New antiviral and antifungal drugs

Comparative toxicological assessment of a water-soluble azole administered both orally and by intravenous continuous infusion in cynomolgus monkeys

The water-soluble azole, 4-[1-[(3-methylaminoacetoxymethyl-pyridin-2-yl)-methyl-carbamoyloxy]- ethyl]-1-[(2R,3R)-3-[4-(4-cyano-phenyl)-thiazol-2-yl]-2- (2,5-difluoro-phenyl)-2-hydroxy-butyl]-1H-[1,2,4]triazol-4-ium chloride hydrochloride (hereinafter referred to as WSA), is a new water-soluble triazole anti-fungal compound. WSA is rapidly converted into its active metabolite after administration by either the intravenous or oral route. The clinical effects of WSA are expected to be consistent whether it is administered by injection (intravenous) or orally. To evaluate and compare the toxicities of WSA via oral and intravenous administration, repeated toxicity studies of WSA were conducted in cynomolgus monkeys (oral dosage levels: 0, 10, 30 and 90 mg/kg/day over a 4-week period; intravenous infusion dosage levels: 0, 10, 30 and 60 mg/kg/day over a 2-week period). In addition, a 2-week oral toxicity study of the active metabolite of WSA was conducted with similar dosages (0, 10, 30 and 90 mg/kg/day). From the results obtained from the evaluation, hepatotoxicity (liver) and endocrinological toxicity (adrenals) were the major toxicities, a finding which is comparable to other previously tested azole compounds. In the 4-week oral toxicity study, the lethal dose of WSA was determined to be 90 mg/kg. However, no animal mortality was observed during the 2-week intravenous continuous infusion study. The toxicokinetics (TK) profile of WSA at 10 and 30 mg/kg dosages illustrated a rapid, dose-dependent conversion of WSA to its active metabolite, and the plasma levels of Cmax and AUC were well correlated to their toxicities. However, at high dosages (60 and 90 mg/kg), WSA demonstrated high exposure beyond the dose-proportional manner. Overall, the results obtained indicate that maintaining an effective concentration and a non-toxic dosage level would be manageable by utilizing an initial intravenous continuous infusion followed by oral administration.

Intravenous RMP-7 increases delivery of ganciclovir into rat brain tumors and enhances the effects of herpes simplex virus thymidine kinase gene therapy

Herpes simplex virus thymidine kinase (HSV-tk) gene therapy for brain tumors depends on ganciclovir (GCV) and its transport across the blood-brain tumor barrier (BBTB). We examined whether RMP-7, the bradykinin analog and potent BBTB permeabilizer, could enhance the efficacy of GCV treatment of brain tumors by increasing the BBTB delivery of GCV. In vitro, a significant bystander cytocidal effect of GCV was shown in mixed HSV-tk-transduced (HSV-tk+) and control vector-transduced (HSV-tk-) C6 glioma cultures. A dose-dependent cytotoxic effect of GCV on untransformed C6 cells was also shown. In vivo, rats with 100% HSV-tk+ or 100% HSV-tk- intracerebral C6 gliomas were treated for 7 days with intravenous infusions of GCV alone or with GCV and RMP-7 (2.5 microg/kg/day). The growth of HSV-tk+ and HSV-tk- gliomas decreased with increasing doses of GCV. A high dosage (100 mg of GCV/kg/day) eradicated all HSV-tk- and HSV-tk+ tumors. An intermediate dosage (5 mg of GCV/kg/day) reduced the growth of HSV-tk- gliomas by 42% if given alone, and by 88% in combination with RMP-7. A low dosage (0.5 mg of GCV/kg/day) in combination with RMP-7 enhanced the regression of HSV-tk+ gliomas by 87% compared with GCV alone. Low-dose GCV was ineffective in HSV-tk- tumors. RMP-7 increased [3H] GCV tumoral uptake by 2.6- and 1.7-fold in the tumor center and periphery, respectively. We conclude that RMP-7 could be an important adjunctive treatment for suicide gene therapy of brain tumors, while an RMP-7/GCV combination may also have a significant antitumor effect in untransfected gliomas.

Intravenous infusion of RMP-7 increases ocular uptake of ganciclovir

PURPOSE

The ability of intravenous (i.v.) infusions of the bradykinin agonist, RMP-7, to permeabilize the blood-ocular barriers (BOB) to the antiviral agent ganciclovir was investigated in guinea-pigs.

