Comparison of efficacy of oral valacyclovir and topical acyclovir in the treatment of herpes simplex keratitis: a randomized clinical trial

In-vitro and in-silico anti-HSV-1 activity of a marine steroid from the jellyfish Cassiopea andromeda venom

In this study, we investigated the potential in vitro anti-HSV-1 activities of the Cassiopea andromeda jellyfish tentacle extract (TE) and its fractions, as well as computational work on the thymidine kinase (TK) inhibitory activity of the identified secondary metabolites. The LD50, secondary metabolite identification, preparative and analytical chromatography, and in silico TK assessment were performed using the Spearman-Karber, GC-MS, silica gel column chromatography, RP-HPLC, LC-MS, and docking methods, respectively. The antiviral activity of TE and the two purified compounds Ca2 and Ca7 against HSV-1 in Vero cells was evaluated by MTT and RT-PCR assays. The LD50 (IV, mouse) values of TE, Ca2, and Ca7 were 104.0 ± 4, 5120 ± 14, and 197.0 ± 7 (μg/kg), respectively. They exhibited extremely effective antiviral activity against HSV-1. The CC50 and MNTD of TE, Ca2, and Ca7 were (125, 62.5), (25, 12.5), and (50, 3.125) μg/ml, respectively. GC-MS analysis of the tentacle extract revealed seven structurally distinct chemical compositions. Four of the seven compounds had a steroid structure. According to the docking results, all compounds showed binding affinity to the active sites of both thymidine kinase chains. Among them, the steroid compound Pregn-5-ene-3,11-dione, 17,20:20,21 bis [methylenebis(oxy)]-, cyclic 3-(1,2-ethane diyl acetal) (Ca2) exhibited the highest affinity for both enzyme chains, surpassing that of standard acyclovir. In silico data confirmed the experimental results. We conclude that the oxosteroid Ca2 may act as a potent agent against HSV-1.

Advancement on Sustained Antiviral Ocular Drug Delivery for Herpes Simplex Virus Keratitis: Recent Update on Potential Investigation

The eyes are the window to the world and the key to communication, but they are vulnerable to multitudes of ailments. More serious than is thought, corneal infection by herpes simplex viruses (HSVs) is a prevalent yet silent cause of blindness in both the paediatric and adult population, especially if immunodeficient. Globally, there are 1.5 million new cases and forty thousand visual impairment cases reported yearly. The Herpetic Eye Disease Study recommends topical antiviral as the front-line therapy for HSV keratitis. Ironically, topical eye solutions undergo rapid nasolacrimal clearance, which necessitates oral drugs but there is a catch of systemic toxicity. The hurdle of antiviral penetration to reach an effective concentration is further complicated by drugs’ poor permeability and complex layers of ocular barriers. In this current review, novel delivery approaches for ocular herpetic infection, including nanocarriers, prodrugs, and peptides are widely investigated, with special focus on advantages, challenges, and recent updates on in situ gelling systems of ocular HSV infections. In general congruence, the novel drug delivery systems play a vital role in prolonging the ocular drug residence time to achieve controlled release of therapeutic agents at the application site, thus allowing superior ocular bioavailability yet fewer systemic side effects. Moreover, in situ gel functions synergistically with nanocarriers, prodrugs, and peptides. The findings support that novel drug delivery systems have potential in ophthalmic drug delivery of antiviral agents, and improve patient convenience when prolonged and chronic topical ocular deliveries are intended.

Toxic Keratoconjunctivitis

Toxic keratoconjunctivitis (TK) is an underrecognized complication of ophthalmic drug use and various environmental or occupational exposures. A detailed history and clinical examination are important to identify the offending agent(s). Common drug-related causes of TK include preservatives in ophthalmic medications, topical antimicrobials, and topical anesthetics. Alternatives to benzalkonium chloride as well as preservative-free formulations should be considered in patients requiring long-term topical medication. More advanced cases of TK may require preservative-free topical steroids and/or antibiotics, and occasionally surgical intervention. Early recognition and appropriate management of TK may help prevent permanent ocular and visual damage.

