Current recommendations for the treatment of genital herpes

The Impact of Antiviral Resistance on Herpetic Keratitis

ABSTRACT

Herpes simplex keratitis resistance to antiviral treatment presents a growing concern. The herpes simplex virus has many different mechanisms of resistance to antiviral treatment, which have been well described. Resistance to acyclovir occurs because of mutations in the viral thymidylate kinase and DNA polymerase that decrease this enzyme's affinity for its substrate. This article discusses factors that explain the prevalence of this resistance, the ability for recurrences in immunocompromised populations, current treatments for acyclovir-resistant herpes simplex keratitis, and novel therapies for this growing concern.

Acyclovir in the Treatment of Herpes Viruses – A Review

Background:

Herpes Simplex (HSV) viruses are widely spread, highly contagious human pathogens. The statistics indicate that 50-90% of adults worldwide are seropositive for these viruses, mainly HSV-1 and HSV-2. The primary infection results in the appearance of watery blisters (cold sores) on the skin, lips, tongue, buccal mucosa or genitals. The ocular infection is the major cause of corneal blindness in the Western World. Once the HSV virus enters human body, it cannot be completely eradicated because HSV viruses are able to change into their latent form which can survive the treatment. The viron resides in trigeminal ganglia of the host, who becomes vulnerable to the reoccurrence of the disease during the whole lifespan. The neurotropic and neuro-invasive properties of HSV are responsible for neurodegenerative illnesses, such as Alzheimer's disease. Acyclovir and its analogues, being the inhibitors of the viral DNA replication, are the only approved medicines for HSV infection therapies.

Objective:

The current paper presents the up-to-date overview of the important pharmacological features of acyclovir, its analogues and their delivery systems including the mechanism of action, routes of administration, absorption and metabolism, as well as side effects of the therapy.

Conclusion:

Acyclovir remains the gold standard in the treatment of herpes virus infections, mainly due to the emerging of the new delivery systems improving considerably its bioavailability. The analogues of acyclovir, especially their esters, characterized by significantly higher bioavailability and safety, may gradually replace acyclovir in selected applications.

New therapies for human cytomegalovirus infections

The recent approval of letermovir marks a new era of therapy for human cytomegalovirus (HCMV) infections, particularly for the prevention of HCMV disease in hematopoietic stem cell transplant recipients. For almost 30 years ganciclovir has been the therapy of choice for these infections and by today's standards this drug exhibits only modest antiviral activity that is often insufficient to completely suppress viral replication, and drives the selection of drug-resistant variants that continue to replicate and contribute to disease. While ganciclovir remains the therapy of choice, additional drugs that inhibit novel molecular targets, such as letermovir, will be required as highly effective combination therapies are developed not only for the treatment of immunocompromised hosts, but also for congenitally infected infants. Sustained efforts, largely in the biotech industry and academia, have identified additional highly active lead compounds that have progressed into clinical studies with varying levels of success and at least two have the potential to be approved in the near future. Some of the new drugs in the pipeline inhibit new molecular targets, remain effective against isolates that have developed resistance to existing therapies, and promise to augment existing therapeutic regimens. Here, we will describe some of the unique features of HCMV biology and discuss their effect on therapeutic needs. Existing drugs will also be discussed and some of the more promising candidates will be reviewed with an emphasis on those progressing through clinical studies. The in vitro and in vivo antiviral activity, spectrum of antiviral activity, and mechanism of action of new compounds will be reviewed to provide an update on potential new therapies for HCMV infections that have progressed significantly in recent years.

2017 European guidelines for the management of genital herpes

Genital herpes is one of the commonest sexually transmitted infections worldwide. Using the best available evidence, this guideline recommends strategies for diagnosis, management, and follow-up of the condition as well as for minimising transmission. Early recognition and initiation of therapy is key and may reduce the duration of illness or avoid hospitalisation with complications, including urinary retention, meningism, or severe systemic illness. The guideline covers a range of common clinical scenarios, such as recurrent genital herpes, infection during pregnancy, and co-infection with human immunodeficiency virus.

Interventions for men and women with their first episode of genital herpes

BACKGROUND

Genital herpes is incurable, and is caused by the herpes simplex virus (HSV). First-episode genital herpes is the first clinical presentation of herpes that a person experiences. Current treatment is based around viral suppression in order to decrease the length and severity of the episode.

OBJECTIVES

To determine the effectiveness and safety of the different existing treatments for first-episode genital herpes on the duration of symptoms and time to recurrence.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (from inception to April 2016), MEDLINE (from inception to April 2016), the Specialised Register of the Cochrane Sexually Transmitted Infections Review Group (from inception to April 2016), EMBASE (from inception to April 2016), PsycINFO (from inception to April 2016), CINAHL (from inception to April 2016), LILACS (from inception to April 2016), AMED (from inception to April 2016), and the Alternative Medicines Specialised Register (from inception to April 2016). We handsearched a number of relevant journals, searched reference lists of all included studies, databases of ongoing trials, and other Internet databases.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) on participants with first-episode genital herpes. We excluded vaccination trials, and trials in which the primary objective assessed a complication of HSV infection.

DATA COLLECTION AND ANALYSIS

All studies written in English were independently assessed by at least two review authors for inclusion, risk of bias for each trial, and to extract data. Studies requiring translation were assessed for inclusion, trial quality, and data extraction by external translators.

