Editorial
Shein-Chung Chow
Abstract
For assessment of biosimilarity of biosimilar products, the United States Food and Drug Administration proposed a stepwise approach for providing totality-of-the-evidence of similarity between a proposed biosimilar product and a US-licensed (reference) product. The stepwise approach starts with assessment of critical quality attributes that are relevant to clinical outcomes in structural and functional characterization in manufacturing process of the proposed biosimilar product. FDA suggests that these critical quality relevant attributes be identified first and then classify them into three tiers depending upon their criticality, e.g., most (Tier 1), mild to moderate (Tier 2), and least (Tier 3) relevant to clinical outcomes. To assist the sponsors, FDA also recommends some potential statistical approaches for assessment of analytical similarity for CQAs from different tiers: equivalence test for CQAs from Tier 1, quality range approach for CQAs from Tier 2, and descriptive raw data and graphical comparison for CQAs from Tier 3. However, FDA mainly focuses on the assessment of analytical similarity for CQAs from Tier 1 and Tier 2. In this article, statistical evaluation and interpretation (with an example) on the FDA’s recommended approach for analytical similarity for CQAs from Tier 1 and Tier 2 are provided.