Experimental and computational analysis of glycan processing at increased monoclonal antibody productivities

Optimization of cell culture conditions is critically important for successful commercial production of therapeutic antibodies; however, improvements in productivity may be offset by changes in critical quality attributes. We assessed the impact of two different process conditions (high and low yield) on growth, productivity, and glycan distribution for two CHO-S clones producing adalimumab, clone 1 (DHFR clone) and clone 2 (GS clone) in fed-batch shake flask cultures. High-yield cultures showed approximately 1.6-fold and 7.4-fold increases in integral of viable cells (IVC) for clones 1 and 2, respectively, compared to the low-yield cultures. Although specific productivity was lower in the high-yield cultures, this decrease was offset by the increased IVC, yielding higher titers in both cell lines. High-yield cultures showed a marked decrease in galactosylation, marked by a decrease in G1F glycans compared with the low-yield cultures, across both clones. Man5 glycans remained unchanged in clone 1 cultures, while a slight increase was observed in the high-yield clone 2 cultures. Metabolic analysis showed significant changes in glucose utilization in high-yield cultures with substantial decreases in specific glucose uptake and lactate yield, particularly for clone 2. Calculation of nucleotide sugar fluxes revealed that the increased utilization of UDP-N-acetylglucosamine and UDP-galactose for cellular glycosylation limited their availability for monoclonal antibody (mAb) glycosylation in high IVC, high-yield cultures, consistent with the observed changes in mAb glycans.