Process economics evaluation and optimization of adeno-associated virus downstream processing.

Adeno-associated virus (AAV) manufacturing has traditionally focused upon lab-scale techniques to culture and purify vector products, leading to limitations in production capacity. The tool presented in this paper assesses the feasibility of using non-scalable technologies at high AAV demands and identifies optimal flowsheets at large-scale that meet both cost and purity targets. The decisional tool comprises (a) a detailed process economics model with the relevant mass balance, sizing, and costing equations for AAV upstream and downstream technologies, (b) a built-in Monte Carlo simulation to assess uncertainties, and (c) a brute-force optimization algorithm for rapid investigation into the optimal purification combinations. The results overall highlighted that switching to more scalable upstream and downstream processing alternatives is economically advantageous. The base case analysis showed the cost and robustness advantages of utilizing suspension cell culture over adherent, as well as a fully chromatographic purification platform over batch ultracentrifugation. Expanding the set of purification options available gave insights into the optimal combination to satisfy both cost and purity targets. As the purity target increased, the optimal polishing solution moved from the non-capsid purifying multimodal chromatography to anion-exchange chromatography or continuous ultracentrifugation.