Implementing a robust platform analytical procedure for measuring adeno-associated virus vector genome titer

The vector genome (vg) titer measurement, which is used to control patient dosing and ensure control over drug product manufacturing, is essential for the development of recombinant adeno-associated virus (AAV) gene therapy products. While qPCR and droplet digital PCR technologies are commonly implemented for measuring vg titer, chromatographic techniques with UV detectors represent promising future approaches, in line with traditional biotherapeutics. Here, we introduce a novel vg titer measurement approach using size-exclusion high-performance liquid chromatography with UV detection, which achieves excellent method precision (<2% relative SD), demonstrates linearity across a range of concentrations and varied particle content, is stability indicating, and can be bridged with existing vg titer methods. As there is no bias between this procedure and existing vg titer procedures, such as qPCR, this method can be implemented even at late stages during pharmaceutical development. The procedure was demonstrated to be applicable across serotypes and transgenes, enabling the approach to be used as a platform method for AAV. Given the method performance and criticality of vg titer measurements for AAV, this approach represents a beneficial technology for AAV therapeutics.