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Hilliard JJ, Jakielaszek C, Mannino F, Hossain M, Qian L, Fishman C, Demons S, Hershfield J, Soffler C, Russo R, Henning L, Novak J, O'Dwyer K. Efficacy of therapeutically administered gepotidacin in a rabbit model of inhalational anthrax. Antimicrob Agents Chemother 2024; 68:e0149723. [PMID: 38358266 PMCID: PMC10916377 DOI: 10.1128/aac.01497-23] [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] [Received: 11/14/2023] [Accepted: 01/17/2024] [Indexed: 02/16/2024] Open
Abstract
Bacillus anthracis is a Gram-positive Centers for Disease Control and Prevention category "A" biothreat pathogen. Without early treatment, inhalation of anthrax spores with progression to inhalational anthrax disease is associated with high fatality rates. Gepotidacin is a novel first-in-class triazaacenaphthylene antibiotic that inhibits bacterial DNA replication by a distinct mechanism of action and is being evaluated for use against biothreat and conventional pathogens. Gepotidacin selectively inhibits bacterial DNA replication via a unique binding mode and has in vitro activity against a collection of B. anthracis isolates including antibacterial-resistant strains, with the MIC90 ranging from 0.5 to 1 µg/mL. In vivo activity of gepotidacin was also evaluated in the New Zealand White rabbit model of inhalational anthrax. The primary endpoint was survival, with survival duration and bacterial clearance as secondary endpoints. The trigger for treatment was the presence of anthrax protective antigen in serum. New Zealand White rabbits were dosed intravenously for 5 days with saline or gepotidacin at 114 mg/kg/d to simulate a dosing regimen of 1,000 mg intravenous (i.v.) three times a day (TID) in humans. Gepotidacin provided a survival benefit compared to saline control, with 91% survival (P-value: 0.0001). All control animals succumbed to anthrax and were found to be blood- and organ culture-positive for B. anthracis. The novel mode of action, in vitro microbiology, preclinical safety, and animal model efficacy data, which were generated in line with Food and Drug Administration Animal Rule, support gepotidacin as a potential treatment for anthrax in an emergency biothreat situation.
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Affiliation(s)
| | | | | | | | - Lian Qian
- GSK, Collegeville, Pennsylvania, USA
| | | | - Samandra Demons
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA
| | - Jeremy Hershfield
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA
| | - Carl Soffler
- US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA
| | - Riccardo Russo
- Rutgers University School of Medicine, Newark, New Jersey, USA
| | - Lisa Henning
- Battelle Biomedical Research Center (BBRC), Columbus, Ohio, USA
| | - Joseph Novak
- Battelle Biomedical Research Center (BBRC), Columbus, Ohio, USA
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2
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Kharga K, Kumar L, Patel SKS. Recent Advances in Monoclonal Antibody-Based Approaches in the Management of Bacterial Sepsis. Biomedicines 2023; 11:biomedicines11030765. [PMID: 36979744 PMCID: PMC10045367 DOI: 10.3390/biomedicines11030765] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/21/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Sepsis is a life-threatening condition characterized by an uncontrolled inflammatory response to an infectious agent and its antigens. Immune cell activation against the antigens causes severe distress that mediates a strong inflammatory response in vital organs. Sepsis is responsible for a high rate of morbidity and mortality in immunosuppressed patients. Monoclonal antibody (mAb)-based therapeutic strategies are now being explored as a viable therapy option for severe sepsis and septic shock. Monoclonal antibodies may provide benefits through two major strategies: (a) monoclonal antibodies targeting the pathogen and its components, and (b) mAbs targeting inflammatory signaling may directly suppress the production of inflammatory mediators. The major focus of mAb therapies has been bacterial endotoxin (lipopolysaccharide), although other surface antigens are also being investigated for mAb therapy. Several promising candidates for mAbs are undergoing clinical trials at present. Despite several failures and the investigation of novel targets, mAb therapy provides a glimmer of hope for the treatment of severe bacterial sepsis and septic shock. In this review, mAb candidates, their efficacy against controlling infection, with special emphasis on potential roadblocks, and prospects are discussed.
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Affiliation(s)
- Kusum Kharga
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan 173229, Himachal Pradesh, India
| | - Lokender Kumar
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan 173229, Himachal Pradesh, India
- Cancer Biology Laboratory, Raj Khosla Centre for Cancer Research, Shoolini University, Solan 173229, Himachal Pradesh, India
- Correspondence: (L.K.); (S.K.S.P.)
| | - Sanjay Kumar Singh Patel
- Department of Chemical Engineering, Konkuk University, Seoul 05029, Republic of Korea
- Correspondence: (L.K.); (S.K.S.P.)
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Kammanadiminti S, Comer J, Meister G, Carnelley T, Toth D, Kodihalli S. Efficacy of ANTHRASIL (Anthrax Immune Globulin Intravenous (Human)) in rabbit and nonhuman primate models of inhalational anthrax: Data supporting approval under animal rule. PLoS One 2023; 18:e0283164. [PMID: 36930692 PMCID: PMC10022752 DOI: 10.1371/journal.pone.0283164] [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: 07/13/2022] [Accepted: 02/21/2023] [Indexed: 03/18/2023] Open
Abstract
To meet the requirements of the Animal Rule, the efficacy of monotherapy with ANTHRASIL® (Anthrax Immune Globulin Intravenous (Human)) for inhalational anthrax was evaluated in blinded studies using rabbit and nonhuman primate models. Animals in both studies were randomized to treatment groups exposed to ~ 200 LD50 Bacillus anthracis (Ames strain) spores by the aerosol route to induce inhalational anthrax. Rabbits (N = 50/group) were treated with either 15 U/kg ANTHRASIL or a volume-matching dose of IGIV after disease onset as determined by the detection of bacterial toxin in the blood. At the end of the study, survival rates were 2% (1 of 48) in the IGIV control group, and 26% (13 of 50) in the ANTHRASIL-treated group (p = 0.0009). Similarly, ANTHRASIL was effective in cynomolgus monkeys (N = 16/group) when administered therapeutically after the onset of toxemia, with 6% survival in the IGIV control and a dose-related increase in survival of 36%, 43%, and 70% with 7.5, 15 or 30 U/kg doses of ANTHRASIL, respectively. These studies formed the basis for approval of ANTHRASIL by FDA under the Animal Rule.
