Biosimilars are evaluated through comparisons with their reference products using abbreviated pathways that have evolved significantly over the past few years. Scientists and regulators now accept that some quality attributes can vary from batch to batch over a product’s lifecycle, even for reference products. Moreover, reference and similar biotechnology products can show differences in noncritical quality attributes but still demonstrate comparable efficacy and safety (1). Here we describe a similarity assessment approach that is also applicable to comparability of lifecycle…