Publications by authors named "Souquet J"

Membrane chromatography devices are a viable alternative to packed-bed resins and enable highly productive purification cascades for monoclonal antibodies and Fc-fusion proteins. In this study, ion exchange and protein A membrane chromatography performances were assessed and compared with their resin counterparts. Protein A dynamic binding capacities were higher than 50 g/L for two of the tested membranes and with a residence time of 0.

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Article Synopsis
  • Biomarkers play a critical role in predicting disease susceptibility and treatment responses, and they are increasingly valuable in the biomanufacturing of therapeutic proteins by enabling data-driven approaches during cell line and process development.
  • Despite the reliance on large screening methods for developing productive cell lines, there is a pressing need to transition to more rational, data-informed strategies as production limits are reached.
  • The review discusses various biological molecules as biomarkers, their detection techniques, and challenges faced, while also exploring their applications and limitations in cell line and bioprocess development.
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Improving current cell line development workflows can either focus on increasing the specific productivity of the cell lines or shortening timelines to reach the clinic as fast as possible. In this work, using the Beacon platform, we have combined two distinct protocols - early cloning with low-viability pools, and IgG membrane staining-, to concomitantly reach both objectives, and generate highly productive CHO clones in shorter timelines. Fast-sorting approaches using low-viability pools in combination with the Beacon platform have recently been reported to shorten CLD timelines.

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Background: Strategies minimizing surgical bleeding, including the antifibrinolytic agent tranexamic acid, play a crucial role in clinical practice to optimize overall surgical outcomes. Despite its proven efficacy in various clinical fields, there is a limited understanding regarding the use of tranexamic acid in plastic and aesthetic procedures. This study is the first investigating the effects of systemically administered tranexamic acid on postoperative blood loss and bleeding complications in fleur-de-lis abdominoplasties and apronectomies.

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Controlling high-mannose (HM) content of therapeutic proteins during process intensification, reformulation for subcutaneous delivery, antibody-drug conjugate or biosimilar manufacturing represents an ongoing challenge. Even though a range of glycosylation levers to increase HM content exist, modulators specially increasing M5 glycans are still scarce. Several compounds of the polyether ionophore family were screened for their ability to selectively increase M5 glycans of mAb products and compared to the well-known α-mannosidase I inhibitor kifunensine known to increase mainly M8-M9 glycans.

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Hollow fiber-based membrane filtration has emerged as the dominant technology for cell retention in perfusion processes yet significant challenges in alleviating filter fouling remain unsolved. In this work, the benefits of co-current filtrate flow applied to a tangential flow filtration (TFF) module to reduce or even completely remove Starling recirculation caused by the axial pressure drop within the module was studied by pressure characterization experiments and perfusion cell culture runs. Additionally, a novel concept to achieve alternating Starling flow within unidirectional TFF was investigated.

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Background: Despite technological advances ensuring stable cell culture perfusion operation over prolonged time, reaching a cellular steady-state metabolism remains a challenge for certain manufacturing cell lines. This study investigated the stabilization of a steady-state perfusion process producing a bispecific antibody with drifting product quality attributes, caused by shifting metabolic activity in the cell culture.

Main Methods: A novel on-demand pyruvate feeding strategy was developed, leveraging lactate as an indicator for tricarboxylic acid (TCA) cycle saturation.

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The COVID-19 pandemic highlighted the urgent need for life-saving treatments, including vaccines, drugs, and therapeutic antibodies, delivered at unprecedented speed. During this period, recombinant antibody research and development cycle times were substantially shortened without compromising quality and safety, thanks to prior knowledge of Chemistry, Manufacturing and Controls (CMC) and integration of new acceleration concepts discussed below. Early product knowledge, selection of a parental cell line with appropriate characteristics, and the application of efficient approaches for generating manufacturing cell lines and manufacturing drug substance from non-clonal cells for preclinical and first-in-human studies are key elements for success.

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Background And Objectives: The background of this study was to evaluate the outcomes of perihilar cholangiocarcinoma (pCCA) patients treated with EUS-guided hepaticogastrostomy (EUS-HGS).

Methods: All patients with pCCA who underwent EUS-HGS from 2010 to 2020 were analyzed. The primary outcome was clinical success; the secondary outcomes were technical success, adverse events (AEs), stent patency, and oncological outcomes.

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Implementation of continuous in lieu of batch upstream processing (USP) and downstream process (DSP) for the production of recombinant therapeutic protein is a significant paradigm change. The present report describes how the first kilograms of monoclonal antibody were produced with equipment originally designed for batch operations while using continuous manufacturing processes and principles. Project timelines for the delivery of clinical material have driven this ambition and helped the transition.

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Patients with nonresectable liver metastases from colorectal cancer have few therapeutic options and a dismal prognosis. Although liver transplantation for this indication has historically a poor reputation, recent advances in the field of chemotherapy and immunosuppression have paved the way to revisit the concept. New data have shown promising results that need to be validated in several ongoing clinical trials.

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Media preparation for perfusion cell culture processes contributes significantly to operational costs and the footprint of continuous operations for therapeutic protein manufacturing. In this study, definitions are given for the use of a perfusion equivalent nutrient feed stream which, when used in combination with basal perfusion medium, supplements the culture with targeted compounds and increases the medium depth. Definitions to compare medium and feed depth are given in this article.

