The ebolaviruses (EBOV, SUDV, BDBV) and marburgviruses (MARV and RAVV), cause periodic outbreaks of severe viral hemorrhagic fever with very high mortality rates. The 2013-2016 Ebola virus disease (EVD) outbreak in West Africa highlighted the serious nature of a filovirus epidemic and its regional and global implications. This outbreak took an enormous toll on people at the front line of the epidemic control, i.e., physicians, nurses, hospital personnel, social workers, and other support staff. Many nurses and physicians lost their lives helping patients and many left their profession out of fear of exposure. The near breakdown of the local healthcare system further fueled the spread of the virus across the region. Therefore, protection of the first responders must be a high priority and is critical for successful outbreak control. Currently, while a prophylactic vaccine is available for EVD, there are no therapeutic or prophylactic countermeasures available for Marburg virus disease (MVD) which has led to many outbreaks and as recently as June 2022. The objective of this proposal is to develop an effective immunoprophylactic for protection of first responders against MVD. Such a product mut be 1) extremely potent to enable economically affordable low dose levels, and 2) have extended bioavailability to provide a reasonably long duration of protection. We and others have isolated several classes of neutralizing monoclonal antibodies (mAbs) for ebolaviruses. However, for marburgviruses only a single class of mAbs against the glycoprotein (GP) has been described that all target a single epitope within the receptor binding site (RBS) of MARV and RAVV GP. Now, using a novel immunization and B cell selection approach with rationally designed antigens we have succeeded in identifying a new class of mAbs that bind to a novel epitope and neutralize marburgviruses at sub- to low-nM concentrations and are up to 100-fold more potent than the RBS binders. A lead antibody, R217, has been selected and shown to protect against MVD in mice, guinea pigs, and nonhuman primates (NHPs). In this SBIR project we propose to engineer the Fc portion of this macaque-human chimeric antibody by introducing mutations (YTE) in the FcRn binding region to extend the half-life of the antibody and evaluate the efficacy of the product. In Aim 1 R217-YTE will be produced in ExpiCHO cells and fully characterized. Pharmacokinetics (PK) will be evaluated in NHPs. In Aim 2, the efficacy of R217-YTE against MVD will be evaluated in the settings of pre- and post-exposure prophylaxis and the required dose level and serum neutralization activity required for protection will be determined. Aim 3 will be focused on generation of a stable manufacturing cell line in CHO cells and a research cell bank to be used for production of future GMP cell banks. If successful, we anticipate further development of the product under DoD or BARDA funding and approval under FDA Animal Rule.
Public Health Relevance Statement: Filoviruses are among the deadliest pathogens known to humans. The Ebola virus disease outbreak in West Africa (2014-2016), caused by the Zaire Ebola virus, resulted in over 28,000 cases and 11,000 deaths. In addition to Ebola virus, a related filovirus called Marburg has caused five outbreaks in the past 10 years with high fatality rates. This proposal is aimed at developing effective immunoprophylactic against Marburg virus for protection of first responders during outbreaks of Marburg virus disease. We have generated several antibody drug candidates that protect against Marburg infection. Under this proposal we will engineer the lead antibody to acquire long term durability after injection and we will perform animal efficacy studies. This study, if successful, will set the stage for clinical development of an effective therapeutic for human use.