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Affiliation(s)
| | - Jason Comer
- Battelle Biomedical Research Center, Columbus, Ohio, United States of America
| | - Gabriel Meister
- Battelle Biomedical Research Center, Columbus, Ohio, United States of America
| | - Trevor Carnelley
- Emergent BioSolutions Canada (Previously Cangene Corporation), Winnipeg, MB, Canada
| | - Derek Toth
- Emergent BioSolutions Canada (Previously Cangene Corporation), Winnipeg, MB, Canada
| | - Shantha Kodihalli
- Emergent BioSolutions Canada (Previously Cangene Corporation), Winnipeg, MB, Canada
- * E-mail:
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4
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Zhang Y, Richards DS, Grotemeyer EN, Jackson TA, Schöneich C. Near-UV and Visible Light Degradation of Iron (III)-Containing Citrate Buffer: Formation of Carbon Dioxide Radical Anion via Fragmentation of a Sterically Hindered Alkoxyl Radical. Mol Pharm 2022; 19:4026-4042. [PMID: 36074094 DOI: 10.1021/acs.molpharmaceut.2c00501] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Citrate is a commonly used buffer in pharmaceutical formulations which forms complexes with adventitious metals such as Fe3+. Fe3+-citrate complexes can act as potent photosensitizers under near-UV and visible light exposure, and recent studies reported evidence for the photo-production of a powerful reductant, carbon dioxide radical anion (•CO2-), from Fe3+-citrate complexes (Subelzu, N.; Schöneich, N., Mol. Pharm. 2020, 17, 4163-4179). The mechanisms of •CO2- formation are currently unknown but must be established to devise strategies against •CO2- formation in pharmaceutical formulations which rely on the use of citrate buffer. In this study, we first established complementary evidence for the photolytic generation of •CO2- from Fe3+-citrate through spin trapping and electron paramagnetic resonance (EPR) spectroscopy, and subsequently used spin trapping in conjunction with tandem mass spectrometry (MS/MS) for mechanistic studies on the pathways of •CO2- formation. Experiments with stable isotope-labeled citrate suggest that the central carboxylate group of citrate is the major source of •CO2-. Competition studies with various inhibitors (alcohols and dimethyl sulfoxide) reveal two mechanisms of •CO2- formation, where one pathway involves β-cleavage of a sterically hindered alkoxyl radical generated from the hydroxyl group of citrate.
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Affiliation(s)
- Yilue Zhang
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
| | - David S Richards
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
| | - Elizabeth N Grotemeyer
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Timothy A Jackson
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
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Abstract
![]()
The paradigm of antivirulence
therapy dictates that bacterial pathogens
are specifically disarmed but not killed by neutralizing their virulence
factors. Clearance of the invading pathogen by the immune system is
promoted. As compared to antibiotics, the pathogen-selective antivirulence
drugs hold promise to minimize collateral damage to the beneficial
microbiome. Also, selective pressure for resistance is expected to
be lower because bacterial viability is not directly affected. Antivirulence
drugs are being developed for stand-alone prophylactic and therapeutic
treatments but also for combinatorial use with antibiotics. This Review
focuses on drug modalities that target bacterial exotoxins after the
secretion or release-upon-lysis. Exotoxins have a significant and
sometimes the primary role as the disease-causing virulence factor,
and thereby they are attractive targets for drug development. We describe
the key pre-clinical and clinical trial data that have led to the
approval of currently used exotoxin-targeted drugs, namely the monoclonal
antibodies bezlotoxumab (toxin B/TcdB, Clostridioides difficile), raxibacumab (anthrax toxin, Bacillus anthracis), and obiltoxaximab (anthrax toxin, Bacillus anthracis), but also to challenges with some of the promising leads. We also
highlight the recent developments in pre-clinical research sector
to develop exotoxin-targeted drug modalities, i.e., monoclonal antibodies,
antibody fragments, antibody mimetics, receptor analogs, neutralizing
scaffolds, dominant-negative mutants, and small molecules. We describe
how these exotoxin-targeted drug modalities work with high-resolution
structural knowledge and highlight their advantages and disadvantages
as antibiotic alternatives.
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Affiliation(s)
- Moona Sakari
- Institute of Biomedicine, Research Unit for Infection and Immunity, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
| | - Arttu Laisi
- Institute of Biomedicine, Research Unit for Infection and Immunity, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
| | - Arto T. Pulliainen
- Institute of Biomedicine, Research Unit for Infection and Immunity, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland
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Stratilo CW, Jager S, Crichton M, Blanchard JD. Evaluation of liposomal ciprofloxacin formulations in a murine model of anthrax. PLoS One 2020; 15:e0228162. [PMID: 31978152 PMCID: PMC6980410 DOI: 10.1371/journal.pone.0228162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/08/2020] [Indexed: 01/01/2023] Open
Abstract
The in vivo efficacy of liposomal encapsulated ciprofloxacin in two formulations, lipoquin and apulmiq, were evaluated against the causative agent of anthrax, Bacillus anthracis. Liposomal encapsulated ciprofloxacin is attractive as a therapy since it allows for once daily dosing and achieves higher concentrations of the antibiotic at the site of initial mucosal entry but lower systemic drug concentrations. The in vivo efficacy of lipoquin and apulmiq delivered by intranasal instillation was studied at different doses and schedules in both a post exposure prophylaxis (PEP) therapy model and in a delayed treatment model of murine inhalational anthrax. In the mouse model of infection, the survival curves for all treatment cohorts differed significantly from the vehicle control. Ciprofloxacin, lipoquin and apulmiq provided a high level of protection (87-90%) after 7 days of therapy when administered within 24 hours of exposure. Reducing therapy to only three days still provided protection of 60-87%, if therapy was provided within 24 hours of exposure. If treatment was initiated 48 hours after exposure the survival rate was reduced to 46-65%. These studies suggest that lipoquin and apulmiq may be attractive therapies as PEP and as part of a treatment cocktail for B. anthracis.
