1
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Antonucci L, Thurman JM, Vivarelli M. Complement inhibitors in pediatric kidney diseases: new therapeutic opportunities. Pediatr Nephrol 2024; 39:1387-1404. [PMID: 37733095 DOI: 10.1007/s00467-023-06120-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 09/22/2023]
Abstract
Historically, the complement system (classical, lectin, alternative, and terminal pathways) is known to play a crucial role in the etiopathogenesis of many kidney diseases. Direct or indirect activation in these settings is revealed by consumption of complement proteins at the serum level and kidney tissue deposition seen by immunofluorescence and electron microscopy. The advent of eculizumab has shown that complement inhibitors may improve the natural history of certain kidney diseases. Since then, the number of available therapeutic molecules and experimental studies on complement inhibition has increased exponentially. In our narrative review, we give a summary of the main complement inhibitors that have completed phase II and phase III studies or are currently used in adult and pediatric nephrology. The relevant full-text works, abstracts, and ongoing trials (clinicaltrials.gov site) are discussed. Data and key clinical features are reported for eculizumab, ravulizumab, crovalimab, avacopan, danicopan, iptacopan, pegcetacoplan, and narsoplimab. Many of these molecules have been shown to be effective in reducing proteinuria and stabilizing kidney function in different complement-mediated kidney diseases. Thanks to their efficacy and target specificity, these novel drugs may radically improve the outcome of complement-mediated kidney diseases, contributing to an improvement in our understanding of their underlying pathophysiology.
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Affiliation(s)
- Luca Antonucci
- Division of Nephrology, Bambino Gesù Children's Hospital IRCCS, Rome, Italy
- Ph.D. Course in Microbiology, Immunology, Infectious Diseases, and Transplants (MIMIT), University of Rome Tor Vergata, Rome, Italy
| | - Joshua M Thurman
- Department of Medicine, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - Marina Vivarelli
- Division of Nephrology, Bambino Gesù Children's Hospital IRCCS, Rome, Italy.
- Division of Nephrology, Laboratory of Nephrology, Bambino Gesù Children's Hospital IRCCS, Piazza S Onofrio 4, 00165, Rome, Italy.
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2
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Peixoto VP, Prudêncio C, Vieira M, Sousa SF. Evaluation of the impact of two C5 genetic variants on C5-eculizumab complex stability at the molecular level. J Biomol Struct Dyn 2024:1-10. [PMID: 38529903 DOI: 10.1080/07391102.2024.2331091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 03/11/2024] [Indexed: 03/27/2024]
Abstract
Complement C5 is the target of the monoclonal antibody eculizumab, used in complement dysregulating disorders, like the rare disease Paroxysmal Nocturnal Hemoglobinuria (PNH). PNH is an acquired hematopoietic stem cell condition characterized by aberrant destruction of erythrocytes, chronic hemolytic anemia, and thromboembolism propensity. C5 is a protein component of the complement system which is part of the immune system of the body and plays a prominent role in the destruction of red blood cells, misidentifying them as a threat. This work describes the application of molecular dynamics simulations to the study of the underlying interactions between complement C5 and eculizumab. This study also reveals the importance of single nucleotide polymorphisms on C5 protein concerning the effective inhibition of the mAB, involving the mechanistic events taking place at the interface spots of the complex. The predicted conformational change in the C5 Arg885/His/Cys mutation has implications on the protein's interaction with eculizumab, compromising their compatibility. The acquired insights into the conformational changes, dynamics, flexibility, and interactions shed light on the knowledge of the function of this biomolecule providing answers about the poor response to the treatment in PNH patient carriers of the mutations. By investigating the intricate dynamics, significant connections between C5 and eculizumab can be uncovered. Such insights may aid in the creation of novel compounds or lead to the enhancement of eculizumab's efficacy.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Vanda P Peixoto
- Chemical and Biomolecular Sciences, School of Health, Polytechnic Institute of Porto, Porto, Portugal
- Center for Translational Health and Medical Biotechnology Research (TBIO), Polytechnic Institute of Porto, Porto, Portugal
- LAQV/REQUIMTE, BioSIM - Departamento de Biomedicina, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Cristina Prudêncio
- Chemical and Biomolecular Sciences, School of Health, Polytechnic Institute of Porto, Porto, Portugal
- Center for Translational Health and Medical Biotechnology Research (TBIO), Polytechnic Institute of Porto, Porto, Portugal
- Institute for Research and Innovation in Health (i3S), University of Porto, Porto, Portugal
| | - Mónica Vieira
- Chemical and Biomolecular Sciences, School of Health, Polytechnic Institute of Porto, Porto, Portugal
- Center for Translational Health and Medical Biotechnology Research (TBIO), Polytechnic Institute of Porto, Porto, Portugal
- Institute for Research and Innovation in Health (i3S), University of Porto, Porto, Portugal
| | - Sérgio F Sousa
- LAQV/REQUIMTE, BioSIM - Departamento de Biomedicina, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
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3
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Jindal S, Pedersen DV, Gera N, Chandler J, Patel R, Neill A, Cone J, Zhang Y, Yuan CX, Millman EE, Carlin D, Puffer B, Sheridan D, Andersen GR, Tamburini P. Characterization of the bispecific VHH antibody gefurulimab (ALXN1720) targeting complement component 5, and designed for low volume subcutaneous administration. Mol Immunol 2024; 165:29-41. [PMID: 38142486 DOI: 10.1016/j.molimm.2023.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 09/29/2023] [Accepted: 12/09/2023] [Indexed: 12/26/2023]
Abstract
The bispecific antibody gefurulimab (also known as ALXN1720) was developed to provide patients with a subcutaneous treatment option for chronic disorders involving activation of the terminal complement pathway. Gefurulimab blocks the enzymatic cleavage of complement component 5 (C5) into the biologically active C5a and C5b fragments, which triggers activation of the terminal complement cascade. Heavy-chain variable region antigen-binding fragment (VHH) antibodies targeting C5 and human serum albumin (HSA) were isolated from llama immune-based libraries and humanized. Gefurulimab comprises an N-terminal albumin-binding VHH connected to a C-terminal C5-binding VHH via a flexible linker. The purified bispecific VHH antibody has the expected exact size by mass spectrometry and can be formulated at greater than 100 mg/mL. Gefurulimab binds tightly to human C5 and HSA with dissociation rate constants at pH 7.4 of 54 pM and 0.9 nM, respectively, and cross-reacts with C5 and serum albumin from cynomolgus monkeys. Gefurulimab can associate with C5 and albumin simultaneously, and potently inhibits the terminal complement activity from human serum initiated by any of the three complement pathways in Wieslab assays. Electron microscopy and X-ray crystallography revealed that the isolated C5-binding VHH recognizes the macroglobulin (MG) 4 and MG5 domains of the antigen and thereby is suggested to sterically prevent C5 binding to its activating convertase. Gefurulimab also inhibits complement activity supported by the rare C5 allelic variant featuring an R885H substitution in the MG7 domain. Taken together, these data suggest that gefurulimab may be a promising candidate for the potential treatment of complement-mediated disorders.
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Affiliation(s)
- Siddharth Jindal
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | | | - Nimish Gera
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Julian Chandler
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Rekha Patel
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Alyssa Neill
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Josh Cone
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Yuchun Zhang
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Chao-Xing Yuan
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Ellen E Millman
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Dan Carlin
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA.
| | - Bridget Puffer
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Douglas Sheridan
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics, Universitetsbyen 83, Aarhus University, Aarhus, Denmark
| | - Paul Tamburini
- Alexion, AstraZeneca Rare Disease, 100 College Street, New Haven, CT 06510, USA
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4
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Duan H, Abram TG, Cruz AR, Rooijakkers SHM, Geisbrecht BV. New Insights into the Complement Receptor of the Ig Superfamily Obtained from Structural and Functional Studies on Two Mutants. Immunohorizons 2023; 7:806-818. [PMID: 38032267 PMCID: PMC10696418 DOI: 10.4049/immunohorizons.2300064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 11/03/2023] [Indexed: 12/01/2023] Open
Abstract
The extracellular region of the complement receptor of the Ig superfamily (CRIg) binds to certain C3 cleavage products (C3b, iC3b, C3c) and inhibits the alternative pathway (AP) of complement. In this study, we provide further insight into the CRIg protein and describe two CRIg mutants that lack multiple lysine residues as a means of facilitating chemical modifications of the protein. Structural analyses confirmed preservation of the native CRIg architecture in both mutants. In contrast to earlier reports suggesting that CRIg binds to C3b with an affinity of ∼1 μM, we found that wild-type CRIg binds to C3b and iC3b with affinities <100 nM, but to C3c with an affinity closer to 1 μM. We observed this same trend for both lysine substitution mutants, albeit with an apparent ∼2- to 3-fold loss of affinity when compared with wild-type CRIg. Using flow cytometry, we confirmed binding to C3 fragment-opsonized Staphylococcus aureus cells by each mutant, again with an ∼2- to 3-fold decrease when compared with wild-type. Whereas wild-type CRIg inhibits AP-driven lysis of rabbit erythrocytes with an IC50 of 1.6 μM, we observed an ∼3-fold reduction in inhibition for both mutants. Interestingly, we found that amine-reactive crosslinking of the CRIg mutant containing only a single lysine results in a significant improvement in inhibitory potency across all concentrations examined when compared with the unmodified mutant, but in a manner sensitive to the length of the crosslinker. Collectively, our findings provide new insights into the CRIg protein and suggest an approach for engineering increasingly potent CRIg-based inhibitors of the AP.
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Affiliation(s)
- Huiquan Duan
- Department of Biochemistry and Molecular Biophysics, Kansas State University; Manhattan, KS
| | - Troy G. Abram
- Department of Biochemistry and Molecular Biophysics, Kansas State University; Manhattan, KS
| | - Ana Rita Cruz
- Department of Medical Microbiology and Immunology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Suzan H. M. Rooijakkers
- Department of Medical Microbiology and Immunology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Brian V. Geisbrecht
- Department of Biochemistry and Molecular Biophysics, Kansas State University; Manhattan, KS
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5
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San PP, Jacob S. Role of complement in myasthenia gravis. Front Neurol 2023; 14:1277596. [PMID: 37869140 PMCID: PMC10585143 DOI: 10.3389/fneur.2023.1277596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 09/18/2023] [Indexed: 10/24/2023] Open
Abstract
Myasthenia gravis is a prototypic neuroimmune disorder with autoantibodies targeting the acetylcholine receptor complex at the neuromuscular junction. Patients present with mainly ocular muscle weakness and tend to have a generalized muscle weakness later in the clinical course. The weakness can be severe and fatal when bulbar muscles are heavily involved. Acetylcholine receptor antibodies are present in the majority of patients and are of IgG1 and IgG3 subtypes which can activate the complement system. The complement involvement plays a major role in the neuromuscular junction damage and the supporting evidence in the literature is described in this article. Complement therapies were initially studied and approved for paroxysmal nocturnal hemoglobinuria and in the past decade, those have also been studied in myasthenia gravis. The currently available randomized control trial and real-world data on the efficacy and safety of the approved and investigational complement therapies are summarized in this review.
