E-5-(2-bromovinyl)-2'-deoxyuridine vs. interferon in the systemic treatment of infection with herpes simplex virus of athymic nude mice

The effects of systemic administration of E-5-(2-bromovinyl)-2'-deoxyuridine (BVDU) and interferon (IFN)--mouse IFN type I (MuIFN-alpha plus -beta), mouse IFN type II (MuIFN-gamma), and polyriboinosinic-polyribocytidylic acid (an IFN inducer)--on the development of herpetic skin lesions and associated mortality were studied in athymic nude (nu/nu) mice inoculated intracutaneously with herpes simplex virus (HSV) type 1 (strain KOS). BVDU was given intraperitoneally or orally at dosages of up to 5 mg per mouse per day; IFN and polyriboinosinic-polyribocytidylic acid were given intraperitoneally at dosages of up to 10(6) units per mouse per day and 100 microgram per mouse per day, respectively. Under conditions in which BVDU effectively suppressed the progression of the disease, IFN and polyriboinosinic-polyribocytidylic acid failed to suppress the disease. Thus, BVDU was superior to IFN in the treatment of HSV infection in immunologically compromised mice.     

Clinical basis of chemotherapy for gastric cancer with uracil and 1-(2'-tetrahydrofuryl)-5-fluorouracil

Studies were performed on the clinical basis of chemotherapy for human cancer with uracil and 1-(2'-tetrahydrofuryl)-5-fluorouracil (FT). In 62 operated patients with stomach, breast, and uterine cancers, the concentration of 5FU and FT were compared in serum, tumor and normal tissues 1, 2, 4, 6, 8, and 12 hours following the administration of 300 mg of UFT (300 mg of FT plus 672 mg uracil, a uracil/FT molar ratio of 4), or FT alone. It was found that the level of 5-FU in tumor tissue remained above 0.05 mcg/g over 12 hours. This value for 5-FU corresponds to a minimum inhibitory concentration in the Vitro experiment with L1210 cells. BLood levels of 5-FU increased up to 0.1 mcg/ml 1 hour after UFT administration and then decreased below 0.05 mcg/ml. The drug concentration in normal tissues was lower than that of the tumor tissues. On the basis of the above findings and phase I study, a protocol of UFT-therapy was made and applied for the treatment of gastric cancer. Our patients were given an oral dose of 300 mg of UFT twice a day per 50 kg body weight (12 mg/kg BW). Therapeutic effects were detectable in 7 of 20 cases. In addition, a combination of mitomycin C (6 mg i.v. weekly) with UFT seemed to improve the response rate (5/7). Diarrhea (15%) and skin pigmentation (10%) were major side effects of UFT.     

On the mechanism of selective inhibition of herpesvirus replication by (E)-5-(2-bromovinyl)-2''-deoxyuridine

Bromovinyldeoxyuridine (BVdUrd) is a potent antiherpesvirus compound with low cytotoxicity. To gain an insight into its selectivity and mechanism of inhibition, we chemically synthesized the 5'-triphosphate of BVdUrd, BVdUTP, and tested its effect on the activities of DNA polymerases [DNA nucleotidyltransferase (DNA directed), EC 2.7.7.7] of two herpesviruses--i.e., herpes simplex virus type 1 (HSV-1) and Epstein-Barr virus (EBV)--as well as cellular DNA polymerases alpha, beta, and gamma. The effects on the DNA polymerases were determined under assay conditions optimal for the individual polymerases. We found that the BVdUTP was considerably more inhibityory to the utilization of dTTP by the HSV-1 DNA polymerase then by the cellular DNA polymerases. For instance, as little as 1 microM BVdUTP inhibited the utilization of dTTP by HSV-1 DNA polymerase 50%, whereas the same concentration inhibited the DNA polymerase alpha and the DNA polymerase beta activities only 9% and 3%, respectively. The BVdUTP inhibited DNA synthesis by competing with the natural substrate, dTTP. The Km for dTTP and the Ki for the BVdUTP of the HSV-1 DNA polymerase were 0.66 and 0.25 microM, respectively. Kinetic analyses with the DNA polymerases alpha and beta and the EBV DNA polymerase also reflected a similar difference in sensitivity between the HSV-1 enzyme and other enzymes. Increasing the concentration of either the DNA template or the enzyme in the reaction mixture did not bring about a significant change in the extent of inhibition. Preincubation of the inhibitor with the enzyme was not necessary for inhibition. Studies on time course of inhibition revealed that the compound is inhibitory even after the initiation of DNA synthesis. These studies indicate that the ability of BVdUTP to preferentially inhibit the HSV-1 DNA polymerase may contribute towards its selective inhibition of the viral DNA replication in infected cells.     