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Affiliation(s)
- Chad W. Stratilo
- Bio Threat Defence Section, Suffield Research Centre, Defence Research and Development Canada, Ralston, Alberta, Canada
- * E-mail:
| | - Scott Jager
- Bio Threat Defence Section, Suffield Research Centre, Defence Research and Development Canada, Ralston, Alberta, Canada
| | - Melissa Crichton
- Bio Threat Defence Section, Suffield Research Centre, Defence Research and Development Canada, Ralston, Alberta, Canada
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7
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Zabihi E, Babaei A, Shahrampour D, Arab-Bafrani Z, Mirshahidi KS, Majidi HJ. Facile and rapid in-situ synthesis of chitosan-ZnO nano-hybrids applicable in medical purposes; a novel combination of biomineralization, ultrasound, and bio-safe morphology-conducting agent. Int J Biol Macromol 2019; 131:107-116. [DOI: 10.1016/j.ijbiomac.2019.01.224] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/01/2019] [Accepted: 01/16/2019] [Indexed: 11/25/2022]
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8
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Solano MI, Woolfitt AR, Boyer AE, Lins RC, Isbell K, Gallegos-Candela M, Moura H, Pierce CL, Barr JR. Accurate and selective quantification of anthrax protective antigen in plasma by immunocapture and isotope dilution mass spectrometry. Analyst 2019; 144:2264-2274. [PMID: 30810119 PMCID: PMC7015108 DOI: 10.1039/c8an02479k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Anthrax protective antigen (83 kDa, PA83) is an essential component of two major binary toxins produced by Bacillus anthracis, lethal toxin (LTx) and edema toxin (ETx). During infection, LTx and ETx contribute to immune collapse, endothelial dysfunction, hemorrhage and high mortality. Following protease cleavage on cell receptors or in circulation, the 20 kDa (PA20) N-terminus is released, activating the 63 kDa (PA63) form which binds lethal factor (LF) and edema factor (EF), facilitating their entry into their cellular targets. Several ELISA-based PA methods previously developed are primarily qualitative or semi-quantitative. Here, we combined protein immunocapture, tryptic digestion and isotope dilution liquid chromatography-mass spectrometry (LC-MS/MS), to develop a highly selective and sensitive method for detection and accurate quantification of total-PA (PA83 + PA63) and PA83. Two tryptic peptides in the 63 kDa region measure total-PA and three in the 20 kDa region measure PA83 alone. Detection limits range from 1.3-2.9 ng mL-1 PA in 100 μL of plasma. Spiked recovery experiments with combinations of PA83, PA63, LF and EF in plasma showed that PA63 and PA83 were quantified accurately against the PA83 standard and that LF and EF did not interfere with accuracy. Applied to a study of inhalation anthrax in rhesus macaques, total-PA suggested triphasic kinetics, similar to that previously observed for LF and EF. This study is the first to report circulating PA83 in inhalation anthrax, typically at less than 4% of the levels of PA63, providing the first evidence that activated PA63 is the primary form of PA throughout infection.
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Affiliation(s)
- Maria I Solano
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta, GA 30341, USA.
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9
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Zhang D, Liu W, Wen Z, Li B, Liu S, Li J, Chen W. Establishment of a New Zealand White Rabbit Model for Lethal Toxin (LT) Challenge and Efficacy of Monoclonal Antibody 5E11 in the LT-Challenged Rabbit Model. Toxins (Basel) 2018; 10:E289. [PMID: 30002351 PMCID: PMC6071005 DOI: 10.3390/toxins10070289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 07/09/2018] [Indexed: 12/23/2022] Open
Abstract
Anthrax caused by Bacillus anthracis is a lethal infectious disease, especially when inhaled, and the mortality rate approaches 100% without treatment. The anthrax antitoxin monoclonal antibody (MAb) 5E11 is a humanized antibody that targets the anthrax protective antigen (PA). The efficacy of 5E11 needs proper animal models. However, anthrax spores are extremely dangerous, so experiments must be conducted under Biosafety Level 3 conditions. Considering the critical effects of lethal toxin (LT) on hosts during infection, we report the establishment of a LT-challenged rabbit model, which caused 100% mortality with a dose of 2 mg PA + 1 mg LF, while a 4 mg PA + 2 mg LF challenge could limit death to within three days. Then, we evaluated 5E11 efficacy against LT. A prophylactic study showed that the i.v. administration of 40 mg/kg 5E11 four days before lethal dose LT challenge could lead to 100% survival. In therapeutic studies, the i.v. administration of 40 mg/kg 5E11 10 min after lethal dose LT challenge could provide complete protection. Overall, we developed a new LT-challenged rabbit model, and our results indicate that 5E11 shows potential for the clinical application in anthrax treatment.
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Affiliation(s)
- Duanyang Zhang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, 20 Dongdajie Street, Fengtai District, Beijing 100071, China.
| | - Weicen Liu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, 20 Dongdajie Street, Fengtai District, Beijing 100071, China.
| | - Zhonghua Wen
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, 20 Dongdajie Street, Fengtai District, Beijing 100071, China.
| | - Bing Li
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, 20 Dongdajie Street, Fengtai District, Beijing 100071, China.
| | - Shuling Liu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, 20 Dongdajie Street, Fengtai District, Beijing 100071, China.
| | - Jianmin Li
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, 20 Dongdajie Street, Fengtai District, Beijing 100071, China.
| | - Wei Chen
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, 20 Dongdajie Street, Fengtai District, Beijing 100071, China.
