Topical cidofovir for the treatment of dermatologic conditions: verruca, condyloma, intraepithelial neoplasia, herpes simplex and its potential use in smallpox

Monkeypox: is topical cidofovir a good idea?

We report the use of topical cidofovir to treat patients with human monkeypox. We found that lesions on the trunk and limbs responded better than facial lesions, while anogenital lesions were affected by local irritation, leading to eventual discontinuation of treatment.

Diphenyl diselenide and cidofovir present anti-viral activity against Bovine Alphaherpesvirus 2 in vitro and in a sheep model

Bovine alphaherpesvirus 2 (BoHV-2) - the agent of bovine herpetic mamillitis (BHM) - is related to Human alphaherpesviruses 1 and 2 (HHV-1, HHV-2) and, as such, has been proposed as a model for vaccine and drug testing. We herein investigated the anti-viral activity in vitro against BoHV-2 of three anti-herpetic drugs: Cidofovir (CDV), Fanciclovir (FAM), Foscarnet (PFA), and diphenyl disselenide (Ph₂Se₂)_, a compound that has showed activity against HHV-2. Plaque reduction assays (PRA) revealed a significant reduction in viral plaques (p < 0.05) in cells treated with Ph₂Se₂ (79.7% reduction) or CDV (62.8%). FAM treatment resulted in a slight decrease in plaque number (22.9%, p < 0.05); PFA showed no activity. The effects of Ph₂Se₂ and CDV, alone or in combination, were investigated in ewes inoculated with BoHV-2 transdermally and submitted to daily topic treatment. Virus inoculated ewes developed lesions progressing through the stages of hyperemia, large papules or depressed dark areas, followed by scab formation. Treatment with Ph₂Se₂ resulted in reduction in clinical score from day 10 pi onwards (P < 0.05), shortening of clinical course and reduction in duration of virus shedding (P < 0.05) compared to untreated controls. Combined treatment (Ph₂Se₂ + CDV) and CDV alone, also led to clinical improvement (P < 0.05), yet less pronounced and delayed. These results are promising towards the use of Ph₂Se₂, alone or in combination with anti-herpetic drugs, in the treatment of udder and teat lesions produced by BoHV-2 in dairy cows.

Update on pharmacotherapy for ocular surface squamous neoplasia

The most frequently encountered non-pigmented tumor of the ocular surface is ocular surface squamous neoplasia (OSSN). Over the past two decades, the pharmacological management of OSSN has grown, with topical 5-fluorouracil, mitomycin, and interferon alpha 2b all being successfully used to treat this disease. Other agents, such as anti-vascular endothelial growth factor (VEGF), retinoic acid, cidofovir and Aloe vera, have less frequently been used in the treatment of OSSN. This review will discuss these pharmacologic agents, summarizing available data and presenting the approach to the treatment of these tumors.

Therapy of human papillomavirus-related disease

This chapter reviews the current treatment of chronic and neoplastic human papillomavirus (HPV)-associated conditions and the development of novel therapeutic approaches. Surgical excision of HPV-associated lower genital tract neoplasia is very successful but largely depends on secondary prevention programmes for identification of disease. Only high-risk HPV-driven chronic, pre-neoplastic lesions and some very early cancers cannot be successfully treated by surgical procedures alone. Chemoradiation therapy of cervical cancer contributes to the 66-79% cervical cancer survival at 5 years. Outlook for those patients with persistent or recurrent cervical cancer following treatment is very poor. Topical agents such as imiquimod (immune response modifier), cidofovir (inhibition of viral replication; induction apoptosis) or photodynamic therapy (direct damage of tumour and augmentation of anti-tumour immunity) have all shown some useful efficacy (~50-60%) in treatment of high grade vulvar intraepithelial neoplasia (VIN). Provider administered treatments of genital warts include cryotherapy, trichloracetic acid, or surgical removal which has the highest primary clearance rate. Patient applied therapies include podophyllotoxin and imiquimod. Recurrence after "successful" treatment is 30-40%. Further improvements could derive from a rational combination of current therapy with new drugs targeting molecular pathways mediated by HPV in cancer. Small molecule inhibitors targeting the DNA binding activities of HPV E1/E2 or the anti-apoptotic consequences of E6/E7 oncogenes are in preclinical development. Proteasome and histone deacetylase inhibitors, which can enhance apoptosis in HPV positive tumour cells, are being tested in early clinical trials. Chronic high-risk HPV infection/neoplasia is characterised by systemic and/or local immune suppressive regulatory or escape factors. Recently two E6/E7 vaccines have shown some clinical efficacy in high grade VIN patients and this correlated with strong and broad systemic HPV-specific T cell response and modulation of key local immune factors. Treatments that can shift the balance of immune effectors locally in combination with vaccination are now being tested. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