5-(2-bromovinyl)-2'-deoxyuridine therapy of herpes zoster diseases in patients with malignant primary diseases

BVDU [(E)-5-(2-bromovinyl)-2'-deoxyuridine] has proved effective in the treatment of varicella-zoster virus diseases in patients with malignancies. In 13 out of 20 patients a prompt cessation of new vesicle formation accompanied by rapid resolution of fever, crusting and complete epithelialisation of cutaneous lesions were noted. Only in few cases a prolonged recovery from the severe zoster occurred. When starting the treatment later than 48 hours after the onset of initial rash the dissemination of epithelial lesions could not be prevented. BVDU was well tolerated. Laboratory abnormalities were observed only in some cases and did not result in interruption of treatment.     

Effect of 9-(1,3-dihydroxy-2-propoxymethyl)guanine and recombinant human beta interferon alone and in combination on simian varicella virus infection in monkeys

Treatment of viral infections with combinations of antiviral agents may permit administration of reduced doses of either or both drugs. Lowered doses may reduce associated toxicity. Intravenous administration of substantial doses of either human recombinant beta interferon (rHuIFN-beta) or 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG) prevents development of simian varicella virus infection in African green monkeys. Daily doses of 2 X 10(6) U of rHuIFN-beta/kg inhibited clinical disease in monkeys inoculated with simian varicella virus, and doses of DHPG between 20 and 60 mg/kg per day were necessary for similar antiviral effects. Intravenous administration of combinations of rHuIFN-beta and DHPG permitted an approximately 100-fold reduction in the effective dose of rHuIFN-beta and a 10-fold reduction in the effective dose of DHPG. Analysis of data relating to viremia by using the method of the median-effect principle showed the combination of rHuIFN-beta and DHPG was strongly synergistic in treatment of this infection.     

Antiviral activity of clevudine [L-FMAU, (1-(2-fluoro-5-methyl-beta, L-arabinofuranosyl) uracil)] against woodchuck hepatitis virus replication and gene expression in chronically infected woodchucks (Marmota monax)

L: -FMAU [1-(2-fluoro-5-methyl-beta,L-arabinofuranosyl) uracil] has been shown to be an effective inhibitor of hepatitis B virus (HBV) and duck hepatitis B virus replication in cell culture and duck hepatitis B virus replication in acutely infected Peking ducks. The woodchuck hepatitis virus (WHV) and its natural host, the Eastern woodchuck (Marmota monax), have been established as a predictive model for the evaluation of antiviral therapies against chronic HBV infection. In this report, the antiviral activity of l-FMAU against WHV replication in chronically infected woodchucks is described. Four weeks of once-daily oral administration of L-FMAU significantly reduced viremia, antigenemia, intrahepatic WHV replication, and intrahepatic expression of woodchuck hepatitis virus core antigen (WHcAg) in a dose-dependent manner. At the highest dose administered (10 mg/kg/d), significant reductions of intrahepatic WHV RNA and covalently closed circular (ccc)WHV-DNA levels also were observed. The reduction in viremia was remarkably rapid at the higher doses of L-FMAU, with greater than 1,000-fold reductions in WHV-DNA serum levels observed after as little as 2 to 3 days of therapy. Following the withdrawal of therapy, a dose-related delay in viremia rebound was observed. At the highest doses used, viremia remained significantly suppressed in at least one half of the treated animals for 10 to 12 weeks' posttreatment. No evidence of drug-related toxicity was observed in the treated animals. L-FMAU is an exceptionally potent antihepadnaviral agent in vitro and in vivo, and is a suitable candidate for antiviral therapy of chronic HBV infection.     