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Multivariate latent variable methods have become a popular and versatile toolset to analyze bioprocess data in industry and academia. This work spans such applications from the evaluation of the role of the standard process variables and metabolites to the metabolomics level, that is, to the extensive number metabolic compounds detectable in the extracellular and intracellular domains. Given the substantial effort currently required for the measurement of the latter groups, a tailored methodology is presented that is capable of providing valuable process insights as well as predicting the glycosylation profile based on only four experiments measured over 12 cell culture days.

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Integrated continuous manufacturing is entering the biopharmaceutical industry. The main drivers range from improved economics, manufacturing flexibility, and more consistent product quality. However, studies on fully integrated production platforms have been limited due to the higher degree of system complexity, limited process information, disturbance, and drift sensitivity, as well as difficulties in digital process integration.

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N-linked glycosylation plays a fundamental role in determining the thermodynamic stability of proteins and is involved in multiple key biological processes. The mechanistic understanding of the intracellular machinery responsible for the stepwise biosynthesis of N-glycans is still incomplete due to limited understanding of in vivo kinetics of N-glycan processing along the secretory pathway. We present a glycoproteomics approach to monitor the processing of site-specific N-glycans in CHO cells.

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Monoclonal antibodies (mAbs) and related recombinant proteins continue to gain importance in the treatment of a great variety of diseases. Despite significant advances, their manufacturing can still present challenges owing to their molecular complexity and stringent regulations with respect to product purity, stability, safety, and so forth. In this context, protein aggregates are of particular concern due to their immunogenic potential.

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Biologically manufactured monoclonal antibodies (mAb) can strongly vary in their efficacy and affinity. Therefore, engineering and production of the mAb is highly regulated and requires product monitoring, especially in terms of N-glycosylation patterns. In this work, we present a high-throughput matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) method based on a microarray technology to monitor N-glycopeptides of IgG1 produced in a perfusion cell culture.

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Perfusion cell culture technologies for the production of therapeuthic recombinant proteins are currently on the rise for diverse applications with the aim of process intensification (Bielser et al., 2018; Chen et al., 2018; Fisher et al.

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On-line monitoring tools for downstream chromatographic processing (DSP) of biotherapeutics can enable fast actions to correct for disturbances in the upstream, gain process understanding, and eventually lead to process optimization. While UV/Vis spectroscopy is mostly assessing the protein's amino acid composition and the application of Fourier transform infrared spectroscopy is limited due to strong water interactions, Raman spectroscopy is able to assess the secondary and tertiary protein structure without significant water interactions. The aim of this work is to implement the Raman technology in DSP, by designing an in-line flow cell with a reduced dead volume of 80 μL and a reflector to increase the signal intensity as well as developing a chemometric modeling path.

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The development of mammalian cell perfusion cultures is still laborious and complex to perform due to the limited availability of scale-down models and limited knowledge of time- and cost-effective procedures. The maximum achievable viable cell density (VCD ), minimum cell-specific perfusion rate (CSPR ), cellular growth characteristics, and resulting bleed rate at steady-state operation are key variables for the effective development of perfusion cultures. In this study, we developed a stepwise procedure to use shake tubes (ST) in combination with benchtop (BR) bioreactors for the design of a mammalian cell perfusion culture at high productivity (23 pg·cell ·day ) and low product loss in the bleed (around 10%) for a given expression system.

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The semicontinuous twin-column multicolumn countercurrent solvent gradient purification (MCSGP) process improves the trade-off between purity and yield encountered in traditional batch chromatography, while its complexity, in terms of hardware requirements and process design, is reduced in comparison to process variants using more columns. In this study, the MCSGP process is experimentally characterized, specifically with respect to its unique degrees of freedom, i.e.

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Perfusion cell culture, confined traditionally to the production of fragile molecules, is currently gaining broader attention in the biomanufacturing of therapeutic proteins. The development of these processes is made difficult by the limited availability of appropriate scale-down models. This is due to the continuous operation that requires complex control and cell retention capacity.

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Glycosylation, a critical product quality attribute, may affect the efficacy and safety of therapeutic proteins in vivo. Chinese hamster ovary fed-batch cell culture batches yielded consistent glycoprofiles of a Fc-fusion antibody comprizing three different N-glycosylation sites. By adding media supplements at specific concentrations in cell culture and applying enzymatic glycoengineering, a diverse N-glycan variant population was generated, including high mannose, afucosylated, fucosylated, agalactosylated, galactosylated, asialylated, and sialylated forms.

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The use of benchtop bioreactors (BRs) for the development of mammalian cell perfusion cultures is expensive and time consuming, given its complexity in equipment and operation. Scale-down models, going from liter to milliliter scale, are needed to support the rapid determination of suitable operating conditions in terms of viable cell density (VCD), perfusion rate, and medium composition. In this study, we compare the performance of steady-state perfusion cultures in orbitally shaken tube and BR systems for a given Chinese hamster ovary cell line.

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Mammalian cell perfusion cultures represent a promising alternative to the current fed-batch technology for the production of various biopharmaceuticals. Long-term operation at a fixed viable cell density (VCD) requires a viable culture and a constant removal of excessive cells. Product loss in the cell removing bleed stream deteriorates the process yield.

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