Trends in Upstream and Downstream Process Development for Antibody Manufacturing

Automated High-Throughput Capillary Circular Dichroism and Intrinsic Fluorescence Spectroscopy for Rapid Determination of Protein Structure

Assessing the physical stability of proteins is one of the most important challenges in the development, manufacture, and formulation of biotherapeutics. Here, we describe a method for combining and automating circular dichroism and intrinsic protein fluorescence spectroscopy. By robotically injecting samples from a 96-well plate into an optically compliant capillary flow cell, complementary information about the secondary and tertiary structural state of a protein can be collected in an unattended manner from considerably reduced volumes of sample compared to conventional techniques. We demonstrate the accuracy and reproducibility of this method. Furthermore, we show how structural screening can be used to monitor unfolding of proteins in two case studies using (i) a chaotropic denaturant (urea) and (ii) low-pH buffers used for monoclonal antibody (mAb) purification during Protein A chromatography.

Emerging biomaterials for downstream manufacturing of therapeutic proteins

Downstream processing is considered one of the most challenging phases of industrial manufacturing of therapeutic proteins, accounting for a large portion of the total production costs. The growing demand for therapeutic proteins in the biopharmaceutical market in addition to a significant rise in upstream titers have placed an increasing burden on the downstream purification process, which is often limited by high cost and insufficient capacities. To achieve efficient production and reduced costs, a variety of biomaterials have been exploited to improve the current techniques and also to develop superior alternatives. In this work, we discuss the significance of utilizing traditional biomaterials in downstream processing and review the recent progress in the development of new biomaterials for use in protein separation and purification. Several representative methods will be highlighted and discussed in detail, including affinity chromatography, non-affinity chromatography, membrane separations, magnetic separations, and precipitation/phase separations. STATEMENT OF SIGNIFICANCE: Nowadays, downstream processing of therapeutic proteins is facing great challenges created by the rapid increase of the market size and upstream titers, starving for significant improvements or innovations in current downstream unit operations. Biomaterials have been widely used in downstream manufacturing of proteins and efforts have been continuously devoted to developing more advanced biomaterials for the implementation of more efficient and economical purification methods. This review covers recent advances in the development and application of biomaterials specifically exploited for various chromatographic and non-chromatographic techniques, highlighting several promising alternative strategies.

The Breakthrough of Biosimilars: A Twist in the Narrative of Biological Therapy

The coming wave of patent expiries of first generation commercialized biotherapeutical drugs has seen the global market open its doors to close copies of these products. These near perfect substitutes, which are termed as “biosimilars”, do not need to undergo intense clinical trials for their approval. However, they are mandated to produce identical similarity from their reference biologics in terms of clinical safety and efficacy. As such, these biosimilar products promise to foster unprecedented access to a wide range of life-saving biologics. However, seeing this promise be fulfilled requires the development of biosimilars to be augmented with product trust, predictable regulatory frameworks, and sustainable policies. It is vital for healthcare and marketing professionals to understand the critical challenges surrounding biosimilar use and implement informed clinical and commercial decisions. A proper framework of pharmacovigilance, education, and scientific exchange for biologics and biosimilars would ensure a dramatic rise in healthcare access and market sustainability. This paper seeks to collate and review all relevant published intelligence of the health and business potential of biosimilars. In doing so, it provides a visualization of the essential steps that are required to be taken for global biosimilar acceptance.

Accelerating Biomanufacturing by Modeling of Continuous Bioprocessing—Piloting Case Study of Monoclonal Antibody Manufacturing

An experimental feasibility study on continuous bioprocessing in pilot-scale of 1 L/day cell supernatant, that is, about 150 g/year product (monoclonal antibody) based on CHO (Chinese hamster ovary) cells for model validation is performed for about six weeks including preparation, start-up, batch, and continuous steady-state operation for at least two weeks stable operation as well as final analysis of purity and yield. A mean product concentration of around 0.4 g/L at cell densities of 25 × 106 cells/mL was achieved. After perfusion cultivation with alternating tangential flow filtration (ATF), an aqueous two-phase extraction (ATPE) followed by ultra-/diafiltration (UF/DF) towards a final integrated counter-current chromatography (iCCC) purification with an ion exchange (IEX) and a hydrophobic interaction (HIC) column prior to lyophilization were successfully operated. In accordance to prior studies, continuous operation is stable and feasible. Efforts of broadly-qualified operation personal as well as the need for an appropriate measurement and process control strategy is shown evidently.

