Many companies follow a general rule when assembling regulatory packages for presenting new biologics: Accentuate the aspects of your new biologic that mimic approved therapies. For companies working on cell-based therapies, however, that is a challenging task. The industry lacks established models, and the current European Medicines Agency (EMA) regulatory definition of a cell-based therapy is simply “an advanced therapy medicinal product” (ATMP) (see EMA guidance box). Regulations for cell therapies cannot always be compared directly with those…