Management of herpes simplex virus epithelial keratitis

PURPOSE OF REVIEW

To review recent advancements in the management of herpes simplex virus (HSV) epithelial keratitis.

RECENT FINDINGS

Trifluridine eye drop, acyclovir (ACV) ointment, ganciclovir gel, and oral ACV are still the main therapeutic agents. Cryopreserved amniotic membrane has been recently used as an adjuvant treatment. Resistance to ACV has become a concerning issue. The animal models of HSV vaccine are able to reduce HSV keratitis. New antivirals are under development.

SUMMARY

Current cases of HSV epithelial keratitis are manageable with available medications, but new advancements are required to decrease disease burden in the future. HSV vaccine can be revolutionary.

Herpes simplex virus keratitis: an update of the pathogenesis and current treatment with oral and topical antiviral agents

Ophthalmic herpes simplex viral keratitis is responsible for a range of ocular manifestations from superficial epithelial disease to stromal keratitis and endotheliitis. The Herpetic Eye Disease Study has guided the management of herpetic eye disease for almost twenty years, but newer medications such as valacyclovir are now available and are considered to have better bioavailability than acyclovir. In this review, we examine the existing evidence on the pathogenesis of different ophthalmic herpes simplex viral keratitis disease modalities and the role of oral and topically administered antiviral drugs in the treatment of herpes simplex viral keratitis.

Effects of antiviral medications on herpetic epithelial keratitis in mice

PURPOSE

Aciclovir (ACV), valaciclovir (VACV) and famciclovir (FCV) are used for systemic infections caused by herpes virus. In Japan, only topical ACV is permitted for use against herpetic keratitis. We investigated the effectiveness of topical ACV, oral VACV and oral FCV on mouse epithelial herpetic keratitis.

METHODS

C57/BL76 mice were inoculated with HSV-1 McKrae strain in the cornea. Once infection was confirmed 4 days after inoculation, topical ACV, oral VACV and FCV were started and administered for 5 days. Control groups were given either topical or oral saline. On days 2, 4, 6 and 10 after medication started, tears, eyeballs, and trigeminal ganglia were examined using viral culture and real-time PCR.

RESULTS

Viral culture of tears detected no HSV in the topical ACV group on day 4 after administration start; with similar results for the oral VACV group on day 4; and the oral FCV group on day 6. Real-time PCR of the eyeballs showed significant decrease of HSV DNA copy number in the topical ACV group on days 4 and 6 compared to the topical saline group. Real-time PCR of the trigeminal ganglia showed significant decrease of HSV DNA copy number in the oral VACV group on days 4 and 6, and in the oral FCV group on day 6 compared to the oral saline group.

CONCLUSION

We suggest that 5-day administration of topical ACV, oral VACV and oral FCV are effective for mouse epithelial herpetic keratitis and sufficiently decrease HSV amounts in the ocular surface and eyeballs.

Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Eye disease due to herpes simplex virus (HSV) commonly presents as epithelial keratitis which, though usually self-limiting, may persist or progress without treatment.

OBJECTIVES

To compare the relative effectiveness of antiviral agents, interferon, and corneal debridement in the treatment of HSV epithelial keratitis.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 12), PubMed (January 1946 to 31 December 2014), EMBASE (January 1980 to 31 December 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to 31 December 2014), System for Information on Grey Literature in Europe (OpenGrey) (January 1995 to 31 December 2014), BIOSIS (January 1926 to 5 May 2014), Scopus (January 1966 to 31 December 2014), Japan Science and Technology Institute (J-Global) (January 1975 to 31 December 2014), China National Knowledge Infrastructure (CNKI) (January 1979 to 31 December 2014), British Library's Electronic Table of Contents (Zetoc) (January 1993 to 7 May 2014). We looked for trials listed on the the metaRegister of Controlled Trials (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en), Chinese Clinical Trial Registry, the U.S. Food and Drug Administration (FDA) (www.fda.gov/), National Institute for Health and Clinical Excellence (NICE) (www.