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10
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Sécher T, Guilleminault L, Reckamp K, Amanam I, Plantier L, Heuzé-Vourc'h N. Therapeutic antibodies: A new era in the treatment of respiratory diseases? Pharmacol Ther 2018; 189:149-172. [PMID: 29730443 DOI: 10.1016/j.pharmthera.2018.05.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Respiratory diseases affect millions of people worldwide, and account for significant levels of disability and mortality. The treatment of lung cancer and asthma with therapeutic antibodies (Abs) is a breakthrough that opens up new paradigms for the management of respiratory diseases. Antibodies are becoming increasingly important in respiratory medicine; dozens of Abs have received marketing approval, and many more are currently in clinical development. Most of these Abs target asthma, lung cancer and respiratory infections, while very few target chronic obstructive pulmonary disease - one of the most common non-communicable causes of death - and idiopathic pulmonary fibrosis. Here, we review Abs approved for or in clinical development for the treatment of respiratory diseases. We notably highlight their molecular mechanisms, strengths, and likely future trends.
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Affiliation(s)
- T Sécher
- INSERM, Centre d'Etude des Pathologies Respiratoires, U1100, F-37032 Tours, France; Université François Rabelais de Tours, F-37032 Tours, France
| | - L Guilleminault
- Pôle des Voies respiratoires, Hôpital Larrey, CHU de Toulouse, F-31059 Toulouse, France; STROMALab, Université de Toulouse, CNRS ERL 5311, EFS, INP-ENVT, Inserm, UPS, F-31013 Toulouse, France
| | - K Reckamp
- City of Hope Comprehensive Cancer Center, Duarte, CA 91010, USA
| | - I Amanam
- City of Hope Comprehensive Cancer Center, Duarte, CA 91010, USA
| | - L Plantier
- INSERM, Centre d'Etude des Pathologies Respiratoires, U1100, F-37032 Tours, France; Université François Rabelais de Tours, F-37032 Tours, France; CHRU de Tours, Service de Pneumologie, F-37000 Tours, France
| | - N Heuzé-Vourc'h
- INSERM, Centre d'Etude des Pathologies Respiratoires, U1100, F-37032 Tours, France; Université François Rabelais de Tours, F-37032 Tours, France.
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Wang-Lin SX, Balthasar JP. Pharmacokinetic and Pharmacodynamic Considerations for the Use of Monoclonal Antibodies in the Treatment of Bacterial Infections. Antibodies (Basel) 2018; 7:antib7010005. [PMID: 31544858 PMCID: PMC6698815 DOI: 10.3390/antib7010005] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/01/2018] [Accepted: 01/02/2018] [Indexed: 12/17/2022] Open
Abstract
Antibiotic-resistant bacterial pathogens are increasingly implicated in hospital- and community-acquired infections. Recent advances in monoclonal antibody (mAb) production and engineering have led to renewed interest in the development of antibody-based therapies for treatment of drug-resistant bacterial infections. Currently, there are three antibacterial mAb products approved by the Food and Drug Administration (FDA) and at least nine mAbs are in clinical trials. Antibacterial mAbs are typically developed to kill bacteria or to attenuate bacterial pathological activity through neutralization of bacterial toxins and virulence factors. Antibodies exhibit distinct pharmacological mechanisms from traditional antimicrobials and, hence, cross-resistance between small molecule antimicrobials and antibacterial mAbs is unlikely. Additionally, the long biological half-lives typically found for mAbs may allow convenient dosing and vaccine-like prophylaxis from infection. However, the high affinity of mAbs and the involvement of the host immune system in their pharmacological actions may lead to complex and nonlinear pharmacokinetics and pharmacodynamics. In this review, we summarize the pharmacokinetics and pharmacodynamics of the FDA-approved antibacterial mAbs and those are currently in clinical trials. Challenges in the development of antibacterial mAbs are also discussed.
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Affiliation(s)
- Shun Xin Wang-Lin
- Department of Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14214, USA.
| | - Joseph P Balthasar
- Department of Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14214, USA.
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12
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Caldwell M, Hathcock T, Brock KV. Passive protection against anthrax in mice with plasma derived from horses hyper-immunized against Bacillus anthracis Sterne strain. PeerJ 2017; 5:e3907. [PMID: 29259839 PMCID: PMC5733894 DOI: 10.7717/peerj.3907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 09/19/2017] [Indexed: 11/20/2022] Open
Abstract
In this study, equine source polyclonal anti-Bacillus anthracis immunoglobulins were generated and utilized to demonstrate passive protection of mice in a lethal challenge assay. Four horses were hyper-immunized with B. anthracis Sterne strain for approximately one year. The geometric mean anti-PA titer in the horses at maximal response following immunization was 1:77,936 (Log2 mean titer 16.25, SEM ± 0.25 95% CI [15.5 -17.0]). The geometric mean neutralizing titer at maximal response was 1:128 (Log2 mean titer 7, SEM ± 0.0, 95% CI 7). Treatment with hyper-immune plasma or purified immunoglobulins was successful in passively protecting A/J mice from a lethal B. anthracis Sterne strain challenge. The treatment of mice with hyper-immune plasma at time 0 h and 24 h post-infection had no effect on survival, but did significantly increase mean time to death (p < 0.0001). Mice treated with purified immunoglobulins at time 0 h and 24 h post-infection in showed significant increase in survival rate (p < 0.001). Bacterial loads in lung, liver and spleen tissue were also assessed and were not significantly different in mice treated with hyper-immune plasma from placebo treated control mice. Mice treated with purified antibodies demonstrated mean colony forming units/gram tissue fourfold less than mice receiving placebo treatment (p < 0.0001). Immunotherapeutics harvested from horses immunized against B. anthracis Sterne strain represent a rapidly induced, inexpensive and effective expansion to the arsenal of treatments against anthrax.