Project Terms: Acceleration; Africa; Antibodies; Clinical Treatment Moab; mAbs; monoclonal Abs; Monoclonal Antibodies; Antigenic Determinants; Binding Determinants; Epitopes; immunogen; Antigens; B-Lymphocytes; B blood cells; B cell; B cells; B-Cells; B-cell; Binding Sites; Combining Site; Reactive Site; Biological Availability; Bioavailability; Physiologic Availability; Biological Products; Biologic Products; Biological Agent; biologics; biopharmaceutical; biotherapeutic agent; Biological Response Modifier Therapy; Biological Therapy; biological therapeutic; biological treatment; biologically based therapeutics; biotherapeutics; biotherapy; Blood Chemical Analysis; Blood Chemical Analyses; blood chemistry; Cell Line; CellLine; Strains Cell Lines; cultured cell line; Cells; Cell Body; Cessation of life; Death; Disease Outbreaks; Outbreaks; Ebola virus; EBOV; Ebola-like Viruses; ebolavirus; Engineering; Epidemic; Family; Fright; Fear; Future; Glycoproteins; Half-Life; Healthcare Systems; Health Care Systems; Health Personnel; Health Care Providers; Healthcare Providers; Healthcare worker; health care personnel; health care worker; health provider; health workforce; healthcare personnel; medical personnel; treatment provider; Hematology; Viral Hemorrhagic Fevers; hemorrhagic fever; Human; Modern Man; Immunity; Immunization; Immunotherapy; Immune mediated therapy; Immunologically Directed Therapy; immune therapeutic approach; immune therapeutic interventions; immune therapeutic regimens; immune therapeutic strategy; immune therapy; immune-based therapies; immune-based treatments; immuno therapy; Infection; Lead; Pb element; heavy metal Pb; heavy metal lead; Licensure; Macaca; Macaque; Macaca fascicularis; Crab-Eating Macaque; Crab-Eating Monkey; Cynomolgus Monkey; Cynomolgus macaque; M fascicularis; M. fascicularis; Marburgvirus; Frankfurt-Marburg Syndrome Virus; Marburg; Marburg virus; Marburg-like Viruses; Marburg Virus Disease; Marburg hemorrhagic fever; mortality; Mus; Mice; Mice Mammals; Murine; Mutation; Genetic Alteration; Genetic Change; Genetic defect; genome mutation; Persons; Nurses; nurse; Patients; Periodicals; periodic; periodical; Hospital Personnel; Drug Kinetics; Pharmacokinetics; Physicians; pressure; Production; Research; Research Personnel; Investigators; Researchers; Resources; Research Resources; Risk; Safety; Social Workers; Testing; Time; Toxicology; Transfection; Viremia; viraemia; viral sepsis; virusemia; Virus; Work; Generations; Measures; CHO Cells; Chinese Hamster Ovary Cell; Guinea Pigs; Guinea Pigs Mammals; Cavia; health care; Healthcare; bases; base; Prophylaxis; Prophylactic treatment; Left; Phase; Variation; Variant; Biochemical; Filoviridae; Filovirus; Blood Serum; Serum; non-human primate; nonhuman primate; African; Funding; Collaborations; Case Fatality Rates; Ebola Virus Disease; Ebola disease; Ebola Hemorrhagic Fever; Therapeutic; fluid; liquid; Liquid substance; Genetic; Exposure to; Nature; neonatal Fc receptor; FcRn; FcRn neonatal transfer protein; prophylactic; Country; neutralizing antibody; Services; experience; mutant; receptor binding; receptor bound; success; stable cell line; chimeric antibody; Animal Model; Animal Models and Related Studies; model of animal; novel; Memory B-Lymphocyte; Memory B Cell; Prevention; hemorrhagic fever virus; Modeling; Fc domain; cell bank; Sudan Ebola virus; SUDV; Sudan ebolavirus; Sudan virus; Zaire Ebola virus; ZEBOV; Zaire ebolavirus; antigen bound; antigen binding; Molecular Interaction; Binding; Fatality rate; Dose; Aman; Small Business Innovation Research Grant; SBIR; Small Business Innovation Research; Vaccinated; Monitor; Process; Development; developmental; Health protection; Advanced Development; determine efficacy; efficacy analysis; efficacy assessment; efficacy determination; efficacy examination; evaluate efficacy; examine efficacy; efficacy evaluation; new approaches; novel approaches; novel strategy; novel strategies; pathogen; neutralizing mAb; neutralizing monoclonal antibodies; innovate; innovative; innovation; MAb Therapeutics; monoclonal antibody drugs; therapeutic mAbs; Therapeutic Monoclonal Antibodies; product development; animal rule; animal efficacy; drug candidate; GP2; Glycoprotein 2, Zymogen Granule Membrane; Zymogen Granule Membrane Glycoprotein 2; GP2 gene; GP1; GTP-Binding Protein 1; GTPBP1; GTPBP1 gene; Preventative vaccine; Prophylactic vaccine; Preventive vaccine; high risk group; high risk individual; high risk people; high risk population; efficacy study; clinical development; Injections; first responder; Ebola; BDBV; Bundibugyo ebola virus; Bundibugyo ebolavirus; Bundibugyo virus; therapeutically effective; rational design; viral outbreak; viral disease outbreak; virus disease outbreak; outbreak control; outbreak containment; outbreak mitigation; epidemic response; epidemic containment; epidemic control; epidemic mitigation; manufacture