MAIN RESULTS

We included 26 trials with 2084 participants analysed. Most of the studies were conducted in the United Kingdom (UK) and United States (US), and involved men and women experiencing their first episode of genital herpes, with the exception of three studies which included only women. We rated the majority of these studies as having an unclear risk of bias; largely due to lack of information supplied in the publications, and due to the age of the trials. This review found low quality evidence from two studies of oral acyclovir, when compared to placebo, reduced the duration of symptoms in individuals undergoing their first episode of genital herpes (mean difference (MD) -3.22, 95% confidence interval (CI) -5.91 to -0.54; I(2) = 52%). In two studies (112 participants), intravenous acyclovir decreased the median number of days that patients with first-episode herpes suffered symptoms. Oral valaciclovir (converted to acyclovir) also showed a similar length of symptom duration when compared to acyclovir in two studies.There is currently no evidence that topical acyclovir reduces symptoms (MD -0.61 days, 95% CI -2.16 to 0.95; 3 RCTs, 195 participants, I(2) statistic = 56%). There is also no current evidence that the topical treatments of cicloxolone cream, carbenoxolone sodium cream, adenosine arabinoside, idoxuridine in dimethyl sulfoxide, when compared to placebo reduced the duration of symptoms in people undergoing their first episode of herpes.Two studies reported no evidence of a reduction in the number of median days to recurrence following treatment with oral acyclovir versus placebo. Adverse events were generally poorly reported by all of the included studies and we were unable to quantitatively analyse this outcome. For those taking acyclovir, there were no serious adverse events; the most common adverse events reported for oral acyclovir were coryza, dizziness, tiredness, diarrhoea and renal colic. For intravenous acyclovir these were phlebitis, nausea and abnormal liver function tests and for topical acyclovir there was pain with the topical application.Those undergoing interferon treatment had significantly more adverse events compared to those taking placebo.

AUTHORS' CONCLUSIONS

There is low quality evidence from this review that oral acyclovir reduced the duration of symptoms for genital herpes. However, there is low quality evidence which did not show that topical antivirals reduced symptom duration for patients undergoing their first episode of genital herpes. This review was limited by the inclusion of skewed data, resulting in few trials that we were able to meta-analyse.

Subclinical generation of acyclovir-resistant herpes simplex virus with mutation of homopolymeric guanosine strings during acyclovir therapy

BACKGROUND

Suppressive therapy in patients with genital herpes has been used in Japan since 2006. Susceptibility and resistance of herpes simplex virus (HSV)-2 to acyclovir were examined in genital isolates from patients receiving suppressive therapy and compared with those from those naïve to acyclovir and receiving episodic treatment with acyclovir.

OBJECTIVE

The aim of this study was to analyze the effect of acyclovir use on the susceptibility to acyclovir and analysis of the thymidine kinase gene by acyclovir treatment.

METHODS

Genital HSV isolates were obtained from three patients groups. Susceptibility to acyclovir, the frequency of acyclovir-resistant clones and mutations in the thymidine kinase gene of acyclovir-resistant clones were determined.

RESULTS

Susceptibility to ACV was significantly higher in isolates from patients receiving suppressive therapy than those naïve to acyclovir and receiving episodic treatment, but the frequencies of resistant clones were similar among the three groups. Mutation in guanosine homopolymeric strings (G-string mutation) was significantly more frequent in clones during episodic treatment and suppressive therapy than clones from patients naïve to ACV. The frequency of G-string mutation was significantly less frequent in isolates from patients naïve to ACV than those experienced ACV therapy.

CONCLUSION

The frequency of acyclovir-resistant mutants was not increased by episodic and suppressive therapy, but exposure to acyclovir significantly generated G-string mutations, possibly induced by acyclovir. Acyclovir therapy had no substantial effects on the susceptibility of HSV-2 or frequency of resistant virus but did generate subclinical G-string mutants in patients' HSV-2.

2014 UK national guideline for the management of anogenital herpes

These guidelines concern the management of anogenital herpes simplex virus infections in adults and give advice on diagnosis, management, and counselling of patients. This guideline replaces the 2007 BASHH herpes guidelines and includes new sections on herpes proctitis, key points to cover with patients regarding transmission and removal of advice on the management of HSV in pregnancy which now has a separate joint BASHH/RCOG guideline.

Synergistic effects of acyclovir and 3, 19-isopropylideneandrographolide on herpes simplex virus wild types and drug-resistant strains

Background

An andrographolide analogue, 3, 19-isopropylideneandrographolide (IPAD), exerts an inhibitory effect on replication of wild-type herpes simplex virus serotype 1 (HSV-1). In this study, we examined the anti-viral activity of IPAD on HSV wild types (HSV-1 strain KOS and HSV-2 clinical isolate) and HSV-1 drug-resistant strains (DRs). Synergistic effects of IPAD with acyclovir (ACV) were also evaluated.

Methods

MTT and cytopathic effect (CPE) reduction assays were performed to determine cytotoxicity and anti-viral activities, respectively. A combination assay was used to determine synergistic effects of IPAD and ACV. Presence of viral DNA and protein in experimental cells was investigated using the polymerase chain reaction and western blotting, respectively.

