Perfusion processes are considered more difficult to model than batch-based fermentation processes because up to a third of a perfusion-based campaign is spent outside “steady-state” production mode. Variabilities in cell density, titer, and harvest rate (HR) during ramp-up necessitate planning and explicit modeling of variabilities in these processes and their subsequent downstream operations. Longer continuous fermentation times require more rigorous attention to risk than do batch-based systems. A flexible purification platform must respond to changing fermentation conditions. Here…