What must generally be established to demonstrate that a biosimilar is "highly similar" to an existing product?

To demonstrate that a biosimilar is "highly similar" to an existing product, data showing structural similarity is essential. This involves detailed comparative analyses of the molecular structure, including size, amino acid sequence, post-translational modifications, and three-dimensional conformation of the biosimilar and the reference product. Regulatory authorities require this structural characterization because even minor differences in structure can lead to variations in safety and efficacy.

Establishing structural similarity lays the foundation for subsequent assessments of safety, immunogenicity, and clinical efficacy. While safety reports from clinical trials play a role in the overall evaluation of biosimilars, they are predicated on having first demonstrated that the biosimilar closely resembles the reference product structurally. Economic benefits analysis and market competitor analysis, while important for commercial considerations, do not address the fundamental regulatory requirement of establishing high similarity at the molecular level. Thus, the focus on structural data is the cornerstone for the approval of biosimilars.