The Glycosylation Design Space for Recombinant Lysosomal Replacement Enzymes Produced in CHO Cells

Lysosomal storage diseases are rare life-threatening disorders caused by deficiency of a lysosomal enzyme, and delivery of a recombinant replacement enzyme is the primary therapy for several of these diseases. The structures of N-glycans on recombinant replacement enzymes are important for their therapeutic efficacy, biodistribution and circulation time. Here we use alpha-galactosidase A (GLA) and beta-glucoscerebrosidase (GBA) as representative replacement enzymes, and present a panel of genetically engineered CHO cells that enable production of lysosomal replacement enzymes with different N-glycan features. We also tested several GLA variants with distinct glycoforms in a Fabry mouse model and present evidence that GLA glycoforms capped with alpha 2-3 linked sialic acids may represent a new strategy to overcome the most critical problems of rapid clearance in liver and poor biodistribution found with current ERTs.