1
|
King DF, Groves H, Weller C, Jones I, Cramer JP, Gilbert PB, Goldblatt D, Gruber MF, Kampmann B, Maïga D, Pasetti MF, Plotkin SA, Precioso A, Wassie L, Wittke F, Kaslow DC. Realising the potential of correlates of protection for vaccine development, licensure and use: short summary. NPJ Vaccines 2024; 9:82. [PMID: 38684704 PMCID: PMC11058756 DOI: 10.1038/s41541-024-00872-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 03/20/2024] [Indexed: 05/02/2024] Open
Affiliation(s)
| | | | | | - Ian Jones
- WHO consultant, Jinja Publishing Ltd, London, UK
| | - Jakob P Cramer
- Coalition for Epidemic Preparedness Innovations (CEPI), 215 Euston Road, London, NW1 2BE, UK
| | - Peter B Gilbert
- Vaccine Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - David Goldblatt
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Marion F Gruber
- International AIDS Vaccine Initiative (IAVI), 125 Broad Street, New York, NY, 10004, USA
| | - Beate Kampmann
- London School of Hygiene & Tropical Medicine (LSHTM) Keppel Street, London, WC1E 7HT, United Kingdom
| | - Diadié Maïga
- World Health Organization (WHO) - Regional Office for Africa, Cité du Djoué, P.O.Box 06, Brazzaville, Republic of Congo
| | - Marcela F Pasetti
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Alexander Precioso
- Instituto Butantan1500, Vital Brasil Avenue, Butantã, São Paulo, SP, 05503900, Brazil
| | - Liya Wassie
- Armauer Hansen Research Institute, Jimma Road, ALERT Campus, Addis Ababa, Ethiopia
| | | | - David C Kaslow
- PATH 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA
- US FDA, Seattle, WA, 98121, USA
| |
Collapse
|
2
|
Bunin DI, Javitz HS, Gahagen J, Bakke J, Lane JH, Andrews DA, Chang PY. Survival and Hematologic Benefits of Romiplostim After Acute Radiation Exposure Supported FDA Approval Under the Animal Rule. Int J Radiat Oncol Biol Phys 2023; 117:705-717. [PMID: 37224926 DOI: 10.1016/j.ijrobp.2023.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/19/2023] [Accepted: 05/02/2023] [Indexed: 05/26/2023]
Abstract
PURPOSE Patients exposed to acute high doses of ionizing radiation are susceptible to dose-dependent bone marrow depression with resultant pancytopenia. Romiplostim (RP; Nplate) is a recombinant thrombopoietin receptor agonist protein that promotes progenitor megakaryocyte proliferation and platelet production and is an approved treatment for patients with chronic immune thrombocytopenia. The goal of our study was to evaluate the postirradiation survival and hematologic benefits of a single dose of RP with or without pegfilgrastim (PF; Neulasta, granulocyte colony stimulating factor) by conducting a well-controlled, treatment-concealed, good laboratory practice-compliant study in rhesus macaques that was compliant with the United States Food and Drug Administration Animal Rule regulatory approval pathway. METHODS AND MATERIALS Irradiated male and female rhesus macaques (20/sex in each of 3 groups: control, RP, and RP + PF) were subcutaneously administered vehicle or RP (5 mg/kg, 10 mL/kg) on day 1 in the presence or absence of 2 doses of PF (0.3 mg/kg, 0.03 mL/kg, days 1 and 8). Total body radiation (680 cGy, 50 cGy/min from cobalt-60 gamma ray source) occurred 24 ± 2 hours previously at a dose targeting 70% lethality for the control cohort over 60 days. The study examined 60-day survival postirradiation as the primary endpoint. Secondary endpoints included incidence, severity, and duration of thrombocytopenia and neutropenia, other hematology parameters, coagulation parameters, and body weight change to provide insights into potential mechanisms of action. RESULTS Compared with sham-treated controls, treated animals demonstrated a 40% to 55% survival benefit compared with controls, less severe clinical signs, reduced incidence of thrombocytopenia and/or neutropenia, earlier hematologic recovery, and reduced morbidity from bacterial infection. CONCLUSIONS These results were pivotal in obtaining Food and Drug Administration approval in January 2021 for RP's new indication as a single administration therapy to increase survival in adults and pediatric patients acutely exposed to myelosuppressive doses of radiation.
Collapse
Affiliation(s)
| | | | - Janet Gahagen
- SRI Biosciences, SRI International, Menlo Park, California
| | - James Bakke
- SRI Biosciences, SRI International, Menlo Park, California
| | | | | | - Polly Y Chang
- SRI Biosciences, SRI International, Menlo Park, California.
| |
Collapse
|
3
|
De Pascalis R, Bhargava V, Espich S, Wu TH, Gelhaus HC, Elkins KL. In vivo and in vitro immune responses against Francisella tularensis vaccines are comparable among Fischer 344 rat substrains. Front Microbiol 2023; 14:1224480. [PMID: 37547680 PMCID: PMC10400713 DOI: 10.3389/fmicb.2023.1224480] [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: 05/17/2023] [Accepted: 06/15/2023] [Indexed: 08/08/2023] Open
Abstract
Identifying suitable animal models and standardizing preclinical methods are important for the generation, characterization, and development of new vaccines, including those against Francisella tularensis. Non-human primates represent an important animal model to evaluate tularemia vaccine efficacy, and the use of correlates of vaccine-induced protection may facilitate bridging immune responses from non-human primates to people. However, among small animals, Fischer 344 rats represent a valuable resource for initial studies to evaluate immune responses, to identify correlates of protection, and to screen novel vaccines. In this study, we performed a comparative analysis of three Fischer rat substrains to determine potential differences in immune responses, to evaluate methods used to quantify potential correlates of protection, and to evaluate protection after vaccination. To this end, we took advantage of data previously generated using one of the rat substrains by evaluating two live vaccines, LVS and F. tularensis SchuS4-ΔclpB (ΔclpB). We compared immune responses after primary vaccination, adaptive immune responses upon re-stimulation of leukocytes in vitro, and sensitivity to aerosol challenge. Despite some detectable differences, the results highlight the similarity of immune responses to tularemia vaccines and challenge outcomes between the three substrains, indicating that all offer acceptable and comparable approaches as animal models to study Francisella infection and immunity.
Collapse
Affiliation(s)
- Roberto De Pascalis
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Varunika Bhargava
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Scott Espich
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, United States
| | - Terry H. Wu
- Center for Infectious Disease and Immunity and Department of Internal Medicine, University of New Mexico, Albuquerque, NM, United States
| | | | - Karen L. Elkins
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, United States
| |
Collapse
|
4
|
von Delft A, Hall MD, Kwong AD, Purcell LA, Saikatendu KS, Schmitz U, Tallarico JA, Lee AA. Accelerating antiviral drug discovery: lessons from COVID-19. Nat Rev Drug Discov 2023; 22:585-603. [PMID: 37173515 PMCID: PMC10176316 DOI: 10.1038/s41573-023-00692-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2023] [Indexed: 05/15/2023]
Abstract
During the coronavirus disease 2019 (COVID-19) pandemic, a wave of rapid and collaborative drug discovery efforts took place in academia and industry, culminating in several therapeutics being discovered, approved and deployed in a 2-year time frame. This article summarizes the collective experience of several pharmaceutical companies and academic collaborations that were active in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antiviral discovery. We outline our opinions and experiences on key stages in the small-molecule drug discovery process: target selection, medicinal chemistry, antiviral assays, animal efficacy and attempts to pre-empt resistance. We propose strategies that could accelerate future efforts and argue that a key bottleneck is the lack of quality chemical probes around understudied viral targets, which would serve as a starting point for drug discovery. Considering the small size of the viral proteome, comprehensively building an arsenal of probes for proteins in viruses of pandemic concern is a worthwhile and tractable challenge for the community.