EVIDENCE

nhs.uk) and the European Medicines Agency (EMA) (www.ema.europa.eu/ema/) as of 31 December 2014. There were no language or date restrictions in the search for trials. We also culled literature digests and conference proceedings as of 15 April 2014. There were no language or date restrictions in the search for trials.

SELECTION CRITERIA

Randomised and quasi-randomised trials of HSV dendritic or geographic epithelial keratitis were included that reported the proportion of eyes healed at one week, two weeks, or both after enrolment.

DATA COLLECTION AND ANALYSIS

We tabulated data on study characteristics, risk of bias, and outcomes and used direct comparisons to estimate a risk ratio (RR) and, when feasible, a hazard ratio (HR) with a 95% confidence interval (CI). Heterogeneity was assessed by an inconsistency index. A multiple treatment comparison meta-analysis consolidated direct and indirect comparisons of relative healing at 14 days.

MAIN RESULTS

One hundred thirty-seven studies involving 8333 eyes met the inclusion criteria. Placebo-controlled studies were heterogeneous in comparison with idoxuridine (RR 1.74; 95% CI 1.03 to 2.91) and few in number for vidarabine (RR 1.81; 95% CI 1.09 to 3.01), interferon (RR 1.32; 95% CI 1.06 to 1.64), and debridement. Vidarabine (RR 1.13; 95% CI 1.02 to 1.25), trifluridine (RR 1.30; 95% CI 1.18 to 1.43), acyclovir (RR 1.23; 95% CI 1.14 to 1.34), and brivudine (RR 1.34; 95% CI 1.18 to 1.51) were more effective than idoxuridine. Trifluridine (RR 1.17; 95% CI 1.03 to 1.32) and acyclovir (RR 1.11; 95% CI 1.03 to 1.19) were more effective than vidarabine. No significant differences in healing emerged among trifluridine, acyclovir, brivudine, and foscarnet although few studies compared brivudine or foscarnet with other antivirals. Any potential advantage of ganciclovir compared to acyclovir was mitigated by study heterogeneity and possible publication bias. Only one study evaluated the joint use of two topical antivirals. In a limited number of studies, oral acyclovir (RR 0.92; 95% CI 0.79 to 1.07) or the combination of oral acyclovir with a topical antiviral (RR 1.36; 95% CI 0.68 to 2.74) appeared as effective as a single topical antiviral agent. Compared to topical antiviral monotherapy, the combination of an antiviral with either interferon or debridement had inconsistent effects on expediting healing and improving outcome.

AUTHORS' CONCLUSIONS

Placebo-controlled studies of HSV epithelial keratitis are limited to superseded interventions. Trifluridine and acyclovir are more effective than idoxuridine or vidarabine and similar in therapeutic effectiveness. Brivudine and foscarnet do not substantially differ in effectiveness from trifluridine or acyclovir. Ganciclovir is at least as effective as acyclovir. The addition of interferon to a nucleoside antiviral agent and the combination of debridement with antiviral treatment need to be further assessed to substantiate any possible advantage in healing.

Ganciclovir ophthalmic gel 0.15% for the treatment of acute herpetic keratitis: background, effectiveness, tolerability, safety, and future applications

Eye disease due to herpes simplex virus (HSV) is a leading cause of ocular morbidity and the number one infectious cause of unilateral corneal blindness in the developed parts of the globe. Recurrent keratitis can result in progressive corneal scarring, thinning, and vascularization. Antiviral agents employed against HSV have primarily been nucleoside analogs. Early generation drugs included idoxuridine, iododesoxycytidine, vidarabine, and trifluridine. While effective, they tended to have low bioavailability and measurable local cellular toxicity due to their nonselective mode of action. Acyclovir 0.3% ointment is a more selective agent, and had become a first-line topical drug for acute HSV keratitis in Europe and other places outside of the US. Ganciclovir 0.15% gel is the most recently approved topical treatment for herpes keratitis. Compared to acyclovir 0.3% ointment, ganciclovir 0.15% gel has been shown to be better tolerated and no less effective in several Phase II and III trials. Additionally, topical ganciclovir does not cause adverse systemic side effects and is therapeutic at lower concentrations. Based on safety, efficacy, and tolerability, ganciclovir 0.15% gel should now be considered a front-line topical drug in the treatment of dendritic herpes simplex epithelial keratitis. Topics of future investigation regarding other potential uses for ganciclovir gel may include the prophylaxis of recurrent HSV epithelial keratitis, treatment of other forms of ocular disease caused by herpesviruses and adenovirus, and ganciclovir gel as an adjunct to antitumor therapy.

