Challenges and Opportunities for the Large-Scale Chemoenzymatic Glycoengineering of Therapeutic N-Glycosylated Monoclonal Antibodies

Adelina Ivanova,Francesco Falcioni

doi:10.3389/fctls.2021.810779

Adelina Ivanova, Francesco Falcioni

Open Access

https://doi.org/10.3389/fctls.2021.810779

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Abstract

Variability in the glycosylation profile of therapeutic monoclonal antibodies (mAbs), due to recombinant production technologies, leads to inconsistencies in effector functions and pharmacokinetic properties, both batch-to-batch and within single batches. It also poses regulatory concerns over the effectiveness of commercially available formulations. In vitro chemoenzymatic glycoengineering of variants displaying a homogeneous glycan profile is a trending strategy for ensuring consistent, controlled, and enhanced therapeutic performance, but reported successes are largely limited to small-scale applications. The major challenges for the industrial-scale introduction of the technique stem from the need for activated sugar donors, which can participate in undesired side reactions, and from the economic cost of the additional enzymatic steps and purification stages. While recent developments within the area address some of these obstacles, it appears that more effort is required in order to access the untapped potential of biocatalysis to enable the robust production of therapeutically superior constructs.

Highlights

Monoclonal antibodies are established pharmaceutical modalities with rapidly expanding application in multiple therapeutic areas (Lin et al, 2015; Seeberger and Cummings, 2017; Li et al, 2020)
We propose that the ideal solution to this issue could be achieved in the future by a combination of enzyme and process engineering: in absence of glycosynthase, the activated oxazoline is stable to chemical hydrolysis under the typical assay conditions
The strategy was initially developed by the Huang group, which converted in situ the glycan from SGP to the corresponding oxazoline in order to homogenously glycosylate Fuc-α-(1,6)-GlcNAc-Fc trastuzumab with Endo-S D233Q glycosynthase (Figure 5A) (Tang et al, 2016)

Summary

Introduction

Monoclonal antibodies (mAbs) are established pharmaceutical modalities with rapidly expanding application in multiple therapeutic areas (Lin et al, 2015; Seeberger and Cummings, 2017; Li et al, 2020). Chemoenzymatic glycoengineering is a two-step process, whereby the native heterogeneous glycans are trimmed off to a single GlcNAc/Fuc-α-(1,6)-GlcNAc unit using wild-type endo-Nacetylglucosaminidases (ENGases) (Fairbanks, 2017), with subsequent biocatalytic en bloc homogenous glycosylation (Figure 2A) (Chao et al, 2020).

Results

Conclusion