Precipitation of complex antibody solutions: influence of contaminant composition and cell culture medium on the precipitation behavior

Preparative protein precipitation is known as a cost-efficient and easy-to-use alternative to chromatographic purification steps. This said, at the moment, there is no process for monoclonal antibodies (mAb) on the market, although especially polyethylene glycol-induced precipitation has shown great potential. One reason might be the highly complex behavior of each component of a crude feedstock during the precipitation process. For different investigated mAbs, significant variations in the host cell protein (HCP) reduction are observed. In contrast to the precipitation behavior of single components, the interactions and interplay in a complex feedstock are not fully understood yet. This work discusses the influence of contaminants on the precipitation behavior of two different mAbs, an IgG1, and an IgG2. By spiking the mAbs with mock solution, a complex feedstock could successfully be mimicked. Spiking contaminants influenced the yield and purity of the mAbs after the precipitation step, compared to the precipitation behavior of the single components. The mixture showed a decrease in the contaminant and mAb solubility. By re-buffering the mock solution prior to spiking, special salts, small molecules like amino acids, vitamins, or sugars could be depleted while larger ones like HCP or DNA were still present. Therefore, it was possible to distinguish the influence of small molecules and larger ones. Hence, mAb-macromolecular interaction could be identified as a possible reason for the observed higher precipitation propensity, while small molecules of the cell culture medium were identified as solubilisation factors during the precipitation process.

Quantification of residual AEBSF-related impurities by reversed-phase liquid chromatography

During research of a broadly neutralizing antibody (bNAb) for HIV-1 infection, site-specific clipping was observed during cell culture incubation. Protease inhibitor, 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF), was supplemented to the cell culture feeding to mitigate clipping as one of the control strategies. It led to the need and development of a new assay to monitor the free AEBSF-related impurities during the purification process. In this work, a reversed-phase liquid chromatography (RPLC-UV) method was developed to measure the total concentration of AEBSF and its major degradant product, 4-(aminoethyl) benzenesulfonic acid (AEBS-OH). This quantitative approach involved hydrolysis pre-treatment to drive all AEBSF to AEBS-OH, a filtration step to remove large molecules, followed by RPLC-UV analysis. The method was qualified and shown to be capable of measuring AEBS-OH down to 0.5 μM with good accuracy and precision, which was then applied for process clearance studies. The results demonstrated that a Protein A purification step in conjunction with a mock ultrafiltration/diafiltration (UF/DF) step could remove AEBSF-related impurities below the detection level. Overall, this study is the first to provide a unique approach for monitoring the clearance of free AEBSF and its related degradant, AEBS-OH, in support of the bNAb research.

Accelerating Biologics Manufacturing by Modeling or: Is Approval under the QbD and PAT Approaches Demanded by Authorities Acceptable Without a Digital-Twin?

Innovative biologics, including cell therapeutics, virus-like particles, exosomes,recombinant proteins, and peptides, seem likely to substitute monoclonal antibodies as the maintherapeutic entities in manufacturing over the next decades. This molecular variety causes agrowing need for a general change of methods as well as mindset in the process development stage,as there are no platform processes available such as those for monoclonal antibodies. Moreover,market competitiveness demands hyper-intensified processes, including accelerated decisionstoward batch or continuous operation of dedicated modular plant concepts. This indicates gaps inprocess comprehension, when operation windows need to be run at the edges of optimization. Inthis editorial, the authors review and assess potential methods and begin discussing possiblesolutions throughout the workflow, from process development through piloting to manufacturingoperation from their point of view and experience. Especially, the state-of-the-art for modeling inred biotechnology is assessed, clarifying differences and applications of statistical, rigorousphysical-chemical based models as well as cost modeling. “Digital-twins” are described and effortsvs. benefits for new applications exemplified, including the regulation-demanded QbD (quality bydesign) and PAT (process analytical technology) approaches towards digitalization or industry 4.0based on advanced process control strategies. Finally, an analysis of the obstacles and possiblesolutions for any successful and efficient industrialization of innovative methods from processdevelopment, through piloting to manufacturing, results in some recommendations. A centralquestion therefore requires attention: Considering that QbD and PAT have been required byauthorities since 2004, can any biologic manufacturing process be approved by the regulatoryagencies without being modeled by a “digital-twin” as part of the filing documentation?

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.