Targeting herpetic keratitis by gene therapy

Ocular gene therapy is rapidly becoming a reality. By November 2012, approximately 28 clinical trials were approved to assess novel gene therapy agents. Viral infections such as herpetic keratitis caused by herpes simplex virus 1 (HSV-1) can cause serious complications that may lead to blindness. Recurrence of the disease is likely and cornea transplantation, therefore, might not be the ideal therapeutic solution. This paper will focus on the current situation of ocular gene therapy research against herpetic keratitis, including the use of viral and nonviral vectors, routes of delivery of therapeutic genes, new techniques, and key research strategies. Whereas the correction of inherited diseases was the initial goal of the field of gene therapy, here we discuss transgene expression, gene replacement, silencing, or clipping. Gene therapy of herpetic keratitis previously reported in the literature is screened emphasizing candidate gene therapy targets. Commonly adopted strategies are discussed to assess the relative advantages of the protective therapy using antiviral drugs and the common gene therapy against long-term HSV-1 ocular infections signs, inflammation and neovascularization. Successful gene therapy can provide innovative physiological and pharmaceutical solutions against herpetic keratitis.

Ocular herpes simplex virus: how are latency, reactivation, recurrent disease and therapy interrelated?

Most humans are infected with herpes simplex virus (HSV) type 1 in early childhood and remain latently infected throughout life. While most individuals have mild or no symptoms, some will develop destructive HSV keratitis. Ocular infection with HSV-1 and its associated sequelae account for the majority of corneal blindness in industrialized nations. Neuronal latency in the peripheral ganglia is established when transcription of the viral genome is repressed (silenced) except for the latency-associated transcripts and microRNAs. The functions of latency-associated transcripts have been investigated since 1987. Roles have been suggested relating to reactivation, establishment of latency, neuronal protection, antiapoptosis, apoptosis, virulence and asymptomatic shedding. Here, we review HSV-1 latent infections, reactivation, recurrent disease and antiviral therapies for the ocular HSV diseases.

Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Eye disease due to herpes simplex virus (HSV) commonly presents as epithelial keratitis.

OBJECTIVES

To compare the relative effectiveness of antiviral agents, interferon, and corneal débridement in the treatment of acute HSV epithelial keratitis.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2010, Issue 4), MEDLINE (January 1950 to October 2010), EMBASE (January 1980 to October 2010), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2010), Zetoc (British Library's Electronic Table of Contents), System for Information on Grey Literature in Europe (openSIGLE), Biosciences Information Service (BIOSIS), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), Japan Information Center of Science and Technology (JICST-EPlus), and China Academic Journals database (CAJ) via China National Knowledge Infrastructure (CNKI) with citations confirmed using China/Asia On Demand (COAD). There were no language or date restrictions in the search for trials. All databases except CNKI and COAD were last searched on 27 October 2010, CNKI and COAD were searched on 1 April 2010. We also searched literature digests, conference proceedings and reference lists.

SELECTION CRITERIA

Of 152 eligible studies,106 comparative treatment trials involving 5872 eyes with dendritic or geographic epithelial keratitis were analysed for corneal healing over two weeks.

DATA COLLECTION AND ANALYSIS

Interventions were compared at 14 days after trial enrolment by calculating a risk ratio (RR) that was adjusted with indirect RR, assessed by an inconsistency index (I(2) ) and supplemented by a seven-day RR and a hazard ratio (HR).

