(12) Patent Application Publication (10) Pub. No.: US 2009/0221523 A1 Tseng Et Al
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US 2009.022 1523A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2009/0221523 A1 Tseng et al. (43) Pub. Date: Sep. 3, 2009 (54) NORTH-2'-DEOXY-METHANO- (86). PCT No.: PCT/US2O06/02O894 CARBATHYMIDNES AS ANTIVIRAL AGENTS AGAINST POXVIRUSES S371 (c)(1), (2), (4) Date: Apr. 3, 2009 (76) Inventors: Christopher K. Tseng, Related U.S. Application Data Burtonsville, MD (US); Victor E. (60) Provisional application No. 60/684.811, filed on May Marquez, Montgomery Village, 25, 2005. MD (US) Publication Classification (51) Int. Cl. Correspondence Address: A 6LX 3L/7072 (2006.01) KNOBBE, MARTENS, OLSON & BEAR, LLP A6IP3L/20 (2006.01) 2040 MAINSTREET, FOURTEENTH FLOOR (52) U.S. Cl. .......................................................... S14/SO IRVINE, CA 92.614 (US) (57) ABSTRACT (21) Appl. No.: 11/920,881 A method for the prevention or treatment of poxvirus infec tion by administering an effective amount of an antiviral agent comprising cyclopropanated carbocyclic 2'-deoxy (22) PCT Filed: May 25, 2006 nucleoside to an individual in need thereof is provided. Patent Application Publication Sep. 3, 2009 Sheet 2 of 3 US 2009/022 1523 A1 HSV-2 TK Goalpox TK humonl TK VV TK VOriod TK monkeypox TK fowlpox TK HSV-1 K african swine fever virus TK VZV TK EBV TK FIF2 Patent Application Publication Sep. 3, 2009 Sheet 3 of 3 US 2009/022 1523 A1 CC (N)-MCT CDV VC – -2 48.61 site - 2322 2027 . US 2009/022 1523 A1 Sep. 3, 2009 NORTH-2-DEOXY. breaks depended on the isolation of infected individuals and METHANOCARBATHYMIDNES AS the vaccination of close contacts. The vaccine was highly ANTIVIRAL AGENTS AGAINST POXVIRUSES effective. If given during the incubation period, it either pre vented or reduced the severity of clinical symptoms. The RELATED APPLICATIONS origin of the vaccine Strain is not known, it is thought that it 0001. This application claims the benefit of priority of may have been horsepox which is now an extinct disease. On U.S. Provisional Application No. 60/684,811, filed May 25, 8 May 1980, the Thirty-third World Health Assembly 2005, the disclosure of which is hereby expressly incorpo declared that smallpox had been eradicated globally. 0007. The discontinuation of routine vaccination has ren rated by reference in its entirety. dered civilian and military populations more Susceptible to a FIELD OF THE INVENTION disease that is not only infectious by aerosol, but also infa mous for its devastating morbidity and mortality. Since 1983, 0002. A method for the prevention or treatment of poxvi there have existed two WHO-approved and inspected reposi rus infection by administering an effective amount of an tories of variola virus: the CDC in the United States and antiviral agent comprising cyclopropanated carbocyclic Vector Laboratories in Russia. Despite the promise of variola 2'-deoxynucleoside to an individual in need thereof is pro virus extinction as a biological entity, the prospect of surrep vided. titious weaponization of Smallpox remains Vexing. Smallpox virus, used as a weapon against an unimmunized population, BACKGROUND OF THE INVENTION has the potential to infect tens of thousands of individuals, kill 0003 Poxviruses (members of the Poxviridae family) are 30% or more of those infected, and trigger the vaccination of the largest and most complex viruses. They are linear double many times that number of individuals. stranded DNA viruses of 130-300 kilobase pair. The 200-400 0008. In most individuals, the smallpox vaccine is safe and nm virion is oval or brick-shaped and can be visualized by effective. However, certain individuals can experience poten light microscopy. The extracellular virion possesses 2 enve tially fatal effects, including eczema vaccinatum, progressive lopes, while the intracellular virus has only 1 envelope. The vaccinia, and postvaccinal encephalitis. In view of the poten virion contains a large number of proteins, at least 10 of which tial adverse effects associated with the Smallpox vaccine, possess enzymatic activity needed for genomic replication. widespread vaccination of the population may not be an Virus replication is equally complex. Infection is initiated by acceptable response to the threat of smallpox bioterrorism. attachment of the virus to one of several cellular receptors. 