologicals include automatic substitution, nomenclature, pharmacovigilance, immunogenicity, and extrapolation of therapeutic indications and clinical data from new biologicals to their copies. While the clinical success and economic benefits of switching from new biologicals to their biosimilars have already been observed, the heterogeneity between countries in the regulatory barriers to the approval of copies of biologicals should be taken into consideration during the regulation of interchangeability of biologicals in Brazil.