Strategies for controlling afucosylation in monoclonal antibodies during upstream manufacturing

Core fucosylation is a highly prevalent and significant feature of N‐glycosylation in therapeutic monoclonal antibodies produced by mammalian cells where its absence (afucosylation) plays a key role in treatment safety and efficacy. Notably, even slight changes in the level of afucosylation can have a considerable impact on the antibody‐dependent cell‐mediated cytotoxicity. Therefore, implementing control over afucosylation levels is important in upstream manufacturing to maintain consistent quality across batches of product, since standard downstream processing does not change afucosylation. In this review, the influences and strategies to control afucosylation are presented. In particular, there is emphasis on upstream manufacturing culture parameters and media supplementation, as these offer particular advantages as control strategies over alternative approaches such as cell line engineering and chemical inhibitors. The review discusses the relationship between the afucosylation influences and the underlying cellular metabolism to promote increased process understanding. Also, briefly highlighted is the value of empirical and mechanistic models in evaluating and designing control methods for core fucosylation. Graphical and Lay Summary Afucosylation is a key glycosylation pattern in therapeutic monoclonal antibodies that can greatly affect the effectiveness and safety of the drug. During the upstream manufacturing stages, several strategies may be employed to control the afucosylation level including the following: chemical inhibitors, culture process parameters, media supplementation, and cell line engineering. This review provides an overview of these strategies and relates thei effectiveness to the underlying metabolic processes of the mammalian cell responsible for generating the monoclonal antibodies.