0009 Most studies have focused so far on the efficacy of The virus then can enter the cell by a number of mechanisms. cidofovir (CDV) against poxviruses. (See De Clercq, et al., Unlike other DNA viruses, poxviruses replicate in the cyto Reviews in Medical Virology, September 2004, vol. 14, no. 5, plasm. The virus contains all the elements for genomic rep pp. 289-300(12)). This compound has demonstrable activity lication, but cellular functions appear necessary for complete against cowpox in mice and against monkeypox in monkeys. viral maturation. In the United States, cidofovir may be used in emergencies as 0004 Infections due to the poxviruses occur in humans an investigational new drug to treat significant adverse events and animals. The orthopoxviruses include Smallpox (variola), following immunization with the current Smallpox vaccine, monkeypox, vaccinia, and cowpox viruses. Parapoxviruses and in the unlikely event of smallpox re-emerging. At present, include orf virus, bovine papular stomatitis virus, pseudoco cidofovir is the drug of choice for therapy of potential small wpox virus, and Sealpox virus. Yatapoxviruses include pox outbreaks and vaccination complications, and an inves tanapox virus andyabapoxviruses, which are found primarily tigational new drug protocol was approved recently for use in in Africa. Molluscipoxviruses include the human poxvirus, response to an actual Smallpox outbreak. Although cidofovir molluscum contagiosum virus. Smallpox and molluscum are is very active against all the orthopoxviruses, it has major specific to humans. The other viruses cause rare Zoonotic limitations in its usefulness. Cidofovir is toxic to kidney infections in humans. tubules and is not active orally, which necessitates intrave 0005 Vaccinia virus can infect humans, and has been used nous administration. From a practical standpoint, it is antici for immunization against Smallpox. Its origins are not known pated that dosing will be limited to a single dose or to no more but it is believed to be a genetically-distinct type of pox virus than two doses in a smallpox outbreak except for immuno which grows readily in a variety of hosts. In man, it causes a compromised individuals who may require lengthy antiviral localized pustule with scar formation. In immunocompro therapy. (See Quenelle, et al. Antimicrobial Agents and Che mised persons or eczematous persons, it sometimes causes a motherapy, October 2003, p. 3275-3280, Vol. 47, No. 10). severe generalized vaccinia infection. Cowpox is acquired by 0010 Nucleoside analogs lacking 2- and 3'-hydroxyl humans usually by milking cows. It then manifests as ulcer groups (dideoxynucleosides), as well as those 2'-deoxy ative lesions (sometimes called “milkers nodules') on the nucleosides where the 3'-hydroxyl function has been chemi hands of dairy workers. Despite its name, rodents are the main cally modified or changed, can function as chain terminators reservoir of cowpox; it spreads secondarily to cows and of DNA synthesis after their triphosphate metabolites are domestic cats. Vaccinia and cowpox are two of only a few incorporated into DNA. This is the basis of the Sanger experimental animal infections available for evaluation of dideoxynucleotide method for DNA sequencing (Sanger et antiviral compounds against orthopoxviruses. al., Proc. Natl. Acad. Sci. USA, 1977). Intense effort has 0006 Smallpox is transmitted by respiratory route from focused on the design and use of these compounds as inhibi lesions in the respiratory tract of patients in the early stage of tors of viral replication (Van Roey et al., Ann. N.Y. Acad. Sci., the disease. During the 12 day incubation period, the virus is 616:29, 1990). Although the conformation of the sugar moi distributed initially to the internal organs and then to the skin. ety in these analogs is believed to play a critical role in Variola major caused severe infections with 20-50% mortal modulating biological activity, including the anti-HIV activ ity, variola minor with <1% mortality. Management of out ity mediated by derivatives such as azidothymidine (AZT) US 2009/022 1523 A1 Sep. 3, 2009 and dideoxyinosine (dd), the main problem encountered in date the stabilizing effect of multiple (N)-methanocarba-Ts in correlating a specific type of Sugar conformation with the the context of the DNA/RNA heteroduplex, a test sequence biological activity of nucleoside analogs is that the Sugar ring targeted to the coding region of the SV40 large T-antigen is quite flexible and its conformation in solution can differ (Wagner, R. W. et al. 1993, Science 260:1510-13) was sub markedly from its conformation in the Solid state (Jagannadh sequently synthesized as the phosphorothioate 5'-CT et al., Biochem. Biophys. Res. Commun., 179:386; Plavec et TCATTTTTTCTTC-3' (SEQ ID NO: 1), where all thy al., Biochem. Biophys. Methods, 25:253). Thus, for nucleo midines (T) were replaced by (N)-methanocarba-Ts sides in general, any structure-activity analysis which is (Marquez, et al., 1996. J. Med. Chem. 39:3739-47). The based solely on the solid-state conformation would be inac additive increase in thermodynamic stability of the heterodu curate unless it was previously determined that both solution plex due to the presence of multiple (N)-methanocarba-T and solid-state conformations were the same. nucleotides was clearly demonstrated with the average stabi 0011. In solution there is a dynamic equilibrium between lization per substitution of ca. 1.3°C. relative to thymidine Northern (N) and Southern (S) type furanose conformers (Marquez, et al., 1996. J. Med. Chem. 39:3739-47). (Taylor et al., Antiviral Chem. Chemother, 1:163-173, 1990) 0015 Conformationally (Northern) locked nucleoside as defined in the pseudorotational cycle.