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Affiliation(s)
- Marc Caldwell
- Department of Pathobiology, Auburn University, Auburn, AL, United States of America
| | - Terri Hathcock
- Department of Pathobiology, Auburn University, Auburn, AL, United States of America
| | - Kenny V. Brock
- Edward Via College of Osteopathic Medicine, Auburn University, Auburn, AL, United States of America
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Rubinson L, Corey A, Hanfling D. Estimation of Time Period for Effective Human Inhalational Anthrax Treatment Including Antitoxin Therapy. PLOS CURRENTS 2017; 9. [PMID: 28856066 PMCID: PMC5555766 DOI: 10.1371/currents.outbreaks.7896c43f69838f17ce1c2c372e79d55d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Introduction: Infrequent natural human inhalational anthrax cases coupled with high bioterrorism risk have brought about use of animal models to serve as the basis for approval of novel treatments. For inhalational anthrax, protective antigen (PA) drives much of the mortality, and raxibacumab, an anti-PA monoclonal antibody, has been approved for therapeutic use using the Animal Rule. Given the paucity of human inhalational anthrax clinical data including PA kinetics, the post-exposure period for effective treatment of human disease remains unknown. The objective of this investigation was to extrapolate animal PA kinetics to a conceptual human model to estimate the post-exposure period for effective treatment of human inhalational anthrax. Methods: Human PA kinetic parameters were extrapolated from reported rabbit and monkey data. PA profiles were simulated with and without antibiotic induced PA clearance to represent antibiotic-sensitive and -resistant infections, respectively. Antitoxin levels equimolar to or greater than concurrent PA levels were considered protective. Results: For antibiotic sensitive infections, treatment with antibiotics alone ≤4 days after spore exposure prevents toxemia. Administration of raxibacumab together with antibiotics protects ≥ 80% of subjects for 3 additional days (7 days post exposure). In the setting of antibiotic resistance, raxibacumab would be protective for at least 6 days post exposure. Conclusions: Although the animal model of disease does not reflect the potential impact of supportive care (e.g. fluid resuscitation received by critically ill patients) on PA kinetics and raxibacumab PK, the simulations suggest that administration of antitoxin in combination with antibiotics should provide a longer postexposure window for effective treatment than for antibiotics alone. In addition, raxibacumab administration soon after exposure to an antibiotic resistant strain should provide effective treatment.
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Affiliation(s)
- Lewis Rubinson
- University of Maryland School of Medicine, R Adams Cowley Shock Trauma Center, Program in Trauma Critical Care, Baltimore, MD, USA
| | | | - Dan Hanfling
- Johns Hopkins University, Center for Health Security, Baltimore, Maryland, USA; Department of Emergency Medicine, George Washington University, Washington, DC, USA
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Nagy CF, Mondick J, Serbina N, Casey LS, Carpenter SE, French J, Guttendorf R. Animal-to-Human Dose Translation of Obiltoxaximab for Treatment of Inhalational Anthrax Under the US FDA Animal Rule. Clin Transl Sci 2017; 10:12-19. [PMID: 27925405 PMCID: PMC5245108 DOI: 10.1111/cts.12433] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/07/2016] [Indexed: 12/14/2022] Open
Abstract
Obiltoxaximab, a monoclonal antibody against protective antigen (PA), is approved for treatment of inhalational anthrax under the US Food and Drug Administration's (FDA) Animal Rule. The human dose was selected and justified by comparing observed obiltoxaximab exposures in healthy and infected New Zealand White rabbits and cynomolgus macaques to observed exposures in healthy humans, to simulated exposures in healthy and infected humans, and to serum PA levels in infected animals. In humans, at 16 mg/kg intravenous, obiltoxaximab AUC was >2 times that in animals, while maximum serum concentrations were comparable to those in animals and were maintained in excess of the concentration required for PA neutralization in infected animals for 2-3 weeks. Obiltoxaximab 16 mg/kg in humans provided exposure beyond that of 16 mg/kg in animals, ensuring a sufficient duration of PA neutralization to allow for adaptive immunity development. Our approach to dose translation may be applicable to other agents being developed under the Animal Rule.
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Affiliation(s)
- CF Nagy
- Department of Clinical OperationsElusys Therapeutics, IncPine BrookNew JerseyUSA
| | - J Mondick
- Metrum Research Group LLCTariffvilleConnecticutUSA
| | - N Serbina
- Department of Research and Nonclinical Development, Elusys Therapeutics, IncPine BrookNew JerseyUSA
| | - LS Casey
- Department of Research and Nonclinical Development, Elusys Therapeutics, IncPine BrookNew JerseyUSA
| | - SE Carpenter
- Department of Research and Nonclinical Development, Elusys Therapeutics, IncPine BrookNew JerseyUSA
| | - J French
- Metrum Research Group LLCTariffvilleConnecticutUSA
| | - R Guttendorf
- Aclairo Pharmaceutical Development Group IncViennaVirginiaUSA
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15
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Efficacy Projection of Obiltoxaximab for Treatment of Inhalational Anthrax across a Range of Disease Severity. Antimicrob Agents Chemother 2016; 60:5787-95. [PMID: 27431222 PMCID: PMC5038317 DOI: 10.1128/aac.00972-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/06/2016] [Indexed: 01/14/2023] Open
Abstract
Inhalational anthrax has high mortality even with antibiotic treatment, and antitoxins are now recommended as an adjunct to standard antimicrobial regimens. The efficacy of obiltoxaximab, a monoclonal antibody against anthrax protective antigen (PA), was examined in multiple studies conducted in two animal models of inhalational anthrax. A single intravenous bolus of 1 to 32 mg/kg of body weight obiltoxaximab or placebo was administered to New Zealand White rabbits (two studies) and cynomolgus macaques (4 studies) at disease onset (significant body temperature increase or detection of serum PA) following lethal challenge with aerosolized Bacillus anthracis spores. The primary endpoint was survival. The relationship between efficacy and disease severity, defined by pretreatment bacteremia and toxemia levels, was explored. In rabbits, single doses of 1 to 16 mg/kg obiltoxaximab led to 17 to 93% survival. In two studies, survival following 16 mg/kg obiltoxaximab was 93% and 62% compared to 0% and 0% for placebo (P = 0.0010 and P = 0.0013, respectively). Across four macaque studies, survival was 6.3% to 78.6% following 4 to 32 mg/kg obiltoxaximab. In two macaque studies, 16 mg/kg obiltoxaximab reduced toxemia and led to survival rates of 31%, 35%, and 47% versus 0%, 0%, and 6.3% with placebo (P = 0.0085, P = 0.0053, P = 0.0068). Pretreatment bacteremia and toxemia levels inversely correlated with survival. Overall, obiltoxaximab monotherapy neutralized PA and increased survival across the range of disease severity, indicating clinical benefit of toxin neutralization with obiltoxaximab in both early and late stages of inhalational anthrax.
