Molecular Modeling of the Deamidation Reaction in Solution: A Theoretical-Computational Study.

In this work, a theoretical-computational method is applied to study the deamidation reaction, a critical post-translational modification in proteins, using a simple model molecule in solution. The method allows one to comprehensively address the environmental effect, thereby enabling one to accurately derive the kinetic rate constants for the three main steps of the deamidation process. The results presented, in rather good agreement with the available experimental data, underline the necessity for a rigorous treatment of environmental factors and a precise kinetic model to correctly assess the overall kinetics of the deamidation reaction.

Digital by design approach to develop a universal deep learning AI architecture for automatic chromatographic peak integration.

Chromatographic data processing has garnered attention due to multiple Food and Drug Administration 483 citations and warning letters, highlighting the need for a robust technological solution. The healthcare industry has the potential to greatly benefit from the adoption of digital technologies, but the process of implementing these technologies can be slow and complex. This article presents a "Digital by Design" managerial approach, adapted from pharmaceutical quality by design principles, for designing and implementing an artificial intelligence (AI)-based solution for chromatography peak integration process in the healthcare industry. We report the use of a convolutional neural network model to predict analytical variability for integrating chromatography peaks and propose a potential GxP framework for using AI in the healthcare industry that includes elements on data management, model management, and human-in-the-loop processes. The component on analytical variability prediction has a great potential to enable Industry 4.0 objectives on real-time release testing, automated quality control, and continuous manufacturing.

Effect of Fc core fucosylation and light chain isotype on IgG1 flexibility.

N-glycosylation plays a key role in modulating the bioactivity of monoclonal antibodies (mAbs), as well as the light chain (LC) isotype can influence their physicochemical properties. However, investigating the impact of such features on mAbs conformational behavior is a big challenge, due to the very high flexibility of these biomolecules. In this work we investigate, by accelerated molecular dynamics (aMD), the conformational behavior of two commercial immunoglobulins G1 (IgG1), representative of κ and λ LCs antibodies, in both their fucosylated and afucosylated forms. Our results show, through the identification of a stable conformation, how the combination of fucosylation and LC isotype modulates the hinge behavior, the Fc conformation and the position of the glycan chains, all factors potentially affecting the binding to the FcγRs. This work also represents a technological enhancement in the conformational exploration of mAbs, making aMD a suitable approach to clarify experimental results.

Comprehensive investigation of a structural variant in a bi-specific, N-and C-terminal Fc-fusion molecule, and its monitoring with LC-MS based method.

There is an increasing interest in the generation of Fc-fusion molecules to exploit the effector functions of Fc and the fusion partner, towards improving the therapeutic potential. The Fc-fusion molecules have unique structural and functional attributes that impart various advantages. However, the manufacturing of Fc-fusion molecules possesses certain challenges in the biopharmaceutical development. The fusion of unnaturally occurring two or more domains in a construct can pose problems for proper folding and are prone to aggregation and degradation. Reshuffling of disulfide bridges represents a posttranslational event that affects folding. This can play a critical role in the correct structure of a molecule and leads to structural heterogeneity in biotherapeutics; it may also impact the in vivo biological activities, safety, and efficacy of the biopharmaceutical. Our work presents an investigation case of a doublet band, as observed only in nonreducing sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) for a bi-specific, N- and C-terminal Fc-fusion molecule. Other characterization and orthogonal methods from the analytical panel did not indicate the presence of two distinct species, including the orthogonal CE-SDS (Caliper Lab Chip GXII). Therefore, it was necessary to determine if the phenomenon was an analytical artifact or a real variant of our Fc-fusion molecule. With the comprehensive mass spectrometry-based characterization, we were able to determine that the doublet band was related to the reshuffling of one disulfide bridge in one of the fused domains. Our work illustrates the application of nonreducing peptide mapping by mass spectrometry to characterize and identify disulfide variants in a complex N- and C-terminal Fc-fusion molecule, and further adoption to monitor the disulfide structural variants in the intermediate process samples to drive the manufacturing of a consistent product with the desired quality attributes.