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Affiliation(s)
- Pyae Phyo San
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Saiju Jacob
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
- Department of Neurology, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
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6
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Struijf EM, De la O Becerra KI, Ruyken M, de Haas CJC, van Oosterom F, Siere DY, van Keulen JE, Heesterbeek DAC, Dolk E, Heukers R, Bardoel BW, Gros P, Rooijakkers SHM. Inhibition of cleavage of human complement component C5 and the R885H C5 variant by two distinct high affinity anti-C5 nanobodies. J Biol Chem 2023; 299:104956. [PMID: 37356719 PMCID: PMC10374974 DOI: 10.1016/j.jbc.2023.104956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 06/27/2023] Open
Abstract
The human complement system plays a crucial role in immune defense. However, its erroneous activation contributes to many serious inflammatory diseases. Since most unwanted complement effector functions result from C5 cleavage into C5a and C5b, development of C5 inhibitors, such as clinically approved monoclonal antibody eculizumab, are of great interest. Here, we developed and characterized two anti-C5 nanobodies, UNbC5-1 and UNbC5-2. Using surface plasmon resonance, we determined a binding affinity of 119.9 pM for UNbC5-1 and 7.7 pM for UNbC5-2. Competition experiments determined that the two nanobodies recognize distinct epitopes on C5. Both nanobodies efficiently interfered with C5 cleavage in a human serum environment, as they prevented red blood cell lysis via membrane attack complexes (C5b-9) and the formation of chemoattractant C5a. The cryo-EM structure of UNbC5-1 and UNbC5-2 in complex with C5 (3.6 Å resolution) revealed that the binding interfaces of UNbC5-1 and UNbC5-2 overlap with known complement inhibitors eculizumab and RaCI3, respectively. UNbC5-1 binds to the MG7 domain of C5, facilitated by a hydrophobic core and polar interactions, and UNbC5-2 interacts with the C5d domain mostly by salt bridges and hydrogen bonds. Interestingly, UNbC5-1 potently binds and inhibits C5 R885H, a genetic variant of C5 that is not recognized by eculizumab. Altogether, we identified and characterized two different, high affinity nanobodies against human C5. Both nanobodies could serve as diagnostic and/or research tools to detect C5 or inhibit C5 cleavage. Furthermore, the residues targeted by UNbC5-1 hold important information for therapeutic inhibition of different polymorphic variants of C5.
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Affiliation(s)
- Eva M Struijf
- Department Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Karla I De la O Becerra
- Structural Biochemistry Group, Faculty of Science, Department of Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Maartje Ruyken
- Department Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Carla J C de Haas
- Department Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Fleur van Oosterom
- Department Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Danique Y Siere
- Department Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Joanne E van Keulen
- Department Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Dani A C Heesterbeek
- Department Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | | | | | - Bart W Bardoel
- Department Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Piet Gros
- Structural Biochemistry Group, Faculty of Science, Department of Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Suzan H M Rooijakkers
- Department Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
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7
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Cone J, Kimmel L, Zhang Y, Johnson K, Sheridan D, Tamburini P. Characterization of multivalent complexes formed in the presence of more than one conventional antibody to terminal complement component C5. PLoS One 2023; 18:e0284502. [PMID: 37079521 PMCID: PMC10118082 DOI: 10.1371/journal.pone.0284502] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 04/02/2023] [Indexed: 04/21/2023] Open
Abstract
This study sought to understand the nature of the immune complexes that could be formed when a patient is exposed simultaneously to two different anti-complement component 5 (C5) antibodies, such as in patients converting from one bivalent, noncompetitive, C5-binding monoclonal antibody to another. Size exclusion chromatography (SEC) in combination with multiangle light scattering was used to assess the potential formation of multivalent complexes among eculizumab, C5, and each of two other anti-C5 bivalent antibodies, TPP-2799 or TP-3544, respectively having the same sequence as either crovalimab or pozelimab currently undergoing clinical trials. Each of these two antibodies bound C5 noncompetitively with eculizumab. In phosphate-buffered saline (PBS), C5-eculizumab in the absence of other antibodies measured <500 kDa; however, inclusion of other antibodies at levels ranging from equimolar and up to a fivefold excess over eculizumab and C5 yielded a series of complexes with some >1500 kDa in size, consistent with incorporation of multiple antibodies and C5 molecules. A similar pattern of complexes was also observed when fluorescently labeled eculizumab and either of the other two antibodies were spiked into human plasma, based on SEC monitored by fluorescence detection. A detailed characterization of the pharmacodynamic and pharmacokinetic properties of such complexes is warranted, as is the incorporation of mitigation processes to avoid their formation in patients converting from one bivalent, noncompetitive, C5-binding monoclonal antibody to another.
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Affiliation(s)
- Josh Cone
- Alexion, AstraZeneca Rare Disease, New Haven, CT, United States of America
| | - Lida Kimmel
- Alexion Pharmaceuticals, Inc., New Haven, CT, United States of America
| | - Yuchun Zhang
- Alexion, AstraZeneca Rare Disease, New Haven, CT, United States of America
| | - Krista Johnson
- Alexion, AstraZeneca Rare Disease, New Haven, CT, United States of America
| | - Douglas Sheridan
- Alexion Pharmaceuticals, Inc., New Haven, CT, United States of America
| | - Paul Tamburini
- Alexion, AstraZeneca Rare Disease, New Haven, CT, United States of America
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8
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Stennett A, Friston K, Harris CL, Wollman AJM, Bronowska AK, Madden KS. The case for complement component 5 as a target in neurodegenerative disease. Expert Opin Ther Targets 2023; 27:97-109. [PMID: 36786123 DOI: 10.1080/14728222.2023.2177532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
INTRODUCTION Complement-based drug discovery is undergoing a renaissance, empowered by new advances in structural biology, complement biology and drug development. Certain components of the complement pathway, particularly C1q and C3, have been extensively studied in the context of neurodegenerative disease, and established as key therapeutic targets. C5 also has huge therapeutic potential in this arena, with its druggability clearly demonstrated by the success of C5-inhibitor eculizumab. AREAS COVERED We will discuss the evidence supporting C5 as a target in neurodegenerative disease, along with the current progress in developing different classes of C5 inhibitors and the gaps in knowledge that will help progress in the field. EXPERT OPINION Validation of C5 as a therapeutic target for neurodegenerative disease would represent a major step forward for complement therapeutics research and has the potential to furnish disease-modifying drugs for millions of patients suffering worldwide. Key hurdles that need to be overcome for this to be achieved are understanding how C5a and C5b should be targeted to bring therapeutic benefit and demonstrating the ability to target C5 without creating vulnerability to infection in patients. This requires greater biological elucidation of its precise role in disease pathogenesis, supported by better chemical/biological tools.
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Affiliation(s)
- Amelia Stennett
- School of Natural and Environmental Sciences, Newcastle University, NE1 7RU, Newcastle-Upon-Tyne, UK
| | - Kallie Friston
- School of Natural and Environmental Sciences, Newcastle University, NE1 7RU, Newcastle-Upon-Tyne, UK
| | - Claire L Harris
- Faculty of Medical Sciences, Newcastle University, NE2 4HH, Newcastle-Upon-Tyne, UK
| | - Adam J M Wollman
- Faculty of Medical Sciences, Newcastle University, NE2 4HH, Newcastle-Upon-Tyne, UK
| | - Agnieszka K Bronowska
- School of Natural and Environmental Sciences, Newcastle University, NE1 7RU, Newcastle-Upon-Tyne, UK
| | - Katrina S Madden
- School of Natural and Environmental Sciences, Newcastle University, NE1 7RU, Newcastle-Upon-Tyne, UK.,Faculty of Medical Sciences, Newcastle University, NE2 4HH, Newcastle-Upon-Tyne, UK
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9
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Schmidt CQ, Smith RJH. Protein therapeutics and their lessons: Expect the unexpected when inhibiting the multi-protein cascade of the complement system. Immunol Rev 2023; 313:376-401. [PMID: 36398537 PMCID: PMC9852015 DOI: 10.1111/imr.13164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Over a century after the discovery of the complement system, the first complement therapeutic was approved for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). It was a long-acting monoclonal antibody (aka 5G1-1, 5G1.1, h5G1.1, and now known as eculizumab) that targets C5, specifically preventing the generation of C5a, a potent anaphylatoxin, and C5b, the first step in the eventual formation of membrane attack complex. The enormous clinical and financial success of eculizumab across four diseases (PNH, atypical hemolytic uremic syndrome (aHUS), myasthenia gravis (MG), and anti-aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD)) has fueled a surge in complement therapeutics, especially targeting diseases with an underlying complement pathophysiology for which anti-C5 therapy is ineffective. Intensive research has also uncovered challenges that arise from C5 blockade. For example, PNH patients can still face extravascular hemolysis or pharmacodynamic breakthrough of complement suppression during complement-amplifying conditions. These "side" effects of a stoichiometric inhibitor like eculizumab were unexpected and are incompatible with some of our accepted knowledge of the complement cascade. And they are not unique to C5 inhibition. Indeed, "exceptions" to the rules of complement biology abound and have led to unprecedented and surprising insights. In this review, we will describe initial, present and future aspects of protein inhibitors of the complement cascade, highlighting unexpected findings that are redefining some of the mechanistic foundations upon which the complement cascade is organized.
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Affiliation(s)
- Christoph Q. Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Richard J. H. Smith
- Departments of Internal Medicine and Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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10
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Smith-Jackson K, Harrison RA. Alternative pathway activation in pregnancy, a measured amount "complements" a successful pregnancy, too much results in adverse events. Immunol Rev 2023; 313:298-319. [PMID: 36377667 PMCID: PMC10100418 DOI: 10.1111/imr.13169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
During pregnancy, the maternal host must adapt in order to enable growth of the fetus. These changes affect all organ systems and are designed both to protect the fetus and to minimize risk to the mother. One of the most prominent adaptations involves the immune system. The semi-allogenic fetoplacental unit has non-self components and must be protected against attack from the host. This requires both attenuation of adaptive immunity and protection from innate immune defense mechanisms. One of the key innate immune players is complement, and it is important that the fetoplacental unit is not identified as non-self and subjected to complement attack. Adaptation of the complement response must, however, be managed in such a way that maternal protection against infection is not compromised. As the complement system also plays a significant facilitating role in many of the stages of a normal pregnancy, it is also important that any necessary adaptation to accommodate the semi-allogenic aspects of the fetoplacental unit does not compromise this. In this review, both the physiological role of the alternative pathway of complement in facilitating a normal pregnancy, and its detrimental participation in pregnancy-specific disorders, are discussed.
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Affiliation(s)
- Kate Smith-Jackson
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Faculty of Medical Science, Newcastle University, Newcastle-upon-Tyne, UK.,The National Renal Complement Therapeutics Centre (NRCTC), Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
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11
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Muacevic A, Adler JR, Hock RA, Nguyen B, Prakash S, Rojas Murguia A, Vahora I, Corral J, Padilla O, Dihowm F. Attack of the Clones: A Patient With Untreated Aplastic Anemia Presenting With Classical Paroxysmal Nocturnal Hemoglobinuria. Cureus 2023; 15:e34093. [PMID: 36843778 PMCID: PMC9946272 DOI: 10.7759/cureus.34093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2023] [Indexed: 01/24/2023] Open
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired X-linked, clonal hematopoietic stem cell disease. Patients with PNH may complain of vague symptomatology that contributes to the challenge of its diagnosis. This is especially true in the clinical context of a coinciding hematologic disorder. Aplastic anemia (AA) is an additional immune-mediated illness that results in the destruction of hematopoietic precursors and pancytopenia. The authors encourage screening for PNH clones in patients initially diagnosed with AA, treating underlying hematologic disease to prevent clonal expansion, and further research to investigate the effectiveness of eculizumab in an unusual "classical" PNH secondary to AA with hypercellular bone marrow.