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16
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Singh VK, Garcia M, Wise SY, Seed TM. Medical countermeasures for unwanted CBRN exposures: Part I chemical and biological threats with review of recent countermeasure patents. Expert Opin Ther Pat 2016; 26:1431-1447. [DOI: 10.1080/13543776.2017.1233178] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Vijay K. Singh
- Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Melissa Garcia
- Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Stephen Y. Wise
- Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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17
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Huang E, Pillai SK, Bower WA, Hendricks KA, Guarnizo JT, Hoyle JD, Gorman SE, Boyer AE, Quinn CP, Meaney-Delman D. Antitoxin Treatment of Inhalation Anthrax: A Systematic Review. Health Secur 2016; 13:365-77. [PMID: 26690378 DOI: 10.1089/hs.2015.0032] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Concern about use of anthrax as a bioweapon prompted development of novel anthrax antitoxins for treatment. Clinical guidelines for the treatment of anthrax recommend antitoxin therapy in combination with intravenous antimicrobials; however, a large-scale or mass anthrax incident may exceed antitoxin availability and create a need for judicious antitoxin use. We conducted a systematic review of antitoxin treatment of inhalation anthrax in humans and experimental animals to inform antitoxin recommendations during a large-scale or mass anthrax incident. A comprehensive search of 11 databases and the FDA website was conducted to identify relevant animal studies and human reports: 28 animal studies and 3 human cases were identified. Antitoxin monotherapy at or shortly after symptom onset demonstrates increased survival compared to no treatment in animals. With early treatment, survival did not differ between antimicrobial monotherapy and antimicrobial-antitoxin therapy in nonhuman primates and rabbits. With delayed treatment, antitoxin-antimicrobial treatment increased rabbit survival. Among human cases, addition of antitoxin to combination antimicrobial treatment was associated with survival in 2 of the 3 cases treated. Despite the paucity of human data, limited animal data suggest that adjunctive antitoxin therapy may improve survival. Delayed treatment studies suggest improved survival with combined antitoxin-antimicrobial therapy, although a survival difference compared with antimicrobial therapy alone was not demonstrated statistically. In a mass anthrax incident with limited antitoxin supplies, antitoxin treatment of individuals who have not demonstrated a clinical benefit from antimicrobials, or those who present with more severe illness, may be warranted. Additional pathophysiology studies are needed, and a point-of-care assay correlating toxin levels with clinical status may provide important information to guide antitoxin use during a large-scale anthrax incident.
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18
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Ambrose EA. Botulinum Neurotoxin, Tetanus Toxin, and Anthrax Lethal Factor Countermeasures. TOPICS IN MEDICINAL CHEMISTRY 2016. [DOI: 10.1007/7355_2016_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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19
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Tsai CW, Morris S. Approval of Raxibacumab for the Treatment of Inhalation Anthrax Under the US Food and Drug Administration "Animal Rule". Front Microbiol 2015; 6:1320. [PMID: 26648915 PMCID: PMC4664625 DOI: 10.3389/fmicb.2015.01320] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/09/2015] [Indexed: 12/16/2022] Open
Abstract
On December 14, 2012, the FDA approved Raxibacumab, the first monoclonal antibody product developed under Project BioShield to achieve this milestone, and the first biologic product to be approved through the FDA animal efficacy rule (or “Animal Rule”). Raxibacumab is approved for the treatment of adult and pediatric patients with inhalational anthrax due to Bacillus anthracis in combination with appropriate antibiotic drugs and for prophylaxis of inhalational anthrax when alternative therapies are not available or not appropriate. The developmental process required for approval of Raxibacumab illustrates many of the challenges that product developers may encounter when pursuing approval under the Animal Rule and highlights a number of important regulatory and policy issues.
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Affiliation(s)
- Chia-Wei Tsai
- Biomedical Advanced Research and Development Authority, Office of the Assistant Secretary for Preparedness and Response, U.S. Department of Health and Human Services Washington, DC, USA
| | - Stephen Morris
- BioProtection Systems/NewLink Genetics Corp. Devens, MA, USA
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20
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Kurbanov EK, Chiu TL, Solberg J, Francis S, Maize KM, Fernandez J, Johnson RL, Hawkinson JE, Walters MA, Finzel BC, Amin EA. Probing the S2′ Subsite of the Anthrax Toxin Lethal Factor Using Novel N-Alkylated Hydroxamates. J Med Chem 2015; 58:8723-33. [DOI: 10.1021/acs.jmedchem.5b01446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elbek K. Kurbanov
- Department
of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Ting-Lan Chiu
- Department
of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Jonathan Solberg
- Institute
for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Subhashree Francis
- Institute
for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Kimberly M. Maize
- Department
of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Jenna Fernandez
- Department
of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Rodney L. Johnson
- Department
of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Jon E. Hawkinson
- Institute
for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Michael A. Walters
- Institute
for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Barry C. Finzel
- Department
of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Elizabeth Ambrose Amin
- Department
of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55414, United States
- Minnesota
Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455, United States
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21
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Passive Immunotherapy Protects against Enteric Invasion and Lethal Sepsis in a Murine Model of Gastrointestinal Anthrax. Toxins (Basel) 2015; 7:3960-76. [PMID: 26426050 PMCID: PMC4626714 DOI: 10.3390/toxins7103960] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 08/19/2015] [Indexed: 01/09/2023] Open
Abstract
The principal portal for anthrax infection in natural animal outbreaks is the digestive tract. Enteric exposure to anthrax, which is difficult to detect or prevent in a timely manner, could be exploited as an act of terror through contamination of human or animal food. Our group has developed a novel animal model of gastrointestinal (GI) anthrax for evaluation of disease pathogenesis and experimental therapeutics, utilizing vegetative Bacillus anthracis (Sterne strain) administered to A/J mice (a complement-deficient strain) by oral gavage. We hypothesized that a humanized recombinant monoclonal antibody (mAb) * that neutralizes the protective antigen (PA) component of B. anthracis lethal toxin (LT) and edema toxin (ET) could be an effective treatment. Although the efficacy of this anti-anthrax PA mAb has been shown in animal models of inhalational anthrax, its activity in GI infection had not yet been ascertained. We hereby demonstrate that passive immunotherapy with anti-anthrax PA mAb, administered at the same time as gastrointestinal exposure to B. anthracis, prevents lethal sepsis in nearly all cases (>90%), while a delay of up to forty-eight hours in treatment still greatly reduces mortality following exposure (65%). Moreover, passive immunotherapy protects against enteric invasion, associated mucosal injury and subsequent dissemination by gastrointestinal B. anthracis, indicating that it acts to prevent the initial stages of infection. * Expired raxibacumab being cycled off the Strategic National Stockpile; biological activity confirmed by in vitro assay.