Phase I trial of 1-(2'-deoxy-2'-fluoro-1-beta-D-arabinofuranosyl)-5-methyluracil (FMAU)

1-(2'-Deoxy-2'-fluoro-1-beta-D-arabinofuranosyl)-5-methyluracil (FMAU), a new pyrimidine nucleoside, is of potential clinical interest both as an anticancer and as an antiviral drug. FMAU is active in vitro and in vivo against P815 and L1210 cell lines resistant to cytarabine. Moreover, in mice inoculated ic with herpes simplex virus Type II, FMAU is 100-fold more potent than vidarabine or acyclovir. We have conducted a phase I trial of FMAU in 17 patients with advanced cancer. The dose levels studied were 2, 4, 8, 16, 32, 64, and 128 mg/m2/day iv for 5 days. The dose-limiting toxic effect was drug-induced central nervous system dysfunction. Although 32 mg/m2/day for 5 days produced only transient, mild symptoms, severe encephalopathy with extrapyramidal dysfunction occurred at 64 and 128 mg/m2/day for 5 days and contributed to two deaths. No toxicity was observed at less than 32 mg/m2. A dose of 32 mg/m2/day for 5 days is suggested for phase II study. Because of its potent and selective antiviral activity, future trials of low doses of FMAU in immunosuppressed patients with herpes virus infections are under consideration.     

Clinical and pathogenetic studies of Medical Lake macaque virus infections in cynomolgus monkeys (simian varicella).

The Medical Lake macaque (MLM) virus produced varicelliform eruptions in cynomolgus monkeys. Not all experimentally infected monkeys developed overt disease; viremia was found, and specific antibodies were detected. Specific lesions were found in skin, lymph nodes, and spleen. Focal inflammatory lesions were present in liver, pancreas, and lung (after intratracheal instillation of virus). MLM virus was recovered from these and other organs. The temporal movements of MLM virus in and out of primary and secondary target organs remained partially unsolved. MLM virus is related to the Wu strain of varicella virus.     

9-(2-Phosphonylmethoxyethyl)adenine (PMEA) effectively inhibits retrovirus replication in vitro and simian immunodeficiency virus infection in rhesus monkeys

9-(2-Phosphonylmethoxyethyl)adenine (PMEA) is a potent and selective inhibitor of the in vitro replication of a number of retroviruses, including HIV-1 and HIV-2, simian immunodeficiency virus (SIV), simian AIDS-related virus (SRV), feline immunodeficiency virus (FIV) and Moloney murine sarcoma virus (MSV). PMEA causes a dose-dependent suppression of the induction of anti-SIVmacgp120 antibodies in SIV mac-infected rhesus monkeys. Complete suppression of anti-SIVmacgp120 antibodies was achieved in SIV-infected animals treated with PMEA at 2 x 10 or 2 x 5 mg/kg per day for 29 days. No toxic side-effects were noted during this treatment period. Antibodies against SIVmac gp120 appeared 1-2 weeks after PMEA treatment was stopped, but the antibody titre reached in these animals was significantly lower than in the SIVmac-infected animals who had not been treated with PMEA. Our data strongly suggest that PMEA should be pursued for its potential in the treatment of AIDS and other retrovirus infections.     

(E)-5-(2-Bromovinyl)-2''-deoxyuridine: a potent and selective anti-herpes agent.

Of a series of five newly synthesized 2'-deoxyuridine derivatives, including 5-vinyl-dUrd, 5-ethynyl-dUrd, 5-(1-chlorovinyl)-dUrd, (E)-5-(2-bromovinyl)-dUrd, and (E)-5-(2-iodovinyl)-dUrd, the last two compounds were found to exert a marked inhibitory effect on the replication of herpes simplex virus type 1 [ID50 (mean inhibitory dose), 0.004-0.02 microgram/ml]. Both (E)-5-(2-bromovinyl)-dUrd and (E)-5-(2-iodovinyl)-dUrd were highly selective in their anti-herpes activity in that they did not affect the growth or metabolism of the host (primary rabbit kidney) cells unless drug concentrations were used that were 5,000- to 10,000-fold greater than those required to inhibit virus multiplication. In this sense (E)-5-(2-bromovinyl)-dUrd and (E)-5-(2-iodovinyl)-dUrd proved more selective in their activity against herpes simplex virus type 1 than all other anti-herpes compounds that have been described so far. In animal model systems (namely, cutaneous herpes infections of athymic nude mice), (E)-5-(2-bromovinyl)-dUrd suppressed the development of herpetic skin lesions and mortality therewith associated, whether the compound was administered topically or systemically. Under the same conditions, the standard anti-herpes drug 5-iodo-dUrd (Idoxuridine) offered little, if any, protection. Although the precise mechanism of action of (E)-5-(2-bromovinyl)-dUrd and (E)-5-(2-iodovinyl)-dUrd remains to be established, preliminary findings indicate that they do not specifically act at the thymidylate synthetase step.     