Collapse
Affiliation(s)
- Annette von Delft
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
- Oxford Biomedical Research Centre, National Institute for Health Research, University of Oxford, Oxford, UK.
| | - Matthew D Hall
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, USA
| | | | | | | | | | | | - Alpha A Lee
- PostEra, Inc., Cambridge, MA, USA.
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| |
Collapse
|
5
|
Bennett CL, Georgantopoulos P, Gale RP, Knopf K, Hrushesky WJ, Nabhan C, Armitage JO. United States' regulatory approved pharmacotherapies for nuclear reactor explosions and anthrax-associated bioterrorism. Expert Opin Drug Saf 2023; 22:783-788. [PMID: 37594915 PMCID: PMC10523714 DOI: 10.1080/14740338.2023.2245748] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 08/04/2023] [Indexed: 08/20/2023]
Abstract
INTRODUCTION Nuclear reactor incidents and bioterrorism outbreaks are concerning public health disasters. Little is known about US Food and Drug Administration (FDA)-approved agents that can mitigate consequences of these events. We review FDA data supporting regulatory approvals of these agents. AREAS COVERED We reviewed pharmaceutical products approved to treat Hematopoietic Acute Radiation Syndrome (H-ARS) and to treat or prevent pulmonary infections following Bacillus anthracis (anthrax) exposure. Four drugs were approved for H-ARS: granulocyte-colony stimulating factor (G-CSF), granulocyte/macrophage colony stimulating factor, pegylated G-CSF, and romiplostim. For bioterrorism-associated anthrax, the FDA approved five antibiotics (doxycycline, penicillin-G, levofloxacin, moxifloxacin, and ciprofloxacin), two monoclonal antibodies (obiltoxaximab and raxibacumab), one polyclonal antitoxin (Anthrax Immune Globulin Intravenous) and two vaccines (Anthrax Vaccine Adsorbed and Anthrax Vaccine Adsorbed with an adjuvant). A national stockpile system ensures that communities have ready access to these agents. Our literature search was based on data included in drugs@FDA (2001-2023). EXPERT OPINION Two potential mass public health disasters are aerosolized anthrax dissemination and radiological incidents. Five agents authorized for anthrax emergencies only have FDA approval for this indication, five antibiotics have FDA approvals as antibiotics for common infections and for bacillus anthrax, and four agents have regulatory approvals for supportive care for cancer and for radiological incidents.
Collapse
Affiliation(s)
- Charles L. Bennett
- The SmartState Center for Medication Safety and Efficacy, the University of South Carolina, College of Pharmacy, the Beckman Research Institute and the City of Hope National Cancer Institute Designated Comprehensive Cancer Center, Duarte, California (CLB), Imperial College London (RPG), and the University of Nebraska College of Medicine/Omaha (JOA)
| | - Peter Georgantopoulos
- The SmartState Center for Medication Safety and Efficacy, the University of South Carolina, College of Pharmacy, the Beckman Research Institute and the City of Hope National Cancer Institute Designated Comprehensive Cancer Center, Duarte, California (CLB), Imperial College London (RPG), and the University of Nebraska College of Medicine/Omaha (JOA)
| | - Robert Peter Gale
- The SmartState Center for Medication Safety and Efficacy, the University of South Carolina, College of Pharmacy, the Beckman Research Institute and the City of Hope National Cancer Institute Designated Comprehensive Cancer Center, Duarte, California (CLB), Imperial College London (RPG), and the University of Nebraska College of Medicine/Omaha (JOA)
| | - Kevin Knopf
- The SmartState Center for Medication Safety and Efficacy, the University of South Carolina, College of Pharmacy, the Beckman Research Institute and the City of Hope National Cancer Institute Designated Comprehensive Cancer Center, Duarte, California (CLB), Imperial College London (RPG), and the University of Nebraska College of Medicine/Omaha (JOA)
| | - William J Hrushesky
- The SmartState Center for Medication Safety and Efficacy, the University of South Carolina, College of Pharmacy, the Beckman Research Institute and the City of Hope National Cancer Institute Designated Comprehensive Cancer Center, Duarte, California (CLB), Imperial College London (RPG), and the University of Nebraska College of Medicine/Omaha (JOA)
| | - Chadi Nabhan
- The SmartState Center for Medication Safety and Efficacy, the University of South Carolina, College of Pharmacy, the Beckman Research Institute and the City of Hope National Cancer Institute Designated Comprehensive Cancer Center, Duarte, California (CLB), Imperial College London (RPG), and the University of Nebraska College of Medicine/Omaha (JOA)
| | - James O. Armitage
- The SmartState Center for Medication Safety and Efficacy, the University of South Carolina, College of Pharmacy, the Beckman Research Institute and the City of Hope National Cancer Institute Designated Comprehensive Cancer Center, Duarte, California (CLB), Imperial College London (RPG), and the University of Nebraska College of Medicine/Omaha (JOA)
| |
Collapse
|
6
|
Gruber MF, Rubin S, Krause PR. Approaches to demonstrating the effectiveness of filovirus vaccines: Lessons from Ebola and COVID-19. Front Immunol 2023; 14:1109486. [PMID: 36817425 PMCID: PMC9932497 DOI: 10.3389/fimmu.2023.1109486] [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: 11/27/2022] [Accepted: 01/24/2023] [Indexed: 02/05/2023] Open
Abstract
Zaire ebolavirus (EBOV), Sudan ebolavirus (SUDV) and Marburg virus (MARV), are members of the Filoviridae family that can cause severe disease and death in humans and animals. The reemergence of Ebola, Sudan and Marburg virus disease highlight the need for continued availability of safe and effectives vaccines as well as development of new vaccines. While randomized controlled trials using disease endpoints provide the most robust assessment of vaccine effectiveness, challenges to this approach include the unpredictable size, location, occurrence and duration of filovirus disease outbreaks. Thus, other approaches to demonstrating vaccine effectiveness have been considered. These approaches are discussed using examples of preventive vaccines against other infectious diseases. In addition, this article proposes a clinical immunobridging strategy using licensed EBOV vaccines as comparators for demonstrating the effectiveness of filovirus vaccine candidates that are based on the same licensed vaccine platform technology.
Collapse
Affiliation(s)
- Marion F. Gruber
- International AIDS Vaccine Initiative, New York, NY, United States,*Correspondence: Marion F. Gruber,
| | - Steven Rubin
- GlaxoSmithKline (GSk), Rockville, MD, United States
| | | |
Collapse
|
7
|
Khan MA, Amin A, Farid A, Ullah A, Waris A, Shinwari K, Hussain Y, Alsharif KF, Alzahrani KJ, Khan H. Recent Advances in Genomics-Based Approaches for the Development of Intracellular Bacterial Pathogen Vaccines. Pharmaceutics 2022; 15:pharmaceutics15010152. [PMID: 36678781 PMCID: PMC9863128 DOI: 10.3390/pharmaceutics15010152] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/12/2022] [Accepted: 12/19/2022] [Indexed: 01/04/2023] Open
Abstract
Infectious diseases continue to be a leading cause of morbidity and mortality worldwide. The majority of infectious diseases are caused by intracellular pathogenic bacteria (IPB). Historically, conventional vaccination drives have helped control the pathogenesis of intracellular bacteria and the emergence of antimicrobial resistance, saving millions of lives. However, in light of various limitations, many diseases that involve IPB still do not have adequate vaccines. In response to increasing demand for novel vaccine development strategies, a new area of vaccine research emerged following the advent of genomics technology, which changed the paradigm of vaccine development by utilizing the complete genomic data of microorganisms against them. It became possible to identify genes related to disease virulence, genetic patterns linked to disease virulence, as well as the genetic components that supported immunity and favorable vaccine responses. Complete genomic databases, and advancements in transcriptomics, metabolomics, structural genomics, proteomics, immunomics, pan-genomics, synthetic genomics, and population biology have allowed researchers to identify potential vaccine candidates and predict their effects in patients. New vaccines have been created against diseases for which previously there were no vaccines available, and existing vaccines have been improved. This review highlights the key issues and explores the evolution of vaccines. The increasing volume of IPB genomic data, and their application in novel genome-based techniques for vaccine development, were also examined, along with their characteristics, and the opportunities and obstacles involved. Critically, the application of genomics technology has helped researchers rapidly select and evaluate candidate antigens. Novel vaccines capable of addressing the limitations associated with conventional vaccines have been developed and pressing healthcare issues are being addressed.
