Systems for regulating biosimilar applications have been successfully operating for 13 years, first in Europe, and more recently, in the United States. Yet challenges still exist in gaining approvals, often as a result of registration information outside the analytical similarity demonstration itself. In particular, the extent of product development data generated to support commercial activities and the readiness of manufacturing sites to produce and control the intended commercial biosimilar product remain obstacles. In addition to the established expectations for biosimilar product development, one of the newer areas that represents an emerging area of regulatory science is the application of statistical tools in analytical comparisons.