Results

A non-cytotoxic concentration of IPAD (20.50 μM) completely inhibited CPE formation induced by HSV wild types and HSV-1 DRs after viral entry into the cells. The anti-HSV activities included inhibition of viral DNA and protein synthesis. The minimum inhibitory concentrations of ACV for HSV wild types and HSV-1 DRs were 20.20 and 2,220.00 μM, respectively. Combination of ACV with IPAD showed synergistic effects in inhibition of CPE formation, viral DNA and protein synthesis by HSV wild types as well as HSV-1 DRs. For the synergistic effects on HSV wild types and HSV-1 DRs, the effective concentrations of ACV were reduced.

Conclusions

These results showed the inhibitory potential of IPAD on HSV wild types and HSV-1 DRs and suggested that IPAD could be used in combination with ACV for treatment of HSV-1 DRs infections.

Long-term valacyclovir suppressive treatment after herpes simplex virus type 2 meningitis: a double-blind, randomized controlled trial

BACKGROUND

Herpes simplex virus type 2 (HSV-2) is a common cause of acute and recurrent aseptic meningitis. Our aim was to determine the impact of antiviral suppression on recurrence of meningitis and to delineate the full spectrum of neurological complications.

METHODS

One hundred and one patients with acute primary or recurrent HSV-2 meningitis were assigned to placebo (n = 51) or 0.5 g of valacyclovir twice daily (n = 50) for 1 year after initial treatment with 1 g of valacyclovir 3 times daily for 1 week in a prospective, placebo-controlled, multicenter trial. The primary outcome was time until recurrence of meningitis. The patients were followed up for 2 years.

RESULTS

The first year, no significant difference was found between the valacyclovir and placebo groups. The second year, without study drugs, the risk of recurrence of verified and probable HSV-2 meningitis was significantly higher among patients exposed to valacyclovir (hazard ratio, 3.29 [95% confidence interval, 10.06-10.21]). One-third of the patients experienced 1-4 meningitis episodes during the study period. A considerable morbidity rate, comprising symptoms from the central, peripheral, and autonomous nervous system, was found in both groups.

CONCLUSIONS

Suppressive treatment with 0.5 g of valacyclovir twice daily was not shown to prohibit recurrent meningitis and cannot be recommended for this purpose after HSV meningitis in general. Protection against mucocutaneous lesions was observed, but the dosage was probably inappropriate for the prevention of HSV activation in the central nervous system. The higher frequency of meningitis, after cessation of active drug, could be interpreted as a rebound phenomenon.

The anti-HSV-2 effect of alumen: In vitro and in vivo experimental studies

This study investigated the anti-HSV-2 effect of alumen through in vitro and in vivo experiments. Viable cell counting was employed to assess the toxicity of alumen on Vero cells. The inhibition rate of HSV-2 was defined as the cytopathic effect (CPE) of the cells infected with the virus. Alumen suppositories of different concentrations were vaginally applied to the guinea pigs which were then infected with HSV-2 via a vaginal route. The clinical symptoms were observed and the local virus titer calculated. The results showed that alumen had an in vitro anti-HSV-2 effect by means of antiviral duplication, direct killing of the virus, and antiviral adsorption. Alumen suppositories of different concentrations could reduce or completely inhibit HSV-2 infection in guinea pigs. It was concluded that alumen had an in vitro anti-HSV-2 effect through multiple approaches and it could suppress in vivo vaginal HSV-2 infection of guinea pig to some extent.

CMX001 potentiates the efficacy of acyclovir in herpes simplex virus infections

Although acyclovir (ACV) has proven to be of value in the therapy of certain herpes simplex virus (HSV) infections, there is a need for more effective therapies, particularly for serious infections in neonates and immunocompromised individuals, where resistance to this drug can be problematic. CMX001 is an orally bioavailable lipid conjugate of cidofovir that is substantially less nephrotoxic than the parent drug and has excellent antiviral activity against all the human herpesviruses. This compound retains full antiviral activity against ACV-resistant laboratory and clinical isolates. The combined efficacy of CMX001 and ACV was evaluated in a new real-time PCR combination assay, which demonstrated that the combination synergistically inhibited the replication of HSV in cell culture. This was also confirmed in murine models of HSV infection, where the combined therapy with these two drugs synergistically reduced mortality. These results suggest that CMX001 may be effective in the treatment of ACV-resistant HSV infections and as an adjunct therapy in individuals with suboptimal responses to ACV.

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.

Activity investigation of pinostrobin towards herpes simplex virus-1 as determined by atomic force microscopy

In the present study, the antiviral activity of pinostrobin towards herpes simplex virus-1 (HSV-1) was investigated by MTT assay and atomic force microscopy. Pinostrobin can inhibit HSV-1 replication with 50% effective concentration (EC(50)) of 22.71 ± 1.72 μg/ml. MTT assay showed HSV-1 was significantly inhibited when pretreated with pinostrobin, with the inhibition of 85.69 ± 2.59%. Significant changes in morphology and size of HSV-1 were observed by atomic force microscopy (AFM) in response to pinostrobin treatment. AFM topography and phase images showed that with increasing time, the envelope was shedded and damaged, finally leading to virus inactivation. With increasing concentration, pinostrobin caused a gradual leakage, also contributing to breakage of the envelope and virus inactivation. Treatment effect of oral pinostrobin in vivo showed that pinostrobin (50mg/kg/dose) possesses definite therapeutical effect in the development of lesion score. In general, the results showed that AFM represents a powerful technique for the investigation of morphology and size of HSV-1 treated by antiviral agents. AFM is applicable to study chemically induced morphological changes at the nanometer level.