Collapse
Affiliation(s)
- Muhammad Ajmal Khan
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- Correspondence: (M.A.K.); or (H.K.)
| | - Aftab Amin
- Division of Life Science, Center for Cancer Research, and State Key Lab of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Awais Farid
- Division of Environment and Sustainability, Hong Kong University of Science and Technology, Hong Kong, China
| | - Amin Ullah
- Molecular Virology Laboratory, Department of Microbiology and Biotechnology, Abasyn University, Peshawar 25000, Pakistan
| | - Abdul Waris
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Khyber Shinwari
- Institute of Chemical Engineering, Department Immuno-Chemistry, Ural Federal University, Yekaterinbiurg 620002, Russia
| | - Yaseen Hussain
- Department of Pharmacy, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Khalaf F. Alsharif
- Department of Clinical Laboratory, College of Applied Medical Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - Khalid J. Alzahrani
- Department of Clinical Laboratory, College of Applied Medical Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - Haroon Khan
- Department of Clinical Laboratory, College of Applied Medical Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
- Correspondence: (M.A.K.); or (H.K.)
| |
Collapse
|
8
|
Alfson KJ, Goez-Gazi Y, Gazi M, Chou YL, Niemuth NA, Mattix ME, Staples H, Klaffke B, Rodriguez GF, Escareno P, Bartley C, Ticer A, Clemmons EA, Dutton III JW, Griffiths A, Meister GT, Sanford DC, Cirimotich CM, Carrion R. Development of a Well-Characterized Cynomolgus Macaque Model of Sudan Virus Disease for Support of Product Development. Vaccines (Basel) 2022; 10:1723. [PMID: 36298588 PMCID: PMC9611481 DOI: 10.3390/vaccines10101723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 10/08/2022] [Accepted: 10/11/2022] [Indexed: 11/30/2022] Open
Abstract
The primary objective of this study was to characterize the disease course in cynomolgus macaques exposed to Sudan virus (SUDV), to determine if infection in this species is an appropriate model for the evaluation of filovirus countermeasures under the FDA Animal Rule. Sudan virus causes Sudan virus disease (SVD), with an average case fatality rate of approximately 50%, and while research is ongoing, presently there are no approved SUDV vaccines or therapies. Well characterized animal models are crucial for further developing and evaluating countermeasures for SUDV. Twenty (20) cynomolgus macaques were exposed intramuscularly to either SUDV or sterile phosphate-buffered saline; 10 SUDV-exposed animals were euthanized on schedule to characterize pathology at defined durations post-exposure and 8 SUDV-exposed animals were not part of the scheduled euthanasia cohort. Survival was assessed, along with clinical observations, body weights, body temperatures, hematology, clinical chemistry, coagulation, viral load (serum and tissues), macroscopic observations, and histopathology. There were statistically significant differences between SUDV-exposed animals and mock-exposed animals for 26 parameters, including telemetry body temperature, clinical chemistry parameters, hematology parameters, activated partial thromboplastin time, serum viremia, and biomarkers that characterize the disease course of SUDV in cynomolgus macaques.
Collapse
Affiliation(s)
- Kendra J. Alfson
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Yenny Goez-Gazi
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Michal Gazi
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Ying-Liang Chou
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Nancy A. Niemuth
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Marc E. Mattix
- Nonclinical Pathology Services, LLC, 5920 Clubhouse Pointe Dr., Medina, OH 44256, USA
| | - Hilary Staples
- Current affiliation: National Emerging Infectious Diseases Laboratory, Department of Microbiology, Boston University School of Medicine, 620 Albany St, Boston, MA 02118, USA
| | - Benjamin Klaffke
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Gloria F. Rodriguez
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Priscilla Escareno
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Carmen Bartley
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Anysha Ticer
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Elizabeth A. Clemmons
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - John W. Dutton III
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Anthony Griffiths
- Current affiliation: National Emerging Infectious Diseases Laboratory, Department of Microbiology, Boston University School of Medicine, 620 Albany St, Boston, MA 02118, USA
| | - Gabe T. Meister
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Daniel C. Sanford
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Chris M. Cirimotich
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Ricardo Carrion
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| |
Collapse
|
9
|
Working correlates of protection predict SchuS4-derived-vaccine candidates with improved efficacy against an intracellular bacterium, Francisella tularensis. NPJ Vaccines 2022; 7:95. [PMID: 35977964 PMCID: PMC9385090 DOI: 10.1038/s41541-022-00506-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 07/01/2022] [Indexed: 11/09/2022] Open
Abstract
Francisella tularensis, the causative agent of tularemia, is classified as Tier 1 Select Agent with bioterrorism potential. The efficacy of the only available vaccine, LVS, is uncertain and it is not licensed in the U.S. Previously, by using an approach generally applicable to intracellular pathogens, we identified working correlates that predict successful vaccination in rodents. Here, we applied these correlates to evaluate a panel of SchuS4-derived live attenuated vaccines, namely SchuS4-ΔclpB, ΔclpB-ΔfupA, ΔclpB-ΔcapB, and ΔclpB-ΔwbtC. We combined in vitro co-cultures to quantify rodent T-cell functions and multivariate regression analyses to predict relative vaccine strength. The predictions were tested by rat vaccination and challenge studies, which demonstrated a clear relationship between the hierarchy of in vitro measurements and in vivo vaccine protection. Thus, these studies demonstrated the potential power a panel of correlates to screen and predict the efficacy of Francisella vaccine candidates, and in vivo studies in Fischer 344 rats confirmed that SchuS4-ΔclpB and ΔclpB-ΔcapB may be better vaccine candidates than LVS.
Collapse
|
10
|
Alfson KJ, Goez-Gazi Y, Gazi M, Chou YL, Niemuth NA, Mattix ME, Staples HM, Klaffke B, Rodriguez GF, Bartley C, Ticer A, Clemmons EA, Dutton JW, Griffiths A, Meister GT, Sanford DC, Cirimotich CM, Carrion R. Development of a Well-Characterized Cynomolgus Macaque Model of Marburg Virus Disease for Support of Vaccine and Therapy Development. Vaccines (Basel) 2022; 10:1314. [PMID: 36016203 PMCID: PMC9414819 DOI: 10.3390/vaccines10081314] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/07/2022] [Accepted: 08/10/2022] [Indexed: 12/03/2022] Open
Abstract
Marburg virus (MARV) is a filovirus that can infect humans and nonhuman primates (NHPs), causing severe disease and death. Of the filoviruses, Ebola virus (EBOV) has been the primary target for vaccine and therapeutic development. However, MARV has an average case fatality rate of approximately 50%, the infectious dose is low, and there are currently no approved vaccines or therapies targeted at infection with MARV. The purpose of this study was to characterize disease course in cynomolgus macaques intramuscularly exposed to MARV Angola variant. There were several biomarkers that reliably correlated with MARV-induced disease, including: viral load; elevated total clinical scores; temperature changes; elevated ALT, ALP, BA, TBIL, CRP and decreased ALB values; decreased lymphocytes and platelets; and prolonged PTT. A scheduled euthanasia component also provided the opportunity to study the earliest stages of the disease. This study provides evidence for the application of this model to evaluate potential vaccines and therapies against MARV and will be valuable in improving existing models.