MAIN RESULTS

Idoxuridine, though uncertainly better in healing outcome than control because of few trials with 14-day follow up, allowed earlier corneal re-epithelialisation. Vidarabine resulted in a significantly better outcome than placebo in one trial (RR 1.96; 95% CI 1.10 to 3.49). Compared to idoxuridine, in combined direct and indirect analyses, vidarabine (RR 1.11; 95% CI 1.03 to 1.19), trifluridine (RR 1.31; 95% CI 1.20 to 1.42), acyclovir (RR 1.23; 95% CI 1.16 to 1.31), brivudine (RR 1.38; 95% CI 1.18 to 1.61), and ganciclovir (RR 1.40; 95% CI 1.25 to 1.57) were significantly more effective. Trifluridine (RR 1.12; 95% CI 1.04 to 1.21) and acyclovir (RR 1.11; 95% CI 1.05 to 1.19) appeared more effective than vidarabine. No significant differences were found in comparisons between acyclovir, trifluridine and brivudine. The comparison of ganciclovir to acyclovir was limited by heterogeneity and possible publication bias. The joint use of two topical antivirals (RR 1.00; 95% CI 0.89 to 1.12) and the use of oral acyclovir alone (RR 0.92; 95% CI 0.79 to 1.07) or combined with a topical antiviral (RR 1.08; 95% CI 0.99 to 1.17) appeared as effective as topical antiviral therapy. Compared to antiviral monotherapy, the combination of an antiviral with interferon (RR 1.03; 95% CI 0.99 to 1.07) or with débridement (RR 1.04; 95% CI 0.95 to 1.14) did not yield significantly better outcomes but may have accelerated healing. The corneal epithelial healing outcome was improved when antiviral therapy was added to débridement (RR 1.21; 95% CI 1.04 to 1.42).

AUTHORS' CONCLUSIONS

Trifluridine and acyclovir are more effective than idoxuridine or vidarabine, and similar in therapeutic effectiveness. Brivudine and ganciclovir are at least as effective as acyclovir. While not improving outcome, the combination of interferon and an antiviral agent may speed healing. The effectiveness of corneal epithelial débridement is improved by an antiviral agent.

Aciclovir-resistant herpes keratitis

Herpes simplex virus (HSV) keratitis is a common cause of ocular morbidity. Resistance to aciclovir is probably under recognized. We describe three cases of aciclovir-resistant herpes simplex virus keratitis treated with systemic foscarnet and present a review of the pharmacological options available to manage this condition.

Therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Many clinical trials have been performed on the acute treatment of dendritic epithelial keratitis. Surveys of ocular antiviral pharmacology and of herpes simplex virus (HSV) eye disease have evaluated different interventions, but a systematic review of all comparative clinical studies has not previously been undertaken.

OBJECTIVES

The objective of this review was to compare the effects of various therapeutic interventions for dendritic or geographic HSV epithelial keratitis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) in The Cochrane Library (Issue 3, 2007), MEDLINE (1966 to September 2007), EMBASE (1980 to September 2007), LILACS (up to September 2007), SIGLE (1980 to September 2007), ZETOC (21 September 2007), BIOSIS (up to 2005), JICT-EPlus (up to 2005), Index Medicus (1960 to 1965), Excerpta Medica Ophthalmology (1960 to 1973), reference lists of primary reports and review articles, and conference proceedings pertaining to ocular virology.

SELECTION CRITERIA

This review included comparative clinical trials that assessed one-week or two-week healing rates of topical ophthalmic or oral antiviral agents and or physical or chemical debridement in people with active epithelial keratitis.

DATA COLLECTION AND ANALYSIS

The review author extracted data and assessed trial quality. Interventions were compared by the proportions of participants healed at seven days and at fourteen days after trial enrolment.

MAIN RESULTS

This review included data from 99 trials that randomised a total of 5363 participants. The topical application of vidarabine, trifluridine, acyclovir or ganciclovir resulted in a high proportion of participants healing within one week of treatment. Among these antiviral agents, no treatment emerged as significantly better for the therapy of dendritic epithelial keratitis. Insufficient placebo-controlled studies were available to assess debridement and other physical or physicochemical methods of treatment. Interferon monotherapy had a slight beneficial effect on dendritic epithelial keratitis but was not better than other antiviral agents. Interferon was very effective when combined with another antiviral agent such as trifluridine.

