GlycoFi's technology to control the glycosylation of recombinant therapeutic proteins.

IMPORTANCE OF THE FIELD: Therapeutic properties of many glycoproteins strongly depend on the composition of their glycans. Most of the current approved glycoproteins are produced in mammalian cell lines, which yield mixture of different glycoforms close to the human one but not fully identical. Glyco-engineering is being developed as a method to control the composition of carbohydrates. Many alternative glycoprotein productions systems are actively investigated including new-engineered yeast strains, as developed by GlycoFi, a biotech company fully owned by Merck & Co. since 2006. AREAS COVERED IN THIS REVIEW: The objectives of this opinion paper is to present a comprehensive overview of the technological breakthrough developed by GlycoFi to produce recombinant human proteins with controlled glycosylation patterns in yeast, in comparison to other glyco-engineering technologies and to discuss the application to large-scale manufacturing of biologicals. WHAT THE READER WILL GAIN: Research papers and recent review articles on protein glycosylation and glyco-engineering, and in-depth search of the bibliography by the GlycoFi's research team, summary of recent meetings discussing the biosimilar topic were analyzed by the authors and will help the reader to gain insight in the field. TAKE HOME MESSAGE: The glyco-engineering technology of the Pichia pastoris N-glycosylation pathway developed by GlycoFi allows producing human proteins with complex N-glycosylation modifications, which are similar to the ones performed in human. Moreover, more homogeneous glycosylation patterns are observed, as opposed to the large heterogeneity of glycan moieties that are found naturally in mammals or in other production systems such as Chinese hamster ovary and NS0 cell lines. These properties associated with the perspective to industrialize the manufacturing process of Pichia makes it a very promising expression system to produce large-scale batches of therapeutics at a lower cost.