Comparability Study Between Ion-Exchange Monolith and Affinity Resin For Purification of AAV8
The main objective of every downstream process (DSP) for AAV is to achieve high recovery while delivering the purest, most potent product possible. The capture step in AAV gene therapy is either affinity or cation exchange chromatography, which both concentrates the product and removes impurities. Following the capture, the eluate is generally further processed to enrich for full capsids and further purification. For this enrichment and polishing of full AAV capsids, CIMmultus QA, a monolith-based anion exchange chromatography, is widely used.
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. The affinity elution sample is reported to contain additional impurities, which influences subsequent steps of the DSP. Processing time is critical to an efficient process since a faster process has an overall lower financial footprint.
A side-by-side comparison was performed using CIMmultus SO3-1mL (2um) column and commercially available affinity resin which 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.