A study of the practicality of cell-free protein synthesis for the commercial manufacture of monoclonal antibodies /

Abstract

Background: Monoclonal antibodies are tetrameric proteins with a complex folded structure, bound together by numerous disulfide bonds, and decorated with a functionally important oligosaccharide. Current production methods rely on recombinant cell cultures. Aims: The aim of this project was to highlight the benefits of a transition to cell-free manufacturing of monoclonal antibodies, to identify the technological gaps which prevent this transition, to suggest possible solutions, and to critically assess the state of development of these new technologies with a view to suggesting areas for further research. Method: A literature review was performed based on a list of pre-defined search terms. The information was grouped into themes aligned with the aims. Results: Cell-free protein synthesis has been used in research for many years, and it is apparent that the technological foundations exist for large-scale cell-free protein manufacture, boosted by recent advances in understanding of folding mechanisms and disulfide bonding. Nevertheless, the complex glycosylation of monoclonal antibodies cannot yet be performed in vitro. In fact, even current cell culture techniques cannot produce a pure glycoprotein. Counterintuitively. this is a strong argument for developing cell-free production technologies as these are less complex, are easier to control, and are more amenable to alternative technologies for glycosylation. Three emerging technologies were identified as possible solutions, each of which may be capable of attaching a pre-formed, pure oligosaccharide to the non-glycosylated monoclonal antibodies that are currently produced in cell-free systems: gene code expansion, antibody-drug conjugation techniques, and glycoengineering. Conclusion: The results are significant as they indicate that cell-free techniques may soon become the predominant platform for the production of mono-clonal antibodies, bringing financial and societal benefits, as well as faster development timelines. A shift to pure glycoforms could mean a much faster introduction of biosimilars, or even their replacement by identical biogenerics.