Comparability Study Of An Ion Exchange Monolith And Affinity Resin For The Purification Of AAV8

By Janja Merkelj Koren, Rok Žigon, Andrej Mihevc, Marko Šnajder, Maja Leskovec, and Aleš Štrancar

The main objective of every downstream process (DSP) for adeno-associated virus (AAV) production is to achieve high recovery, purity, and potency. The capture step for AAV purification is typically either affinity or cation exchange chromatography, both of which concentrate the product and remove impurities. Following the capture, the eluate is generally further processed to enrich for full capsids and carry out further purification. CIMmultus® QA, a monolith-based anion exchange chromatography column, is widely used for the enrichment and polishing of full AAV capsids¹.

Since the polishing step relies on only small differences in charge of the AAV capsids, any process-induced heterogeneity or charge modulation of the capture eluate will diminish the separation efficiency and affect the step’s robustness. Affinity elution samples are reported to contain additional impurities² which influence the performance and duration of subsequent DSP steps. A side-by-side comparison was performed using a CIMmultus® SO3—1 mL (2 µm) column and a commercially available affinity resin that binds several AAV serotypes. Both columns were evaluated for process and step recoveries, impurity reduction, product capacity, and processing time. The results shown are based on two parallel experiments for each capture approach.