The search for new therapies for human cytomegalovirus infections

Ganciclovir (GCV), the therapy of choice for human cytomegalovirus (CMV) infections and foscarnet, a drug used to treat GCV-resistant CMV infections was approved more than twenty years ago. Although cidofovir and a prodrug of GCV have since been added to the armamentarium, a highly effective drug without significant toxicities has yet to be approved. Such a therapeutic agent is required for treatment of immunocompromised hosts and infants, which bear the greatest burden of disease. The modest antiviral activity of existing drugs is insufficient to completely suppress viral replication, which results in the selection of drug-resistant variants that remain pathogenic, continue to replicate, and contribute to disease. Sustained efforts, largely in the biotech industry and academia, have identified highly active lead compounds that have progressed into clinical studies with varying levels of success. A few of these compounds inhibit new molecular targets, remain effective against isolates that have developed resistance to existing therapies, and promise to augment existing therapies. Some of the more promising drugs will be discussed with an emphasis on those progressing to clinical studies. Their antiviral activity both in vitro and in vivo, spectrum of antiviral activity, and mechanism of action will be reviewed to provide an update on the progress of potential new therapies for CMV infections.

Comparative in vitro study on the anti-herpetic effect of phytochemically characterized aqueous and ethanolic extracts of Salvia officinalis grown at two different locations

Aqueous and ethanolic extracts of Salvia officinalis (Lamiaceae) from two different locations (Garden and Swabian Mountains) were examined in vitro on RC-37 cells for their antiviral activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) using a plaque reduction assay. The 50% inhibitory concentrations (IC50) of the extracts for HSV plaque formation were determined in dose-response studies. All extracts tested revealed a high virucidal activity against free HSV-1 and HSV-2. The experimental data exhibited a significant higher sensitivity of HSV against the extracts derived from Garden in comparison with those from Swabian Mountains. The most active one was the Garden 20% ethanol extract with IC50 values of 0.18 microg/ml for HSV-1 and 0.04 microg/ml for HSV-2. In order to identify the mode of antiviral action, the extracts were added to the host cells (RC-37) or viruses at different stages of infection. Independently of the location, both types of herpes viruses were considerably inactivated after treatment with the extracts prior to cell infection. Plaque formation was significantly reduced by >90% for HSV-1 and by >99% for HSV-2. Pretreatment of the host cells with both Garden and Swabian Mountains 20% and 40% ethanolic extracts prior to virus infection revealed a strong reduction of HSV-2 plaque formation by 94% and 70% (Garden) and 99% and 45% (Swabian Mountains), respectively. In time-activity studies with free HSV-1 over a period of 2h, a clearly time-dependent activity was demonstrated whereby the ethanolic extracts of both locations revealed a much higher activity than the aqueous ones. The 20% ethanolic extracts of both locations are of special interest and were effective when added to host cells and free virus. A topical application with a dual mode of action would be ideal against recurrent herpes infections.

Human herpes simplex virus infections: epidemiology, pathogenesis, symptomatology, diagnosis, and management

Eight of the more than 80 known herpesviruses are human pathogens. Human herpes simplex virus (HSV) is a contagious infection with a large reservoir in the general population. It has a potential for significant complications in the immunocompromised host. In addition, psychological distress caused by the negative stigma associated with genital herpes and visible facial lesions in those experiencing frequent outbreaks renders it a challenging clinical dilemma. This article reviews the epidemiology, pathogenesis, and diagnostic features of HSV infections, providing the clinician with an up-to-date understanding of the available management strategies for mucocutaneous HSV-induced disease.

Antimicrobial resistance prevention initiative--an update: proceedings of an expert panel on resistance

Antimicrobial resistance is a growing problem that complicates the treatment of important nosocomial and community-acquired infections. It is a worldwide problem that spans the range of human pathogens, including bacteria, fungi, and viruses. This update from the Antimicrobial Resistance Prevention Initiative (ARPI) provides a review of some important trends in antibiotic, antifungal, and antiviral resistance. Areas of focus include multidrug-resistant bacteria in the hospital setting; the growing problem of community-acquired methicillin-resistant Staphylococcus aureus; triazole and polyene resistance in nosocomial infections caused by non-Candida albicans or Aspergillus species, and the utility of in vitro susceptibility testing for these fungal infections; antiviral resistance in alpha- or beta-herpesviruses causing genital herpes or cytomegalovirus infection in immunocompromised hosts; and concerns about a possible pandemic involving avian influenza A and the importance of minimizing emergence of resistant strains of this highly pathogenic virus. The challenges in each area are different, but the general keys to addressing the growing problem of antimicrobial resistance continue to be responsible antimicrobial stewardship and the development of newer antimicrobial agents.