The Biologics Revolution and Endotoxin Test Concerns

The advent of “at will” production of biologics in lieu of harvesting animal proteins (i.e. insulin) or human cadaver proteins (i.e. growth hormone) has revolutionized the treatment of disease. While the fruits of the biotechnology revolution are widely acknowledged, the realization of the differences in the means of production and changes in the manner of control of potential impurities and contaminants in regard to the new versus the old are less widely appreciated. This chapter is an overview of the biologics revolution in terms of the rigors of manufacturing required to produce them, their mechanism of action, and caveats of endotoxin control. It is a continulation of the previous chapter that established a basic background knowledge of adaptive immune principles necessary to understand the mode of action of both disease causation and biologics therapeutic treatment via immune modulation.

Fermentation Titer Optimization and Impact on Energy and Water Consumption during Downstream Processing

A common focus of fermentation process optimization is the product titer. Different strategies to boost fermentation titer target whole-cell biocatalyst selection, process control, and medium composition. Working at higher product concentrations reduces the water that needs to be removed in the case of aqueous systems and, therefore, lowers the cost of downstream separation and purification. Different approaches to achieve higher titer in fermentation are examined. Energy and water consumption data collected from different Cargill fermentation plants, i.e., ethanol, lactic acid, and 2-keto-L-gulonic acid, confirm that improvements in fermentation titer play a decisive role in downstream economics and environmental footprint.

Accelerated pharmaceutical protein development with integrated cell free expression, purification, and bioconjugation

The use of living cells for the synthesis of pharmaceutical proteins, though state-of-the-art, is hindered by its lengthy process comprising of many steps that may affect the protein’s stability and activity. We aimed to integrate protein expression, purification, and bioconjugation in small volumes coupled with cell free protein synthesis for the target protein, ciliary neurotrophic factor. Split-intein mediated capture by use of capture peptides onto a solid surface was efficient at 89–93%. Proof-of-principle of light triggered release was compared to affinity chromatography (His₆ fusion tag coupled with Ni-NTA). The latter was more efficient, but more time consuming. Light triggered release was clearly demonstrated. Moreover, we transferred biotin from the capture peptide to the target protein without further purification steps. Finally, the target protein was released in a buffer-volume and composition of our choice, omitting the need for protein concentration or changing the buffer. Split-intein mediated capture, protein trans splicing followed by light triggered release, and bioconjugation for proteins synthesized in cell free systems might be performed in an integrated workflow resulting in the fast production of the target protein.

Integrating Engineering, Manufacturing, and Regulatory Considerations in the Development of Novel Antivenoms

Snakebite envenoming is a neglected tropical disease that requires immediate attention. Conventional plasma-derived snakebite antivenoms have existed for more than 120 years and have been instrumental in saving thousands of lives. However, both a need and an opportunity exist for harnessing biotechnology and modern drug development approaches to develop novel snakebite antivenoms with better efficacy, safety, and affordability. For this to be realized, though, development approaches, clinical testing, and manufacturing must be feasible for any novel treatment modality to be brought to the clinic. Here, we present engineering, manufacturing, and regulatory considerations that need to be taken into account for any development process for a novel antivenom product, with a particular emphasis on novel antivenoms based on mixtures of monoclonal antibodies. We highlight key drug development challenges that must be addressed, and we attempt to outline some of the important shifts that may have to occur in the ways snakebite antivenoms are designed and evaluated.

Overview of Antibody Drug Delivery

Monoclonal antibodies (mAbs) are one of the most important classes of therapeutic proteins, which are used to treat a wide number of diseases (e.g., oncology, inflammation and autoimmune diseases). Monoclonal antibody technologies are continuing to evolve to develop medicines with increasingly improved safety profiles, with the identification of new drug targets being one key barrier for new antibody development. There are many opportunities for developing antibody formulations for better patient compliance, cost savings and lifecycle management, e.g., subcutaneous formulations. However, mAb-based medicines also have limitations that impact their clinical use; the most prominent challenges are their short pharmacokinetic properties and stability issues during manufacturing, transport and storage that can lead to aggregation and protein denaturation. The development of long acting protein formulations must maintain protein stability and be able to deliver a large enough dose over a prolonged period. Many strategies are being pursued to improve the formulation and dosage forms of antibodies to improve efficacy and to increase the range of applications for the clinical use of mAbs.

