PAK BioSolutions today announced the publication of a peer-reviewed study on integrated, continuous purification of adeno-associated virus serotype 8 (AAV8) using the PAK PD™ Process Development Scale Continuous Purification System. Conducted in collaboration with iBET – Instituto de Biologia Experimental e Tecnológica, the study, “Streamlining AAV8 Purification with Cyclic Integrated Capture–Polishing Chromatography,” was published in Separation and Purification Technology.
The research team developed an integrated capture and polishing process for AAV8 under repeated cycling operation. The process was operated for 12 hours with reproducible, stable cycle-to-cycle performance. It achieved full-capsid enrichment and impurity reduction comparable to that reported for established batch processes, demonstrating the feasibility of integrated continuous downstream processing for viral vectors.
Why Continuous Downstream Processing Matters for AAV
AAV vectors are a leading platform for in vivo gene therapy, underpinning several approved treatments and a growing pipeline of clinical programs. As these therapies advance toward commercialization, increasing clinical adoption and higher dosing requirements are placing greater demands on downstream processing. Manufacturers need to increase throughput while maintaining product quality.
Process intensification offers a way forward, but continuous operation has largely been limited to individual purification steps, with continuous capture typically paired with batch polishing. This study brings capture and polishing together in a single integrated continuous process.
Capture and Polishing in One Process
The team combined AAVX affinity capture with Mustang® Q anion-exchange membrane polishing, using two alternating columns at each step. As one column loaded, the other underwent elution and regeneration. PAK’s automation coordinated column switching, inline dilution of the capture eluate, and transfer to the polishing step, enabling capture and polishing to operate in parallel.
“This study brings integrated, continuous downstream processing to AAV purification, helping gene therapy manufacturers move toward more efficient manufacturing strategies,” said Joanna Pezzini, CEO of PAK BioSolutions.
Continuous AAV8 Purification Results
Over 12 hours of stable, cycle-to-cycle operation, the integrated process:
- Achieved full-capsid enrichment from 34% after affinity capture to 79% in the final polished product pools
- Recovered 44% of vector genomes from feed to final pool
- Reduced dsDNA to below the assay detection limit after capture, and host cell protein to below the detection limit after polishing
The continuous purification process implemented on a PAK PD™ system achieved product quality consistent with that reported for established batch AAV purification workflows employing affinity capture and anion-exchange (AEX) polishing. The final full-capsid content of 79% falls within the 68–81% range reported for batch anion-exchange polishing of AAV8. The authors note that batch AAV purification workflows can be translated into an integrated continuous format through defined process adaptation, without requiring custom control development or bespoke system engineering.
Building on PAK BioSolutions’ work with monoclonal antibodies (mAbs), this study extends the body of peer-reviewed research using PAK systems to adeno-associated virus (AAV) vectors. PAK systems were previously used in a 14-day, fully integrated continuous downstream mAb run with AstraZeneca (Ramos et al., Biotechnology and Bioengineering, 2023). PAK systems have also supported GMP clinical manufacturing of drug product, including a First-in-Human (FIH) clinical trial application.
Read more here.