Antimicrobial resistance prevention initiative--an update: proceedings of an expert panel on resistance

Antimicrobial resistance is a growing problem that complicates the treatment of important nosocomial and community-acquired infections. It is a worldwide problem that spans the range of human pathogens, including bacteria, fungi, and viruses. This update from the Antimicrobial Resistance Prevention Initiative (ARPI) provides a review of some important trends in antibiotic, antifungal, and antiviral resistance. Areas of focus include multidrug-resistant bacteria in the hospital setting; the growing problem of community-acquired methicillin-resistant Staphylococcus aureus; triazole and polyene resistance in nosocomial infections caused by non-Candida albicans or Aspergillus species, and the utility of in vitro susceptibility testing for these fungal infections; antiviral resistance in alpha- or beta-herpesviruses causing genital herpes or cytomegalovirus infection in immunocompromised hosts; and concerns about a possible pandemic involving avian influenza A and the importance of minimizing emergence of resistant strains of this highly pathogenic virus. The challenges in each area are different, but the general keys to addressing the growing problem of antimicrobial resistance continue to be responsible antimicrobial stewardship and the development of newer antimicrobial agents.

Herpes simplex and varicella zoster viruses: forgotten but not gone

Herpesvirus infections are common complications of organ transplantation. The most frequent herpesvirus infections are caused by cytomegalovirus (CMV), herpes simplex (HSV) and varicella zoster (VZV). Despite expansion of the therapeutic armamentarium, HSV and VZV continue to cause morbidity and occasional mortality in transplant recipients. Here we review the incidence and risk factors for HSV and VZV disease, their clinical presentation, effects of newer immunosuppressive regimens and prophylaxis for HSV and VZV in solid organ transplant recipients.

Recurrent antiviral-resistant genital herpes in an immunocompetent patient

Herpes simplex virus type 2 (HSV-2) resistance to antiviral drugs has been described primarily in immunocompromised patients. We report an apparently immunocompetent, human immunodeficiency virus-negative male patient who has experienced repeated HSV-2 genital outbreaks despite receiving antiviral prophylaxis with several different drugs. Several of the HSV-2 genital isolates from this patient have been confirmed as resistant to acyclovir and penciclovir. Antiviral resistance occurred in the setting of long-term prednisone treatment and intermittent acyclovir prophylaxis at suboptimal doses and persisted despite the cessation of oral steroid treatment. The patient's genital herpes outbreaks were not controlled by high-dose prophylaxis with acyclovir, valacyclovir, and famciclovir. Cessation of antiviral prophylaxis resulted in reversion of this patient's HSV-2 isolates to acyclovir and penciclovir sensitivity, although resistant virus reappeared when antiviral prophylaxis was resumed. Transmission of a sensitive HSV-2 strain from this patient to a female sex partner was observed. These observations confirm previous reports that resistance to acyclovir may develop during prophylactic therapy in an otherwise well, immunocompetent patient. These findings support the conclusion that both drug-sensitive and drug-resistant HSV-2 strains established latency in this patient and that both strains are capable of frequent reactivation.

Gold standard medical therapy for glaucoma: defining the criteria identifying measures for an evidence-based analysis

BACKGROUND

Over the past decade, several new medical therapies have become available for the treatment of primary open-angle glaucoma (POAG). A systematic evidence-based approach for identifying an optimal therapeutic agent is lacking.

OBJECTIVES

The aims of this review were to critically evaluate published treatment recommendations for POAG and, based on a systematic review of the literature, to develop criteria that would define a "gold standard" medical therapy that reflects new treatment advances and established therapeutic goals.

METHODS

A MEDLINE search spanning the years 1966 to 2002 and using the search terms gold standard, drug of choice, agent of choice, benchmark, ophthalmology, eye, and glaucoma was conducted and the results reviewed by a panel of 15 experts in the field of glaucoma. Published treatment recommendations for POAG were discussed. Criteria, anchored to medical evidence, for distinguishing a standard of medical therapy for POAG were defined.

RESULTS

The terms connoting a gold standard therapy were found in only 258 of approximately 368,000 ophthalmology-related citations and 53 of almost 23,000 glaucoma citations, validating the need to define therapeutic standards. The lack of recommendations for the use of new classes of ocular hypotensive agents was acknowledged. Criteria identified to evaluate intraocular pressure (IOP)-lowering agents as gold standards included the following: efficacy in reducing IOP consistently over a 24-hour period to a level that will preserve the visual field and protect the optic nerve without inducing tachyphylaxis and tolerance, paucity of local and systemic adverse effects, promotion of patient compliance, and applicability in diverse patient populations.

CONCLUSIONS

These criteria should be employed as measures for evidence-based analyses to evaluate available and future IOP-lowering medical therapies for POAG. The conceptual framework presented may be applicable to other therapeutic areas.

[Up to date in sexually transmitted infections: epidemiology, diagnostic approaches and treatments]

In the last years, there have been important advances in sexually transmitted infections such as genome sequencing of Treponema pallidum, Chlamydia trachomatis or Mycoplasma genitalium; the new taxonomic position of Calymmatobacterium granulomatis; commercial diagnostic systems based on nucleic acid amplification; the emergence of quinolone resistance in Neisseria gonorrhoeae; new therapeutic approaches in vulvovaginal candidiasis that include boric acid; the demonstration that valacyclovir reduces the risk of transmission of genital herpes or the availability of immune-response modifier in the treatment of genital warts, and that are questions in the goal of this review. Viral hepatitis and HIV were no reviewed by space reasons.