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22
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Efficacy of Single and Combined Antibiotic Treatments of Anthrax in Rabbits. Antimicrob Agents Chemother 2015; 59:7497-503. [PMID: 26392505 DOI: 10.1128/aac.01376-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/14/2015] [Indexed: 02/07/2023] Open
Abstract
Respiratory anthrax is a fatal disease in the absence of early treatment with antibiotics. Rabbits are highly susceptible to infection with Bacillus anthracis spores by intranasal instillation, succumbing within 2 to 4 days postinfection. This study aims to test the efficiency of antibiotic therapy to treat systemic anthrax in this relevant animal model. Delaying the initiation of antibiotic administration to more than 24 h postinfection resulted in animals with systemic anthrax in various degrees of bacteremia and toxemia. As the onset of symptoms in humans was reported to start on days 1 to 7 postexposure, delaying the initiation of treatment by 24 to 48 h (time frame for mass distribution of antibiotics) may result in sick populations. We evaluated the efficacy of antibiotic administration as a function of bacteremia levels at the time of treatment initiation. Here we compare the efficacy of treatment with clarithromycin, amoxicillin-clavulanic acid (Augmentin), imipenem, vancomycin, rifampin, and linezolid to the previously reported efficacy of doxycycline and ciprofloxacin. We demonstrate that treatment with amoxicillin-clavulanic acid, imipenem, vancomycin, and linezolid were as effective as doxycycline and ciprofloxacin, curing rabbits exhibiting bacteremia levels of up to 10(5) CFU/ml. Clarithromycin and rifampin were shown to be effective only as a postexposure prophylactic treatment but failed to treat the systemic (bacteremic) phase of anthrax. Furthermore, we evaluate the contribution of combined treatment of clindamycin and ciprofloxacin, which demonstrated improvement in efficacy compared to ciprofloxacin alone.
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23
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Ohanjanian L, Remy KE, Li Y, Cui X, Eichacker PQ. An overview of investigational toxin-directed therapies for the adjunctive management of Bacillus anthracis infection and sepsis. Expert Opin Investig Drugs 2015; 24:851-65. [PMID: 25920540 DOI: 10.1517/13543784.2015.1041587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Sepsis with Bacillus anthracis infection has a very high mortality rate despite appropriate antibiotic and supportive therapies. Over the past 15 years, recent outbreaks in the US and in Europe, coupled with anthrax's bioterrorism weapon potential, have stimulated efforts to develop adjunctive therapies to improve clinical outcomes. Since lethal toxin and edema toxin (LT and ET) make central contributions to the pathogenesis of B. anthracis, these have been major targets in this effort. AREAS COVERED Here, the authors review different investigative biopharmaceuticals that have been recently identified for their therapeutic potential as inhibitors of LT or ET. Among these inhibitors are two antibody preparations that have been included in the Strategic National Stockpile (SNS) and several more that have reached Phase I testing. Presently, however, many of these candidate agents have only been studied in vitro and very few tested in bacteria-challenged models. EXPERT OPINION Although a large number of drugs have been identified as potential therapeutic inhibitors of LT and ET, in most cases their testing has been limited. The use of the two SNS antibody therapies during a large-scale exposure to B. anthracis will be difficult. Further testing and development of agents with oral bioavailability and relatively long shelf lives should be a focus for future research.
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Affiliation(s)
- Lernik Ohanjanian
- National Institutes of Health, Clinical Center, Critical Care Medicine Department , Building 10, Room 2C145, Bethesda, MD 20892 , USA +1 301 402 2914 ; +1 301 402 1213 ;
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24
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Added benefit of raxibacumab to antibiotic treatment of inhalational anthrax. Antimicrob Agents Chemother 2014; 59:1145-51. [PMID: 25487792 DOI: 10.1128/aac.04606-14] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although antibiotics treat bacteremia in inhalational anthrax, pathogenesis is mainly driven by bacterial exotoxins. Raxibacumab, an IgG1 monoclonal antibody, binds the protective antigen (PA) of Bacillus anthracis, thus blocking toxin effects and leading to improved survival in the rabbit and monkey models of inhalational anthrax. To assess raxibacumab's added benefit over levofloxacin (LVX) alone, rabbits surviving to 84 h after a challenge with 200 times the median (50%) lethal dose of B. anthracis spores were randomized to receive 3 daily intragastric LVX doses of 50 mg/kg of body weight, with the first LVX dose administered just prior to administration of a single intravenous dose of placebo or 40 mg/kg raxibacumab. The percentages of animals alive at 28 days following the last LVX dose were compared between the 2 treatment groups using a two-sided likelihood-ratio chi-square test. The 82% survival rate for the LVX-raxibacumab combination was higher than the 65% survival rate for LVX alone (P=0.0874). There were nearly 2-fold fewer deaths for the combination (7 deaths; n=39) than for LVX alone (13 deaths; n=37), and the survival time was prolonged for the combination (P=0.1016). Toxin-neutralizing-activity titers were similar for both treatment groups, suggesting that survivors in both groups were able to mount a toxin-neutralizing immune response. Microscopic findings considered consistent with anthrax were present in animals that died or became moribund on study in both treatment groups, and there were no anthrax-related findings in animals that survived. Overall, raxibacumab provided a meaningful benefit over antibiotic alone when administered late in the disease course.
