Tuning mobile phase properties to improve empty and full particle separation in adeno-associated virus productions by anion exchange chromatography

Abstract

In the past decade, recombinant adeno-associated virus (rAAV) has gained increased attention as a prominent gene therapy technology to treat monogenetic diseases. One of the challenges in rAAV production is the enrichment of full rAAV particles containing the gene of interest (GOI) payload. By adjusting the mobile phase properties of anion-exchange chromatography (AEX), it was demonstrated that empty and full separation of rAAV was improved in monolith based preparative AEX chromatography. When compared to the baseline method using NaCl, the use of tetraethylammonium acetate (TEA-Ac) in the AEX mobile phase resulted in enhanced resolution from 0.75 to 1.23 between “Empty” and “Full” peaks by salt linear gradient elution, as well as increased the percentage of full rAAV particles from 20% to 36% and genome recovery from 59% to 62%. Furthermore, a dual wash plus step elution AEX method was developed. Wherein, the first wash step harnesses TEA-Ac to separate empty and full capsids, which is followed by a second wash step that ensures no TEA-Ac salt is carried over into AEX eluate. The resulting optimized AEX purification method has the potential to be adapted for manufacturing and purification processes involving various rAAV production platforms that experience empty and full rAAV separation challenges.