Resistance of Herpes Simplex Virus Infections to Nucleoside Analogues in HIV‐Infected Patients

Antiviral treatment of herpes simplex virus (HSV) infections with nucleoside analogues has been well established for >2 decades, but isolation of drug-resistant HSV from immunocompetent patients has remained infrequent (0.1%-0.7% of isolates) during this period. Even when drug-resistant HSV is isolated from an immunocompetent patient, this virus, with rare exceptions, is cleared normally without adverse clinical outcome. Although drug-resistant HSV is more commonly isolated from immunocompromised patients (4%-7% of isolates) and is more likely to be clinically significant, the prevalence of drug-resistant HSV even among these patients, has been stable over the past 2 decades. Despite this stable prevalence, disease due to drug-resistant HSV remains an important problem for many immunocompromised patients, including those with HIV infection. This article reviews the prevalence, pathogenesis, and implications of drug-resistant HSV infections in HIV-infected patients.

Treatment of herpes simplex virus infections

Herpes simplex virus (HSV) types 1 and 2 are ubiquitous organisms that cause infections in human populations throughout the world. The clinical manifestations of HSV infections are varied, ranging from asymptomatic disease to life-threatening illness in neonates and immunocompromised hosts. This article will review the common presentations for HSV disease and the current recommendations for the treatment of these infections. A detailed summary of the antiviral drugs used to treat HSV infections is also presented.

Parameters of CpG oligodeoxynucleotide-induced protection against intravaginal HSV-2 challenge

Synthetic oligodeoxynucleotides (ODN) containing unmethylated CpG dinucleotides within the context of certain flanking bases (CpG motifs) have been shown to induce potent innate and adaptive immune responses. Vaginal delivery of CpG ODN alone protects mice from vaginal herpes simplex virus type-2 (HSV-2) challenge. Here, we investigated the importance of timing of delivery, formulation, route and dose of vaginally administered CpG ODN in the prevention or treatment of intravaginal (IVAG) HSV-2 infection. Mice treated intravaginally with CpG ODN containing a phosphorothioate backbone 24 hours prior to IVAG HSV-2 challenge survived infection, showed minimal vaginal pathology, and had virtually no detectable virus in vaginal washes, when compared to mice treated with non-CpG ODN. Genital treatment of HSV-2 infected mice with CpG ODN 4 hours after infection resulted in increased survival and decreased pathology and vaginal virus titers, whereas treatment of infected mice with CpG ODN 24 and 72 hours after IVAG HSV-2 infection had no effect on disease progression. Both liquid and solid (delivered on a bio-erodible muco-adhesive film) formulations of CpG ODN were effective in protection against genital HSV-2 following vaginal delivery. Lastly, IVAG delivery of 10 micro g of CpG ODN protected as well as a 100 micro g dose.

Current treatment options to prevent perinatal transmission of herpes simplex virus

Neonatal herpes is a potentially devastating consequence of perinatal transmission of the herpes simplex virus (HSV), with significant morbidity and mortality. Treatment options are available, but must begin early in disease with manifestations that are often protean. Thus, preventive measures need to be optimised. Antiviral suppression in late pregnancy of women with a history of recurrent genital herpes will decrease symptomatic recurrence at delivery and appears to reduce caesarian section rates. However, primary HSV Type 2 and primary HSV Type 1 episodes have the highest neonatal transmission rates and thus, effective prevention may require the identification and suppression of the discordant partner. Significant experience has been gained with the use of acyclovir in pregnancy and it is recommended for both episodic and suppressive therapy in pregnant women. Its use has been demonstrated to be cost-effective in suppressive therapy, although issues regarding compliance and the potential for neonatal neutropenia need to be addressed. The more conveniently dosed prodrugs valacyclovir and famciclovir are being evaluated for use in pregnancy.

Short-course oral antiviral treatment for recurrent genital herpes

OBJECTIVE

To evaluate the literature regarding short-course oral therapy for recurrent genital herpes.

DATA SOURCES

Literature was accessed through MEDLINE (1966-March 2003), IOWA Drug Information Service (1966-March 2003), and International Pharmaceutical Abstracts (1966-March 2003).

DATA SYNTHESIS

Data are available describing short-course (2 or 3 d) therapy with acyclovir and valacyclovir. Short-course acyclovir therapy was superior to placebo. Three- and 5-day regimens of valacyclovir were equivalent. Early initiation of therapy may be more important than duration of therapy.

CONCLUSIONS

More head-to-head studies are needed to determine the most efficacious and cost-effective short-course regimens for recurrent genital herpes.

Efficacy of Thai medicinal plant extracts against herpes simplex virus type 1 infection in vitro and in vivo

Twenty Thai medicinal plant extracts were evaluated for anti-herpes simplex virus type 1 (HSV-1) activity. Eleven of them inhibited plaque formation of HSV-1 more than 50% at 100microg/ml in a plaque reduction assay. Aglaia odorata, Moringa oleifera, and Ventilago denticulata among the 11 were also effective against thymidine kinase-deficient HSV-1 and phosphonoacetate-resistant HSV-1 strains. These therapeutic efficacies were characterized using a cutaneous HSV-1 infection in mice. The extract of M. oleifera at a dose of 750mg/kg per day significantly delayed the development of skin lesions, prolonged the mean survival times and reduced the mortality of HSV-1 infected mice as compared with 2% DMSO in distilled water (P<0.05). The extracts of A. odorata and V. denticulata were also significantly effective in limiting the development of skin lesions (P<0.05). There were no significant difference between acyclovir and these three plant extracts in the delay of the development of skin lesions and no significant difference between acyclovir and M. oleifera in mean survival times. Toxicity of these plant extracts were not observed in treated mice. Thus, these three plant extracts may be possible candidates of anti-HSV-1 agents.

