Established bioprocesses for producing antibodies as a basis for future planning

Economic Analysis of Batch and Continuous Biopharmaceutical Antibody Production: A Review

PURPOSE

There is a growing interest in continuous biopharmaceutical processing due to the advantages of small footprint, increased productivity, consistent product quality, high process flexibility and robustness, facility cost-effectiveness, and reduced capital and operating cost. To support the decision making of biopharmaceutical manufacturing, comparisons between conventional batch and continuous processing are provided.

METHODS

Various process unit operations in different operating modes are summarized. Software implementation, as well as computational methods used, are analyzed pointing to the advantages and disadvantages that have been highlighted in the literature. Economic analysis methods and their applications in different parts of the processes are also discussed with examples from publications in the last decade.

RESULTS

The results of the comparison between batch and continuous process operation alternatives are discussed. Possible improvements in process design and analysis are recommended. The methods used here do not reflect Lilly's cost structures or economic evaluation methods.

CONCLUSION

This paper provides a review of the work that has been published in the literature on computational process design and economic analysis methods on continuous biopharmaceutical antibody production and its comparison with a conventional batch process.

Glycoengineering of antibody (Herceptin) through yeast expression and in vitro enzymatic glycosylation

Monoclonal antibodies (mAbs) have been developed as therapeutics, especially for the treatment of cancer, inflammation, and infectious diseases. Because the glycosylation of mAbs in the Fc region influences their interaction with effector cells that kill antibody-targeted cells, and the current method of antibody production is relatively expensive, efforts have been directed toward the development of alternative expressing systems capable of large-scale production of mAbs with desirable glycoforms. In this study, we demonstrate that the mAb trastuzumab expressed in glycoengineered P. pastoris can be remodeled through deglycosylation by endoglycosidases identified from the Carbohydrate Active Enzymes database and through transglycosylation using glycans with a stable leaving group to generate a homogeneous antibody designed to optimize the effector functions. The 10 newly identified recombinant bacterial endoglycosidases are complementary to existing endoglycosidases (EndoA, EndoH, EndoS), two of which can even accept sialylated tri- and tetraantennary glycans as substrates.

Integrated continuous bioprocessing: Economic, operational, and environmental feasibility for clinical and commercial antibody manufacture

This paper presents a systems approach to evaluating the potential of integrated continuous bioprocessing for monoclonal antibody (mAb) manufacture across a product's lifecycle from preclinical to commercial manufacture. The economic, operational, and environmental feasibility of alternative continuous manufacturing strategies were evaluated holistically using a prototype UCL decisional tool that integrated process economics, discrete-event simulation, environmental impact analysis, operational risk analysis, and multiattribute decision-making. The case study focused on comparing whole bioprocesses that used either batch, continuous or a hybrid combination of batch and continuous technologies for cell culture, capture chromatography, and polishing chromatography steps. The cost of goods per gram (COG/g), E-factor, and operational risk scores of each strategy were established across a matrix of scenarios with differing combinations of clinical development phase and company portfolio size. The tool outputs predict that the optimal strategy for early phase production and small/medium-sized companies is the integrated continuous strategy (alternating tangential flow filtration (ATF) perfusion, continuous capture, continuous polishing). However, the top ranking strategy changes for commercial production and companies with large portfolios to the hybrid strategy with fed-batch culture, continuous capture and batch polishing from a COG/g perspective. The multiattribute decision-making analysis highlighted that if the operational feasibility was considered more important than the economic benefits, the hybrid strategy would be preferred for all company scales. Further considerations outside the scope of this work include the process development costs required to adopt continuous processing. © 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 33:854-866, 2017.

Allogeneic cell therapy bioprocess economics and optimization: single-use cell expansion technologies

For allogeneic cell therapies to reach their therapeutic potential, challenges related to achieving scalable and robust manufacturing processes will need to be addressed. A particular challenge is producing lot-sizes capable of meeting commercial demands of up to 10(9) cells/dose for large patient numbers due to the current limitations of expansion technologies. This article describes the application of a decisional tool to identify the most cost-effective expansion technologies for different scales of production as well as current gaps in the technology capabilities for allogeneic cell therapy manufacture. The tool integrates bioprocess economics with optimization to assess the economic competitiveness of planar and microcarrier-based cell expansion technologies. Visualization methods were used to identify the production scales where planar technologies will cease to be cost-effective and where microcarrier-based bioreactors become the only option. The tool outputs also predict that for the industry to be sustainable for high demand scenarios, significant increases will likely be needed in the performance capabilities of microcarrier-based systems. These data are presented using a technology S-curve as well as windows of operation to identify the combination of cell productivities and scale of single-use bioreactors required to meet future lot sizes. The modeling insights can be used to identify where future R&D investment should be focused to improve the performance of the most promising technologies so that they become a robust and scalable option that enables the cell therapy industry reach commercially relevant lot sizes. The tool outputs can facilitate decision-making very early on in development and be used to predict, and better manage, the risk of process changes needed as products proceed through the development pathway.

An engineered diatom acting like a plasma cell secreting human IgG antibodies with high efficiency

BACKGROUND

Although there are many different expression systems for recombinant production of pharmaceutical proteins, many of these suffer from drawbacks such as yield, cost, complexity of purification, and possible contamination with human pathogens. Microalgae have enormous potential for diverse biotechnological applications and currently attract much attention in the biofuel sector. Still underestimated, though, is the idea of using microalgae as solar-fueled expression system for the production of recombinant proteins.

