Development and implementation of an LC-MS-based multi-attribute method for adeno-associated virus

The multi-attribute method (MAM), a mass spectrometry technique for quantifying amino acid modifications at the peptide level, is becoming a prominent analytical tool in the development of biotherapeutics. The method has promise for adeno-associated virus (AAV) therapeutics, where capsid protein modifications have been directly linked to reduced transduction efficiency. Given this link, a robust and precise procedure to quantitate capsid modifications would be beneficial for implementation throughout biotherapeutic development. Herein, an AAV product was characterized, and capsid sequence liabilities were identified. A peptide map MAM method was developed to quantitate select sites of modifications and was validated according to ICH Q2(R2). Through this exercise, the method was demonstrated to be suitable to quantitate several sites of deamidation and the method was applied during stability, process development, and product comparability studies. Additionally, preliminary data demonstrated that the method was not limited to monitoring deamidation but also could be applied to other post-translational and chemical modifications.