Asn25 Deamidation as an Allosteric Tool to Increase IFNß-1a Biological Activity.

Interferon beta (IFNß) is a well-known cytokine, belonging to the type I family, that exerts antiviral, immunomodulatory, and antiproliferative activity. It has been reported that the artificially deamidated form of recombinant IFNß-1a at Asn25 position shows an increased biological activity. As a deepening of the previous study, the molecular mechanism underlying this biological effect was investigated in this work by combining experimental and computational techniques. Specifically, the binding to IFNAR1 and IFNAR2 receptors and the canonical pathway of artificially deamidated IFNß-1a molecule were analyzed in comparison to the native form. As a result, a change in receptor affinity of deamidated IFNß-1a with respect to the native form was observed, and to better explore this molecular interaction, molecular dynamics simulations were carried out. Results confirmed, as previously hypothesized, that the N25D mutation can locally change the interaction network of the mutated residue but also that this effect can be propagated throughout the molecule. In fact, many residues not involved in the interaction with IFNAR1 in the native form participate to the recognition in the deamidated molecule, enhancing the binding to IFNAR1 receptor and consequently an increase of signaling cascade activation. In particular, a higher STAT1 phosphorylation and interferon-stimulated gene expression was observed under deamidated IFNß-1a cell treatment. In conclusion, this study increases the scientific knowledge of deamidated IFNß-1a, deciphering its molecular mechanism, and opens new perspectives to novel therapeutic strategies.

Rapid cGMP manufacturing of COVID-19 monoclonal antibody using stable CHO cell pools.

Therapeutic proteins, including monoclonal antibodies, are typically manufactured using clonally derived, stable host cell lines, since consistent and predictable cell culture performance is highly desirable. However, selecting and preparing banks of stable clones takes considerable time, which inevitably extends overall development timelines for new therapeutics by delaying the start of subsequent activities, such as the scale-up of manufacturing processes. In the context of the coronavirus disease 2019 (COVID-19) pandemic, with its intense pressure for accelerated development strategies, we used a novel transposon-based Leap-In Transposase® system to rapidly generate high-titer stable pools and then used them directly for large scale-manufacturing of an anti-severe acute respiratory syndrome coronavirus 2 monoclonal antibody under cGMP. We performed the safety testing of our non-clonal cell bank, then used it to produce material at a 200L-scale for preclinical safety studies and formulation development work, and thereafter at 2000L scale for supply of material for a Phase 1 clinical trial. Testing demonstrated the comparability of critical product qualities between the two scales and, more importantly, that our final clinical trial product met all pre-set product quality specifications. The above expediated approach provided clinical trial material within 4.5 months, in comparison to 12-14 months for production of clinical trial material via the conventional approach.

IgG1 conformational behavior: elucidation of the N-glycosylation role via molecular dynamics.

Currently, monoclonal antibodies (mAbs) are the most used biopharmaceuticals for human therapy. One of the key aspects in their development is the control of effector functions mediated by the interaction between fragment crystallizable (Fc) and Fcγ receptors, which is a secondary mechanism of the action of biotherapeutics. N-glycosylation at the Fc portion can regulate these mechanisms, and much experimental evidence suggests that modifications of glycosidic chains can affect antibody binding to FcγRIIIa, consequently impacting the immune response. In this work, we try to elucidate via in silico procedures the structural role exhibited by glycans, particularly fucose, in mAb conformational freedom that can potentially affect the receptor recognition. By using adalimumab, a marketed IgG1, as a general template, after rebuilding its three-dimensional (3D) structure through homology modeling approaches, we carried out molecular dynamics simulations of three differently glycosylated species: aglycosylated, afucosylated, and fucosylated antibody. Trajectory analysis showed different dynamical behaviors and pointed out that sugars can influence the overall 3D structure of the antibody. As a result, we propose a putative structural mechanism by which the presence of fucose introduces conformational constraints in the whole antibody and not only in the Fc domain, preventing a conformation suitable for the interaction with the receptor. As secondary evidence, we observed a high flexibility of the antibodies that is translated into an asymmetric behavior of Fab portions shown by all the simulated biopolymers, making the dynamical asymmetry a new, to our knowledge, molecular aspect that may be further investigated. In conclusion, these findings can help understand the contribution of sugars on the structural architecture of mAbs, paving the way to novel strategies of pharmaceutical development.