[Acyclovir-resistant herpes exulcerans et persistens. Type II]

Immunocompromised patients are developing in an increasing frequency acyclovir-resistant herpes simplex infections. Different treatment options need to be evaluated considering the possible side effects in regard to the patients' immunocompromised status. A 73-year-old woman with B-cell lymphatic leukemia with a secondary antibody deficiency syndrome and anemia suffered for one year with perianal ulcerations caused by acyclovir-resistant herpes simplex infection Type II. Based on previous reports about successful treatment of acyclovir-resistant herpes simplex infections with foscarnet, cidofovir or vidarabine and considering the different side effects of these drugs as well as the underlying diseases of the patient, we treated her with foscarnet intravenously. After 3 months the ulcers showed a nearly complete remission.

Therapeutic Options for Herpes Simplex Infections

Herpes simplex viruses are responsible for a number of disease states in infected individuals. Capable of establishing latent infection, herpes simplex can reactivate, causing pain, discomfort, and psychosocial consequences. Because no cure is available, treatment modalities for herpes simplex infection are required, from both personal and public health standpoints. To date, therapy has centered around the use of antiviral drugs to control infection and suppress recurrences. To expand the scope of available treatments, efforts have focused on the development of vaccines against herpes simplex virus and new agents such as immune response modifiers. Recent data suggest that these new agents are promising in their therapeutic potential.

Herpes simplex virus resistance to acyclovir and penciclovir after two decades of antiviral therapy

Acyclovir, penciclovir, and their prodrugs have been widely used during the past two decades for the treatment of herpesvirus infections. In spite of the distribution of over 2.3 x 10(6) kg of these nucleoside analogues, the prevalence of acyclovir resistance in herpes simplex virus isolates from immunocompetent hosts has remained stable at approximately 0.3%. In immuncompromised patients, in whom the risk for developing resistance is much greater, the prevalence of resistant virus has also remained stable but at a higher level, typically 4 to 7%. These observations are examined in the light of characteristics of the virus, the drugs, and host factors.

Treatment of mucocutaneous presentations of herpes simplex virus infections

Infections by herpes simplex virus (HSV) types I and II are diverse and quite frequent. After primary infection, the virus establishes a life-long latency in the sensory ganglia and recrudescences may occur at an unpredictable rate. Recurrent labial and genital herpes infections represent the majority of clinical manifestations of HSV infections. Their management is currently well established using evidence-based medicine data. Primary labial herpes is generally not treated with antivirals in otherwise healthy children, although intravenous aciclovir may be offered in severe primary infections, particularly in the immunocompromised patient. The decision whether or not to treat recurrent labial herpes should be evaluated individually and depends on the frequency and severity of relapses, the impairment of the quality of life, and the cost of therapy. Patients with mild disease may benefit from topical therapy, and those with severe and frequent recurrences may be considered for intermittent or long-term oral antiviral therapy. Primary genital herpes is treated with oral or intravenous antivirals, depending on the severity of the infection and associated symptoms. Recurrent genital herpes can be managed with episodic short courses of oral antivirals in patients whose recurrences are moderate to severe and rare, and have a clear prodrome. Patients with >5 episodes/year, severe recurrences or unrecognisable prodromes may be best managed with long-term suppressive antiviral prophylaxis. HSV is also responsible for a variety of other clinical manifestations, including herpetic whitlow, neonatal infection, disseminated and atypical cutaneous infections, traumatic herpes, eczema herpeticum, and HSV-associated erythema multiforme. HSV infection may also represent a complication following cosmetic procedures of the oro-facial region, surgical and dental interventions, sun exposure and burns. Precise treatment guidelines for these HSV infections are not firmly established.

Current treatments and perceptions of genital herpes: a European-wide view

A European panel of physicians reviewed the current treatments and perceptions of recurrent genital herpes (GH) across the continent. The panel consisted of specialists in dermatology and venereology from France, Finland, Germany, Italy, Norway, Spain, Sweden and the UK. A wide variety of factors that influence GH management were considered, including different health delivery systems, funding and cultural differences. The poor awareness of GH among both the general public and physicians was highlighted. The effectiveness of GH management was then examined from a patient's viewpoint, including the confirmation of the diagnosis, information and counselling about GH, as well as prescriptions for treatment. It was agreed that both physicians and patients often feel uncomfortable about discussing the disease, and that a European-wide effort is needed to re-educate patients and physicians about GH. The panel identified clear and unmet needs to manage a patient with clinical recurrences and to attempt to reduce the risk of GH transmission. Finally, resiquimod, an immune response modifier, was considered as a potential treatment option for GH.

