ABSTRACT
For comparisons between drug products, some criteria for testing similarity are available in either regulatory guidelines/guidances and/or the literature. These criteria include (1) criteria for the assessment of in vivo bioequivalence testing and in vitro bioequivalence testing (FDA, 1992, 1999, 2003; Chow and Liu, 2008), (2) similarity factors for dissolution profiles comparison (Moore and Flanner, 1996; Chow and Ki, 1997; FDA, 1997), and (3) tests for consistency in raw materials, in-process materials, and end-products for quality control/assurance (Tse et al., 2006). These criteria are useful for assessing biosimilarity. However, these criteria do not discuss the issue regarding the degree of similarity. In general, these criteria can be classified into (1) absolute change versus relative change, (2) aggregated versus disaggregated, (3) scaled (weighted) versus unscaled (unweighted), or (4) moment-based (MB) versus probability-based (PB) criteria.