Tocilizumab for the treatment of severe COVID-19 pneumonia with hyperinflammatory syndrome and acute respiratory failure: A single center study of 100 patients in Brescia, Italy.

A hyperinflammatory syndrome (HIS) may cause a life-threatening acute respiratory distress syndrome (ARDS) in patients with COVID-19 pneumonia. A prospective series of 100 consecutive patients admitted to the Spedali Civili University Hospital in Brescia (Italy) between March 9th and March 20th with confirmed COVID-19 pneumonia and ARDS requiring ventilatory support was analyzed to determine whether intravenous administration of tocilizumab (TCZ), a monoclonal antibody that targets the interleukin 6 (IL-6) receptor, was associated with improved outcome. Tocilizumab was administered at a dosage of 8 mg/kg by two consecutive intravenous infusions 12 h apart. A third infusion was optional based on clinical response. The outcome measure was an improvement in acute respiratory failure assessed by means of the Brescia COVID Respiratory Severity Score (BCRSS 0 to 8, with higher scores indicating higher severity) at 24-72 h and 10 days after tocilizumab administration. Out of 100 treated patients (88 M, 12 F; median age: 62 years), 43 received TCZ in the intensive care unit (ICU), while 57 in the general ward as no ICU beds were available. Of these 57 patients, 37 (65%) improved and suspended noninvasive ventilation (NIV) (median BCRSS: 1 [IQR 0-2]), 7 (12%) patients remained stable in NIV, and 13 (23%) patients worsened (10 died, 3 were admitted to ICU). Of the 43 patients treated in the ICU, 32 (74%) improved (17 of them were taken off the ventilator and were discharged to the ward), 1 (2%) remained stable (BCRSS: 5) and 10 (24%) died (all of them had BCRSS≥7 before TCZ). Overall at 10 days, the respiratory condition was improved or stabilized in 77 (77%) patients, of whom 61 showed a significant clearing of diffuse bilateral opacities on chest x-ray and 15 were discharged from the hospital. Respiratory condition worsened in 23 (23%) patients, of whom 20 (20%) died. All the patients presented with lymphopenia and high levels of C-reactive protein (CRP), fibrinogen, ferritin and IL-6 indicating a HIS. During the 10-day follow-up, three cases of severe adverse events were recorded: two patients developed septic shock and died, one had gastrointestinal perforation requiring urgent surgery and was alive at day 10. In conclusion, our series showed that COVID-19 pneumonia with ARDS was characterized by HIS. The response to TCZ was rapid, sustained, and associated with significant clinical improvement.

A deamidated interferon-ß variant binds to integrin αvß3.

Human type I interferons are a family of pleiotropic cytokines with antiviral, anti-proliferative and immunomodulatory activities. They signal through the same cell surface receptors IFNAR1 and IFNAR2 yet evoking markedly different physiological effects. One differentiating factor of interferon-beta (IFN-ß) from other type I interferons is the presence of theAsn-Gly-Arg (NGR) sequence motif, which, upon deamidation, converts to Asp-Gly-Arg (DGR) and iso-Asp-Gly-Arg (iso-DGR) motifs. In other proteins, the NGR and iso-DGR motifs are reported as CD13- and αvß3, αvß5, αvß6, αvß8 and α5ß1 integrin-binding motifs, respectively. The scope of this study was to perform exploratory surface plasmon resonance (SPR) experiments to assess the binding properties of a deamidated IFN-ß variant to integrins. For this purpose, integrin αvß3 was selected as a reference model within the iso-DGR- integrin binding members. The obtained results show that deamidated IFN-ß binds integrin αvß3 with nanomolar affinity and that the response was dependent on the deamidation extent. Based on these results, it can be expected that deamidated IFN-ß also binds to other integrin family members that are able to bind to the iso-DGR binding motif. The novel binding properties could help elucidate specific IFN-ß attributes that under physiological conditions may be modulated by the deamidation.