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25
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Kammanadiminti S, Patnaikuni RK, Comer J, Meister G, Sinclair C, Kodihalli S. Combination therapy with antibiotics and anthrax immune globulin intravenous (AIGIV) is potentially more effective than antibiotics alone in rabbit model of inhalational anthrax. PLoS One 2014; 9:e106393. [PMID: 25226075 PMCID: PMC4165586 DOI: 10.1371/journal.pone.0106393] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 08/06/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND We have evaluated the therapeutic efficacy of AIGIV when given in combination with levofloxacin and the effective window of treatment to assess the added benefit provided by AIGIV over standard antibiotic treatment alone in a New Zealand white rabbit model of inhalational anthrax. METHODS Rabbits were exposed to lethal dose of aerosolized spores of Bacillus anthracis (Ames strain) and treated intravenously with either placebo, (normal immune globulin intravenous, IGIV) or 15 U/kg of AIGIV, along with oral levofloxacin treatment at various time points (30-96 hours) after anthrax exposure. RESULTS The majority of treated animals (>88%) survived in both treatment groups when treatment was initiated within 60 hours of post-exposure. However, reduced survival of 55%, 33% and 25% was observed for placebo + levofloxacin group when the treatment was initiated at 72, 84 and 96 hours post-exposure, respectively. Conversely, a survival rate of 65%, 40% and 71% was observed in the AIGIV + levofloxacin treated groups at these time points. CONCLUSIONS The combination of AIGIV with antibiotics provided an improvement in survival compared to levofloxacin treatment alone when treatment was delayed up to 96 hours post-anthrax exposure. Additionally, AIGIV treatment when given as an adjunct therapy at any of the time points tested did not interfere with the efficacy of levofloxacin.
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Affiliation(s)
| | | | - Jason Comer
- Battelle Biomedical Research Center, West Jefferson, Columbus, Ohio, United States of America
| | - Gabriel Meister
- Battelle Biomedical Research Center, West Jefferson, Columbus, Ohio, United States of America
| | - Chris Sinclair
- Department of Clinical Research, Cangene Corporation, Winnipeg, Manitoba, Canada
| | - Shantha Kodihalli
- Department of Clinical Research, Cangene Corporation, Winnipeg, Manitoba, Canada
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Abstract
Anthrax is a highly contagious and potentially fatal human disease caused by Bacillus anthracis, an aerobic, Gram-positive, spore-forming rod-shaped bacterium with worldwide distribution as a zoonotic infection in herbivore animals. Bioterrorist attacks with inhalational anthrax have prompted the development of more effective treatments. Antibodies against anthrax toxin have been shown to decrease mortality in animal studies. Raxibacumab is a recombinant human monoclonal antibody developed against inhalational anthrax. The drug received approval after human studies showed its safety and animal studies demonstrated its efficacy for treatment as well as prophylaxis against inhalational anthrax. It works by preventing binding of the protective antigen component of the anthrax toxin to its receptors in host cells, thereby blocking the toxin's deleterious effects. Recently updated therapy guidelines for Bacillus anthracis recommend the use of antitoxin treatment. Raxibacumab is the first monoclonal antitoxin antibody made available that can be used with the antibiotics recommended for treatment of the disease. When exposure is suspected, raxibacumab should be given with anthrax vaccination to augment immunity. Raxibacumab provides additional protection against inhalational anthrax via a mechanism different from that of either antibiotics or active immunization. In combination with currently available and recommended therapies, raxibacumab should reduce the morbidity and mortality of inhalational anthrax.
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Affiliation(s)
- Carlos E Kummerfeldt
- Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Medical University of South Carolina, Charleston, SC, USA
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27
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Efficacy and safety of AVP-21D9, an anthrax monoclonal antibody, in animal models and humans. Antimicrob Agents Chemother 2014; 58:3618-25. [PMID: 24733473 DOI: 10.1128/aac.02295-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis. Timely administration of antibiotics approved for the treatment of anthrax disease may prevent associated morbidity and mortality. However, any delay in initiating antimicrobial therapy may result in increased mortality, as inhalational anthrax progresses rapidly to the toxemic phase of disease. An anthrax antitoxin, AVP-21D9, also known as Thravixa (fully human anthrax monoclonal antibody), is being developed as a therapeutic agent against anthrax toxemia. The efficacy of AVP-21D9 in B. anthracis-infected New Zealand White rabbits and in cynomolgus macaques was evaluated, and its safety and pharmacokinetics were assessed in healthy human volunteers. The estimated mean elimination half-life values of AVP-21D9 in surviving anthrax-challenged rabbits and nonhuman primates (NHPs) ranged from approximately 2 to 4 days and 6 to 11 days, respectively. In healthy humans, the mean elimination half-life was in the range of 20 to 27 days. Dose proportionality was observed for the maximum serum concentration (Cmax) of AVP-21D9 and the area under the concentration-time curve (AUC). In therapeutic efficacy animal models, treatment with AVP-21D9 resulted in survival of up to 92% of the rabbits and up to 67% of the macaques. Single infusions of AVP-21D9 were well tolerated in healthy adult volunteers across all doses evaluated, and no serious adverse events were reported. (This study has been registered at ClinicalTrials.gov under registration no. NCT01202695.).
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