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12
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Gytz Olesen H, Michailidou I, Zelek WM, Vreijling J, Ruizendaal P, de Klein F, Marquart JA, Kuipers TB, Mei H, Zhang Y, Ahasan M, Johnson KK, Wang Y, Morgan BP, van Dijk M, Fluiter K, Andersen GR, Baas F. Development, Characterization, and in vivo Validation of a Humanized C6 Monoclonal Antibody that Inhibits the Membrane Attack Complex. J Innate Immun 2022; 15:16-36. [PMID: 35551129 PMCID: PMC10643903 DOI: 10.1159/000524587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/08/2022] [Indexed: 11/19/2022] Open
Abstract
Damage and disease of nerves activates the complement system. We demonstrated that activation of the terminal pathway of the complement system leads to the formation of the membrane attack complex (MAC) and delays regeneration in the peripheral nervous system. Animals deficient in the complement component C6 showed improved recovery after neuronal trauma. Thus, inhibitors of the MAC might be of therapeutic use in neurological disease. Here, we describe the development, structure, mode of action, and properties of a novel therapeutic monoclonal antibody, CP010, against C6 that prevents formation of the MAC in vivo. The monoclonal antibody is humanized and specific for C6 and binds to an epitope in the FIM1-2 domain of human and primate C6 with sub-nanomolar affinity. Using biophysical and structural studies, we show that the anti-C6 antibody prevents the interaction between C6 and C5/C5b by blocking the C6 FIM1-2:C5 C345c axis. Systemic administration of the anti-C6 mAb caused complete depletion of free C6 in circulation in transgenic rats expressing human C6 and thereby inhibited MAC formation. The antibody prevented disease in experimental autoimmune myasthenia gravis and ameliorated relapse in chronic relapsing experimental autoimmune encephalomyelitis in human C6 transgenic rats. CP010 is a promising complement C6 inhibitor that prevents MAC formation. Systemic administration of this C6 monoclonal antibody has therapeutic potential in the treatment of neuronal disease.
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Affiliation(s)
- Heidi Gytz Olesen
- Department of Molecular Biology and Genetics - Protein Science, Aarhus University, Aarhus, Denmark
| | | | - Wioleta M Zelek
- Division of Infection and Immunity and Dementia Research Institute, Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff, UK
| | | | | | - Ferry de Klein
- Core Facility Genomics, Amsterdam UMC, Amsterdam, The Netherlands
| | | | - Thomas B Kuipers
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences, LUMC, Leiden, The Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences, LUMC, Leiden, The Netherlands
| | - Yuchun Zhang
- Alexion, AstraZeneca Rare Disease, New Haven, Connecticut, USA
| | - Muhammad Ahasan
- Alexion, AstraZeneca Rare Disease, New Haven, Connecticut, USA
| | | | - Yi Wang
- Alexion, AstraZeneca Rare Disease, New Haven, Connecticut, USA
| | - B Paul Morgan
- Division of Infection and Immunity and Dementia Research Institute, Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff, UK
| | | | - Kees Fluiter
- Department of Clinical Genetics, LUMC, Leiden, The Netherlands,
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics - Protein Science, Aarhus University, Aarhus, Denmark
| | - Frank Baas
- Department of Clinical Genetics, LUMC, Leiden, The Netherlands
- Complement Pharma BV, Amsterdam, The Netherlands
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13
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Abdulrazaq A, Smith R, Digala LP, Govindarajan R. Minimal Manifestations With Eculizumab Therapy in a Patient With Refractory Generalized Seropositive Myasthenia Gravis. J Clin Neuromuscul Dis 2022; 23:170-173. [PMID: 35188923 DOI: 10.1097/cnd.0000000000000388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
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14
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Li L, Liu H, Wang H, Liu Z, Chen Y, Liu C, Zhao X, Li L, Wang H, Shao Z, Fu R. Clinical observation of low-dose combination chemotherapy in refractory/recurrent paroxysmal nocturnal hemoglobinuria patients: A single-center retrospective analysis. J Clin Lab Anal 2022; 36:e24239. [PMID: 35028973 PMCID: PMC8841174 DOI: 10.1002/jcla.24239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/29/2021] [Accepted: 01/02/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND We performed a retrospective analysis to investigate the clinical characteristics and therapeutic strategies of 20 refractory/recurrent PNH patients, including the clinical efficacy of chemotherapy treatment, safety, and survival. METHODS The clinical data of 20 classic PNH patients who were refractory/recurrent or had glucocorticoid dependence in our hospital were analyzed, including clinical manifestations, laboratory examinations, treatment efficacy, and survival. RESULTS Seventeen patients had a marked improvement in anemia after chemotherapy, 14 patients acquired blood transfusion independence, and the Hb of 3 patients increased to normal levels. Although 6 patients still needed blood transfusion, the transfusion interval was significantly prolonged. The percentages of LDH, TBIL, and RET, which are indicators of hemolysis, were significantly lower than those before chemotherapy. The dosage of adrenal glucocorticoids was reduced by more than half compared with that before chemotherapy. CONCLUSIONS Chemotherapy can reduce PNH clones, promote normal hematopoiesis, and control hemolytic attack. It is a promising and widely used therapeutic method.
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Affiliation(s)
- Liyan Li
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Hui Liu
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Honglei Wang
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Zhaoyun Liu
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Yingying Chen
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Chunyan Liu
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Xiaoyu Zhao
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Lijuan Li
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Huaquan Wang
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Zonghong Shao
- Department of HematologyTianjin Medical University General HospitalTianjinChina
| | - Rong Fu
- Department of HematologyTianjin Medical University General HospitalTianjinChina
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15
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Jiao L, Li H, Guo S. Eculizumab treatment for myasthenia gravis subgroups: 2021 update. J Neuroimmunol 2022; 362:577767. [PMID: 34823117 DOI: 10.1016/j.jneuroim.2021.577767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 11/01/2021] [Accepted: 11/13/2021] [Indexed: 01/21/2023]
Abstract
Eculizumab is a recombinant humanized monoclonal antibody that targets the complement protein C5, inhibiting its cleavage into C5a and C5b and ultimately preventing the formation of C5b-9 membrane attack complex (MACs), thereby protecting the neuromuscular junction from the damage of complement activation. In 2017, eculizumab became the second FDA-approved medication for AchR-positive generalized myasthenia gravis (gMG) patients based on the successful results of a randomized, double-blinded, placebo-controlled, phase 2, phase 3 study (the REGAIN trial) and its open-label extension study. Despite the efficacy of eculizumab in treating AchR antibody-positive refractory gMG was demonstrated in the REGAIN study, there is few information on its efficacy in other subgroup of MG patients including seronegative MG, thymoma-associated MG and MG crisis. This narrative review summarizes current clinical studies of eculizumab in these refractory gMG patients, with a focus on the therapeutic efficacy and tolerability in different subgroup of MG.
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Affiliation(s)
- Li Jiao
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China
| | - Honghao Li
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China
| | - Shougang Guo
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China.
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16
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Lu Y, Zhao YL, Xiong M, Sun RJ, Cao XY, Wei ZJ, Lu DP. Unmanipulated haploidentical donor and matched unrelated donor hematopoietic stem cell transplantation in patients with paroxysmal nocturnal hemoglobinuria: a single-center study. Leuk Lymphoma 2021; 63:1211-1219. [PMID: 34913818 DOI: 10.1080/10428194.2021.2015588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
We analyzed the outcomes of 32 patients with paroxysmal nocturnal hemoglobinuria (PNH) who underwent either a haploidentical donor (HID) or a matched unrelated donor (MUD) hematopoietic stem cell transplantation (HSCT). Seventeen patients received an HSCT from an HID and 15 patients received an HSCT from an MUD. The median follow-up time of the surviving patients was 36 months (range: 12-96 months). No significant differences were observed in the 3-year overall survival (OS) between the HID and MUD cohorts (74.1%±11.4% vs. 93.3%±6.4%, respectively, p=.222) or in the 3-year failure-free survival (68.8%±11.8% vs. 86.7%±8.8%, respectively, p=.307). Treatment-related mortality occurred in five patients. A univariate analysis of risk factors revealed platelet engraftment failure negatively impacted OS and FFS. We conclude that HID and MUD-HSCT are feasible and can be effective options for those PNH patients with concomitant bone marrow failure, recurrent life-threatening thrombosis, and uncontrollable hemolysis.
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Affiliation(s)
- Yue Lu
- Department of Bone Marrow Transplantation, Hebei Yanda Lu Daopei Hospital, Langfang, China
| | - Yan-Li Zhao
- Department of Bone Marrow Transplantation, Hebei Yanda Lu Daopei Hospital, Langfang, China
| | - Min Xiong
- Department of Bone Marrow Transplantation, Hebei Yanda Lu Daopei Hospital, Langfang, China
| | - Rui-Juan Sun
- Department of Bone Marrow Transplantation, Hebei Yanda Lu Daopei Hospital, Langfang, China
| | - Xing-Yu Cao
- Department of Bone Marrow Transplantation, Hebei Yanda Lu Daopei Hospital, Langfang, China
| | - Zhi-Jie Wei
- Department of Bone Marrow Transplantation, Hebei Yanda Lu Daopei Hospital, Langfang, China
| | - Dao-Pei Lu
- Department of Bone Marrow Transplantation, Hebei Yanda Lu Daopei Hospital, Langfang, China
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17
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Novel Selection Approaches to Identify Antibodies Targeting Neoepitopes on the C5b6 Intermediate Complex to Inhibit Membrane Attack Complex Formation. Antibodies (Basel) 2021; 10:antib10040039. [PMID: 34698051 PMCID: PMC8544208 DOI: 10.3390/antib10040039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/18/2021] [Accepted: 09/25/2021] [Indexed: 11/16/2022] Open
Abstract
The terminal pathway of complement is implicated in the pathology of multiple diseases and its inhibition is, therefore, an attractive therapeutic proposition. The practicalities of inhibiting this pathway, however, are challenging, as highlighted by the very few molecules in the clinic. The proteins are highly abundant, and assembly is mediated by high-affinity protein-protein interactions. One strategy is to target neoepitopes that are present transiently and only exist on active or intermediate complexes but not on the abundant native proteins. Here, we describe an antibody discovery campaign that generated neoepitope-specific mAbs against the C5b6 complex, a stable intermediate complex in terminal complement complex assembly. We used a highly diverse yeast-based antibody library of fully human IgGs to screen against soluble C5b6 antigen and successfully identified C5b6 neoepitope-specific antibodies. These antibodies were diverse, showed good binding to C5b6, and inhibited membrane attack complex (MAC) formation in a solution-based assay. However, when tested in a more physiologically relevant membrane-based assay these antibodies failed to inhibit MAC formation. Our data highlight the feasibility of identifying neoepitope binding mAbs, but also the technical challenges associated with the identification of functionally relevant, neoepitope-specific inhibitors of the terminal pathway.
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18
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Kim BJ, Mastellos DC, Li Y, Dunaief JL, Lambris JD. Targeting complement components C3 and C5 for the retina: Key concepts and lingering questions. Prog Retin Eye Res 2021; 83:100936. [PMID: 33321207 PMCID: PMC8197769 DOI: 10.1016/j.preteyeres.2020.100936] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 12/13/2022]
Abstract
Age-related macular degeneration (AMD) remains a major cause of legal blindness, and treatment for the geographic atrophy form of AMD is a significant unmet need. Dysregulation of the complement cascade is thought to be instrumental for AMD pathophysiology. In particular, C3 and C5 are pivotal components of the complement cascade and have become leading therapeutic targets for AMD. In this article, we discuss C3 and C5 in detail, including their roles in AMD, biochemical and structural aspects, locations of expression, and the functions of C3 and C5 fragments. Further, the article critically reviews developing therapeutics aimed at C3 and C5, underscoring the potential effects of broad inhibition of complement at the level of C3 versus more specific inhibition at C5. The relationships of complement biology to the inflammasome and microglia/macrophage activity are highlighted. Concepts of C3 and C5 biology will be emphasized, while we point out questions that need to be settled and directions for future investigations.