Collapse
Affiliation(s)
- Kendra J. Alfson
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Yenny Goez-Gazi
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Michal Gazi
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Ying-Liang Chou
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Nancy A. Niemuth
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Marc E. Mattix
- Nonclinical Pathology Services, LLC, 5920 Clubhouse Pointe Dr., Medina, OH 44256, USA
| | - Hilary M. Staples
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Benjamin Klaffke
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Gloria F. Rodriguez
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Carmen Bartley
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Anysha Ticer
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Elizabeth A. Clemmons
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - John W. Dutton
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Anthony Griffiths
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| | - Gabe T. Meister
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Daniel C. Sanford
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Chris M. Cirimotich
- Battelle Biomedical Research Center (BBRC), 1425 Plain City Georgesville Road, West Jefferson, OH 43162, USA
| | - Ricardo Carrion
- Texas Biomedical Research Institute, 8715 W. Military Dr., San Antonio, TX 78227, USA
| |
Collapse
|
11
|
Natural History of Sudan ebolavirus to Support Medical Countermeasure Development. Vaccines (Basel) 2022; 10:vaccines10060963. [PMID: 35746571 PMCID: PMC9228702 DOI: 10.3390/vaccines10060963] [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: 05/05/2022] [Revised: 06/09/2022] [Accepted: 06/11/2022] [Indexed: 11/23/2022] Open
Abstract
Sudan ebolavirus (SUDV) is one of four members of the Ebolavirus genus known to cause Ebola Virus Disease (EVD) in humans, which is characterized by hemorrhagic fever and a high case fatality rate. While licensed therapeutics and vaccines are available in limited number to treat infections of Zaire ebolavirus, there are currently no effective licensed vaccines or therapeutics for SUDV. A well-characterized animal model of this disease is needed for the further development and testing of vaccines and therapeutics. In this study, twelve cynomolgus macaques (Macaca fascicularis) were challenged intramuscularly with 1000 PFUs of SUDV and were followed under continuous telemetric surveillance. Clinical observations, body weights, temperature, viremia, hematology, clinical chemistry, and coagulation were analyzed at timepoints throughout the study. Death from SUDV disease occurred between five and ten days after challenge at the point that each animal met the criteria for euthanasia. All animals were observed to exhibit clinical signs and lesions similar to those observed in human cases which included: viremia, fever, dehydration, reduced physical activity, macular skin rash, systemic inflammation, coagulopathy, lymphoid depletion, renal tubular necrosis, hepatocellular degeneration and necrosis. The results from this study will facilitate the future preclinical development and evaluation of vaccines and therapeutics for SUDV.
Collapse
|
12
|
Affiliation(s)
- H Cody Meissner
- From the Department of Pediatrics, Tufts Children's Hospital, Tufts Medical Center, Boston
| |
Collapse
|
13
|
Tesfamariam M, Binette P, Long CM. Preclinical Animal Models for Q Fever Vaccine Development. Front Cell Infect Microbiol 2022; 12:828784. [PMID: 35223553 PMCID: PMC8866712 DOI: 10.3389/fcimb.2022.828784] [Citation(s) in RCA: 5] [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: 12/03/2021] [Accepted: 01/19/2022] [Indexed: 12/13/2022] Open
Abstract
Coxiella burnetii is a zoonotic pathogen responsible for the human disease Q fever. While an inactivated whole cell vaccine exists for this disease, its widespread use is precluded by a post vaccination hypersensitivity response. Efforts for the development of an improved Q fever vaccine are intricately connected to the availability of appropriate animal models of human disease. Accordingly, small mammals and non-human primates have been utilized for vaccine-challenge and post vaccination hypersensitivity modeling. Here, we review the animal models historically utilized in Q fever vaccine development, describe recent advances in this area, discuss the limitations and strengths of these models, and summarize the needs and criteria for future modeling efforts. In summary, while many useful models for Q fever vaccine development exist, there remains room for growth and expansion of these models which will in turn increase our understanding of C. burnetii host interactions.
Collapse
|
14
|
Moore BD, Macleod C, Henning L, Krile R, Chou YL, Laws TR, Butcher WA, Moore KM, Walker NJ, Williamson ED, Galloway DR. Predictors of Survival after Vaccination in a Pneumonic Plague Model. Vaccines (Basel) 2022; 10:vaccines10020145. [PMID: 35214604 PMCID: PMC8876284 DOI: 10.3390/vaccines10020145] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/04/2022] [Accepted: 01/11/2022] [Indexed: 11/28/2022] Open
Abstract
Background: The need for an updated plague vaccine is highlighted by outbreaks in endemic regions together with the pandemic potential of this disease. There is no easily available, approved vaccine. Methods: Here we have used a murine model of pneumonic plague to examine the factors that maximise immunogenicity and contribute to survival following vaccination. We varied vaccine type, as either a genetic fusion of the F1 and V protein antigens or a mixture of these two recombinant antigens, as well as antigen dose-level and formulation in order to correlate immune response to survival. Results: Whilst there was interaction between each of the variables of vaccine type, dose level and formulation and these all contributed to survival, vaccine formulation in protein-coated microcrystals (PCMCs) was the key contributor in inducing antibody titres. From these data, we propose a cut-off in total serum antibody titre to the F1 and V proteins of 100 µg/mL and 200 µg/mL, respectively. At these thresholds, survival is predicted in this murine pneumonic model to be >90%. Within the total titre of antibody to the V antigen, the neutralising antibody component correlated with dose level and was enhanced when the V antigen in free form was formulated in PCMCs. Antibody titre to F1 was limited by fusion to V, but this was compensated for by PCMC formulation. Conclusions: These data will enable clinical assessment of this and other candidate plague vaccines that utilise the same vaccine antigens by identifying a target antibody titre from murine models, which will guide the evaluation of clinical titres as serological surrogate markers of efficacy.
Collapse
Affiliation(s)
- Barry D. Moore
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XQ, UK; (B.D.M.); (C.M.)
| | - Clair Macleod
- Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XQ, UK; (B.D.M.); (C.M.)
| | - Lisa Henning
- Battelle Biomedical Research Center, West Jefferson, OH 43162, USA; (L.H.); (R.K.); (Y.-L.C.)
| | - Robert Krile
- Battelle Biomedical Research Center, West Jefferson, OH 43162, USA; (L.H.); (R.K.); (Y.-L.C.)
| | - Ying-Liang Chou
- Battelle Biomedical Research Center, West Jefferson, OH 43162, USA; (L.H.); (R.K.); (Y.-L.C.)
| | - Thomas R. Laws
- CBR Division, Dstl Porton Down, Salisbury SP4 0JQ, UK; (T.R.L.); (W.A.B.); (K.M.M.); (N.J.W.)
| | - Wendy A. Butcher
- CBR Division, Dstl Porton Down, Salisbury SP4 0JQ, UK; (T.R.L.); (W.A.B.); (K.M.M.); (N.J.W.)
| | - Kristoffer M. Moore
- CBR Division, Dstl Porton Down, Salisbury SP4 0JQ, UK; (T.R.L.); (W.A.B.); (K.M.M.); (N.J.W.)
| | - Nicola J. Walker
- CBR Division, Dstl Porton Down, Salisbury SP4 0JQ, UK; (T.R.L.); (W.A.B.); (K.M.M.); (N.J.W.)
| | - Ethel Diane Williamson
- CBR Division, Dstl Porton Down, Salisbury SP4 0JQ, UK; (T.R.L.); (W.A.B.); (K.M.M.); (N.J.W.)
