An optimization study of an integrated periodic counter-current chromatography (PCC) process in a monoclonal antibody (mAb) downstream process at lab scale, is presented in this paper. The optimization was based on a mechanistic model of the breakthrough curve in the protein-A capture step. Productivity and resin utilization were the objective functions, while yield during the loading of the capture column was set as a constraint. Different integration approaches were considered, and the effect of the feed concentration, yield and the protein-A resin was studied. The breakthrough curve and the length of the product recovery, which depended on the integration approach, determined the process scheduling. Several optimal Pareto solutions were obtained. At 0.5 mg mL-1 and 99% yield, a maximum productivity of 0.38 mg mL-1 min-1 with a resin utilization of 60% was obtained. On the other hand, the maximum resin utilization was 95% with a productivity of 0.10 mg mL-1 min-1. Due to the constraint of the process scheduling, a lower productivity could be achieved in the integration approaches with higher recovery time, which was more remarkable at higher concentrations. Therefore, it was shown that a holistic approach, where all the purification steps are considered in the process optimization, is needed to design a PCC in a downstream process.

In this study, we demonstrated the first, to our knowledge, integrated continuous bioprocess (ICB) designed for the production of acid‐sensitive monoclonal antibodies, prone to aggregate at low pH, on pilot scale. A high cell density perfusion culture, stably maintained at 100 × 10⁶ cells/ml, was integrated with the downstream process, consisting of a capture step with the recently developed Protein A ligand, Z_Ca; a solvent/detergent‐based virus inactivation; and two ion‐exchange chromatography steps. The use of a mild pH in the downstream process makes this ICB suitable for the purification of acid‐sensitive monoclonal antibodies. Integration and automation of the downstream process were achieved using the Orbit software, and the same equipment and control system were used in initial small‐scale trials and the pilot‐scale downstream process. High recovery yields of around 90% and a productivity close to 1 g purified antibody/L/day were achieved, with a stable glycosylation pattern and efficient removal of impurities, such as host cell proteins and DNA. Finally, negligible levels of antibody aggregates were detected owing to the mild conditions used throughout the process. The present work paves the way for future industrial‐scale integrated continuous biomanufacturing of all types of antibodies, regardless of acid stability.