Harmonization of Biosimilar Regulatory Frameworks for Autoimmune Therapies: A Comparative Assessment of Safety, Efficacy, and Approval Pathways of EMA, FDA, and CDSCO Using Infliximab as a Case Study

Background Biosimilar drugs are essential to expanding access to affordable treatments for chronic autoimmune diseases, yet regulatory requirements remain complex, with distinct pathways applied by the European Medicines Agency (EMA), the U.S. Food and Drug Administration (FDA), and India’s Central Drugs Standard Control Organization (CDSCO). Purpose This study compares EMA, FDA, and CDSCO regulatory guidelines for biosimilars, examining analytical and non-clinical comparability, clinical pharmacology, immunogenicity studies, comparative clinical trials, and the principles of extrapolation of indications and interchangeability, using the monoclonal antibody infliximab as a case study. Materials and Methods Publicly available regulatory guidelines, scientific literature, and official agency documents from EMA, FDA, and CDSCO were systematically reviewed and compared across a structured framework of key regulatory elements, supported by an in-depth analysis of infliximab biosimilar approvals across the three agencies. Results All three agencies emphasize comprehensive analytical and non-clinical characterization as the foundation for biosimilar approval, and require comparative pharmacokinetic (PK) and pharmacodynamic (PD) studies and immunogenicity assessments, with a shared shift toward reducing or eliminating comparative clinical efficacy and safety trials when robust analytical and PK/PD data adequately establish biosimilarity. All three broadly accept extrapolation of indications. However, considerable variation persists in interchangeability: the FDA maintains specific, higher-evidence requirements for “interchangeable biosimilars,” the EMA leaves interchangeability decisions to individual member states, and CDSCO lacks a formal interchangeability designation. Further differences exist in clinical trial waiver criteria, analytical comparability acceptance thresholds, and immunogenicity data interpretation. Conclusion While progress has been made in aligning scientific principles for biosimilar approval, further cooperation through enhanced international regulatory collaboration, standardized data requirements, integrated use of real-world evidence, and transparent communication policies is needed to bridge remaining gaps, facilitate global development, and improve patient access to safe and effective biosimilars worldwide.