Project: Development of monoclonal antibody-based passive immune therapy and companion diagnostics for severe Klebsiella infections

The major aim of the project is to discover product candidates for the subsequent development of novel life-saving treatments for patients suffering from severe infections caused by the Gram negative Klebsiella pneumoniae bacterium. The appearance of drug resistant Klebsiella strains in our hospitals induces great fear, because it threatens the lives of vulnerable patients and newborn babies._x000D__x000D_Our scientific concept is to apply passive immunization with human antibodies to aid the elimination of the bacteria from infected patients. The technology basis of the approach is the discovery of human monoclonal antibodies using well defined bacterial components. For the quick identification of the most relevant Klebsiella strains, the consortium will develop assays suitable for the development of companion diagnostics. In addition to therapeutic and diagnostic product candidates, the consortium will generate invaluable information regarding the human immune response to Klebsiella, the genomic and biochemical basis of surface structure variability and epidemiology._x000D__x000D_The emergence of multi-drug-resistant bacteria is a great and continually growing challenge for the healthcare systems. Particularly, nosocomial infections are getting out of control, resulting in reduced patient survival and greatly increased healthcare costs. Current antibiotics are not able to keep nosocomial infections under control, and novel ones are marketed at a falling rate, and expected to only delay the problem of multi- and pan-drug resistance. Klebsiella pneumoniae is among the most important Gram-negative nosocomial pathogens, based on its frequency, antibiotic resistance rate and severity of infections. Lethality rate of severe bloodstream infections (BSI) and hospital associated pneumonia (HAP), including ventilation associated pneumonia (VAP) in intensive care units (ICUs) can reach up to 65%._x000D__x000D_Since toxins are not of primary importance in Klebsiella pathogenesis, protective antibodies need to bind to the surface of Klebsiella and induce the elimination of the bacterium by the complement and/or the immune system. The first CO activity of the consortium will be to develop diagnostic assays for the detection of different Klebsiella serotype strains that are responsible for the most severe infections. Two complementary methods will be applied in parallel; one will be based on genome sequencing of clinical isolates and the other on serotype specific antibodies generated in animals. These assays will allow characterization of clinical isolates collected from patients suffering from drug resistant Klebsiella infections. The most relevant surface components will be used for the generation of monoclonal antibodies by two different methods. Human B cells from intestinal and blood samples will be screened for specificity to Klebsiella surface antigens (using highly purified and labeled bacterial components) and their antibody genes will be cloned and expressed in mammalian cell lines. In parallel, monoclonal antibodies will be also obtained from immunized animals by B cell cloning and/or phage display approach. Monoclonal antibodies will be pre-screened in vitro for antibacterial effect (direct killing and opsonophagocytosis) and then tested in animal models to measure protection from lethal Klebsiella infections. Animal derived lead antibodies will be humanized to avoid immunogenicity in humans. _x000D__x000D_There are no such diagnostic and therapeutic products on the market or even in development (to our knowledge) that are aimed by this consortium. The number of patients eligible for a new therapy we propose here is continuously growing due to the increasing aging and vulnerable populations and the spread of antibiotic resistant strains. The market potential of the proposed therapeutic mAb and companion diagnostics together is estimated to be > 300 million EUR peak sales worldwide._x000D__x000D_The consortium consists of four members each contributing with unique expertise to the overall goal of this multi-disciplinary project. The consortium leader Arsanis Biosciences, Austria is a biotechnology company dedicated to the development of human monoclonal antibody based prophylaxis and therapies against severe infectious diseases. GATC Biotech, Constance, Germany is Europe’s leading service provider of DNA sequencing and bioinformatics with focus on the continuous development and improvement of the latest technologies. Hedda Wardemann from the Max Planck Institute for Infectious Biology, Germany is a leading scientist in the field of characterization of human antibody diversity and her group is mastering the efficient cloning and expression of antibodies from single human B cells. Jolanta Lukasiewicz at the Institute of Immunology and Experimental Therapy, Wroclaw, Poland, is an expert in structural and biochemical analysis of bacterial carbohydrates and characterization of the protective immune response given to bacterial surface components._x000D__x000D_

Acronym	KLEBSICURE (Reference Number: 7563)
Duration	01/08/2012 - 31/07/2015
Project Topic	The consortium is aiming to develop a human monoclonal antibody based passive immunization against fast emerging multi-drug resistant Klebsiella infections that are associated with high lethality in hospitals. To identify patients for the therapy, quick companion diagnostics will be also developed.
Project Results (after finalisation)	O-serotyping of Klebsiella pneumoniae was established using immunological (i.e. mAbs), genotypic (i.e. PCR), and structural (i.e. NMR) analysis. These typing assays were validated on a large panel of clinical isolates collected from various geographical regions. Based on these epidemiology studies the O-type distribution of drug resistant clinical isolates was established, which guided development of mAbs as therapeutic product candidates. Accordingly, the consortium aimed at selection of 3 classes of mAbs with specificities to O1, O3 and galactan-III, a novel serotype discovered during this work._x000D_Lead candidates for all three projects have been nominated. Humanized murine mAbs deriving from a hybridoma platform were benchmarked against fully human mAbs selected from a B-cell platform. Against the galactan-III antigen a humanized mAb with a novel mode of action was selected, while in case of the O1 and O3 antigens the fully human mAbs outperformed the humanized mAbs. For the latter mAbs licensing for further development between the consortium Ps have been initiated. _x000D_Protection in murine models was shown for all lead mAbs. Mode of action for protection was elucidated by in vitro assays as well as using appropriate animal models. All mAbs were expressed in eukaryotic cell lines, and manufacturability testing for further development has started._x000D_The supportive research activities focused on the characterization of the novel serotypes identified, genetic background for identified O-antigen modifications, and epitope mapping for the selected antibodies, as well as the nature of the immune response against specific Klebsiella O-types._x000D_
Network	Eurostars
Call	Eurostars Cut-Off 8

Project partner

Number	Name	Role	Country
4	Arsanis Biosciences GmbH	Coordinator	Austria
4	GATC Biotech AG	Partner	Germany
4	Ludwik Hirszfeld Institute of Immunology and Experimental Therapy	Partner	Poland
4	MAX PLANCK GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN E.V.	Partner	Germany