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Affiliation(s)
- Benjamin J Kim
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | | | - Yafeng Li
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joshua L Dunaief
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - John D Lambris
- Department of Laboratory Medicine and Pathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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19
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Emerging Role of C5 Complement Pathway in Peripheral Neuropathies: Current Treatments and Future Perspectives. Biomedicines 2021; 9:biomedicines9040399. [PMID: 33917266 PMCID: PMC8067968 DOI: 10.3390/biomedicines9040399] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/12/2022] Open
Abstract
The complement system is a key component of innate immunity since it plays a critical role in inflammation and defense against common pathogens. However, an inappropriate activation of the complement system is involved in numerous disorders, including peripheral neuropathies. Current strategies for neuropathy-related pain fail to achieve adequate pain relief, and although several therapies are used to alleviate symptoms, approved disease-modifying treatments are unavailable. This urgent medical need is driving the development of therapeutic agents for this condition, and special emphasis is given to complement-targeting approaches. Recent evidence has underscored the importance of complement component C5a and its receptor C5aR1 in inflammatory and neuropathic pain, indicating that C5a/C5aR1 axis activation triggers a cascade of events involved in pathophysiology of peripheral neuropathy and painful neuro-inflammatory states. However, the underlying pathophysiological mechanisms of this signaling in peripheral neuropathy are not fully known. Here, we provide an overview of complement pathways and major components associated with dysregulated complement activation in peripheral neuropathy, and of drugs under development targeting the C5 system. C5/C5aR1 axis modulators could represent a new strategy to treat complement-related peripheral neuropathies. Specifically, we describe novel C5aR allosteric modulators, which may potentially become new tools in the therapeutic armory against neuropathic pain.
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20
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Nozaki Y. New Insights Into Novel Therapeutic Targets in ANCA-Associated Vasculitis. Front Immunol 2021; 12:631055. [PMID: 33868250 PMCID: PMC8047311 DOI: 10.3389/fimmu.2021.631055] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 03/18/2021] [Indexed: 11/13/2022] Open
Abstract
Biologics targeting inflammation-related molecules in the immune system have been developed to treat rheumatoid arthritis (RA), and these RA treatments have provided revolutionary advances. Biologics may also be an effective treatment for anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, particularly in patients with resistance to standard treatments. Despite the accumulation of clinical experience and the increasing understanding of the pathogenesis of vasculitis, it is becoming more difficult to cure vasculitis. The treatment of vasculitis with biologics has been examined in clinical trials, and this has also enhanced our understanding of the pathogenesis of vasculitis. A humanized anti-interleukin-5 monoclonal antibody known as mepolizumab was recently demonstrated to provide clinical benefit in the management of eosinophilic granulomatosis with polyangiitis in refractory and relapsing disease, and additional new drugs for vasculitis are being tested in clinical trials, while others are in abeyance. This review presents the new findings regarding biologics in addition to the conventional immunosuppressive therapy for ANCA-associated vasculitis.
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Affiliation(s)
- Yuji Nozaki
- Department of Hematology and Rheumatology, Kindai University Faculty of Medicine, Osaka-sayama, Japan
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21
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Macpherson A, Laabei M, Ahdash Z, Graewert MA, Birtley JR, Schulze MSE, Crennell S, Robinson SA, Holmes B, Oleinikovas V, Nilsson PH, Snowden J, Ellis V, Mollnes TE, Deane CM, Svergun D, Lawson AD, van den Elsen JM. The allosteric modulation of complement C5 by knob domain peptides. eLife 2021; 10:63586. [PMID: 33570492 PMCID: PMC7972453 DOI: 10.7554/elife.63586] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/11/2021] [Indexed: 12/22/2022] Open
Abstract
Bovines have evolved a subset of antibodies with ultra-long heavy chain complementarity determining regions that harbour cysteine-rich knob domains. To produce high-affinity peptides, we previously isolated autonomous 3–6 kDa knob domains from bovine antibodies. Here, we show that binding of four knob domain peptides elicits a range of effects on the clinically validated drug target complement C5. Allosteric mechanisms predominated, with one peptide selectively inhibiting C5 cleavage by the alternative pathway C5 convertase, revealing a targetable mechanistic difference between the classical and alternative pathway C5 convertases. Taking a hybrid biophysical approach, we present C5-knob domain co-crystal structures and, by solution methods, observed allosteric effects propagating >50 Å from the binding sites. This study expands the therapeutic scope of C5, presents new inhibitors, and introduces knob domains as new, low molecular weight antibody fragments, with therapeutic potential. Antibodies are proteins produced by the immune system that can selectively bind to other molecules and modify their behaviour. Cows are highly equipped at fighting-off disease-causing microbes due to the unique shape of some of their antibodies. Unlike other jawed vertebrates, cows’ antibodies contain an ultra-long loop region that contains a ‘knob domain’ which sticks out from the rest of the antibody. Recent research has shown that when detached, the knob domain behaves like an antibody fragment, and can independently bind to a range of different proteins. Antibody fragments are commonly developed in the laboratory to target proteins associated with certain diseases, such as arthritis and cancer. But it was unclear whether the knob domains from cows’ antibodies could also have therapeutic potential. To investigate this, Macpherson et al. studied how knob domains attach to complement C5, a protein in the inflammatory pathway which is a drug target for various diseases, including severe COVID-19. The experiments identified various knob domains that bind to complement C5 and inhibits its activity by altering its structure or movement. Further tests studying the structure of these interactions, led to the discovery of a common mechanism by which inhibitors can modify the behaviour of this inflammatory protein. Complement C5 is involved in numerous molecular pathways in the immune system, which means many of the drugs developed to inhibit its activity can also leave patients vulnerable to infection. However, one of the knob domains identified by Macpherson et al. was found to reduce the activity of complement C5 in some pathways, whilst leaving other pathways intact. This could potentially reduce the risk of bacterial infections which sometimes arise following treatment with these types of inhibitors. These findings highlight a new approach for developing drug inhibitors for complement C5. Furthermore, the ability of knob domains to bind to multiple sites of complement C5 suggests that this fragment could be used to target proteins associated with other diseases.
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Affiliation(s)
- Alex Macpherson
- UCB, Slough, United Kingdom.,Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Maisem Laabei
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | | | | | | | | | - Susan Crennell
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Sarah A Robinson
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | | | | | - Per H Nilsson
- UCB, Slough, United Kingdom.,Department of Chemistry and Biomedicine, Linnaeus University, Kalmar, Sweden.,Department of Immunology, Oslo University Hospital, University of Oslo, Oslo, Norway
| | | | | | - Tom Eirik Mollnes
- Department of Immunology, Oslo University Hospital, University of Oslo, Oslo, Norway.,Research Laboratory, Bodø Hospital, K.G. Jebsen TREC, University of Tromsø, Tromsø, Norway.,Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Charlotte M Deane
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Dmitri Svergun
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | | | - Jean Mh van den Elsen
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom.,Centre for Therapeutic Innovation, University of Bath, Bath, United Kingdom
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22
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Beltagy A, Aghamajidi A, Trespidi L, Ossola W, Meroni PL. Biologics During Pregnancy and Breastfeeding Among Women With Rheumatic Diseases: Safety Clinical Evidence on the Road. Front Pharmacol 2021; 12:621247. [PMID: 34122062 PMCID: PMC8189556 DOI: 10.3389/fphar.2021.621247] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 01/04/2021] [Indexed: 12/31/2022] Open
Abstract
Females are generally more affected by autoimmune diseases, a fact that underlines the relationship with pregnancy and the safety of anti-rheumatic drugs in pregnancy and lactation. Biologic therapies are increasingly prescribed to treat and maintain remission in a significant number of systemic autoimmune rheumatic diseases. The experience with the use of biologics during gestation is extremely lacking because of the observational nature of the available studies and the difficulty in designing proper clinical trials in pregnancy. Among the studied biologics, more information was published on TNFα inhibitors and, in particular, on their potential passage through the placenta and impact on the fetus. Currently, a fragment of anti-TNFα monoclonal IgG, certolizumab pegol, is considered safe with almost no placental transfer. Subsequent observations are suggesting a comparable safety for the soluble TNFα receptor etanercept. Another biologic, eculizumab, the anti-C5a antibody used to treat complement-mediated microangiopathies, is also considered safe due to the unique engineered IgG2/4κ formulation that limits its passage through the placental barrier. Still, long-term data about children born to women treated with biologics in pregnancy are not attainable. Data on breastfeeding are currently available for several biologics. This article reviews the literature available about which drugs are considered safe during pregnancy and lactation, which are not, and on future prospects.
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Affiliation(s)
- Asmaa Beltagy
- Istituto Auxologico Italiano, IRCCS, Immunorheumatology Research Laboratory, Milan, Italy.,Rheumatology and Clinical Immunology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Azin Aghamajidi
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Laura Trespidi
- Department of Obstetrics and Gynaecology, Fondazione Ca Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Wally Ossola
- Department of Obstetrics and Gynaecology, Fondazione Ca Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Pier Luigi Meroni
- Istituto Auxologico Italiano, IRCCS, Immunorheumatology Research Laboratory, Milan, Italy
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23
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Broadly effective metabolic and immune recovery with C5 inhibition in CHAPLE disease. Nat Immunol 2021; 22:128-139. [PMID: 33398182 PMCID: PMC7856263 DOI: 10.1038/s41590-020-00830-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/28/2020] [Indexed: 01/29/2023]
Abstract
Complement hyperactivation, angiopathic thrombosis and protein-losing enteropathy (CHAPLE disease) is a lethal disease caused by genetic loss of the complement regulatory protein CD55, leading to overactivation of complement and innate immunity together with immunodeficiency due to immunoglobulin wasting in the intestine. We report in vivo human data accumulated using the complement C5 inhibitor eculizumab for the medical treatment of patients with CHAPLE disease. We observed cessation of gastrointestinal pathology together with restoration of normal immunity and metabolism. We found that patients rapidly renormalized immunoglobulin concentrations and other serum proteins as revealed by aptamer profiling, re-established a healthy gut microbiome, discontinued immunoglobulin replacement and other treatments and exhibited catch-up growth. Thus, we show that blockade of C5 by eculizumab effectively re-establishes regulation of the innate immune complement system to substantially reduce the pathophysiological manifestations of CD55 deficiency in humans.
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24
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Mantegazza R, Vanoli F, Frangiamore R, Cavalcante P. Complement Inhibition for the Treatment of Myasthenia Gravis. Immunotargets Ther 2020; 9:317-331. [PMID: 33365280 PMCID: PMC7751298 DOI: 10.2147/itt.s261414] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 12/02/2020] [Indexed: 12/11/2022] Open
Abstract
Generalized myasthenia gravis (gMG) is a rare autoimmune disorder affecting the neuromuscular junction (NMJ). Approximately 80-90% of patients display antibodies directed against the nicotinic acetylcholine receptor (AChR). A major drive of AChR antibody-positive MG pathology is represented by complement activation. The role of the complement cascade has been largely demonstrated in patients and in MG animal models. Complement activation at the NMJ leads to focal lysis of the post-synaptic membrane, disruption of the characteristic folds, and reduction of AChR. Given that the complement system works as an activation cascade, there are many potential targets that can be considered for therapeutic intervention. Preclinical studies have confirmed the efficacy of complement inhibition in ameliorating MG symptoms. Eculizumab, an antibody directed towards C5, has recently been approved for the treatment of AChR antibody-positive gMG. Other complement inhibitors, targeting C5 as well, are currently under phase III study. Complement inhibitors, however, may present prohibitive costs. Therefore, the identification of a subset of patients more or less prone to respond to such therapies would be beneficial. For such purpose, there is a critical need to identify possible biomarkers predictive of therapeutic response, a field not yet sufficiently explored in MG. This review aims to give an overview of the complement cascade involvement in MG, the evolution of complement-inhibiting therapies and possible biomarkers useful to tailor and monitor complement-directed therapies.