Demonstration of physicochemical and functional similarity between the proposed biosimilar adalimumab MSB11022 and Humira®.

Biosimilars are biological products that are highly similar to existing products approved by health authorities. Demonstration of similarity starts with the comprehensive analysis of the reference product and its proposed biosimilar at the physicochemical and functional levels. Here, we report the results of a comparative analysis of a proposed biosimilar adalimumab MSB11022 and its reference product, Humira®. Three batches of MSB11022 and up to 23 batches of Humira® were analyzed by a set of state-of-the-art orthogonal methods. Primary and higher order structure analysis included N/C-terminal modifications, molecular weight of heavy and light chains, C-terminal lysine truncation, disulfide bridges, secondary and tertiary structures, and thermal stability. Purity ranged from 98.4%-98.8% for MSB11022 batches (N = 3) and from 98.4%-99.6% for Humira® batches (N = 19). Isoform analysis showed 5 isoform clusters within the pI range of 7.94-9.14 and 100% glycan site occupancy for both MSB11022 and Humira®. Functional analysis included Fab-dependent inhibition of tumor necrosis factor (TNF)-induced cytotoxicity in L929-A9 cell line and affinity to soluble and transmembrane forms of TNF, as well as Fc-dependent binding to Fcγ and neonatal Fc receptors and C1q complement proteins. All tested physicochemical and functional parameters demonstrated high similarity of MSB11022 and Humira®, with lower variability between MSB11022 and Humira® batches compared with variability within individual batches of Humira®. Based on these results, MSB11022 is anticipated to have safety and efficacy comparable to those of Humira®.

Subvisible (2-100 µm) particle analysis during biotherapeutic drug product development: Part 2, experience with the application of subvisible particle analysis.

Measurement and characterization of subvisible particles (including proteinaceous and non-proteinaceous particulate matter) is an important aspect of the pharmaceutical development process for biotherapeutics. Health authorities have increased expectations for subvisible particle data beyond criteria specified in the pharmacopeia and covering a wider size range. In addition, subvisible particle data is being requested for samples exposed to various stress conditions and to support process/product changes. Consequently, subvisible particle analysis has expanded beyond routine testing of finished dosage forms using traditional compendial methods. Over the past decade, advances have been made in the detection and understanding of subvisible particle formation. This article presents industry case studies to illustrate the implementation of strategies for subvisible particle analysis as a characterization tool to assess the nature of the particulate matter and applications in drug product development, stability studies and post-marketing changes.

Reciprocal Translocation Observed in End-of-Production Cells of a Commercial CHO-Based Process.