Use of immunostimulatory sequence-containing oligonucleotides as topical therapy for genital herpes simplex virus type 2 infection

Synthetic oligonucleotides containing CpG motifs in specific sequence contexts have been shown to induce potent immune responses. We have evaluated mucosal administration of two immunostimulatory sequence (ISS)-containing phosphorothioate-stabilized oligonucleotides for antiherpetic efficacy in animal models. The ISS oligonucleotides, suspended in phosphate-buffered saline, were tested in mouse and guinea pig vaginal models of herpes simplex virus type 2 (HSV-2) infection. For comparison, groups of untreated, non-ISS oligonucleotide-treated, and acyclovir-treated animals also were monitored. The results indicated that vaginal epithelial application of ISS (up to 6 h after viral inoculation) with mice lethally challenged with HSV-2 delayed disease onset and reduced the number of animals that developed signs of disease (P = 0.003). ISS application significantly increased survival rates over those of controls (P = 0.0014). The ISS also impacted an established infection in the guinea pig model of HSV-2 disease. A single administration of ISS (21 days after viral inoculation) significantly reduced the frequency and severity of HSV-2 lesions compared to results with non-ISS oligonucleotide-treated and untreated guinea pigs (P < 0.01). HSV-2 is shed from the vaginal cavity of the guinea pig in the absence of lesions, similar to the case with humans. As an additional indication of ISS efficacy, the magnitude of viral shedding also was significantly reduced in ISS-treated animals (P < 0.001). These effects appeared to be immunologically mediated, since ISS had no direct effect on HSV-2 replication in vitro using standard plaque assays. These data suggest that ISS may be useful in the treatment and control of genital herpes in humans.

Progress in meeting today's demands in genital herpes: an overview of current management

Treatment of genital herpes requires accurate diagnosis, patient support, and effective treatment. Diagnosis is usually straightforward for classic presentations characterized by vesicular lesions but can be challenging for atypical presentations, which are more common. Diagnosis of asymptomatic infection requires access to molecular technology or type-specific serologic assays. Misconceptions about herpes simplex infection are common and patient education is essential. Patient concerns extend beyond disease frequency and severity-the psychological impact should not be underestimated. Antiviral therapy is relevant at all stages of infection. Acyclovir, valacyclovir, and famciclovir are effective and well tolerated for genital herpes treatment. Continuous suppressive therapy controls all symptoms of recurrent disease and helps to relieve disease complications. The prodrugs valacyclovir and famciclovir offer easier, less-frequent dosing than required for acyclovir. Valacyclovir achieves effective suppression when taken once a day. Interventions to prevent genital herpes transmission and to control the global problem are urgently required.

The management of herpes simplex virus infections

Herpes simplex virus persists in a latent form for the life of its host, periodically reactivating and often resulting in significant psychosocial distress for the patient. Currently no cure is available. Antiviral therapy is the main treatment modality, used either orally, intravenously, or topically to prohibit further replication of the virus and thereby minimize cellular destruction. However, immunologic advances in the treatment and prevention of herpes simplex infections are promising and continue to be studied.

Immunomodulation as a treatment strategy for genital herpes: review of the evidence

In this review, we discuss the ongoing development of a new treatment option for genital herpes (GH), the disease caused by herpes simplex virus (HSV) types I and II. Following infection, the virus establishes a latent infection in peripheral neurons, which periodically activates to cause recurrent skin lesions or asymptomatic shedding in the anogenital area. A new class of drugs, the immune response modifiers (IRMs), modulates the immune system against viral infection. This approach is currently being tested as a treatment for GH. We first review the effectiveness of treatment of other viral diseases with imiquimod, the first IRM to be licensed (Aldara, imiquimod 5% cream), and one used for the treatment of external anogenital warts. We then focus on resiquimod, an analog of imiquimod, which shows early promise as a new treatment option for GH. The evidence from in vitro and in vivo studies, in particular the guinea pig model of GH, describing the effectiveness and mode of action of this novel immunopharmacological agent is presented. Resiquimod stimulates specific cells of the innate immune system (including monocytes/macrophages, dendritic cells (DC) and B lymphocytes) to produce cytokines (in particular IFN-alpha, IL-12, TNF-alpha and IFN-gamma) that initiate and drive the development of the Th1 acquired immune response against HSV-infected cells. Recent results from clinical trials and in vivo studies in animal models are consistent with the hypothesis that the development of HSV-specific cell-mediated immunity may prove to be the key in providing a long-lasting protection against GH recurrences.

New treatments for genital herpes

Genital herpes is a sexually transmitted disease that has been widely investigated from both an epidemiological and a diagnostic viewpoint. Better knowledge of the disease has pointed to the important role of asymptomatic herpes simplex virus type 2 shedding as a major culprit for the spread of the virus in the world, the latest statistics showing that the incidence of genital herpes is constantly increasing. The reference compound for the treatment and prophylaxis of genital herpes is acyclovir. Recently, two drugs with better oral bioavailability, valaciclovir, the oral prodrug of acyclovir, and famciclovir, the oral prodrug of penciclovir, have been made available. Nevertheless, there is a need to develop additional approaches, to extend the therapeutic possibilities and to face the problem of emerging resistant viruses, mostly in immunocompromised patients. Therefore, efforts have been made in different directions including the exploration of new targets for antiviral chemotherapy, the use of immunomodulators and the development of specific vaccines.