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Affiliation(s)
- Renato Mantegazza
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Fiammetta Vanoli
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Rita Frangiamore
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Paola Cavalcante
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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25
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Passot C, Sberro-Soussan R, Bertrand D, Caillard S, Schvartz B, Domenger C, Contin-Bordes C, Paintaud G, Halimi JM, Ternant D, Gatault P. Feasibility and safety of tailored dosing schedule for eculizumab based on therapeutic drug monitoring: Lessons from a prospective multicentric study. Br J Clin Pharmacol 2020; 87:2236-2246. [PMID: 33118186 DOI: 10.1111/bcp.14627] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 10/13/2020] [Accepted: 10/17/2020] [Indexed: 12/23/2022] Open
Abstract
AIMS Eculizumab is an anti-C5 monoclonal antibody approved for rare diseases including atypical haemolytic-uraemic syndrome. The maintenance phase dosing regimen is identical for all adult patients: 1200 mg every 2 weeks. Recent studies reported an overexposure in many patients when considering a target trough concentration range of 50-100 mg/L. The aim of the present work was to validate the feasibility of therapeutic drug monitoring of eculizumab in atypical haemolytic-uraemic syndrome patients. METHODS We performed a 2-step prospective multicentre study. In the first phase, we developed a pharmacokinetic population model using data from 40 patients and identified patients for whom a 1-week lengthening of interval between infusions would lead to a trough concentration above 100 mg/L. In the second phase, selected patients were allocated a 1-week extension and eculizumab trough concentrations were monitored. RESULTS The model confirmed the previously reported influence of bodyweight on elimination clearance and predicted that 36 (90%) patients would be eligible for interval extension. In the second phase of the study, a 1-week lengthening of interval between infusions was performed in 15 patients whose trough concentration at the next visit was predicted with a Bayesian model to be above 100 mg/L. After interval extension, 10 patients (67%) presented measured trough concentrations over 100 mg/L. No biological or clinical recurrence of disease was observed, even in the 5 patients with concentrations below 100 mg/L in whom the initial dosing regimen was resumed. CONCLUSION Safe eculizumab interval adjustment is feasible with a PK monitoring.
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Affiliation(s)
- Christophe Passot
- EA7501, University of Tours, France.,Laboratory of Pharmacology-Toxicology, CHRU de Tours, France.,Integrated Center for Oncology, Angers, France
| | - Rebecca Sberro-Soussan
- Service de Néphrologie et Transplantation Adulte, Hôpital Necker-Enfants Malades, Université Paris Descartes, Assistance Publique-Hôpitaux de Paris, Paris, France
| | | | - Sophie Caillard
- Nephrology and Transplant Department, Strasbourg University Hospital, Strasbourg, France
| | | | | | | | - Gilles Paintaud
- EA7501, University of Tours, France.,Laboratory of Pharmacology-Toxicology, CHRU de Tours, France
| | - Jean-Michel Halimi
- EA4245 Transplant Immunology and Inflammation, Université de Tours, Tours, France.,Service de Néphrologie-Hypertension artérielle, Dialyses, Transplantation rénale, CHRU Tours, France
| | - David Ternant
- EA7501, University of Tours, France.,Laboratory of Pharmacology-Toxicology, CHRU de Tours, France
| | - Philippe Gatault
- EA4245 Transplant Immunology and Inflammation, Université de Tours, Tours, France.,Service de Néphrologie-Hypertension artérielle, Dialyses, Transplantation rénale, CHRU Tours, France
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26
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Zrzavy T, Wimmer I, Rommer PS, Berger T. Immunology of COVID-19 and disease-modifying therapies: The good, the bad and the unknown. Eur J Neurol 2020; 28:3503-3516. [PMID: 33090599 PMCID: PMC7675490 DOI: 10.1111/ene.14578] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/04/2020] [Indexed: 01/08/2023]
Abstract
Objective The outbreak of the SARS‐CoV‐2 pandemic, caused by a previously unknown infectious agent, posed unprecedented challenges to healthcare systems and unmasked their vulnerability and limitations worldwide. Patients with long‐term immunomodulatory/suppressive therapies, as well as their physicians, were and are concerned about balancing the risk of infection and effects of disease‐modifying therapy. Over the last few months, knowledge regarding SARS‐CoV‐2 has been growing tremendously, and the first experiences of infections in patients with multiple sclerosis (MS) have been reported. Methods This review summarizes the currently still limited knowledge about SARS‐CoV‐2 immunology and the commonly agreed modes of action of approved drugs in immune‐mediated diseases of the central nervous system (MS and neuromyelitis optica spectrum disorder). Specifically, we discuss whether immunosuppressive/immunomodulatory drugs may increase the risk of SARS‐CoV‐2 infection and, conversely, may decrease the severity of a COVID‐19 disease course. Results At present, it can be recommended in general that none of those therapies with a definite indication needs to be stopped per se. A possibly increased risk of infection for most medications is accompanied by the possibility to reduce the severity of COVID‐19. Conclusions Despite the knowledge gain over the last few months, current evidence remains limited, and, thus, further clinical vigilance and systematic documentation is essential.
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Affiliation(s)
- Tobias Zrzavy
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Isabella Wimmer
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Paulus S Rommer
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Thomas Berger
- Department of Neurology, Medical University of Vienna, Vienna, Austria
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27
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Holmøy T, Høglund RA, Illes Z, Myhr KM, Torkildsen Ø. Recent progress in maintenance treatment of neuromyelitis optica spectrum disorder. J Neurol 2020; 268:4522-4536. [PMID: 33011853 PMCID: PMC8563615 DOI: 10.1007/s00415-020-10235-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 02/07/2023]
Abstract
Background Treatment of neuromyelitis optica spectrum disorder (NMOSD) has so far been based on retrospective case series. The results of six randomized clinical trials including five different monoclonal antibodies targeting four molecules and three distinct pathophysiological pathways have recently been published. Methods Literature search on clinical trials and case studies in NMOSD up to July 10. 2020. Results We review mechanism of action, efficacy and side effects, and consequences for reproductive health from traditional immunosuppressants and monoclonal antibodies including rituximab, inebilizumab, eculizumab, tocilizumab and satralizumab. Conclusion In NMOSD patients with antibodies against aquaporin 4, monoclonal antibodies that deplete B cells (rituximab and inebilizumab) or interfere with interleukin 6 signaling (tocilizumab and satralizumab) or complement activation (eculizumab) have superior efficacy compared to placebo. Tocilizumab and rituximab were also superior to azathioprine in head-to-head studies. Rituximab, tocilizumab and to some extent eculizumab have well-known safety profiles for other inflammatory diseases, and rituximab and azathioprine may be safe during pregnancy.
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Affiliation(s)
- Trygve Holmøy
- Department of Neurology, Akershus University Hospital, Lørenskog, Norway. .,Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Rune Alexander Høglund
- Department of Neurology, Akershus University Hospital, Lørenskog, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Zsolt Illes
- Department of Neurology, Odense University Hospital, Odense, Denmark.,Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Kjell-Morten Myhr
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Neuro-SysMed, Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Øivind Torkildsen
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Neuro-SysMed, Department of Neurology, Haukeland University Hospital, Bergen, Norway
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28
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Zelek WM, Menzies GE, Brancale A, Stockinger B, Morgan BP. Characterizing the original anti-C5 function-blocking antibody, BB5.1, for species specificity, mode of action and interactions with C5. Immunology 2020; 161:103-113. [PMID: 32557571 PMCID: PMC7496778 DOI: 10.1111/imm.13228] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/05/2020] [Accepted: 06/07/2020] [Indexed: 12/11/2022] Open
Abstract
The implication of complement in multiple diseases over the last 20 years has fuelled interest in developing anti-complement drugs. To date, the focus has been on C5; blocking cleavage of C5 prevents formation of two pro-inflammatory activities, C5a anaphylatoxin and membrane attack complex. The concept of C5 blockade to inhibit inflammation dates back 30 years to the description of BB5.1, an anti-C5 blocking monoclonal antibody raised in C5-deficient mice. This antibody proved an invaluable tool to demonstrate complement involvement in mouse disease models and catalysed enthusiasm for anti-complement drug development, culminating in the anti-human C5 monoclonal antibody eculizumab, the most successful anti-complement drug to date, already in clinical use for several rare diseases. Despite its key role in providing proof-of-concept for C5 blockade, the mechanism of BB5.1 inhibition remains poorly understood. Here, we characterized BB5.1 cross-species inhibition, C5 binding affinity and chain specificity. BB5.1 efficiently inhibited C5 in mouse serum but not in human or other rodent sera; it prevented C5 cleavage and C5a generation. BB5.1 bound the C5 α-chain with high affinity and slow off-rate. BB5.1 complementarity-determining regions were obtained and docking algorithms were used to predict the likely binding interface on mouse C5.
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Affiliation(s)
- Wioleta M. Zelek
- Systems Immunity University Research InstituteSchool of MedicineCardiff UniversityCardiffUK
| | | | - Andrea Brancale
- School of Pharmacy and Pharmaceutical SciencesCardiff UniversityCardiffUK
| | | | - Bryan Paul Morgan
- Systems Immunity University Research InstituteSchool of MedicineCardiff UniversityCardiffUK
- Dementia Research InstituteCardiff UniversityCardiffUK
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29
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Fukuzawa T, Nezu J. SKY59, A Novel Recycling Antibody for Complement-mediated Diseases. Curr Med Chem 2020; 27:4157-4164. [PMID: 31622197 DOI: 10.2174/0929867326666191016115853] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 03/28/2019] [Accepted: 03/28/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND The complement system usually helps protect against microbial infection, but it could also be involved in the onset of various diseases. Inhibition of complement component 5 (C5) with eculizumab has resulted in a significant reduction of hemolysis, reduction of thromboembolic events, and increased survival in patients with Paroxysmal Nocturnal Hemoglobinuria (PNH). However, eculizumab requires frequent intravenous infusions due to the abundance of C5 in plasma and some patients may still experience breakthrough hemolysis. This review introduces the recent body of knowledge on recycling technology and discusses the likely therapeutic benefits of SKY59, a novel recycling antibody, for PNH and complement-mediated disorders. METHODS By using recycling technology, we created a novel anti-C5 antibody, SKY59, capable of binding to C5 pH-dependently. RESULTS In cynomolgus monkeys, SKY59 robustly inhibited C5 and complement activity for significantly longer than a conventional antibody. SKY59 also showed an inhibitory effect on C5 variant p.Arg885His, whereas eculizumab does not suppress complement activity in patients with this type of mutation. CONCLUSION SKY59 is a promising anti-C5 biologic agent that has significant advantages over current therapies such as long duration of action and efficacy against C5 variants.
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Affiliation(s)
- Taku Fukuzawa
- Research Division, Chugai Pharmaceutical Co., Ltd., Gotemba, Shizuoka, Japan
| | - Junichi Nezu
- Research Division, Chugai Pharmaceutical Co., Ltd., Gotemba, Shizuoka, Japan
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30
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Bernth Jensen JM, Laursen NS, Jensen RK, Andersen GR, Jensenius JC, Sørensen UBS, Thiel S. Complement activation by human IgG antibodies to galactose-α-1,3-galactose. Immunology 2020; 161:66-79. [PMID: 32583419 PMCID: PMC7450175 DOI: 10.1111/imm.13229] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 12/13/2022] Open
Abstract
Some human antibodies may paradoxically inhibit complement activation on bacteria and enhance pathogen survival in humans. This property was also claimed for IgG antibodies reacting with terminal galactose-α-1,3-galactose (Galα3Gal; IgG anti-αGal), a naturally occurring and abundant antibody in human plasma that targets numerous different pathogens. To reinvestigate these effects, we used IgG anti-αGal affinity isolated from a pool of normal human IgG and human hypogammaglobulinaemia serum as a complement source. Flow cytometry was performed to examine antibody binding and complement deposition on pig erythrocytes, Escherichia coli O86 and Streptococcus pneumoniae serotype 9V. Specific nanobodies were used to block the effect of single complement factors and to delineate the complement pathways involved. IgG anti-αGal was capable of activating the classical complement pathway on all the tested target cells. The degree of activation was exponentially related to the density of bound antibody on E. coli O86 and pig erythrocytes, but more linearly on S. pneumoniae 9V. The alternative pathway of complement amplified complement deposition. Deposited C3 fragments covered the activating IgG anti-αGal, obstructing its detection and highlighting this as a likely general caveat in studies of antibody density and complement deposition. The inherent capacity for complement activation by the purified carbohydrate reactive IgG anti-αGal was similar to that of normal human IgG. We propose that the previously reported complement inhibition by IgG anti-αGal relates to suboptimal assay configurations, in contrast to the complement activating property of the antibodies demonstrated in this paper.
