Triple Space-Time Yield in Discontinuous Antibody Biomanufacturing by Combination of Synergetic Process Intensification Strategies

Monoclonal antibodies are the workhorse of the pharmaceutical industry due to their potential to treat a variety of different diseases while providing high specificity and efficiency. As a consequence, a variety of production processes have been established within the biomanufacturing industry. However, the rapidly increasing demand for therapeutic molecules amid the recent COVID-19 pandemic demonstrated that there still is a clear need to establish novel, highly productive, and flexible production processes. Within this work, we designed a novel discontinuous process by combining two intensification strategies, thus increasing inoculation density and media exchange via a fluidized bed centrifuge, to fulfill the need for a flexible and highly productive production process for therapeutic molecules. To establish this new process, firstly, a small-scale experiment was conducted to verify synergies between both intensification strategies, followed by a process transfer towards the proof-of-concept scale. The combination of these two-process intensification measures revealed overall synergies resulting in decreased process duration (-37%) and strongly enhanced product formation (+116%) in comparison to the not-intensified standard operation. This led to an impressive threefold increase in space-time yield, while only negligible differences in product quality could be observed. Overall, this novel process not only increases the ways to react to emergency situations thanks to its flexibility and possible short development times, but also represents a possible alternative to the current established processes due to high increases in productivity, in comparison to standard fed-batch operations.

A novel hybrid bioprocess strategy addressing key challenges of advanced biomanufacturing

Monoclonal antibodies (mAb) are commonly manufactured by either discontinuous operations like fed-batch (FB) or continuous processes such as steady-state perfusion. Both process types comprise opposing advantages and disadvantages in areas such as plant utilization, feasible cell densities, media consumption and process monitoring effort. In this study, we show feasibility of a promising novel hybrid process strategy that combines beneficial attributes of both process formats. In detail, our strategy comprises a short duration FB, followed by a fast media exchange and cell density readjustment, marking the start of the next FB cycle. Utilizing a small-scale screening tool, we were able to identify beneficial process parameters, including FB interval duration and reinoculation cell density, that allow for multiple cycles of the outlined process in a reproducible manner. In addition, we could demonstrate scalability of the process to a 5L benchtop system, using a fluidized-bed centrifuge as scalable media exchange system. The novel process showed increased productivity (+217%) as well as longer cultivation duration, in comparison to a standard FB with a significantly lower media consumption per produced product (-50%) and a decreased need for process monitoring, in comparison to a perfusion cultivation. Further, the process revealed constant glycosylation pattern in comparison to the perfusion cultivation and has strong potential for further scale-up, due to the use of fully scalable cultivation and media exchange platforms. In summary, we have developed a novel hybrid process strategy that tackles the key challenges of current biomanufacturing of either low productivity or high media consumption, representing a new and innovative approach for future process intensification efforts.

Cost-efficient cell clarification using an intensified fluidized bed centrifugation platform approach

The intensification of industrial biopharmaceutical production and the integration of process steps pave the way for patients to access affordable treatments. The predominantly batchwise biomanufacturing of established cell clarification technologies, stainless steel disc stack centrifugation (DSC) and single-use (SU) depth filtration (DF), pose technological and economical bottlenecks, that include low biomass loading capacities and low product recoveries. Therefore, a novel SU-based clarification platform was developed combining fluidized bed centrifugation (FBC) with integrated filtration. The feasibility of this approach was investigated for high cell concentration with more than 100E6 cells/mL. Furthermore, scalability to 200 L bioreactor scale was tested for moderate cell concentrations. In both trials, low harvest turbidities (4 NTU) and superior antibody recoveries (95%) were achieved. The impact on the overall economics of industrial SU biomanufacturing using an up-scaled FBC approach was compared with DSC and DF technologies for different process parameters. As a result, the FBC showed to be the most cost-effective alternative for annual mAb production below 500 kg. In addition, the FBC clarification of increasing cell concentrations was found to have minimal impact on overall process costs, in contrast to established technologies, demonstrating that the FBC approach is particularly suitable for intensified processes.

Boosting Productivity for Advanced Biomanufacturing by Re-Using Viable Cells

Monoclonal antibodies (mAb) have gained enormous therapeutic application during the last decade as highly efficient and flexible tools for the treatment of various diseases. Despite this success, there remain opportunities to drive down the manufacturing costs of antibody-based therapies through cost efficiency measures. To reduce production costs, novel process intensification methods based on state-of-the-art fed-batch and perfusion have been implemented during the last few years. Building on process intensification, we demonstrate the feasibility and benefits of a novel, innovative hybrid process that combines the robustness of a fed-batch operation with the benefits of a complete media exchange enabled through a fluidized bed centrifuge (FBC). In an initial small-scale FBC-mimic screening, we investigated multiple process parameters, resulting in increased cell proliferation and an elongated viability profile. Consecutively, the most productive process scenario was transferred to the 5-L scale, further optimized and compared to a standard fed-batch process. Our data show that the novel hybrid process enables significantly higher peak cell densities (163%) and an impressive increase in mAb amount of approximately 254% while utilizing the same reactor size and process duration of the standard fed-batch operation. Furthermore, our data show comparable critical quality attributes (CQAs) between the processes and reveal scale-up possibilities and no need for extensive additional process monitoring. Therefore, this novel process intensification strategy yields strong potential for transfer into future industrial manufacturing processes.