AUTHORS' CONCLUSIONS

Currently available antiviral agents are effective and nearly equivalent. The combination of a nucleoside antiviral with either debridement or with interferon seems to speed healing. Future trials of the acute treatment of HSV epithelial keratitis must aim to achieve adequate statistical power for assessing the primary outcome of epithelial healing and should consider the effect of lesion size and other characteristics on treatment response.

Evidence-based treatment of herpes simplex virus keratitis: a systematic review

Herpes simplex virus (HSV) keratitis is a common cause of ocular and visual morbidity. In this article, we systematically review published randomized clinical trials (RCTs) for HSV epithelial and stromal keratitis in order to establish a rational evidence-based foundation for treatment of these disorders. Articles for review were identified in the MEDLINE database from January 1, 1966, to May 30, 2006. Our review criteria stipulated that each study be performed in prospective, randomized, and double-blinded fashion, that it be controlled, and that it rely on specific clinical criteria for diagnosis and outcome. Of articles thus identified in the English language press, 38 articles met our review criteria, 30 for HSV epithelial keratitis and 8 (comprising 7 RCTs) for HSV stromal keratitis. From these studies, we concluded that the best evidence from treatment trials on HSV epithelial keratitis supports the use of topical trifluridine and topical or oral acyclovir, and suggests a possible additional benefit for topical interferon. The best evidence from RCTs for HSV stromal keratitis supports the use of topical corticosteroids given together with a prophylactic antiviral to shorten the duration of active HSV stromal keratitis, and the use of long-term suppressive oral acyclovir therapy to reduce the incidence of recurrent HSV keratitis.

Therapeutic interventions for herpes simplex virus epithelial keratitis

BACKGROUND

Many clinical trials have been performed on the acute treatment of dendritic epithelial keratitis. Surveys of ocular antiviral pharmacology and of herpes simplex virus (HSV) eye disease have evaluated different interventions, but a systematic review of all comparative clinical studies has not previously been undertaken.

OBJECTIVES

The objective of this review was to compare the effects of various therapeutic interventions for dendritic or geographic HSV epithelial keratitis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) in The Cochrane Library (Issue 3, 2006), MEDLINE (1966 to July 2006, week 3), EMBASE (1980 to 2006, week 30), LILACS (up to August 2006), SIGLE (1980 to March 2005), ZETOC (1 August 2006), BIOSIS (up to 2005), JICT-EPlus (up to 2005), Index Medicus (1960 to 1965), Excerpta Medica Ophthalmology (1960 to 1973), reference lists of primary reports and review articles, and conference proceedings pertaining to ocular virology.

SELECTION CRITERIA

This review included comparative clinical trials that assessed one-week or two-week healing rates of topical ophthalmic or oral antiviral agents and or physical or chemical debridement in people with active epithelial keratitis.

DATA COLLECTION AND ANALYSIS

The review author extracted data and assessed trial quality. Interventions were compared by the proportions of participants healed at seven days and at fourteen days after trial enrolment.

MAIN RESULTS

This review included data from 98 trials that randomised a total of 5211 participants. Compared to idoxuridine, the topical application of vidarabine, trifluridine, or acyclovir resulted in a significantly greater proportion of participants healing within one week of treatment. Among these latter three antiviral agents, no treatment emerged as significantly better for the therapy of dendritic epithelial keratitis. Insufficient placebo-controlled studies were available to assess debridement and other physical or physicochemical methods of treatment. Interferon monotherapy had a slight beneficial effect on dendritic epithelial keratitis but was not better than other antiviral agents. Interferon was very effective when combined with another antiviral agent such as trifluridine.

AUTHORS' CONCLUSIONS

Currently available antiviral agents are effective and nearly equivalent. The combination of a nucleoside antiviral with either debridement or with interferon seems to speed healing. Future trials of the acute treatment of HSV epithelial keratitis must aim to achieve adequate statistical power for assessing the primary outcome of epithelial healing and should consider the effect of lesion size and other characteristics on treatment response.