Stability and preliminary pharmacokinetic studies of 1-(2-chloroethyl)-3-[1-(5'-paranitrobenzoyl-2',3'-isopropylidene)-alpha, beta-D-ribofuranosyl]-1-nitrosourea (RFCNU), a nonimmunosuppressive nitrosourea.

Using high-performance liquid chromatography, the stability of RFCNU was monitored as a function of pH in aqueous buffers at 37 degrees C and as a function of temperature in plasma. The kinetics of degradation of RFCNU are apparently first-order. The log kappa-pH profile demonstrated the hydroxyl ion-catalyzed solvolysis and a maximum stability around pH 3.0. This analytic assay was reliable for quantitating intact RFCNU in biologic fluids. After administration of 400 mg of RFCNU orally to a female patient, no intact drug was excreted in the urine and plasma levels were very low.     

Imaging bacterial infections with radiolabeled 1-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-5-iodouracil

Bacterial infections provide diagnostic dilemmas that could be enlightened by modern imaging technologies. We have developed a simple method for imaging bacterial infections in mice that relies on the phosphorylation and trapping of the thymidine kinase (TK) substrate 1-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-5-[125I] iodouracil ([125I]FIAU) within bacteria. FIAU was found to inhibit the growth of WT Escherichia coli but not a TK- strain, indicating that WT E. coli could metabolize this compound. In silico analyses demonstrated that all pathogenic strains of bacteria whose genomes have been sequenced contain a TK gene highly homologous to the E. coli TK. Accordingly, we demonstrated that localized infections caused by representatives of five genera of bacteria could be readily imaged with [125I]FIAU. Such imaging provides a general method for the diagnosis of localized bacterial infections that could be translatable to the clinic.     

Infection of owl monkeys (Aotus trivirgatus) and cynomolgus monkeys (Macaca fascicularis) with hepatitis E virus from Mexico.

Owl and cynomolgus monkeys were inoculated with hepatitis E virus (HEV) to compare disease models and produce antibody and virus. By immune electron microscopy (IEM), all six owl monkeys were shown to have serologic responses manifested by unusually high levels of anti-HEV at 6 months, but only three developed hepatitis. Virus-related antigen in liver (HEV Ag) was detected by immunofluorescence microscopy of biopsies from two of four owl monkeys; one with HEV Ag also had HEV in acute-phase bile (detected by IEM) and feces (detected by infecting another owl monkey). In contrast, cynomolgus monkeys propagated HEV to higher levels and all five had hepatitis. Moderate-to-high levels of HEV Ag correlated with detectable HEV in bile for both species. Thus, the value of using HEV-infected cynomolgus was confirmed. Owl monkeys were shown to be HEV-susceptible and sources of high-level anti-HEV; Sustained anti-HEV in these monkeys may also be useful for understanding immune responses.     

A case of adult-onset varicella pneumonia and varicella-zoster virus (VZV) meningitis resulting from a reoccurrence of varicella

The patient was a 74-year old male who presented with a skin rash, cough, and impaired consciousness. A diffuse, systemic, dark red rash was observed and he was admitted. Varicella infection was diagnosed based on the varicella-zoster virus (VZV)-IgM levels. The extremely high VZV- IgG levels observed were unlikely to be present in an initial infection and the infection was thought to be a reoccurrence. Diffuse nodular shadows measuring < or = 5 mm in diameter were observed on chest computed tomography (CT);this was consistent with the typical imaging findings of varicella pneumonia. The cerebrospinal fluid (CSF) was positive for CSF VZV-IgM antibody, CSF VZV-PCR, and CSF antibody titer index. A diagnosis of varicella meningitis was made. When both respiratory and neurological symptoms are observed in patients with varicella infection, it is necessary to consider a combined diagnosis of varicella pneumonia and varicella meningitis/encephalitis and perform chest imaging and a CSF examination. Repeated asymptomatic re-infection is considered necessary in order to maintain a lifelong immunity to varicella; however, the opportunities for asymptomatic re-infection are decreasing with the declining birth rate and trend toward small families. As a result, reoccurrences of varicella infection in the elderly are expected to increase with rapidly increasing longevity.