Antiviral drugs for viruses other than human immunodeficiency virus

Most viral diseases, with the exception of those caused by human immunodeficiency virus, are self-limited illnesses that do not require specific antiviral therapy. The currently available antiviral drugs target 3 main groups of viruses: herpes, hepatitis, and influenza viruses. With the exception of the antisense molecule fomivirsen, all antiherpes drugs inhibit viral replication by serving as competitive substrates for viral DNA polymerase. Drugs for the treatment of influenza inhibit the ion channel M(2) protein or the enzyme neuraminidase. Combination therapy with Interferon-α and ribavirin remains the backbone treatment for chronic hepatitis C; the addition of serine protease inhibitors improves the treatment outcome of patients infected with hepatitis C virus genotype 1. Chronic hepatitis B can be treated with interferon or a combination of nucleos(t)ide analogues. Notably, almost all the nucleos(t) ide analogues for the treatment of chronic hepatitis B possess anti-human immunodeficiency virus properties, and they inhibit replication of hepatitis B virus by serving as competitive substrates for its DNA polymerase. Some antiviral drugs possess multiple potential clinical applications, such as ribavirin for the treatment of chronic hepatitis C and respiratory syncytial virus and cidofovir for the treatment of cytomegalovirus and other DNA viruses. Drug resistance is an emerging threat to the clinical utility of antiviral drugs. The major mechanisms for drug resistance are mutations in the viral DNA polymerase gene or in genes that encode for the viral kinases required for the activation of certain drugs such as acyclovir and ganciclovir. Widespread antiviral resistance has limited the clinical utility of M(2) inhibitors for the prevention and treatment of influenza infections. This article provides an overview of clinically available antiviral drugs for the primary care physician, with a special focus on pharmacology, clinical uses, and adverse effects.

Bowenoid papulosis of the genitalia successfully treated with topical tazarotene: a report of two cases

Bowenoid papulosis is a rare condition of the genital area caused by human papilloma virus. Clinically, it resembles viral wart and histopathologically Bowen's disease. We herein report two male patients presenting with multiple flat papules on the penis and scrotum. The second patient was HIV-positive. Histopathology showed features of bowenoid papulosis. Both the patients were treated with topical tazarotene gel 0.05%. Lesions cleared within 2 weeks in both the patients.Second patient had recurrences that cleared after retreatment with tazarotene.

Papillomavirus and treatment

Human papillomaviruses (HPVs) are small DNA viruses responsible for a broad range of clinical presentations, characterized histologically by the proliferation of epithelial cells. HPVs are responsible for benign as well as malignant lesions, the most frequent of the latter being cervical carcinoma. A better knowledge of the immunobiology of these lesions allowed the development of prophylactic vaccines (for the most frequent genital types) that are presently under evaluation. The present paper describes different approaches for the treatment of HPV lesions, still mostly based on surgery, and underlines the importance of developing adjuvant therapies.

5-(Dimethoxymethyl)-2'-deoxyuridine: a novel gem diether nucleoside with anti-orthopoxvirus activity

To provide potential new leads for the treatment of orthopoxvirus infections, the 5-position of the pyrimidine nucleosides have been modified with a gem diether moiety to yield the following new nucleosides: 5-(dimethoxymethyl)-2'-deoxyuridine (2b), 5-(diethoxymethyl)-2'-deoxyuridine (3b), 5-formyl-2'-deoxyuridine ethylene acetal (4b), and 5-formyl-2'-deoxyuridine propylene acetal (5b). These were evaluated in human foreskin fibroblast cells challenged with the vaccinia virus or cowpox virus. Of the four gem diether nucleosides, only the dimethyl gem diether congener showed significant antiviral activity against both viruses. This antiviral activity did not appear to be related to the decomposition to the 5-formyl-2'-deoxyuridine, which was itself devoid of anti-orthopoxvirus activity in these assays. Moreover, at the pH of the in vitro assays, 2b was very stable with a decomposition (to aldehyde) half-life of >15 d. The anti-orthopoxvirus activity of pyrimidine may be favored by the introduction of hydrophilic moieties to the 5-position side chain.

Advances in Antiviral Therapy

Infections with five of the herpesviruses (herpes simplex virus 1 [HSV-1], HSV-2, varicella zoster virus, Epstein-Barr virus, and cytomegalovirus) are treated with topical or systemic antiviral therapies. There are more than 100 genotypes of human papillomaviruses (HPVs), which may manifest as warts, skin cancers, cervical cancer, anogenital cancers, and upper digestive tract cancers. Molluscum contagiosum (MC) is a common, benign viral infection of the skin. Immunomodulating agents, such as imiquimod, act on HPV and MC indirectly by inducing host immune responses, such as cytokines and cell-mediated immunity, and thereby reduce recurrences. There are multiple vaccines available for certain viral diseases and others in development for HSV-2 and HPV.

Therapy of pediatric genital diseases

Infants and children have special issues with regard to genital disease. Infants are incontinent, and have an increase in local irritation and infection risk. In addition, the adult sex hormones which enhance the health of genital skin are deficient. Also, the choice of therapy must be modified to take into account the more fragile nature of prepubertal skin, the tolerance of children to painful treatments, and the lack of experience of some medications in children.