title: Sample size requirement in analytical studies for similarity assessment.
abstract: For the assessment of biosimilar products, the FDA recommends a stepwise approach for obtaining the totality-of-the-evidence for assessing biosimilarity between a proposed biosimilar product and its corresponding innovative biologic product. The stepwise approach starts with analytical studies for assessing similarity in critical quality attributes (CQAs), which are relevant to clinical outcomes at various stages of the manufacturing process. For CQAs that are the most relevant to clinical outcomes, the FDA requires an equivalence test be performed for similarity assessment based on an equivalence acceptance criterion (EAC) that is obtained using a single test value of some selected reference lots. In practice, we often have extremely imbalanced numbers of reference and test lots available for the establishment of EAC. In this case, to assist the sponsors, the FDA proposed an idea for determining the number of reference lots and the number of test lots required in order not to have imbalanced sample sizes when establishing EAC for the equivalence test based on extensive simulation studies. Along this line, this article not only provides statistical justification of Dong, Tsong, and Weng's proposal, but also proposes an alternative method for sample size requirement for the Tier 1 equivalence test.
authors.affiliation: a Department of Biostatistics and Bioinformatics , Duke University School of Medicine , Durham , North Carolina , USA.
authors.forename: Shein-Chung
authors.initials: SC
authors.lastname: Chow
authors.affiliation: b Center for Food and Drug Inspection , China Food and Drug Administration , Beijing , China.
authors.forename: Fuyu
authors.initials: F
authors.lastname: Song
authors.affiliation: c Department of Drug & Cosmetics Registration , China Food and Drug Administration , Beijing , China.
authors.forename: He
authors.initials: H
authors.lastname: Bai
mesh_terms: D059451:Biosimilar Pharmaceuticals / Q000592:standards*; D003627:Data Interpretation, Statistical; D006801:Humans; D011786:Quality Control; D012107:Research Design; D018401:Sample Size
chemical_list: D059451:Biosimilar Pharmaceuticals
keywords: Analytical similarity assessment; equivalence acceptance criterion (EAC); equivalence test; stepwise approach; tiered approach; totality-of-the-evidence