Antisense antiviral compounds and methods for treating a filovirus infection
Inventors
Stein, David A. • Iversen, Patrick L. • Bavari, Sina • Weller, Dwight D.
Assignees
Sarepta Therapeutics Inc • United States Department of the Army • US Army Medical Research and Development Command
Publication Number
US-7507196-B2
Publication Date
2009-03-24
Expiration Date
2025-10-31
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
The invention provides antisense antiviral compounds and methods of their use and production in inhibition of growth of viruses of the Filoviridae family, and in the treatment of a viral infection. The compounds and methods relate to the treatment of viral infections in mammals including primates by Ebola and Marburg viruses. The antisense antiviral compounds are morpholino oligonucleotides having: a) a nuclease resistant backbone, b) 15-40 nucleotide bases, and c) a targeting sequence of at least 15 bases in length that hybridizes to a target region selected from the following: i) the AUG start site region of VP35, as exemplified by SEQ ID NOS:67-71 or ii) the AUG start site region of VP24, as exemplified by SEQ ID NOS:72-76.
Core Innovation
The invention provides antisense antiviral compounds and methods to inhibit growth of viruses of the Filoviridae family, particularly Ebola and Marburg viruses, and to treat viral infections in mammals including primates. The antisense compounds are morpholino oligonucleotides characterized by a nuclease-resistant backbone, 15-40 nucleotide bases, and a targeting sequence of at least 15 bases in length that hybridizes to selected target regions in the AUG start site of viral proteins VP35 or VP24 as exemplified by specific SEQ ID NOS.
The problem being solved is the lack of effective antiviral therapies for serious infections caused by minus-strand RNA viruses such as Ebola and Marburg viruses of the Filoviridae family. Existing treatments are limited to supportive care, and host-directed therapies or vaccines have proven insufficient in nonhuman primates. Filoviruses are highly infectious and lethal, with difficulty in working under stringent biocontainment conditions hindering therapeutic development. There is a need for a sequence-specific therapeutic agent that can effectively inhibit viral gene expression and replication.
The antisense compounds of the invention bind specifically to the positive-strand mRNA start-site regions of VP35 or VP24, forming stable heteroduplexes with melting temperatures of at least 45°C, and exhibit resistance to nuclease degradation. The compounds can be conjugated to arginine-rich polypeptides to enhance cellular uptake. Methods include treating infected subjects with therapeutically effective amounts of these antisense morpholino oligomers to inhibit replication of filoviruses, and vaccinating mammals by pretreatment followed by exposure to attenuated virus.
Claims Coverage
This patent includes multiple claims centered on methods of treating Filovirus infection using antisense morpholino oligomers, detailing key inventive features of the antiviral compounds and their characteristics.
Use of morpholino oligomers with positively charged intersubunit linkages
The antiviral composition comprises morpholino subunits linked by phosphorous-containing intersubunit linkages joining a morpholino nitrogen to a 5′ exocyclic carbon, where at least 2 and no more than half of these linkages are positively charged at physiological pH, enhancing activity and cellular uptake.
Targeting sequence complementary to AUG start-site of viral VP35 mRNA
The antisense oligomer contains a targeting sequence forming a heteroduplex with the AUG start-site region of positive-strand mRNA for Filovirus viral protein 35 (VP35), thereby specifically inhibiting virus production.
Heteroduplex stability with melting temperature of at least 45°C
The formed heteroduplex between the antisense oligomer and target sequence exhibits a dissociation melting temperature of at least 45° C., ensuring stable and effective hybridization.
Oligomer length and structural characteristics
The oligomer ranges between 12 and 40 subunits and includes intersubunit linkages conforming to defined chemical structures exemplified in the patent, ensuring nuclease resistance and binding specificity.
Application to Ebola virus, specifically Zaire strain
The method specifically contemplates treatment against Ebola virus infections, including viruses of the Ebola Zaire strain, using the described antisense oligomer.
The claimed invention covers therapeutic methods using morpholino antisense oligomers with partially cationic backbones and targeting sequences complementary to the AUG start site of the VP35 viral mRNA to inhibit Filovirus replication, especially Ebola virus, with defined stability and structural parameters.
Stated Advantages
The antisense compounds effectively inhibit Ebola virus replication in vitro and in vivo in rodents and nonhuman primates, including fully protecting mice from lethal challenge and significantly increasing survival in primates.
Use of cationic intersubunit linkages increases antisense activity by 10-100 fold compared to uncharged analogs.
The compounds demonstrate favorable pharmacokinetics and safety profiles suitable for human use.
Combination therapies targeting multiple viral genes (VP35, VP24, L) show enhanced efficacy and potential synergy.
Treatment induces a protective immune response, enabling vaccination-like immunity and protection upon re-challenge.
Documented Applications
Treatment of mammals, including humans and nonhuman primates, infected with Filovirus family viruses such as Ebola and Marburg viruses by administering antisense morpholino oligomers targeting viral VP35 and VP24 mRNAs.
Use of antisense oligomers conjugated to arginine-rich peptides to enhance cellular uptake for therapeutic efficacy.
Vaccination method involving pretreatment of subjects with antisense compounds followed by exposure to attenuated Ebola virus to induce protective immunity.
Diagnostic application by detecting antisense oligomer-viral RNA heteroduplexes in body fluids for viral strain identification.
Interested in licensing this patent?