- Correspondence:
| | - Darrell R. Galloway
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, USA;
| |
Collapse
|
15
|
Novel Transcriptional and Translational Biomarkers of Tularemia Vaccine Efficacy in a Mouse Inhalation Model: Proof of Concept. Microorganisms 2021; 10:microorganisms10010036. [PMID: 35056485 PMCID: PMC8778127 DOI: 10.3390/microorganisms10010036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/15/2021] [Accepted: 12/20/2021] [Indexed: 11/18/2022] Open
Abstract
Francisella tularensis subspecies tularensis (Ftt) is extremely virulent for humans when inhaled as a small particle aerosol (<5 µm). Inhalation of ≥20 viable bacteria is sufficient to initiate infection with a mortality rate ≥30%. Consequently, in the past, Ftt became a primary candidate for biological weapons development. To counter this threat, the USA developed a live vaccine strain (LVS), that showed efficacy in humans against inhalation of virulent Ftt. However, the breakthrough dose was fairly low, and protection waned with time. These weaknesses triggered extensive research for better vaccine candidates. Previously, we showed that deleting the clpB gene from virulent Ftt strain, SCHU S4, resulted in a mutant that was significantly less virulent than LVS for mice, yet better protected them from aerosol challenge with wild-type SCHU S4. To date, comprehensive searches for correlates of protection for SCHU S4 ΔclpB among molecules that are critical signatures of cell-mediated immunity, have yielded little reward. In this study we used transcriptomics analysis to expand the potential range of molecular correlates of protection induced by vaccination with SCHU S4 ΔclpB beyond the usual candidates. The results provide proof-of-concept that unusual host responses to vaccination can potentially serve as novel efficacy biomarkers for new tularemia vaccines.
Collapse
|
16
|
Dassanayake MK, Khoo TJ, An J. Antibiotic resistance modifying ability of phytoextracts in anthrax biological agent Bacillus anthracis and emerging superbugs: a review of synergistic mechanisms. Ann Clin Microbiol Antimicrob 2021; 20:79. [PMID: 34856999 PMCID: PMC8641154 DOI: 10.1186/s12941-021-00485-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 11/22/2021] [Indexed: 01/17/2023] Open
Abstract
Background and objectives The chemotherapeutic management of infections has become challenging due to the global emergence of antibiotic resistant pathogenic bacteria. The recent expansion of studies on plant-derived natural products has lead to the discovery of a plethora of phytochemicals with the potential to combat bacterial drug resistance via various mechanisms of action. This review paper summarizes the primary antibiotic resistance mechanisms of bacteria and also discusses the antibiotic-potentiating ability of phytoextracts and various classes of isolated phytochemicals in reversing antibiotic resistance in anthrax agent Bacillus anthracis and emerging superbug bacteria. Methods Growth inhibitory indices and fractional inhibitory concentration index were applied to evaluate the in vitro synergistic activity of phytoextract-antibiotic combinations in general. Findings A number of studies have indicated that plant-derived natural compounds are capable of significantly reducing the minimum inhibitory concentration of standard antibiotics by altering drug-resistance mechanisms of B. anthracis and other superbug infection causing bacteria. Phytochemical compounds allicin, oleanolic acid, epigallocatechin gallate and curcumin and Jatropha curcas extracts were exceptional synergistic potentiators of various standard antibiotics. Conclusion Considering these facts, phytochemicals represents a valuable and novel source of bioactive compounds with potent antibiotic synergism to modulate bacterial drug-resistance.
Collapse
Affiliation(s)
- Mackingsley Kushan Dassanayake
- School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Malaysia.
| | - Teng-Jin Khoo
- School of Pharmacy, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Malaysia
| | - Jia An
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore
| |
Collapse
|
17
|
Gómez Román R, Tornieporth N, Cherian NG, Shurtleff AC, L'Azou Jackson M, Yeskey D, Hacker A, Mungai E, Le TT. Medical countermeasures against henipaviruses: a review and public health perspective. THE LANCET. INFECTIOUS DISEASES 2021; 22:e13-e27. [PMID: 34735799 PMCID: PMC8694750 DOI: 10.1016/s1473-3099(21)00400-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/02/2021] [Accepted: 07/02/2021] [Indexed: 12/14/2022]
Abstract
Henipaviruses, including Nipah virus, are regarded as pathogens of notable epidemic potential because of their high pathogenicity and the paucity of specific medical countermeasures to control infections in humans. We review the evidence of medical countermeasures against henipaviruses and project their cost in a post-COVID-19 era. Given the sporadic and unpredictable nature of henipavirus outbreaks, innovative strategies will be needed to circumvent the infeasibility of traditional phase 3 clinical trial regulatory pathways. Stronger partnerships with scientific institutions and regulatory authorities in low-income and middle-income countries can inform coordination of appropriate investments and development of strategies and normative guidelines for the deployment and equitable use of multiple medical countermeasures. Accessible measures should include global, regional, and endemic in-country stockpiles of reasonably priced small molecules, monoclonal antibodies, and vaccines as part of a combined collection of products that could help to control henipavirus outbreaks and prevent future pandemics.
Collapse
Affiliation(s)
- Raúl Gómez Román
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | - Nadia Tornieporth
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway; University of Applied Sciences & Arts, Hanover, Germany
| | | | - Amy C Shurtleff
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | | | - Debra Yeskey
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | - Adam Hacker
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | - Eric Mungai
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | - Tung Thanh Le
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway.
| |
Collapse
|
18
|
Q Fever Vaccine Development: Current Strategies and Future Considerations. Pathogens 2021; 10:pathogens10101223. [PMID: 34684172 PMCID: PMC8539696 DOI: 10.3390/pathogens10101223] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 11/16/2022] Open
Abstract
Q fever is a zoonotic disease caused by the intracellular pathogen Coxiella burnetii. This disease typically manifests as a self-limiting, febrile illness known as acute Q fever. Due to the aerosol transmissibility, environmental persistence, and infectivity of C. burnetii, this pathogen is a notable bioterrorism threat. Despite extensive efforts to develop next-generation human Q fever vaccines, only one vaccine, Q-Vax®, is commercially available. Q-Vax® is a phase I whole-cell vaccine, and its licensed use is limited to Australia, presumably due to the potential for a post-vaccination hypersensitivity response. Pre-clinical Q fever vaccine development is a major area of interest, and diverse approaches have been undertaken to develop an improved Q fever vaccine. Following a brief history of Q fever vaccine development, current approaches will be discussed along with future considerations for an improved Q fever vaccine.
