Herpes virus antiviral agents resistance

Foscamet is an antiviral agent that inhibits replication of all known herpes viruses, including cytomegalovirus (CMV), herpes simplex virus types 1 and 2 (HSV-1, HSV-2), human herpes virus 6 (HHV-6), Epstein-Barr virus (EBV) and varicella-zoster virus (VZV). It is indicated in the treatment of CMV retinitis in patients with AIDS treatment of acyclovir-resistant mucocutaneous HSV infections in immunocompromised patients and as combination therapy with ganciclovir for patients who have relapsed after monotherapy with either drug. 

Andrei, G., Snoeck, R., and De Clercq, E. (1995) Susceptibilities of several drug-resistant herpes simplex virus type 1 strains to alternative antiviral compounds. Antimicrob. Agents Chemother. 39,1632-1635. 

Preliminary studies with azauridine suggest that this material was effective for the treatment of herpes simplex and zoster infections of the human eye (69). Rabbits infected with vaccinia virus vaccine were com-pletely protected from pustule formation and erythema by 2-3 grams of compound injected IV (70). This material apparently has a low order of toxicity. 5-Bromo-2-deoxyuridine was found to inhibit a new virus, equine herpes 3, in rabbit kidney cells as well as pseudorabies, a DMA. virus, whereas vesicular stomatitis, an RNA virus, was resistant (71). A large number of nucleosides have been synthesized and tested in various systems for antiviral activity. 1-p-D-Arabinofuranosylcytosine (cytarabine ara-C) blocked DNA synthesis of herpes-infected cells (72) while a number of structurally related compounds showed some antiviral activity, although less than the parent compound (73,74,75,76). It is still too early to determine the ultimate value of these newer agents as "antiviral" drugs. 

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