What are the key challenges in scaling AAV manufacturing for gene therapy?

AAV manufacturing scale-up challenges include: achieving high vector yields (triple transfection is labor-intensive and difficult to scale), maintaining serotype purity and potency, separating full from empty capsids (ultracentrifugation doesn't scale well), developing robust producer cell lines with comparable quality to transfection, ensuring consistent capsid ratios in mixed-serotype preparations, and managing process analytics for heterogeneous populations. Downstream challenges include developing scalable chromatography for high purity, measuring potency beyond qPCR titers (infectivity assays variability), and establishing specifications for novel serotypes. Cost remains prohibitive for many indications. Emerging solutions include stable producer lines (Rep-Cap integration), suspension culture adaptation, and affinity chromatography advances.