Collapse
|
19
|
Nikolay B, Ribeiro Dos Santos G, Lipsitch M, Rahman M, Luby SP, Salje H, Gurley ES, Cauchemez S. Assessing the feasibility of Nipah vaccine efficacy trials based on previous outbreaks in Bangladesh. Vaccine 2021; 39:5600-5606. [PMID: 34426025 DOI: 10.1016/j.vaccine.2021.08.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Nipah virus (NiV) is an emerging, bat-borne pathogen that can be transmitted from person-to-person. Vaccines are currently being developed for NiV, and studies have been funded to evaluate their safety and immunogenicity. An important unanswered question is whether it will be possible to evaluate the efficacy of vaccine candidates in phase III clinical trials in a context where spillovers from the zoonotic reservoir are infrequent and associated with small outbreaks. The objective of this study was to investigate the feasibility of conducting a phase III vaccine trial in Bangladesh, the only country regularly reporting NiV cases. METHODS We used simulations based on previously observed NiV cases from Bangladesh, an assumed vaccine efficacy of 90% and other NiV vaccine target characteristics, to compare three vaccination study designs: (i) cluster randomized ring vaccination, (ii) cluster randomized mass vaccination, and (iii) an observational case-control study design. RESULTS The simulations showed that, assuming a ramp-up period of 10 days and a mean hospitalization delay of 4 days,a cluster-randomized ring vaccination trial would require 516 years and over 163,000 vaccine doses to run a ring vaccination trial under current epidemic conditions. A cluster-randomized mass vaccination trial in the two most affected districts would take 43 years and 1.83 million vaccine doses. An observational case-control design in these two districts would require seven years and 2.5 million vaccine doses. DISCUSSION Without a change in the epidemiology of NiV, ring vaccination or mass vaccination trials are unlikely to be completed within a reasonable time window. In this light, the remaining options are: (i) not conducting a phase III trial until the epidemiology of NiV changes, (ii) identifying alternative ways to licensure such as observational studies or controlled studies in animals such as in the US Food and Drug Administration's (FDA) Animal Rule.
Collapse
Affiliation(s)
- Birgit Nikolay
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, 75015 Paris, France
| | | | - Marc Lipsitch
- Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | | | - Stephen P Luby
- Infectious Diseases and Geographic Medicine Division, Stanford University, Stanford, CA, USA
| | - Henrik Salje
- Department of Genetics, University of Cambridge, Cambridge, UK.
| | - Emily S Gurley
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Simon Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR2000, CNRS, 75015 Paris, France
| |
Collapse
|
20
|
Modern Development and Production of a New Live Attenuated Bacterial Vaccine, SCHU S4 ΔclpB, to Prevent Tularemia. Pathogens 2021; 10:pathogens10070795. [PMID: 34201577 PMCID: PMC8308573 DOI: 10.3390/pathogens10070795] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/18/2021] [Accepted: 06/20/2021] [Indexed: 12/04/2022] Open
Abstract
Inhalation of small numbers of Francisella tularensis subspecies tularensis (Ftt) in the form of small particle aerosols causes severe morbidity and mortality in people and many animal species. For this reason, Ftt was developed into a bona fide biological weapon by the USA, by the former USSR, and their respective allies during the previous century. Although such weapons were never deployed, the 9/11 attack quickly followed by the Amerithrax attack led the U.S. government to seek novel countermeasures against a select group of pathogens, including Ftt. Between 2005–2009, we pursued a novel live vaccine against Ftt by deleting putative virulence genes from a fully virulent strain of the pathogen, SCHU S4. These mutants were screened in a mouse model, in which the vaccine candidates were first administered intradermally (ID) to determine their degree of attenuation. Subsequently, mice that survived a high dose ID inoculation were challenged by aerosol or intranasally (IN) with virulent strains of Ftt. We used the current unlicensed live vaccine strain (LVS), first discovered over 70 years ago, as a comparator in the same model. After screening 60 mutants, we found only one, SCHU S4 ΔclpB, that outperformed LVS in the mouse ID vaccination-respiratory-challenge model. Currently, SCHU S4 ΔclpB has been manufactured under current good manufacturing practice conditions, and tested for safety and efficacy in mice, rats, and macaques. The steps necessary for advancing SCHU S4 ΔclpB to this late stage of development are detailed herein. These include developing a body of data supporting the attenuation of SCHU S4 ΔclpB to a degree sufficient for removal from the U.S. Select Agent list and for human use; optimizing SCHU S4 ΔclpB vaccine production, scale up, and long-term storage; and developing appropriate quality control testing approaches.
Collapse
|
21
|
Bohning K, Sonnberg S, Chen HL, Zahralban-Steele M, Powell T, Hather G, Patel HK, Dean HJ. A high throughput reporter virus particle microneutralization assay for quantitation of Zika virus neutralizing antibodies in multiple species. PLoS One 2021; 16:e0250516. [PMID: 33891631 PMCID: PMC8064526 DOI: 10.1371/journal.pone.0250516] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 04/06/2021] [Indexed: 12/20/2022] Open
Abstract
Zika virus is a Flavivirus, transmitted via Aedes mosquitos, that causes a range of symptoms including Zika congenital syndrome. Zika has posed a challenging situation for health, public and economic sectors of affected countries. To quantitate Zika virus neutralizing antibody titers in serum samples, we developed a high throughput plate based Zika virus reporter virus particle (RVP) assay that uses an infective, non-replicating particle encoding Zika virus surface proteins and capsid (CprME) and a reporter gene (Renilla luciferase). This is the first characterization of a Zika virus RVP assay in 384-well format using a Dengue replicon Renilla reporter construct. Serially diluted test sera were incubated with RVPs, followed by incubation with Vero cells. RVPs that have not been neutralized by antibodies in the test sera entered the cells and expressed Renilla luciferase. Quantitative measurements of neutralizing activity were determined using a plate-based assay and commercially available substrate. The principle of limiting the infection to a single round increases the precision of the assay measurements. RVP log10EC50 titers correlated closely with titers determined using a plaque reduction neutralization test (PRNT) (R2>95%). The plate-based Zika virus RVP assay also demonstrated high levels of precision, reproducibility and throughput. The assay employs identical reagents for human, rhesus macaque and mouse serum matrices. Spiking studies indicated that the assay performs equally well in different species, producing comparable titers irrespective of the serum species. The assay is conducted in 384-well plates and can be automated to simultaneously achieve high throughput and high reproducibility.
Collapse
Affiliation(s)
- Kelly Bohning
- Takeda Vaccines, Inc., Cambridge, Massachusetts, United States of America
| | - Stephanie Sonnberg
- Takeda Vaccines, Inc., Cambridge, Massachusetts, United States of America
| | - Hui-Ling Chen
- Takeda Vaccines, Inc., Cambridge, Massachusetts, United States of America
| | | | - Timothy Powell
- Takeda Vaccines, Inc., Cambridge, Massachusetts, United States of America
| | - Greg Hather
- Takeda Vaccines, Inc., Cambridge, Massachusetts, United States of America
| | - Hetal K. Patel
- Takeda Vaccines, Inc., Cambridge, Massachusetts, United States of America
| | - Hansi J. Dean
- Takeda Vaccines, Inc., Cambridge, Massachusetts, United States of America
| |
Collapse
|
22
|
Monrad JT, Sandbrink JB, Cherian NG. Promoting versatile vaccine development for emerging pandemics. NPJ Vaccines 2021; 6:26. [PMID: 33574335 PMCID: PMC7878788 DOI: 10.1038/s41541-021-00290-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/04/2021] [Indexed: 12/22/2022] Open
Abstract
The ongoing COVID-19 pandemic has demonstrated the importance of rapid and versatile development of emergency medical countermeasures such as vaccines. We discuss the role of platform vaccines and prototype pathogen research in modern vaccine development, and outline how previous pathogen-specific funding approaches can be improved to adequately promote vaccine R&D for emerging pandemics. We present a more comprehensive approach to financing vaccine R&D, which maximises biomedical pandemic preparedness by promoting flexible vaccine platforms and translatable research into prototype pathogens. As the numerous platform-based SARS-CoV-2 vaccines show, funders can accelerate pandemic vaccine development by proactively investing in versatile platform technologies. For certain emerging infectious diseases, where vaccine research can translate to other related pathogens with pandemic potential, investment decisions should reflect the full social value of increasing overall preparedness, rather than just the value of bringing a vaccine to market for individual pathogens.
Collapse
Affiliation(s)
- Joshua T Monrad
- Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK.