A novel protocol to prepare cell probes for the quantification of microbial adhesion and biofilm initiation on structured bioinspired surfaces using AFM for single-cell force spectroscopy: Dedicated to Prof. em. Dr. Dr. H.C. Karl Schügerl on the occasion of his 90th birthday

We present a novel protocol that uses single-cell force spectroscopy to characterize the bacteria-to-surface interactions involved in early steps of biofilm formation. Bacteria are immobilized as a monolayer by electrostatic interactions on a polyethylenimine-coated silica bead, and the Escherichia coli-bead complex is then glued on a tipless cantilever. We validated our new protocol by comparing to earlier published methods using single bacteria, but in contrast to these, which carry out bacterial attachment to the bead after fixation to the cantilever, our protocol results in more reliable production of usable cell probes. Measurements of interactions of E. coli with bio-inspired surfaces by single-cell force spectroscopy yielded comparable detachment forces to those found with the previous methods.

Introduction of a novel proliferation assay for pharmacological studies allowing the combination of BrdU detection and phenotyping

A recently developed technology for the non-enzymatic detection of the thymidine analog 5-bromo-2-deoxyuridine (BrdU) has been evaluated. In contrast to previous enzymatic approaches, Ultraviolet-Induced Detection (UVID) of halogenated pyrimidines allows for a mild detection procedure which enables the simultaneous detection of cellular markers and DNA-synthesis without enzyme-specific disadvantages. Superantigen-stimulated peripheral blood mononuclear cells (PBMNCs) have been treated with two different inhibitors of proliferation and the cell cycle of different lymphocyte subsets has been analysed. Both pentoxifylline (POF) and 2-methoxyestradiol (2ME2) exhibited strong antiproliferative activity, but led to distinctive changes in the cell cycle distribution. This study shows that the UVID technology is a simple and viable method which should find a wide range of applications in immunological and pharmacodynamic assays.

Collection efficiencies of CD34+ progenitor cells and mononuclear cells in leukapheresis products quantified by flow cytometry and calculated on the basis of a new formula

BACKGROUND AND OBJECTIVES

Optimal mobilization and harvest of hematopoietic progenitors are essential for peripheral blood stem cell transplantation after myeloablative high-dose chemotherapy. Conflicting data have been published concerning the most useful, cost-effective collection strategy which is also convenient for patients.

MATERIALS AND METHODS

A total of 66 leukaphereses in 20 patients were retrospectively evaluated. We assessed the predictive value of the number of white blood cells, mononuclear cells (MNCs) and CD34+ cells in peripheral blood for the yield of CD34+ cells in leukapheresis products. The concentrations of MNCs and CD34+ cells were quantified simultaneously by a flow cytometric procedure using fluorescent microparticles. Their collection efficiencies were calculated based on a newly developed formula.

RESULTS

The collected hematopoietic progenitor concentration could be predicted only by the number of peripheral blood CD34+ cells prior to apheresis (r = 0.902; p<0.01). Furthermore, the mobilization of at least 30 CD34+ cells/microl peripheral blood was a good predictor that a single leukapheresis would yield a minimum of 2.0x10(6) CD34+ cells/kg body weight. The collection efficiencies calculated by the new formula were 55.2+/-10.7% and 57.7+/-11.2% for MNCs and CD34+ cells, respectively.

CONCLUSION

The precise quantification of MNCs and CD34+ cells by a direct flow cytometric assay, as well as the new formula to determine the collection efficiencies, has an impact on optimizing high-quality stem cell products.

Evaluation of a flow cytometric method for simultaneous leukocyte phenotyping and quantification by fluorescent microspheres

We describe a flow cytometric method using a newly designed product, fluorochrome-containing microspheres (Flow Count fluorospheres), which facilitates the precise quantification of cells in whole blood samples or heterogeneous cell suspensions on a single-cell level. These microparticles are easily distinguishable from other events of interest and can be detected by their light-scattering and fluorescence properties. In contrast to the traditional manual or automated cell-counting techniques, this method offers the opportunity to quantify cells simultaneously with flow cytometric immunophenotyping without additional cell loss or other cell preparation steps. We evaluated the accuracy and reproducibility of this flow cytometric method on the determination of CD45+ leukocyte counts and compared the results with those obtained by conventional techniques. Particular interest was focused on the behavior of cells and fluorospheres regarding their sedimentation rate over the period of analysis. The data from 48 blood samples with low, normal, and high leukocyte counts confirmed the reliability and comparability of the flow cytometric method, permitting the determination of white blood cell concentration at least to a limit of 100 cells/microL. A broad field of applications will benefit from this flow cytometric supplement because it is easy to perform and highly accurate. The results appear to be transferable to clinical decision-making monitoring of CD4+ lymphocytes in patients infected with human immunodeficiency virus or of CD34+ hematopoietic cells, optimizing the harvest for peripheral blood stem cell transplantation.