Process Analytical Technology for Advanced Process Control in Biologics Manufacturing with the Aid of Macroscopic Kinetic Modeling

Productivity improvements of mammalian cell culture in the production of recombinant proteins have been made by optimizing cell lines, media, and process operation. This led to enhanced titers and process robustness without increasing the cost of the upstream processing (USP); however, a downstream bottleneck remains. In terms of process control improvement, the process analytical technology (PAT) initiative, initiated by the American Food and Drug Administration (FDA), aims to measure, analyze, monitor, and ultimately control all important attributes of a bioprocess. Especially, spectroscopic methods such as Raman or near-infrared spectroscopy enable one to meet these analytical requirements, preferably in-situ. In combination with chemometric techniques like partial least square (PLS) or principal component analysis (PCA), it is possible to generate soft sensors, which estimate process variables based on process and measurement models for the enhanced control of bioprocesses. Macroscopic kinetic models can be used to simulate cell metabolism. These models are able to enhance the process understanding by predicting the dynamic of cells during cultivation. In this article, in-situ turbidity (transmission, 880 nm) and ex-situ Raman spectroscopy (785 nm) measurements are combined with an offline macroscopic Monod kinetic model in order to predict substrate concentrations. Experimental data of Chinese hamster ovary cultivations in bioreactors show a sufficiently linear correlation (R² ≥ 0.97) between turbidity and total cell concentration. PLS regression of Raman spectra generates a prediction model, which was validated via offline viable cell concentration measurement (RMSE ≤ 13.82, R² ≥ 0.92). Based on these measurements, the macroscopic Monod model can be used to determine different process attributes, e.g., glucose concentration. In consequence, it is possible to approximately calculate (R² ≥ 0.96) glucose concentration based on online cell concentration measurements using turbidity or Raman spectroscopy. Future approaches will use these online substrate concentration measurements with turbidity and Raman measurements, in combination with the kinetic model, in order to control the bioprocess in terms of feeding strategies, by employing an open platform communication (OPC) network—either in fed-batch or perfusion mode, integrated into a continuous operation of upstream and downstream.

Fed-Batch CHO Cell Culture for Lab-Scale Antibody Production

Fed-batch culture is the most commonly used upstream process in industry today for recombinant monoclonal antibody production using Chinese hamster ovary (CHO) cells. Developing and optimizing this process in the lab is crucial for establishing process knowledge, which enables rapid and predictable tech-transfer to manufacturing scale. In this chapter, we describe stepwise how to carry out fed-batch CHO cell culture for lab-scale antibody production.

Integration of Aqueous Two-Phase Extraction as Cell Harvest and Capture Operation in the Manufacturing Process of Monoclonal Antibodies

Substantial improvements have been made to cell culturing processes (e.g., higher product titer) in recent years by raising cell densities and optimizing cultivation time. However, this has been accompanied by an increase in product-related impurities and therefore greater challenges in subsequent clarification and capture operations. Considering the paradigm shift towards the design of continuously operating dedicated plants at smaller scales—with or without disposable technology—for treating smaller patient populations due to new indications or personalized medicine approaches, the rising need for new, innovative strategies for both clarification and capture technology becomes evident. Aqueous two-phase extraction (ATPE) is now considered to be a feasible unit operation, e.g., for the capture of monoclonal antibodies or recombinant proteins. However, most of the published work so far investigates the applicability of ATPE in antibody-manufacturing processes at the lab-scale and for the most part, only during the capture step. This work shows the integration of ATPE as a combined harvest and capture step into a downstream process. Additionally, a model is applied that allows early prediction of settler dimensions with high prediction accuracy. Finally, a reliable process development concept, which guides through the necessary steps, starting from the definition of the separation task to the final stages of integration and scale-up, is presented.

