In the latest draft chapter released by the US Pharmacopeia, the organisation has recognised the role of mass photometry in advancing gene therapy quality.
Chapter <1067>, which details best practices for the manufacture and quality control of recombinant adeno-associated virus (AAV) gene therapy products, highlights the potential of mass photometry alongside AUC and TEM for accurately measuring capsid filling.
According to the chapter, by combining these technologies, AAV developers can accurately characterise their capsids, allowing them to determine how empty, full, or partially filled they are.
By employing this tech combination, AAV manufacturers can standardise the quality assessment and control process.
Developed in collaboration with leading scientists across multiple laboratories, USP’s new AAV standards tackle the essential need for consistency and reliability in AAV assessments.
Mass photometry was used alongside SEC-MALS, AUC, UV-vis, and CD-MS to characterise USP’s new AAV8 (Empty Capsids) and AAV8 (Full Capsids) reference standards, and is now included in USP’s Gene Therapy Analytical Guide.
Detailed on the USP’s reference standard certificates for AAV8 (Full Capsids) and AAV8 (Empty Capsids), Refeyn’s SamuxMP mass photometer is optimized for AAV characterisation to offer quick and easy empty/full capsid ratio measurements with minimal sample.
On top of quantitative characterisation of AAVs of all serotypes, the SamuxMP can quantify partially-filled and overfilled capsides, while detecting impurities and aggregation that might impact overall product quality.
Refeyn’s MassFerence P2 Calibrant was also used alongside the SamuxMP for the certificates’ method parameters.
The US Pharmacopeia's recognition of mass photometry was also recommended by the British Pharmacopeia in 2024, who included the technology in its Advanced Therapy Medicinal Products Guidance on Characterisation of the Capsid Particle Population in rAAV Products.
"We are thrilled that mass photometry has been recognised by the USP, as this demonstrates that the method is being accepted as a valuable part of the AAV analytics toolbox," noted Refeyn's Market Development Director, Gabriella Kiss.
"Mass photometry has a lot to offer because it's simple and easy-to-use when measuring a significant CQA, while ensuring consistent and reliable analytics," she added.
A recent webinar presented by scientists from the USP and Pharmaron Biologics divulges insights into the new USP standards to support AAV quality testing and analytical characterisation, as well as how they use mass photometry for AAV capsid optimisation.