UNLABELLED: During the validation of an additional working cell bank derived from a validated master cell bank to support the commercial production continuum of a recombinant protein, we observed an unexpected chromosomal location of the gene of interest in some end-of-production cells. This event-identified by fluorescence in situ hybridization and multicolour chromosome painting as a reciprocal translocation involving a chromosome region containing the gene of interest with its integral coding and flanking sequences-was unique, occurred probably during or prior to multicolour chromosome painting establishment, and was transmitted to the descending generations. Cells bearing the translocation had a transient and process-independent selective advantage, which did not affect process performance and product quality. However, this first report of a translocation affecting the gene of interest location in Chinese Hamster Ovary cells used for producing a biotherapeutic indicates the importance of the demonstration of the integrity of the gene of interest in end-of-production cells. LAY ABSTRACT: The expression of recombinant therapeutic proteins in mammalian cells depends on the establishment of a cell line with the gene of interest integrated in the host genome and stably expressed over time. Before being used for commercial production, cell lines are submitted to a qualification program in order to ensure their phenotypic and genotypic characteristics and the efficacy and safety of the product. During the production life cycle of a therapeutic protein, additional cells banks have to be validated after exhaustion of the current qualified cell bank in order to support the commercial production continuum of the recombinant protein. It is during the validation of an additional working cell bank derived from a validated master cell bank that we detected a different chromosome bearing the gene of interest in a portion of cells at the end of the upstream production phase. In our case, this event did not affect the process performance, the product quality, or its safety profile, but it highlights the need to characterize the integrity of the gene of interest in end-of-production cells when producing recombinant proteins for human use.

Subvisible (2-100 µm) Particle Analysis During Biotherapeutic Drug Product Development: Part 1, Considerations and Strategy.

Measurement and characterization of subvisible particles (defined here as those ranging in size from 2 to 100 µm), including proteinaceous and nonproteinaceous particles, is an important part of every stage of protein therapeutic development. The tools used and the ways in which the information generated is applied depends on the particular product development stage, the amount of material, and the time available for the analysis. In order to compare results across laboratories and products, it is important to harmonize nomenclature, experimental protocols, data analysis, and interpretation. In this manuscript on perspectives on subvisible particles in protein therapeutic drug products, we focus on the tools available for detection, characterization, and quantification of these species and the strategy around their application.

In vitro biological characterization of IFN-ß-1a major glycoforms.

Recombinant human interferon ß-1a (IFN-ß-1a) is extensively used as the first-line treatment of relapsing forms of multiple sclerosis. Its glycosylation is recognized as having a complex impact on a wide range of molecule characteristics and functions. The present study reports the enrichment of IFN-ß-1a glycoforms and their physicochemical and biological characterization by means of electrospray ionization-mass spectrometry, sialic acid content, thermal denaturation and various in vitro bioassays (antiproliferative, antiviral, immunomodulatory and reporter gene assay). The glycoforms were fractionated by means of cation-exchange chromatography using recombinant IFN-ß-1a derived from Chinese Hamster Ovary cell culture as starting material. The obtained fractions contained bi- and higher-antennarity glycans as described in the European Pharmacopoeia monograph (Nr. 1639E, Interferon beta 1a concentrated solution). The in vitro bioassay responses revealed a correlation mainly with the glycan antennarity. It is therefore suggested that all glycoforms have biological activity and play a role in modulating the overall IFN-ß biological activity with higher-antennarity glycoforms being able to better sustain IFN-ß-1a bioactivity over time. These data indicate the role of IFN-ß-1a glycosylation in vivo and shed new light on the role of the glycosylation heterogeneity, in particular with regard to antennarity, on biological properties of glycoproteins.

Pitfalls in diagnosing mitochondrial neurogastrointestinal encephalomyopathy.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disorder caused by mutations in the gene encoding thymidine phosphorylase and is characterized by external ophthalmoparesis, gastrointestinal dysmotility, leukoencephalopathy, and neuropathy. The availability of new therapeutic options (peritoneal dialysis, allogeneic stem cell transplantation, enzyme replacement) makes it necessary to diagnose the disease early, which is not always achieved due to the difficulty in recognizing this disorder, especially in case of atypical presentation. We describe three MNGIE patients with atypical onset of the disease. In the first patient the main symptoms were long-standing chronic fever, recurrent acute migrant arthritis, and gastrointestinal disorders mimicking autoimmune or inflammatory intestinal diseases; the second patient complained only of exercise intolerance and muscle cramps, and the third patient had a CIDP-like polyneuropathy. This study stresses the insidious heterogeneous clinical onset of some cases of MNGIE, expands the spectrum of the phenotype, and suggests considering MNGIE in the differential diagnosis of enteropathic arthritis, isolated exercise intolerance, and inflammatory polyneuropathies not responsive to the usual treatment. A better understanding of the clinical heterogeneity of MNGIE is necessary in order to diagnose atypical cases and promote early diagnosis, which is now absolutely necessary in view of the new available therapies.