- Department of Health Policy, London School of Economics, London, UK.
- Future of Humanity Institute, University of Oxford, Oxford, UK.
| | - Jonas B Sandbrink
- Future of Humanity Institute, University of Oxford, Oxford, UK
- Medical Sciences Division, University of Oxford, Oxford, UK
| | - Neil G Cherian
- The Coalition of Epidemic Preparedness Innovations, Oslo, Norway
- Johns Hopkins Center for Health Security, Baltimore, USA
| |
Collapse
|
23
|
Rahman IU, Ali N, Ijaz F, Afzal A, Abd Allah EF. COVID-19 - Important considerations for developing and using a vaccine. Hum Vaccin Immunother 2021; 17:414-415. [PMID: 32693665 DOI: 10.1080/21645515.2020.1781507] [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: 10/23/2022] Open
Abstract
The novel coronavirus SARS-CoV-2 after emerging in China has caused a global pandemic that is risking the lives of millions. COVID-19 has spread across the world at a very rapid rate raising concerns of capacity limitations and lack of unified responses at the global level, particularly from the world's most developed countries. The spread of further infection has been curtailed by lockdown and mass social distancing that has been enforced in most parts of the world. There are no clinical data yet suggesting that any available candidate vaccine will be effective for COVID-19 which will be a critical need for eventually preventing this disease. Extensive research is underway with some success in identification of monoclonal antibodies from COVID-19 recovered patients, which may inform on vaccine development. The clinical evaluations of COVID-19 vaccines need to follow standardized protocols that are essential for safeguarding humans. In absence of a vaccine or a widely available effective therapy, quarantine and other preventive measures are essential in curtailing the risk of pandemic spread.
Collapse
Affiliation(s)
| | - Niaz Ali
- Department of Botany, Hazara University , Mansehra, Pakistan
| | - Farhana Ijaz
- Department of Botany, Hazara University , Mansehra, Pakistan
| | - Aftab Afzal
- Department of Botany, Hazara University , Mansehra, Pakistan
| | - Elsayed Fathi Abd Allah
- Department of Plant Production, College of Food and Agriculture Science, King Saud University , Riyadh, Saudi Arabia
| |
Collapse
|
24
|
Navigating facilitated regulatory pathways during a disease X pandemic. NPJ Vaccines 2020; 5:101. [PMID: 33110630 PMCID: PMC7584587 DOI: 10.1038/s41541-020-00249-5] [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: 03/20/2020] [Accepted: 09/25/2020] [Indexed: 11/09/2022] Open
Abstract
In 2018, the Bill and Melinda Gates Foundation convened over thirty subject matter experts in clinical development, manufacturing, and regulatory assessment to determine how the development and approval of medical countermeasures could be accelerated in the event of Disease X. Disease X is the result of a presently unknown pathogen with epidemic or pandemic potential. A key opportunity to accelerate the scientific assessment and regulatory approval of medical countermeasures exists within efficient navigation of facilitated regulatory pathways. It was identified that not all stakeholders will be able to skillfully navigate the facilitated pathways offered by the various regulatory agencies during a public health emergency. To democratize this knowledge, we have written an overview of the facilitated approaches which have been developed and refined by Stringent Regulatory Authorities and the World Health Organization for the primary assessment of medical products. We discuss the conditions necessary for use of these approaches, scenarios in which certain pathways may be applicable, and the pros and cons of these approaches. We also address opportunities available to developers in, or developers who wish to access, low-income countries that may have nascent regulatory frameworks.
Collapse
|
25
|
Sanicas M, Sanicas M, Diop D, Montomoli E. A review of COVID-19 vaccines in development: 6 months into the pandemic. Pan Afr Med J 2020; 37:124. [PMID: 33425157 PMCID: PMC7755367 DOI: 10.11604/pamj.2020.37.124.24973] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 07/29/2020] [Indexed: 11/17/2022] Open
Abstract
The advent of the COVID-19 pandemic and the dynamics of its spread is unprecedented. Therefore, the need for a vaccine against the virus is huge. Researchers worldwide are working around the clock to find a vaccine. Experts estimate that a fast-tracked vaccine development process could speed a successful candidate to market in approximately 12-18 months. The objective of this review was to describe the coronavirus vaccines candidates in development and the important considerations. The review was conducted through a thematic analysis of the literature on COVID-19 vaccines in development. It only included data until the end of June 2020, 6 months after the emergence of the COVID-19. Different approaches are currently used to develop COVID-19 vaccines from traditional live-attenuated, inactivated, subunit vaccines, to more novel technologies such as DNA or mRNA vaccines. The race is on to find both medicines and vaccines for the COVID-19 pandemic. As with drugs, vaccine candidates go through pre-clinical testing first before they go through the three phases of clinical trials in humans. Of the over 130 vaccine candidates, 17 are in clinical trials while others are expected to move to clinical testing after the animal studies.
Collapse
Affiliation(s)
- Merlin Sanicas
- Centre de Recherche en Cancérologie de Marseille, Université Aix-Marseille, Marseille, France
| | - Melvin Sanicas
- Clinical Development, Takeda Pharmaceuticals International AG, Zurich, Switzerland
| | | | - Emanuele Montomoli
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy.,VisMederi Life Science Research, Siena, Italy
| |
Collapse
|
26
|
Savransky V, Ionin B, Reece J. Current Status and Trends in Prophylaxis and Management of Anthrax Disease. Pathogens 2020; 9:E370. [PMID: 32408493 PMCID: PMC7281134 DOI: 10.3390/pathogens9050370] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/29/2020] [Accepted: 05/07/2020] [Indexed: 12/30/2022] Open
Abstract
Bacillus anthracis has been identified as a potential military and bioterror agent as it is relatively simple to produce, with spores that are highly resilient to degradation in the environment and easily dispersed. These characteristics are important in describing how anthrax could be used as a weapon, but they are also important in understanding and determining appropriate prevention and treatment of anthrax disease. Today, anthrax disease is primarily enzootic and found mostly in the developing world, where it is still associated with considerable mortality and morbidity in humans and livestock. This review article describes the spectrum of disease caused by anthrax and the various prevention and treatment options. Specifically we discuss the following; (1) clinical manifestations of anthrax disease (cutaneous, gastrointestinal, inhalational and intravenous-associated); (2) immunology of the disease; (3) an overview of animal models used in research; (4) the current World Health Organization and U.S. Government guidelines for investigation, management, and prophylaxis; (5) unique regulatory approaches to licensure and approval of anthrax medical countermeasures; (6) the history of vaccination and pre-exposure prophylaxis; (7) post-exposure prophylaxis and disease management; (8) treatment of symptomatic disease through the use of antibiotics and hyperimmune or monoclonal antibody-based antitoxin therapies; and (9) the current landscape of next-generation product candidates under development.
Collapse
Affiliation(s)
- Vladimir Savransky
- Emergent BioSolutions Inc., 300 Professional Drive, Gaithersburg, MD 20879, USA; (B.I.); (J.R.)
| | | | | |
Collapse
|
27
|
Meeting report: WHO consultation on accelerating Lassa fever vaccine development in endemic countries, Dakar, 10–11 September 2019. Vaccine 2020; 38:4135-4141. [DOI: 10.1016/j.vaccine.2020.01.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 01/07/2020] [Indexed: 01/08/2023]
|
28
|
Abstract
Exciting clinical results from 2 clinical TB vaccine trials were published in 2018. These, plus promising preclinical candidates form a healthy pipeline of potential vaccines against the leading cause of death from a single infectious agent. The only licensed vaccine, the BCG, continues to be an important tool in protecting against severe forms of TB in children, but has not stopped the diseases causing 1.3 million deaths per year. This review provides an overview of the current TB vaccine pipeline, highlighting recent findings, describes work relating to epidemiologic impact of vaccines, and discusses the future of TB vaccine development.