RESULTS

In this study, we show for the first time that completely assembled and functional human IgG antibodies can not only be expressed to high levels in algal systems, but also secreted very efficiently into the culture medium. We engineered the diatom Phaeodactylum tricornutum to synthesize and secrete a human IgG antibody against the Hepatitis B Virus surface protein. As the diatom P. tricornutum is not known to naturally secrete many endogenous proteins, the secreted antibodies are already very pure making extensive purification steps redundant and production extremely cost efficient.

CONCLUSIONS

Microalgae combine rapid growth rates with all the advantages of eukaryotic expression systems, and offer great potential for solar-powered, low cost production of pharmaceutical proteins.

Engineering aggregation resistance in IgG by two independent mechanisms: lessons from comparison of Pichia pastoris and mammalian cell expression

Aggregation is an important concern for therapeutic antibodies, since it can lead to reduced bioactivity and increase the risk of immunogenicity. In our analysis of immunoglobulin G (IgG) molecules of identical amino acid sequence but produced either in mammalian cells (HEK293) or in the yeast Pichia pastoris (PP), dramatic differences in their aggregation susceptibilities were encountered. The antibodies produced in Pichia were much more resistant to aggregation under many conditions, a phenomenon found to be mainly caused by two factors. First, the mannose-rich glycan of the IgG from Pichia, while slightly thermally destabilizing the IgG, strongly inhibited its aggregation susceptibility, compared to the complex mammalian glycan. Second, on the Pichia-produced IgGs, amino acids belonging to the α-factor pre-pro sequence were left at the N-termini of both chains. These additional residues proved to considerably increase the temperature of the onset of aggregation and reduced the aggregate formation after extended incubation at elevated temperatures. The attachment of these residues to IgGs produced in cell culture confirmed their beneficial effect on the aggregation resistance. Secretion of IgGs with native N-termini in the yeast system became possible after systematic engineering of the precursor proteins and the processing site. Taken together, the present results will be useful for the successful production of full-length IgGs in Pichia, give indications on how to engineer aggregation-resistant IgGs and shed new light on potential biophysical effects of tag sequences in general.

Glycoengineered Pichia produced anti-HER2 is comparable to trastuzumab in preclinical study

Mammalian cell culture systems are used predominantly for the production of therapeutic monoclonal antibody (mAb) products. A number of alternative platforms, such as Pichia engineered with a humanized N-linked glycosylation pathway, have recently been developed for the production of mAbs. The glycosylation profiles of mAbs produced in glycoengineered Pichia are similar to those of mAbs produced in mammalian systems. This report presents for the first time the comprehensive characterization of an anti-human epidermal growth factor receptor 2 (HER2) mAb produced in a glycoengineered Pichia, and a study comparing the anti-HER2 from Pichia, which had an amino acid sequence identical to trastuzumab, with trastuzumab. The comparative study covered a full spectrum of preclinical evaluation, including bioanalytical characterization, in vitro biological functions, in vivo anti-tumor efficacy and pharmacokinetics in both mice and non-human primates. Cell signaling and proliferation assays showed that anti-HER2 from Pichia had antagonist activities comparable to trastuzumab. However, Pichia-produced material showed a 5-fold increase in binding affinity to FcγIIIA and significantly enhanced antibody dependant cell-mediated cytotoxicity (ADCC) activity, presumably due to the lack of fucose on N-glycans. In a breast cancer xenograft mouse model, anti-HER2 was comparable to trastuzumab in tumor growth inhibition. Furthermore, comparable pharmacokinetic profiles were observed for anti-HER2 and trastuzumab in both mice and cynomolgus monkeys. We conclude that glycoengineered Pichia provides an alternative production platform for therapeutic mAbs and may be of particular interest for production of antibodies for which ADCC is part of the clinical mechanism of action.

Improving bioreactor cultivation conditions for sensitive cell lines by dynamic membrane aeration

Although the importance of animal cell culture for the industrial (large scale) production of pharmaceutical products is continuously increasing, the sensibility of the cells towards their cultivation environment is still a challenging issue. In comparison to microbial cultures, cell cultures which are not protected by a cell wall are much more sensitive to shear stress and foam formation. Reactor design as well as the selection of 'robust' cell lines is particularly important for these circumstances. Nevertheless, even 'sensitive' cell lines are selected for certain pharmaceutical processes due to various reasons. These sensitive cell lines have even higher requirements regarding their cultivation environment. Important characteristics for the corresponding reactor design are a high (volumetric) gas mass transfer coefficient, low volumetric power input, low shear stress, low susceptibility to bio-fouling, the ability to cultivate sticky cells and sufficient mixing properties. Membrane aeration has been a long-known possibility to meet some of these requirements, but has not often been applied in recent years. The reasons lie mainly in low gas mass transfer rates, a limited installable volume-specific membrane surface area, restrictions in scalability and problems with membrane fouling. The dynamic membrane aeration bioreactor aeration is a simple concept for bubble-free oxygen supply of such sensitive cultures. It overcomes limitations and draw-backs of previous systems. Consisting of an oscillating, centrally arranged rotor (stirrer) that is wrapped with silicone membrane tubing, it enables doubling the gas mass transfer at the same shear stress in the investigated cultivation scales of 12, 20, 100, and 200 L. Continuous cultivation at these scales allows the same product output as fed-batch cultivation does at tremendously larger reactor volumes. Apart from introducing this novel technology, the presentation comprises selected cultivation results obtained for blood coagulation factor VIII in continuous mode and a therapeutic monoclonal antibody in fed-batch mode in comparison to reference trials.