METHODS

Different i.v. dosing regimens included pre-treatment with RMP-7 (0.2 microg/kg/min for 5 min) followed by either [3H]-ganciclovir (1 microCi/0.2 ml/min) alone, and/or co-infusion with RMP-7 and [3H]-ganciclovir. At specific times the animals were sacrificed, their eyes removed, and the retina and lens epithelium dissected and analyzed for the amount of radioactivity.

RESULTS

Using the ratio of tissue vs. integrated plasma radioactivity concentration, a two-fold increase in ganciclovir steady-state levels were observed in the retina as well as lens epithelium following RMP-7 pretreatment. Peak uptake effects were achieved with a 4.5 min ganciclovir infusion. Neither longer infusions of ganciclovir alone, nor co-infusions of RMP-7 and ganciclovir further enhanced the uptake effects. Kinetic analysis indicated that RMP-7 increased the rate of ganciclovir entry (K(IN)) in studied ocular tissues, while the efflux of drug (K(OUT)) was not affected by this treatment. Finally, ganciclovir retina:plasma ratios elevated by RMP-7 pre-treatment, remained higher than control ratios within 60 min following cessation of 4.5 min ganciclovir infusion.

CONCLUSIONS

These data offer further evidence that BOB and in particular the blood-retinal barrier can be permeabilized via bradykinin receptor stimulation. As the i.v. infusions of RMP-7 enhanced the retinal uptake of ganciclovir, it is suggested that a combination of RMP-7 and ganciclovir may provide a novel approach for treating cytomegalovirus retinis.

Invasive aspergillosis complicated by subclavian artery occlusion and costal osteomyelitis after autologous bone marrow transplantation

A 47 year old woman presented with invasive pulmonary aspergillosis complicated by subclavian artery occlusion and rib fracture due to fungal osteomyelitis. This followed persistent pancytopenia resulting from autologous bone marrow transplantation for metastatic breast cancer.

Management of genital herpes simplex infection

Herpes simplex infection of the genitals is a common condition, more often due to herpes simplex virus (HSV) type 2 than to type 1 virus. There is a severe first attack followed by mild recurrences which are more common and more frequent after HSV-2 than after HSV-1 genital infection. Clinical features with prodrome, vesicles and erosions may be characteristic allowing rapid clinical diagnosis. When possible laboratory confirmation should be attempted. General management includes simple hygiene, avoidance of sexual transmission, use of condoms, and notifying partners. Oral acyclovir (Zovirax, Wellcome) is the drug of choice for initial attacks and should be considered for all women with this diagnosis. Intravenous acyclovir may be used for very severe attacks. Men with initial attacks may be treated with oral acyclovir but mild disease affecting only skin may be treated with 5% acyclovir cream. Recurrences are short so acyclovir has less effect. Frequent recurrences can be troublesome and may be suppressed by continuous oral acyclovir, or individual attacks may be aborted with intermittent therapy. Various systemic complications may occur; an important but rare problem is primary herpes in late pregnancy. Acyclovir is effective in the treatment of the troublesome herpes simplex disease associated with human immunodeficiency infection. Acyclovir is one of the more expensive treatments for sexually transmitted diseases. At present in many countries costs are being examined, and application of the principles outlined here should help to minimize cost and maximize care.

Ethical problems raised by anti-HIV vaccination

At present questions are being asked world-wide about the risk of the AIDS epidemic. The discovery of an anti-HIV vaccine has become an urgent priority, but it also raises a number of sensitive questions. Ethical problems in this field are particularly delicate, since the perspectives of individual health and public health do not seem to coincide. Our research team conducted a review of more than 400 articles on the ethical problems raised by AIDS. We concentrated particularly on the ethical and legal issues raised by research on anti-HIV vaccine. These problems fall into three main categories: therapeutic assays, which must be controlled by a strict agreement defined by international norms; manufacture of the future vaccine, raising legal difficulties which must be faced and solved now; distribution of the vaccine to the population, which should be conducted on a general basis, i.e. it should be offered to all individuals and not only to risk groups.

Gynaecological infections and strategies for treatment

Frequently, encountered gynaecologic infections and pathogens involved are presented. A review is given of bartholinitis, vulvovaginitis-bacterial vaginosis, candidiasis, trichomoniasis cervicitis and pelvic inflammatory disease: Neisseria gonorrhoeae, Chlamydia trachomatis and herpes simplex virus 2. Of each infection a thorough description of clinical symptoms and diagnostic criteria is followed by up-to-date treatment advices. For vulvovaginitis, cervicitis and pelvic inflammatory disease antifungal and antimicrobial agents, route of administration, the required daily dosage and time of administration are presented in an overview table.