High resolution TOF MS coupled to CE for the analysis of isotopically resolved intact proteins.

Intact protein analysis by mass spectrometry is of great interest for the characterisation of biotechnological products. Exact mass measurement in combination with isotopic resolution allows the detection of modifications leading to small mass changes like deamidation or reduction of disulfide bonds directly on the level of the intact protein. Here, a concept is presented based on time-of-flight mass spectrometry. A bench top TOF MS and a high resolution TOF MS were used to resolve the isotopes of intact recombinant human growth hormone and intact human erythropoietin, respectively. Thus, these 22 and around 30kDa large proteins can be characterised sensitively in great detail and along with capillary electrophoretic separation unambiguous identification of minor protein modifications like deamidation is possible.

Degradation of an Fc-fusion recombinant protein by host cell proteases: Identification of a CHO cathepsin D protease.

A host-cell-related proteolytic activity was identified in a recombinant Fc-fusion protein production process. This report describes the strategy applied to characterize and isolate the enzyme responsible for this degradation by combining cell culture investigation and dedicated analytical tools. After isolation and sequencing of the clipped fragment generated in post-capture material, enzymatic activity was traced in different culture conditions, allowing identification of viable CHO cells as the source of protease. Inhibitors and pH screenings showed that the enzyme belongs to an aspartic protease family and is preferably active at acidic pH. The protease was isolated by purification on a pepstatin A column and characterized as a protein related to cathepsin D. An additional metallo-protease inhibited by EDTA was identified with an optimum activity at neutral pH. This study is an example of how quality and stability of therapeutic recombinant molecules are strongly influenced by cell culture parameters.

Heterogeneity of commercial recombinant human growth hormone (r-hGH) preparations containing a thioether variant.

The objective of the present study was to assess (I) the potential presence of a recently discovered thioether variant in commercially available recombinant human growth hormone (r-hGH) preparations, and (II) the impact of the thioether modification on the in-vivo bioactivity and the receptor binding kinetics. Samples were tested employing European (EP) and US Pharmacopeia (USP) Somatropin monograph and mass spectrometry methods. None of the international standards contained this variant. All products conformed to EP specifications but six out of eight lots contained the variant. An artificially enriched thioether sample exhibited a significantly reduced in vivo biopotency and altered receptor-binding properties compared with a control. The absence of the variant in the pituitary hGH standard, and the possibility to generate it artificially suggests that it is not naturally occurring and that it may arise from an uncontrolled manufacturing process. Controlled studies may be required to assess its clinical efficacy and safety. EP and USP methods may need to be adapted to reliably detect the presence of the variant.

Onset and enhancement of systemic sclerosis after treatments for multiple sclerosis.

The coexistence of systemic sclerosis (SSc) and multiple sclerosis (MS) in the same patient has been described in few cases. We refer here a further case of association between these diseases, which highlight the difficulty of treating such patients. A 57-year-old male with relapsing-remitting MS since 20 years, shortly after having received high-dose corticosteroids for a relapse of MS, suddenly developed SSc, with onset of Raynaud phenomenon simultaneous to that of scleroderma skin involvement, new appearance of accelerated arterial hypertension, and rapidly progressive oliguric renal failure, indicative of scleroderma renal crisis, that was controlled with ramipril, irbesartan and amlodipin. A further disabling relapse of MS was treated with interferon-beta, but 19 months later he developed multiple severe digital necrotic ulcers, that resolved with interferon discontinuation and therapy with iloprost. This case report shows that some form of treatment useful for MS might enhance the manifestations of SSc.