N-Glycosylation is a critical component of many protein-based therapeutics, required for appropriate stability, immunogenicity, and pharmacokinetics. In addition, it is essential for key antibody activities, including ADCC (antibody-dependent cell-mediated cytotoxicity) and CDC (complement-dependent cytotoxicity). Taken all together, glycosylation is a Critical Quality Attribute (CQA) for antibodies and other proteins.
“The challenge to biotherapeutics manufacturing is to scale up production of a glycosylated protein, while maintaining the precise glycosylation profile throughout the process,” say Sylvain Marcel, PhD, vp, protein expression sciences at iBio. “This is very difficult when using mammalian cells, since expression and post translational modifications can change dramatically as bioreactor volume increases. Different cell types and expression systems may produce glycan profiles that are significantly different from one another. Under diverse culture conditions mammalian cell lines such as CHO, NSO, and PER.C6 can produce a wide variety of glycan structures.”
To overcome this problem, the iBio group uses tobacco plants as their bioreactor, since with one plant or a thousand, performance will be identical. Marcel uses a series of genetically engineered tobacco plants, through a sequence of protocols referred to as Fast Glycaneering. By removing the genes for plant glycosylating enzymes and replacing them with human glycosylating machinery, they are able to generate an authentic humanized afucosylated Rituximab for their partner CC-Pharming. “A big benefit of this system is that the glycan profile is very tightly controlled, so essentially you get a single glycoform that meets your needs,” Marcel continued.
The developmental timeline for plant protein production is much faster than that achieved with conventional mammalian cell systems, such as CHO. There is no need for cell line development, viral clearance studies or bioreactor scaleup. Marcel states that the timeline can be shortened from a typical 20-22 months using CHO or comparable mammalian cell systems to 12 months or less with a tobacco plant expression system.
The Fast Glycaneering process allows customized N-glycosylation to meet target profiles, specifically antibodies that harbor afucosylated humanized N-glycans (with increased ADCC) or humanized N-glycans. A further benefit of the system is that the process parameters for upstream production are highly consistent, making automation and next generation process controls possible. Along these lines, iBio recently moved further toward “Bioprocessing 4.0” through a collaboration with EdgePoint AI to deploy its artificial intelligence (AI)/blockchain-driven vision system in iBio’s highly automated GMP manufacturing facility. The system uses AI-driven vision systems to record activities and workflows that can be used to streamline operations, provide process-related documentation and to gather data that can lead to improved processes.
“We have observed greater batch-to-batch glycan profiles and process performance consistency using our plant-based system as compared to CHO-produced material. One of our goals is to now take the consistent upstream process and deploy it with our automated systems and AI vision to create an end-to-end manufacturing process that can approach the concept of Industry 4.0 which is a challenge for the production of biologics” said Marcel.