Boehringer Ingelheim and Pfizer have developed a unique continuous bioprocess consisting of a short duration perfusion upstream and fully integrated downstream. The process is designed to generate at least 1 kg of material from a 100 L bioreactor in approximate 2 weeks. The upstream strategy utilizes a non-steady state, short duration perfusion process to achieve volumetric productivities ranging from 0.5 to 4 g/L/day. This creates a unique challenge for the downstream process as the titer and impurity load change over the duration of the culture.