Collapse
Affiliation(s)
- Lisa Stockdale
- Department of Paediatrics, University of Oxford, Oxford, UK; NIHR Oxford Biomedical Research Centre and Oxford University Hospitals NHS Foundation Trust, Oxford, UK. https://twitter.com/LisaStockdale
| | - Helen Fletcher
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
| |
Collapse
|
29
|
Williamson ED, Westlake GE. Vaccines for emerging pathogens: prospects for licensure. Clin Exp Immunol 2019; 198:170-183. [PMID: 30972733 PMCID: PMC6797873 DOI: 10.1111/cei.13284] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2019] [Indexed: 12/28/2022] Open
Abstract
Globally, there are a number of emerging pathogens. For most, there are no licensed vaccines available for human use, although there is ongoing research and development. However, given the extensive and increasing list of emerging pathogens and the investment required to bring vaccines into clinical use, the task is huge. Overlaid on this task is the risk of anti‐microbial resistance (AMR) acquisition by micro‐organisms which can endow a relatively harmless organism with pathogenic potential. Furthermore, climate change also introduces a challenge by causing some of the insect vectors and environmental conditions prevalent in tropical regions to begin to spread out from these traditional areas, thus increasing the risk of migration of zoonotic disease. Vaccination provides a defence against these emerging pathogens. However, vaccines for pathogens which cause severe, but occasional, disease outbreaks in endemic pockets have suffered from a lack of commercial incentive for development to a clinical standard, encompassing Phase III clinical trials for efficacy. An alternative is to develop such vaccines to request US Emergency Use Authorization (EUA), or equivalent status in the United States, Canada and the European Union, making use of a considerable number of regulatory mechanisms that are available prior to licensing. This review covers the status of vaccine development for some of the emerging pathogens, the hurdles that need to be overcome to achieve EUA or an equivalent regional or national status and how these considerations may impact vaccine development for the future, such that a more comprehensive stockpile of promising vaccines can be achieved.
Collapse
Affiliation(s)
- E D Williamson
- CBR Division, Defence Science and Technology Laboratory, Salisbury, Wiltshire, UK
| | - G E Westlake
- CBR Division, Defence Science and Technology Laboratory, Salisbury, Wiltshire, UK
| |
Collapse
|
30
|
McLean RK, Graham SP. Vaccine Development for Nipah Virus Infection in Pigs. Front Vet Sci 2019; 6:16. [PMID: 30778392 PMCID: PMC6369168 DOI: 10.3389/fvets.2019.00016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/16/2019] [Indexed: 01/29/2023] Open
Abstract
Nipah virus (NiV) causes a severe and often fatal neurological disease in humans. Whilst fruit bats are considered the natural reservoir, NiV also infects pigs and may cause an unapparent or mild disease. Direct pig-to-human transmission was responsible for the first and still most devastating NiV outbreaks in Malaysia and Singapore in 1998–99, with nearly 300 human cases and over 100 fatalities. Pigs can therefore play a key role in the epidemiology of NiV by acting as an “amplifying” host. The outbreak in Singapore ended with the prohibition of pig imports from Malaysia and the Malaysian outbreak was ended by culling 45% of the country's pig population with costs exceeding US$500 million. Despite the importance of NiV as an emerging disease with the potential for pandemic, no vaccines, or therapeutics are currently approved for human or livestock use. In this mini-review, we will discuss current knowledge of NiV infection in pigs; our ongoing work to develop a NiV vaccine for use in pigs; and the pig as a model to support human vaccine development.
Collapse
Affiliation(s)
| | - Simon P Graham
- The Pirbright Institute, Pirbright, United Kingdom.,School of Veterinary Medicine, University of Surrey, Guildford, United Kingdom
| |
Collapse
|
31
|
Abstract
The recent epidemic of Zika virus (ZIKV) in the Americas has revealed the devastating consequences of ZIKV infection, particularly in pregnant women. Congenital Zika syndrome, characterized by malformations and microcephaly in neonates as well as developmental challenges in children, highlights the need for the development of a safe and effective vaccine. Multiple vaccine candidates have been developed and have shown promising results in both animal models and phase I clinical trials. However, important challenges remain for the clinical development of these vaccines. In this Progress article, we discuss recent preclinical studies and lessons learned from first-in-human clinical trials with ZIKV vaccines.
Collapse
|
32
|
Roberts LM, Powell DA, Frelinger JA. Adaptive Immunity to Francisella tularensis and Considerations for Vaccine Development. Front Cell Infect Microbiol 2018; 8:115. [PMID: 29682484 PMCID: PMC5898179 DOI: 10.3389/fcimb.2018.00115] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/23/2018] [Indexed: 11/13/2022] Open
Abstract
Francisella tularensis is an intracellular bacterium that causes the disease tularemia. There are several subspecies of F. tularensis whose ability to cause disease varies in humans. The most virulent subspecies, tularensis, is a Tier One Select Agent and a potential bioweapon. Although considerable effort has made to generate efficacious tularemia vaccines, to date none have been licensed for use in the United States. Despite the lack of a tularemia vaccine, we have learned a great deal about the adaptive immune response the underlies protective immunity. Herein, we detail the animal models commonly used to study tularemia and their recapitulation of human disease, the field's current understanding of vaccine-mediated protection, and discuss the challenges associated with new vaccine development.
Collapse
Affiliation(s)
- Lydia M Roberts
- Immunity to Pulmonary Pathogens Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, United States
| | - Daniel A Powell
- Department of Immunobiology and Valley Fever Center for Excellence, University of Arizona, Tucson, AZ, United States
| | - Jeffrey A Frelinger
- Department of Immunobiology and Valley Fever Center for Excellence, University of Arizona, Tucson, AZ, United States
| |
Collapse
|
33
|
Titball RW, Burtnick MN, Bancroft GJ, Brett P. Burkholderia pseudomallei and Burkholderia mallei vaccines: Are we close to clinical trials? Vaccine 2017; 35:5981-5989. [DOI: 10.1016/j.vaccine.2017.03.022] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/17/2017] [Accepted: 03/07/2017] [Indexed: 10/19/2022]
|
34
|
The state of gene therapy research in Africa, its significance and implications for the future. Gene Ther 2017; 24:581-589. [PMID: 28692018 PMCID: PMC7094717 DOI: 10.1038/gt.2017.57] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/04/2017] [Accepted: 07/05/2017] [Indexed: 12/12/2022]
Abstract
Gene therapy has made impressive recent progress and has potential for treating a wide range of diseases, many of which are important to Africa. However, as a result of lack of direct public funding and skilled personnel, direct research on gene therapy in Africa is currently limited and resources to support the endeavor are modest. A strength of the technology is that it is based on principles of rational design, and the tools of gene therapy are now highly versatile. For example gene silencing and gene editing may be used to disable viral genes for therapeutic purposes. Gene therapy may thus lead to cure from infections with HIV-1, hepatitis B virus and Ebola virus, which are of significant public health importance in Africa. Although enthusiasm for gene therapy is justified, significant challenges to implementing the technology remain. These include ensuring efficient delivery of therapeutic nucleic acids to target cells, limiting unintended effects, cost and complexity of treatment regimens. In addition, implementation of effective legislation that will govern gene therapy research will be a challenge. Nevertheless, it is an exciting prospect that gene therapy should soon reach the mainstream of medical management. Participation of African researchers in the exciting developments is currently limited, but their involvement is important to address health problems, develop capacity and enhance economic progress of the continent.
Collapse
|