AAV Purification Solutions for Gene Therapy Development

Combining selective capture with appropriate polishing steps can help manage trade-offs between recovery and purity across the AAV purification process. Affinity chromatography enables high-purity capture while maintaining yield through selective binding and optimized elution conditions. Polishing steps using ion exchange chromatography (IEX) can then address residual impurities and enrich full capsids. Process parameters, including load density, gradient design, and pooling strategy, influence the balance between yield and purity . Establishing acceptable ranges for these parameters during development, guided by product quality requirements and analytical characterization, supports consistent performance across scales and manufacturing campaigns.

Affinity capture has increasingly become the primary capture step in many AAV workflows, reflecting a similar evolution to monoclonal antibody (mAb) purification, where Protein A (ProA) affinity chromatography became widely adopted for primary capture. Affinity is chosen for its high selectivity early in downstream processing, enabling significant impurity reduction and AAV recovery in a single step. Ion exchange chromatography plays a complementary role later in the workflow to address residual impurities and refine purity based on impurity profiles and process needs, particularly for full capsid enrichment and reduction of process-related contaminants.

Successful scale-up of AAV purification processes depends on resin selection, column scalability, and process robustness as workflows transition from development to cGMP manufacturing. Few chromatography formats scale with the same robustness or operational flexibility at larger volumes. Packed-bed resin-based approaches are often considered for long-term manufacturing readiness due to their scalability, mechanical stability, and compatibility with automated systems. Process parameters should remain consistent across scales, with loading conditions, residence times, and elution strategies verified using scale-down models. Emphasis on consistency, reproducibility, and compatibility with cGMP operations supports regulatory submissions and commercial manufacturing success.

While analytical results are essential for developing effective and robust downstream processes, high-purity materials are essential for developing sensitive, reproducible analytical methods, as impurities in reference standards can compromise assay accuracy and consistency. If impurities are not adequately removed, they may interfere with analytical readouts and increase variability in release results. Aligning purification and analytical strategies early in development can support more rapid process development, strengthen regulatory submissions, support well-defined specifications, and enable consistent long-term process control.

Chromatography and purification solutions that can support both current process development needs and longer-term manufacturing goals include affinity resins with broad serotype specificity, anion exchange resins optimized for full capsid enrichment, and chromatography column formats that enable scalable processing. Affinity chromatography using camelid antibody-based ligands can capture a wide range of AAV serotypes in a single platform. Anion exchange chromatography resins with large throughpores, like the POROS bead, are advantageous for AAV applications and enable full capsid enrichment and impurity clearance. Pre-packed chromatography columns support rapid process development and streamlined technology transfer, saving valuable time during manufacturing. These solutions can help address current purification challenges while establishing a foundation for scalable cGMP manufacturing.