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Affiliation(s)
| | - Nick Stub Laursen
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | | | | | | | | | - Steffen Thiel
- Department of BiomedicineAarhus UniversityAarhusDenmark
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31
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Pharmacology, Pharmacokinetics and Pharmacodynamics of Eculizumab, and Possibilities for an Individualized Approach to Eculizumab. Clin Pharmacokinet 2020; 58:859-874. [PMID: 30758736 PMCID: PMC6584251 DOI: 10.1007/s40262-019-00742-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Eculizumab is the first drug approved for the treatment of complement-mediated diseases, and current dosage schedules result in large interindividual drug concentrations. This review provides insight into the pharmacokinetic and pharmacodynamic properties of eculizumab, both for reported on-label (paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, generalized myasthenia gravis) and off-label (hematopoietic stem cell transplantation-associated thrombotic microangiopathy) indications. Furthermore, we discuss the potential of therapeutic drug monitoring to individualize treatment and reduce costs.
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32
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Zarantonello A, Presumey J, Simoni L, Yalcin E, Fox R, Hansen A, Olesen HG, Thiel S, Johnson MB, Stevens B, Laursen NS, Carroll MC, Andersen GR. An Ultrahigh-Affinity Complement C4b-Specific Nanobody Inhibits In Vivo Assembly of the Classical Pathway Proconvertase. THE JOURNAL OF IMMUNOLOGY 2020; 205:1678-1694. [PMID: 32769120 DOI: 10.4049/jimmunol.2000528] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/09/2020] [Indexed: 01/07/2023]
Abstract
The classical and lectin pathways of the complement system are important for the elimination of pathogens and apoptotic cells and stimulation of the adaptive immune system. Upon activation of these pathways, complement component C4 is proteolytically cleaved, and the major product C4b is deposited on the activator, enabling assembly of a C3 convertase and downstream alternative pathway amplification. Although excessive activation of the lectin and classical pathways contributes to multiple autoimmune and inflammatory diseases and overexpression of a C4 isoform has recently been linked to schizophrenia, a C4 inhibitor and structural characterization of the convertase formed by C4b is lacking. In this study, we present the nanobody hC4Nb8 that binds with picomolar affinity to human C4b and potently inhibits in vitro complement C3 deposition through the classical and lectin pathways in human serum and in mouse serum. The crystal structure of the C4b:hC4Nb8 complex and a three-dimensional reconstruction of the C4bC2 proconvertase obtained by electron microscopy together rationalize how hC4Nb8 prevents proconvertase assembly through recognition of a neoepitope exposed in C4b and reveals a unique C2 conformation compared with the alternative pathway proconvertase. On human induced pluripotent stem cell-derived neurons, the nanobody prevents C3 deposition through the classical pathway. Furthermore, hC4Nb8 inhibits the classical pathway-mediated immune complex delivery to follicular dendritic cells in vivo. The hC4Nb8 represents a novel ultrahigh-affinity inhibitor of the classical and lectin pathways of the complement cascade under both in vitro and in vivo conditions.
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Affiliation(s)
| | - Jessy Presumey
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Léa Simoni
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Esra Yalcin
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Rachel Fox
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Annette Hansen
- Department of Biomedicine, Aarhus University, DK8000 Aarhus, Denmark
| | - Heidi Gytz Olesen
- Department of Molecular Biology and Genetics, Aarhus University, DK8000 Aarhus, Denmark
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, DK8000 Aarhus, Denmark
| | - Matthew B Johnson
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115
| | - Beth Stevens
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115.,Department of Neurology, Harvard Medical School, Boston, MA 02115.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115; and
| | - Nick Stub Laursen
- Department of Molecular Biology and Genetics, Aarhus University, DK8000 Aarhus, Denmark
| | - Michael C Carroll
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115.,Department of Pediatrics, Harvard Medical School, Boston, MA 02115
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, DK8000 Aarhus, Denmark;
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33
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Gembillo G, Siligato R, Cernaro V, Santoro D. Complement Inhibition Therapy and Dialytic Strategies in Paroxysmal Nocturnal Hemoglobinuria: The Nephrologist's Opinion. J Clin Med 2020; 9:E1261. [PMID: 32357555 PMCID: PMC7287718 DOI: 10.3390/jcm9051261] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/18/2020] [Accepted: 04/21/2020] [Indexed: 12/24/2022] Open
Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal disease that presents an estimated incidence of 1.3 cases per million per year, with a prevalence of 15.9 cases per million. It is characterized by hemolysis, bone marrow dysfunction with peripheral blood cytopenia, hypercoagulability, thrombosis, renal impairment and arterial and pulmonary hypertension. Hemolysis and subsequent hemosiderin accumulation in tubular epithelium cells induce tubular atrophy and interstitial fibrosis. The origin of PNH is the somatic mutation in the X-linked phosphatidylinositol glycan class A (PIG-A) gene located on Xp22: this condition leads to the production of clonal blood cells with a deficiency in those surface proteins that protect against the lytic action of the activated complement system. Despite the increased knowledge of this syndrome, therapies for PNH were still only experimental and symptomatic, until the introduction of the C5 complement blockade agent Eculizumab. A second generation of anti-complement agents is currently under investigation, representing future promising therapeutic strategies for patients affected by PNH. In the case of chronic hemolysis and renal iron deposition, a multidisciplinary approach should be considered to avoid or treat acute tubular injury or acute kidney injury (AKI). New promising perspectives derive from complement inhibitors and iron chelators, as well as more invasive treatments such as immunoadsorption or the use of dedicated hemodialysis filters in the presence of AKI.
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Affiliation(s)
- Guido Gembillo
- Unit of Nephrology, Department of Clinical and Experimental Medicine, University of Messina, 98125 Messina, Italy; (R.S.); (V.C.); (D.S.)
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Abstract
The complement system is a crucial antimicrobial system in the human body. However, controlling its regulation is essential, and failure to do so is implicated in a number of clinical inflammatory pathologies leading to great interest in therapeutic complement inhibition. We have identified and characterized a class of complement inhibitors from biting ticks. Utilizing both cryoelectron microscopy and X-ray crystallography we provide a comprehensive understanding of their mechanism of inhibition at the level of the terminal pathway of complement. We present a high-resolution cryoelectron microscopy structure of complement C5, the molecule targeted by the major therapeutic Eculizumab. In addition, we reveal the fold of the CirpT family of tick inhibitors and their unique mode of inhibition. The complement system is a crucial part of innate immune defenses against invading pathogens. The blood-meal of the tick Rhipicephalus pulchellus lasts for days, and the tick must therefore rely on inhibitors to counter complement activation. We have identified a class of inhibitors from tick saliva, the CirpT family, and generated detailed structural data revealing their mechanism of action. We show direct binding of a CirpT to complement C5 and have determined the structure of the C5–CirpT complex by cryoelectron microscopy. This reveals an interaction with the peripheral macro globulin domain 4 (C5_MG4) of C5. To achieve higher resolution detail, the structure of the C5_MG4–CirpT complex was solved by X-ray crystallography (at 2.7 Å). We thus present the fold of the CirpT protein family, and provide detailed mechanistic insights into its inhibitory function. Analysis of the binding interface reveals a mechanism of C5 inhibition, and provides information to expand our biological understanding of the activation of C5, and thus the terminal complement pathway.
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35
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Zewde NT. Multiscale Solutions to Quantitative Systems Biology Models. Front Mol Biosci 2019; 6:119. [PMID: 31737643 PMCID: PMC6831518 DOI: 10.3389/fmolb.2019.00119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/14/2019] [Indexed: 11/13/2022] Open
Affiliation(s)
- Nehemiah T Zewde
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
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36
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Zelek WM, Taylor PR, Morgan BP. Development and characterization of novel anti-C5 monoclonal antibodies capable of inhibiting complement in multiple species. Immunology 2019; 157:283-295. [PMID: 31120547 PMCID: PMC6620185 DOI: 10.1111/imm.13083] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/23/2019] [Accepted: 05/14/2019] [Indexed: 12/29/2022] Open
Abstract
Over the last decade there has been an explosion in complement therapies; one-third of the drugs in the clinic or in development target C5 protein. Eculizumab, a monoclonal antibody (mAb) that binds C5 and blocks its cleavage by the convertase, is the current reference standard treatment for atypical haemolytic uraemic syndrome (aHUS) and paroxysmal nocturnal haemoglobinuria (PNH) and in clinical trials for many other diseases. Here we describe a panel of novel anti-C5 mAb, including mAb that, like Eculizumab, are efficient inhibitors of complement but, unlike Eculizumab, inhibit across species, including human, rat, rabbit and guinea pig. Several inhibitory anti-C5 mAb were identified and characterized for C5 binding and lytic inhibitory capacity in comparison to current therapeutic anti-C5 mAb; three clones, 4G2, 7D4 and 10B6, were selected and further characterized for ligand specificity and affinity and cross-species inhibitory activity. The mAb 10B6 was human-specific whereas mAb 4G2 and 7D4 efficiently inhibited lysis by human, rabbit and rat serum, and weakly inhibited guinea pig complement; 7D4 also weakly inhibited mouse complement in vitro The rat C5-cross-reactive mAb 4G2, when administered intraperitoneally in a rat model of myasthenia gravis, effectively blocked the disease and protected muscle endplates from destruction. To our knowledge this is the first report of an anti-C5 function blocking mAb that permits preclinical studies in rats.
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Affiliation(s)
- Wioleta M. Zelek
- Division of Infection and ImmunitySchool of MedicineSystems Immunity Research InstituteCardiff UniversityWalesUK
| | - Philip R. Taylor
- Division of Infection and ImmunitySchool of MedicineSystems Immunity Research InstituteCardiff UniversityWalesUK
| | - B. Paul Morgan
- Division of Infection and ImmunitySchool of MedicineSystems Immunity Research InstituteCardiff UniversityWalesUK
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37
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Editorial on: Eculizumab in aquaporin-4-positive neuromyelitis optica spectrum disorder. Mult Scler Relat Disord 2019; 33:A1-A2. [PMID: 31324299 DOI: 10.1016/j.msard.2019.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Abstract
The humanized monoclonal antibody eculizumab (Soliris®) is a complement inhibitor indicated for use in anti-acetylcholine receptor (AChR) antibody-positive adults with generalized myasthenia gravis (gMG) in the USA, refractory gMG in the EU, or gMG with symptoms that are difficult to control with high-dose IVIg therapy or PLEX in Japan. It is the first complement inhibitor to be approved for use in these patients. In the well-designed, 26-week REGAIN study in patients with anti-AChR-positive refractory gMG, although a statistically significant benefit of eculizumab over placebo in the prespecified primary endpoint analysis (change from baseline in MG-activities of daily living (ADL) score assessed by worst-rank ANCOVA) was not formally demonstrated, preplanned and post hoc sensitivity analyses of this outcome, as well as other secondary outcomes supported the efficacy of eculizumab. Overall, patients receiving eculizumab experienced significant improvements in the ADL, muscle strength and health-related quality of life (HR-QOL) parameters relative to patients receiving placebo. Moreover, an ongoing extension of REGAIN showed that treatment benefits with eculizumab were sustained during continued therapy for at least 52 weeks. Eculizumab was generally well tolerated in these studies, with a tolerability profile similar to that reported previously in other indications. Although several questions remain, such as duration of treatment, cost effectiveness and long-term efficacy and tolerability, current evidence indicates that eculizumab is a valuable emerging therapy for patients with refractory gMG.