Host Cell Proteins in Biologics Manufacturing: The Good, the Bad, and the Ugly

Significant progress in the manufacturing of biopharmaceuticals has been made by increasing the overall titers in the USP (upstream processing) titers without raising the cost of the USP. In addition, the development of platform processes led to a higher process robustness. Despite or even due to those achievements, novel challenges are in sight. The higher upstream titers created more complex impurity profiles, both in mass and composition, demanding higher separation capacities and selectivity in downstream processing (DSP). This creates a major shift of costs from USP to DSP. In order to solve this issue, USP and DSP integration approaches can be developed and used for overall process optimization. This study focuses on the characterization and classification of host cell proteins (HCPs) in each unit operation of the DSP (i.e., aqueous two-phase extraction, integrated countercurrent chromatography). The results create a data-driven feedback to the USP, which will serve for media and process optimizations in order to reduce, or even eliminate nascent critical HCPs. This will improve separation efficiency and may lead to a quantitative process understanding. Different HCP species were classified by stringent criteria with regard to DSP separation parameters into “The Good, the Bad, and the Ugly” in terms of pI and MW using 2D-PAGE analysis depending on their positions on the gels. Those spots were identified using LC-MS/MS analysis. HCPs, which are especially difficult to remove and persistent throughout the DSP (i.e., “Bad” or “Ugly”), have to be evaluated by their ability to be separated. In this approach, HCPs, considered “Ugly,” represent proteins with a MW larger than 15 kDa and a pI between 7.30 and 9.30. “Bad” HCPs can likewise be classified using MW (>15 kDa) and pI (4.75–7.30 and 9.30–10.00). HCPs with a MW smaller than 15 kDa and a pI lower than 4.75 and higher than 10.00 are classified as “Good” since their physicochemical properties differ significantly from the product. In order to evaluate this classification scheme, it is of utmost importance to use orthogonal analytical methods such as IEX, HIC, and SEC.

Untargeted LC-MS/MS Profiling of Cell Culture Media Formulations for Evaluation of High Temperature Short Time Treatment Effects

An untargeted LC-MS/MS platform was implemented for monitoring variations in CHO cell culture media upon exposure to high temperature short time (HTST) treatment, a commonly used viral clearance upstream strategy. Chemically defined (CD) and hydrolysate-supplemented media formulations were not visibly altered by the treatment. The absence of solute precipitation effects during media treatment and very modest shifts in pH values observed indicated sufficient compatibility of the formulations evaluated with the HTST-processing conditions. Unsupervised chemometric analysis of LC-MS/MS data, however, revealed clear separation of HTST-treated samples from untreated counterparts as observed from analysis of principal components and hierarchical clustering sample grouping. An increased presence of Maillard products in HTST-treated formulations contributed to the observed differences which included organic acids, observed particularly in chemically defined formulations, and furans, pyridines, pyrazines, and pyrrolidines which were determined in hydrolysate-supplemented formulations. The presence of Maillard products in media did not affect cell culture performance with similar growth and viability profiles observed for CHO-K1 and CHO-DP12 cells when cultured using both HTST-treated and untreated media formulations.

What NMR can do in the biopharmaceutical industry

Nuclear magnetic resonance (NMR) spectroscopy has a unique capability to probe the primary and higher order molecular structure and the structural dynamics of biomolecules at an atomic resolution, and this capability has been greatly fortified over the last five decades by an astonishing NMR instrumental and methodological development. Because of these factors, NMR has become a primary tool for the structure investigation of biomolecules, spawning a whole scientific subfield dedicated to the subject. This role of NMR is by now well established and broadly appreciated, especially in the context of academic research dealing with proteins that are purified and isotope-labeled in order to facilitate the necessary sophisticated multidimensional NMR measurements. However, the more recent industrial development, manufacturing, and quality control of biopharmaceuticals provide a different framework for NMR. For example, protein drug substances are not isotope-labeled and are present in a medium of excipients, which make structural NMR measurements much more difficult. On the other hand, biotechnology involves many other analytical requirements that can be efficiently addressed by NMR. In this respect the scope and limitations of NMR are less well understood. Having the non-expert reader in mind, herein we wish to highlight the ways in which modern NMR can effectively support biotechnological developments. Our focus will be on biosimilar proteins, pointing out certain cases where its use is probably essential. Based partly on literature data, and partly on our own hands-on experience, this paper is intended to be a guide for choosing the proper NMR approach for analytical questions concerning the structural comparability of therapeutic proteins, monitoring technology-related impurities, protein quantification, analysis of spent media, identification of extractable and leachable components, etc. Also, we focus on critical considerations, particularly those coming from drug authority guidelines, which limit the use of the well-established NMR tools in everyday practice.

Industrial Production of Therapeutic Proteins: Cell Lines, Cell Culture, and Purification

A central pillar of the biotechnology and pharmaceutical industries continues to be the development of biological drug products manufactured from engineered mammalian cell lines. Since the hugely successful launch of human tissue plasminogen activator in 1987 and erythropoietin in 1988, the biopharmaceutical market has grown immensely. In 2014, biotherapeutics made up a significant portion of global drug sales as 7 of the top 10 and 21 of top 50 selling pharmaceuticals in the world were biologics with over US$100 billion in global sales (Table 1, [1]).