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Affiliation(s)
- Sohita Dhillon
- Springer, Private Bag 65901, Mairangi Bay, Auckland, 0754, New Zealand.
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Rizk DV, Maillard N, Julian BA, Knoppova B, Green TJ, Novak J, Wyatt RJ. The Emerging Role of Complement Proteins as a Target for Therapy of IgA Nephropathy. Front Immunol 2019; 10:504. [PMID: 30941137 PMCID: PMC6433978 DOI: 10.3389/fimmu.2019.00504] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/25/2019] [Indexed: 12/28/2022] Open
Abstract
IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide and a common cause of end-stage renal disease. Evaluation of a kidney biopsy is necessary for diagnosis, with routine immunofluorescence microscopy revealing dominant or co-dominant IgA immunodeposits usually with complement C3 and sometimes IgG and/or IgM. IgA nephropathy reduces life expectancy by more than 10 years and leads to kidney failure in 20–40% of patients within 20 years of diagnosis. There is accumulating clinical, genetic, and biochemical evidence that complement plays an important role in the pathogenesis of IgA nephropathy. The presence of C3 differentiates the diagnosis of IgA nephropathy from the subclinical deposition of glomerular IgA. Markers for the activation of the alternative and mannan-binding lectin (MBL) pathways in renal-biopsy specimens are associated with disease activity and portend a worse renal outcome. Complement proteins in the circulation have also been evaluated in IgA nephropathy and found to be of prognostic value. Recently, genetic studies have identified IgA nephropathy-associated loci. Within these loci are genes encoding products involved in complement regulation and interaction with immune complexes. Put together, these data identify the complement cascade as a rational treatment target for this chronic kidney disease. Recent case reports on the successful use of humanized anti-C5 monoclonal antibody eculizumab are consistent with this hypothesis, but a better understanding of the role of complement in IgA nephropathy is needed to guide future therapeutic interventions.
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Affiliation(s)
- Dana V Rizk
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Nicolas Maillard
- Department of Nephrology, Dialysis, Transplantation, CHU de Saint-Etienne, GIMAP, EA3064, Université Jean Monnet, COMUE Université de Lyon, Rhône-Alpes, France
| | - Bruce A Julian
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Barbora Knoppova
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States.,Department of Immunology, Faculty of Medicine and Dentistry, Palacky University and University Hospital, Olomouc, Czechia
| | - Todd J Green
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jan Novak
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Robert J Wyatt
- Department of Pediatrics, University of Tennessee Health Sciences Center, Memphis, TN, United States
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40
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Yatime L, Merle NS, Hansen AG, Friis NA, Østergaard JA, Bjerre M, Roumenina LT, Thiel S, Kristensen P, Andersen GR. A Single-Domain Antibody Targeting Complement Component C5 Acts as a Selective Inhibitor of the Terminal Pathway of the Complement System and Thus Functionally Mimicks the C-Terminal Domain of the Staphylococcus aureus SSL7 Protein. Front Immunol 2018; 9:2822. [PMID: 30555486 PMCID: PMC6281825 DOI: 10.3389/fimmu.2018.02822] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 11/15/2018] [Indexed: 11/13/2022] Open
Abstract
The complement system is an efficient anti-microbial effector mechanism. On the other hand abnormal complement activation is involved in the pathogenesis of multiple inflammatory and hemolytic diseases. As general inhibition of the complement system may jeopardize patient health due to increased susceptibility to infections, the development of pathway-specific complement therapeutics has been a long-lasting goal over the last decades. In particular, pathogen mimicry has been considered as a promising approach for the design of selective anti-complement drugs. The C-terminal domain of staphylococcal superantigen-like protein 7 (SSL7), a protein secreted by Staphylococcus aureus, was recently found to be a specific inhibitor of the terminal pathway of the complement system, providing selective inhibition of cell lysis mediated by the membrane attack complex (MAC). We describe here the selection by phage display of a humanized single-domain antibody (sdAb) mimicking the C-terminal domain of SSL7. The antibody, called sdAb_E4, binds complement C5 with an affinity in the low micromolar range. Furthermore, sdAb_E4 induces selective inhibition of MAC-mediated lysis, allowing inhibition of red blood cell hemolysis and inhibition of complement deposition on apopto-necrotic cells, while maintaining efficient bactericidal activity of the complement terminal pathway. Finally, we present preliminary results indicating that sdAb_E4 may also be efficient in inhibiting hemolysis of erythrocytes from patients with paroxysmal nocturnal hemoglobinuria. Our data provide a proof of concept for the design of a selective MAC inhibitor capable of retaining complement bacteriolytic activity and this study opens up promising perspectives for the development of an sdAb_E4-derived therapeutics with application in the treatment of complement-mediated hemolytic disorders.
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Affiliation(s)
- Laure Yatime
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Nicolas S Merle
- Centre de Recherche des Cordeliers, INSERM, UMR_S 1138, Paris, France
| | | | - Niels Anton Friis
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.,Centre de Recherche des Cordeliers, INSERM, UMR_S 1138, Paris, France
| | - Jakob A Østergaard
- The Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus University, Aarhus, Denmark
| | - Mette Bjerre
- The Medical Research Laboratory, Department of Clinical Medicine, Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus University, Aarhus, Denmark
| | - Lubka T Roumenina
- Centre de Recherche des Cordeliers, INSERM, UMR_S 1138, Paris, France
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Peter Kristensen
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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41
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Heesterbeek DAC, Angelier ML, Harrison RA, Rooijakkers SHM. Complement and Bacterial Infections: From Molecular Mechanisms to Therapeutic Applications. J Innate Immun 2018; 10:455-464. [PMID: 30149378 DOI: 10.1159/000491439] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/21/2018] [Indexed: 12/22/2022] Open
Abstract
Complement is a complex protein network of plasma, and an integral part of the innate immune system. Complement activation results in the rapid clearance of bacteria by immune cells, and direct bacterial killing via large pore-forming complexes. Here we review important recent discoveries in the complement field, focusing on interactions relevant for the defense against bacteria. Understanding the molecular interplay between complement and bacteria is of great importance for future therapies for infectious and inflammatory diseases. Antibodies that support complement-dependent bacterial killing are of interest for the development of alternative therapies to treat infections with antibiotic-resistant bacteria. Furthermore, a variety of novel therapeutic complement inhibitors have been developed to prevent unwanted complement activation in autoimmune inflammatory diseases. A better understanding of how such inhibitors may increase the risk of bacterial infections is essential if such therapies are to be successful.
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Affiliation(s)
- Dani A C Heesterbeek
- Department of Medical Microbiology, Utrecht University Medical Center, Utrecht, The Netherlands
| | - Mathieu L Angelier
- Department of Medical Microbiology, Utrecht University Medical Center, Utrecht, The Netherlands
| | - Richard A Harrison
- Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
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42
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Zelek WM, Stott M, Walters D, Harris CL, Morgan BP. Characterizing a pH-switch anti-C5 antibody as a tool for human and mouse complement C5 purification and cross-species inhibition of classical and reactive lysis. Immunology 2018; 155:396-403. [PMID: 29981529 PMCID: PMC6187208 DOI: 10.1111/imm.12982] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/26/2018] [Accepted: 06/29/2018] [Indexed: 12/17/2022] Open
Abstract
C5 plays a major role in complement activation; C5 convertase cleaves C5 into the pro‐inflammatory C5a, and C5b, the nidus for the formation of the lytic membrane attack complex. C5 is a major target for anti‐complement drugs, necessitating better methods for the study of C5 function. Purification of C5 is complicated; classical methods involve precipitation or pH shifts that result in functional loss and low yield. We here present a method for C5 purification using a novel anti‐C5 monoclonal antibody (mAb); RO7112689 (C5i mAb, SKY59), pH‐switch engineered to induce antibody–antigen dissociation in the acidic endosome (~ pH 5·5). RO7112689 was bound on an affinity column; applied serum was completely depleted of C5. Elution at pH 5 produced fully active C5 at 98% yield. The mAb also bound C5b in the C5b6 complex, preventing C5b6 binding to target membranes and enabling purification of C5b6 from activated serum. RO7112689 inhibited C5 in mouse serum and efficiently purified mouse C5. Used as capture, RO7112689 produced sensitive and specific assays for human and mouse C5. This novel antibody enables efficient production of intact, fully active, pure human and mouse C5, and quantification of C5 in these species. The demonstration that RO7112689 binds C5b6 adds an additional mechanism of membrane attack complex inhibition by this mAb.
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Affiliation(s)
- Wioleta M Zelek
- Systems Immunity Research Institute and Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, UK
| | - Matthew Stott
- Systems Immunity Research Institute and Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, UK
| | - David Walters
- Systems Immunity Research Institute and Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, UK
| | - Claire L Harris
- Institute of Cellular Medicine, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - B Paul Morgan
- Systems Immunity Research Institute and Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, UK
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43
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Zwarthoff SA, Berends ETM, Mol S, Ruyken M, Aerts PC, Józsi M, de Haas CJC, Rooijakkers SHM, Gorham RD. Functional Characterization of Alternative and Classical Pathway C3/C5 Convertase Activity and Inhibition Using Purified Models. Front Immunol 2018; 9:1691. [PMID: 30083158 PMCID: PMC6064732 DOI: 10.3389/fimmu.2018.01691] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/10/2018] [Indexed: 12/24/2022] Open
Abstract
Complement is essential for the protection against infections; however, dysregulation of complement activation can cause onset and progression of numerous inflammatory diseases. Convertase enzymes play a central role in complement activation and produce the key mediators of complement: C3 convertases cleave C3 to generate chemoattractant C3a and label target cells with C3b, which promotes phagocytosis; C5 convertases cleave C5 into chemoattractant C5a, and C5b, which drives formation of the membrane attack complex. Since convertases mediate nearly all complement effector functions, they are ideal targets for therapeutic complement inhibition. A unique feature of convertases is their covalent attachment to target cells, which effectively confines complement activation to the cell surface. However, surface localization precludes detailed analysis of convertase activation and inhibition. In our previous work, we developed a model system to form purified alternative pathway (AP) C5 convertases on C3b-coated beads and quantify C5 conversion via functional analysis of released C5a. Here, we developed a C3aR cell reporter system that enables functional discrimination between C3 and C5 convertases. By regulating the C3b density on the bead surface, we observe that high C3b densities are important for conversion of C5, but not C3, by AP convertases. Screening of well-characterized complement-binding molecules revealed that differential inhibition of AP C3 convertases (C3bBb) and C5 convertases [C3bBb(C3b)n] is possible. Although both convertases contain C3b, the C3b-binding molecules Efb-C/Ecb and FHR5 specifically inhibit C5 conversion. Furthermore, using a new classical pathway convertase model, we show that these C3b-binding proteins not only block AP C3/C5 convertases but also inhibit formation of a functional classical pathway C5 convertase under well-defined conditions. Our models enable functional characterization of purified convertase enzymes and provide a platform for the identification and development of specific convertase inhibitors for treatment of complement-mediated disorders.
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Affiliation(s)
- Seline A Zwarthoff
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Evelien T M Berends
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Sanne Mol
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Maartje Ruyken
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Piet C Aerts
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Mihály Józsi
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Carla J C de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Suzan H M Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Ronald D Gorham
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
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44
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Macpherson A, Liu X, Dedi N, Kennedy J, Carrington B, Durrant O, Heywood S, van den Elsen J, Lawson ADG. The rational design of affinity-attenuated OmCI for the purification of complement C5. J Biol Chem 2018; 293:14112-14121. [PMID: 30030376 PMCID: PMC6130949 DOI: 10.1074/jbc.ra118.004043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/03/2018] [Indexed: 12/04/2022] Open
Abstract
Complement component C5 is the target of the mAb eculizumab and is the focus of a sustained drug discovery effort to prevent complement-induced inflammation in a range of autoimmune diseases. The immune evasion protein OmCI binds to and potently inactivates C5; this tight-binding interaction can be exploited to affinity-purify C5 protein from serum, offering a vastly simplified protocol compared with existing methods. However, breaking the high-affinity interaction requires conditions that risk denaturing or activating C5. We performed structure-guided in silico mutagenesis to identify prospective OmCI residues that contribute significantly to the binding affinity. We tested our predictions in vitro, using site-directed mutagenesis, and characterized mutants using a range of biophysical techniques, as well as functional assays. Our biophysical analyses suggest that the C5–OmCI interaction is complex with potential for multiple binding modes. We present single mutations that lower the affinity of OmCI for C5 and combinations of mutations that significantly decrease or entirely abrogate formation of the complex. The affinity-attenuated forms of OmCI are suitable for affinity purification and allow elution under mild conditions that are nondenaturing or activating to C5. We present the rational design, biophysical characterization, and experimental validation of affinity-reduced forms of OmCI as tool reagents to enable the affinity purification of C5.
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Affiliation(s)
- Alex Macpherson
- From the UCB-Celltech, Slough SL1 3WE, United Kingdom and .,the Department of Biology and Biochemistry, University of Bath, Bath BA2 7AX, United Kingdom
| | - Xiaofeng Liu
- From the UCB-Celltech, Slough SL1 3WE, United Kingdom and
| | - Neesha Dedi
- From the UCB-Celltech, Slough SL1 3WE, United Kingdom and
| | | | | | - Oliver Durrant
- From the UCB-Celltech, Slough SL1 3WE, United Kingdom and
| | - Sam Heywood
- From the UCB-Celltech, Slough SL1 3WE, United Kingdom and
| | - Jean van den Elsen
- the Department of Biology and Biochemistry, University of Bath, Bath BA2 7AX, United Kingdom
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45
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Zewde N, Morikis D. A computational model for the evaluation of complement system regulation under homeostasis, disease, and drug intervention. PLoS One 2018; 13:e0198644. [PMID: 29874282 PMCID: PMC5991421 DOI: 10.1371/journal.pone.0198644] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/22/2018] [Indexed: 12/21/2022] Open
Abstract
The complement system is an intricate defense network that rapidly removes invading pathogens. Although many complement regulators are present to protect host cells under homeostasis, the impairment of Factor H (FH) regulatory mechanism has been associated with several autoimmune and inflammatory diseases. To understand the dynamics involved in the pivotal balance between activation and regulation, we have developed a comprehensive computational model of the alternative and classical pathways of the complement system. The model is composed of 290 ordinary differential equations with 142 kinetic parameters that describe the state of complement system under homeostasis and disorder through FH impairment. We have evaluated the state of the system by generating concentration-time profiles for the biomarkers C3, C3a-desArg, C5, C5a-desArg, Factor B (FB), Ba, Bb, and fC5b-9 that are influenced by complement dysregulation. We show that FH-mediated disorder induces substantial levels of complement activation compared to homeostasis, by generating reduced levels of C3 and FB, and to a lesser extent C5, and elevated levels of C3a-desArg, Ba, Bb, C5a-desArg, and fC5b-9. These trends are consistent with clinically observed biomarkers associated with complement-mediated diseases. Furthermore, we introduced therapy states by modeling known inhibitors of the complement system, a compstatin variant (C3 inhibitor) and eculizumab (C5 inhibitor). Compstatin demonstrates strong restorative effects for early-stage biomarkers, such as C3a-desArg, FB, Ba, and Bb, and milder restorative effects for late-stage biomarkers, such as C5a-desArg and fC5b-9, whereas eculizumab has strong restorative effects on late-stage biomarkers, and negligible effects on early-stage biomarkers. These results highlight the need for patient-tailored therapies that target early complement activation at the C3 level, or late-stage propagation of the terminal cascade at the C5 level, depending on the specific FH-mediated disease and the manifestations of a patient's genetic profile in complement regulatory function.
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Affiliation(s)
- Nehemiah Zewde
- Department of Bioengineering, University of California, Riverside, California, United States of America
| | - Dimitrios Morikis
- Department of Bioengineering, University of California, Riverside, California, United States of America
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46
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Jensen RK, Pihl R, Gadeberg TAF, Jensen JK, Andersen KR, Thiel S, Laursen NS, Andersen GR. A potent complement factor C3-specific nanobody inhibiting multiple functions in the alternative pathway of human and murine complement. J Biol Chem 2018; 293:6269-6281. [PMID: 29497000 PMCID: PMC5925797 DOI: 10.1074/jbc.ra117.001179] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/07/2018] [Indexed: 12/30/2022] Open
Abstract
The complement system is a complex, carefully regulated proteolytic cascade for which suppression of aberrant activation is of increasing clinical relevance, and inhibition of the complement alternative pathway is a subject of intense research. Here, we describe the nanobody hC3Nb1 that binds to multiple functional states of C3 with subnanomolar affinity. The nanobody causes a complete shutdown of alternative pathway activity in human and murine serum when present in concentrations comparable with that of C3, and hC3Nb1 is shown to prevent proconvertase assembly, as well as binding of the C3 substrate to C3 convertases. Our crystal structure of the C3b-hC3Nb1 complex and functional experiments demonstrate that proconvertase formation is blocked by steric hindrance between the nanobody and an Asn-linked glycan on complement factor B. In addition, hC3Nb1 is shown to prevent factor H binding to C3b, rationalizing its inhibition of factor I activity. Our results identify hC3Nb1 as a versatile, inexpensive, and powerful inhibitor of the alternative pathway in both human and murine in vitro model systems of complement activation.
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Affiliation(s)
| | - Rasmus Pihl
- Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
| | | | - Jan K. Jensen
- From the Departments of Molecular Biology and Genetics and
| | | | - Steffen Thiel
- Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
| | | | - Gregers R. Andersen
- From the Departments of Molecular Biology and Genetics and , To whom correspondence should be addressed:
Dept. of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark. Tel.:
45-5144-6530; Fax:
45-8619-6500; E-mail:
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47
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Sheridan D, Yu ZX, Zhang Y, Patel R, Sun F, Lasaro MA, Bouchard K, Andrien B, Marozsan A, Wang Y, Tamburini P. Design and preclinical characterization of ALXN1210: A novel anti-C5 antibody with extended duration of action. PLoS One 2018; 13:e0195909. [PMID: 29649283 PMCID: PMC5897016 DOI: 10.1371/journal.pone.0195909] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 04/02/2018] [Indexed: 11/24/2022] Open
Abstract
Eculizumab, a monoclonal antibody (mAb) directed against complement protein C5, is considered to be the current standard of care for patients with paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome. This study describes the generation and preclinical attributes of ALXN1210, a new long-acting anti-C5 mAb, obtained through select modifications to eculizumab to both largely abolish target-mediated drug disposition (TMDD) and increase recycling efficiency via the neonatal Fc receptor (FcRn). To attenuate the effect of TMDD on plasma terminal half-life (t1/2), histidine substitutions were engineered into the complementarity-determining regions of eculizumab to enhance the dissociation rate of the mAb:C5 complex in the acidic early endosome relative to the slightly basic pH of blood. Antibody variants with optimal pH-dependent binding to C5 exhibited little to no TMDD in mice in the presence of human C5. To further enhance the efficiency of FcRn-mediated recycling of the antibody, two additional substitutions were introduced to increase affinity for human FcRn. These substitutions yielded an additional doubling of the t½ of surrogate anti-mouse C5 antibodies with reduced TMDD in transgenic mice expressing the human FcRn. In conclusion, ALXN1210 is a promising new therapeutic candidate currently in clinical development for treatment of patients with PNH and atypical hemolytic uremic syndrome.
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Affiliation(s)
- Douglas Sheridan
- Research, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
- * E-mail:
| | - Zhao-Xue Yu
- Research, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
| | - Yuchun Zhang
- Research, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
| | - Rekha Patel
- Product Characterization, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
| | - Fang Sun
- Research, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
| | - Melissa A. Lasaro
- Research, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
| | - Keith Bouchard
- Research, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
| | - Bruce Andrien
- Early Assay Development, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
| | - Andre Marozsan
- Research, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
| | - Yi Wang
- Research, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
| | - Paul Tamburini
- Research, Alexion Pharmaceuticals, Inc., New Haven, Connecticut, United States of America
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48
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Hansen SB, Laursen NS, Andersen GR, Andersen KR. Introducing site-specific cysteines into nanobodies for mercury labelling allows de novo phasing of their crystal structures. Acta Crystallogr D Struct Biol 2017; 73:804-813. [PMID: 28994409 PMCID: PMC5633906 DOI: 10.1107/s2059798317013171] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 09/14/2017] [Indexed: 11/10/2022] Open
Abstract
The generation of high-quality protein crystals and the loss of phase information during an X-ray crystallography diffraction experiment represent the major bottlenecks in the determination of novel protein structures. A generic method for introducing Hg atoms into any crystal independent of the presence of free cysteines in the target protein could considerably facilitate the process of obtaining unbiased experimental phases. Nanobodies (single-domain antibodies) have recently been shown to promote the crystallization and structure determination of flexible proteins and complexes. To extend the usability of nanobodies for crystallographic work, variants of the Nb36 nanobody with a single free cysteine at one of four framework-residue positions were developed. These cysteines could be labelled with fluorophores or Hg. For one cysteine variant (Nb36-C85) two nanobody structures were experimentally phased using single-wavelength anomalous dispersion (SAD) and single isomorphous replacement with anomalous signal (SIRAS), taking advantage of radiation-induced changes in Cys-Hg bonding. Importantly, Hg labelling influenced neither the interaction of Nb36 with its antigen complement C5 nor its structure. The results suggest that Cys-Hg-labelled nanobodies may become efficient tools for obtaining de novo phase information during the structure determination of nanobody-protein complexes.
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Affiliation(s)
- Simon Boje Hansen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus, Denmark
| | - Nick Stub Laursen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus, Denmark
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus, Denmark
| | - Kasper R. Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus, Denmark
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49
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Nilsson PH, Thomas AM, Bergseth G, Gustavsen A, Volokhina EB, van den Heuvel LP, Barratt-Due A, Mollnes TE. Eculizumab-C5 complexes express a C5a neoepitope in vivo: Consequences for interpretation of patient complement analyses. Mol Immunol 2017; 89:111-114. [DOI: 10.1016/j.molimm.2017.05.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 02/07/2023]
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50
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Schatz-Jakobsen JA, Pedersen DV, Andersen GR. Structural insight into proteolytic activation and regulation of the complement system. Immunol Rev 2017; 274:59-73. [PMID: 27782336 DOI: 10.1111/imr.12465] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complement system is a highly complex and carefully regulated proteolytic cascade activated through three different pathways depending on the activator recognized. The structural knowledge regarding the intricate proteolytic enzymes that activate and control complement has increased dramatically over the last decade. This development has been pivotal for understanding how mutations within complement proteins might contribute to pathogenesis and has spurred new strategies for development of complement therapeutics. Here we describe and discuss the complement system from a structural perspective and integrate the most recent findings obtained by crystallography, small-angle X-ray scattering, and electron microscopy. In particular, we focus on the proteolytic enzymes governing activation and their products carrying the biological effector functions. Additionally, we present the structural basis for some of the best known complement inhibitors. The large number of accumulated molecular structures enables us to visualize the relative size, position, and overall orientation of many of the most interesting complement proteins and assembled complexes on activator surfaces and in membranes.
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Affiliation(s)
| | - Dennis V Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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