Acute Herpetic Keratitis: What is the Role for Ganciclovir Ophthalmic Gel?

Treatments for Ocular Diseases in Pregnancy and Breastfeeding: A Narrative Review

Pregnancy is a medical condition in which the physiological changes in the maternal body and the potential impact on the developing fetus require a cautious approach in terms of drug administration. Individual treatment, a thorough assessment of the extent of the disease, and a broad knowledge of the therapeutic options and different routes of administration of ophthalmic drugs are essential to ensure the best possible results while minimizing risks. Although there are currently several routes of administration of drugs for the treatment of eye diseases, even with topical administration, there is a certain amount of systemic absorption that must be taken into account. Despite continuous developments and advances in ophthalmic drugs, no updated data are available on their safety profile in these contexts. The purpose of this review is both to summarize the current information on the safety of ophthalmic treatments during pregnancy and lactation and to provide a practical guide to the ophthalmologist for the treatment of eye diseases while minimizing harm to the developing fetus and addressing maternal health needs.

20 years since the Herpetic Eye Disease Study: Lessons, developments and applications to clinical practice

Herpes Simplex Virus (HSV) is the most common virus that causes eye disease. Although around 60% of the world's population are seropositive for HSV antigens, fortunately, it is estimated that only 1% of seropositive individuals develop eye disease. The most common ocular manifestation of HSV is keratitis, while uveitis and retinal necrosis occur in a small number of cases. HSV keratitis is a debilitating disease, for several reasons: pain , photophobia, and vision loss in acute disease, latency of the virus which leads to infection reactivation from various triggers, scarring, and neovascularisation, leading to permanent vision loss with poor visual rehabilitation prospects. The Herpetic Eye Disease Study (HEDS) was a landmark series of randomised controlled trials in the 1990s that set the benchmark for evidence-based treatment guidelines for anterior eye herpetic disease. Since this time, there has been a change in the distribution of seroprevalence of herpes in the community, a simplified diagnostic classification, advances in treatment options, an emergence of new and a better understanding of risk factors, and discoveries in science that show promise for vaccine and novel future treatments. However, many of the principles of the HEDS study remain rightly entrenched in clinical practice. In this article, the HEDS study is revisited 20 years on through the lens of published literature, to determine current best practise and look towards the future.

Peripapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer changes on optical coherence tomography in patients with unilateral hypertensive cytomegalovirus anterior uveitis

PURPOSE

To investigate whether peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thinning are present in patients with unilateral hypertensive Cytomegalovirus anterior uveitis (hCMV AU).

METHODS

We included 19 eyes with unilateral hCMV AU and their unaffected fellow eyes as the control group in this study. Peripapillary RNFL and macular GCIPL changes were determined using spectral-domain (SD) - optical coherence tomography (OCT).

RESULTS

The overall calculated mean pRNFL thickness was significantly lower in the effected eyes with hCMV AU than in the uneffected fellow eyes (p = 0.012). The mean macular GCIPL thickness in the affected eyes was also significantly lower than in the normal eyes (p < 0.001).

CONCLUSION

Measurement of pRNFL and macular GCIPL thickness with OCT may detect signs of damage before the visual field changes in patients with hypertensive CMV AU. Early aggressive treatment in these patients may prevent further glaucomatous damage.

Management of cytomegalovirus corneal endotheliitis

Background

Cytomegalovirus (CMV) can manifest as corneal endotheliitis in immunocompetent individuals. Early diagnosis is prudent to prevent endothelial cell loss, which could ultimately lead to corneal decompensation. CMV DNA was first detected in an eye with corneal endotheliitis in 2006; since then, clinical evidence from numerous case reports and case series have accumulated.

Main text

In this narrative review, we identified several drugs, including ganciclovir, valganciclovir, and their combination in oral, intravenous, intravitreal, and topical forms in different concentrations, together with the judicious use of topical steroids, have reported variable success. There has yet to be any prospective comparative study evaluating the efficacy and safety of these assorted forms of treatment; clinical evidence is based on case reports and case series. CMV endotheliitis presenting with corneal edema can masquerade as other corneal diseases and thus poses a great challenge especially in post-keratoplasty eyes. Heightened awareness is needed before and after keratoplasty to start prompt prophylaxis and treatment.

Conclusion

There is no consensus on the management of CMV endotheliitis. Further studies are much needed to elucidate the optimal treatment modality, regime, and duration in the treatment and prophylaxis of CMV endotheliitis.

Formulation development and in vitro evaluation of transferrin-conjugated liposomes as a carrier of ganciclovir targeting the retina

Ganciclovir (GCV) is an antiviral drug approved for treatment of cytomegalovirus (CMV) retinitis. It can be delivered to the eye via systemic administrations. However, local delivery of GCV that targets the retina is considered as an alternative to increase efficacy of the treatment and lessen side effects. Thus, this study aimed to develop formulations of transferrin (Tf)-conjugated liposomes containing GCV (Tf-GCV-LPs) for intravitreal injection and topical instillation. Tf-GCV-LPs were prepared by the reverse-phase evaporation technique and then conjugated to Tf. Their physicochemical properties were evaluated. The optimized formulation was selected and subjected to the cytotoxicity test, cellular uptake study in the human retinal pigment epithelial cells (the ARPE-19 cells) and antiviral activity evaluation. The results showed that physicochemical properties of Tf-GCV-LPs were affected by formulation compositions. The optimized Tf-GCV-LPs had a particle size lower than 100 nm with a negative value of zeta potential. They were safe for the ARPE-19 cells. These Tf-GCV-LPs were taken up by these cells via Tf receptors-mediated endocytosis and showed inhibitory activity on CMV in the infected cells. Therefore, the optimized Tf-GCV-LPs could be accepted as a promising drug delivery system for targeted GCV delivery to the retina in the treatment of CMV retinitis.

Successful Management of Herpes Simplex Keratitis With Oral Valganciclovir in Patients Unresponsive or Allergic to Conventional Antiviral Therapy

PURPOSE

To describe 4 cases of presumably immunocompetent patients with herpes simplex virus (HSV) keratitis unresponsive (n = 3) or allergic (n = 1) to conventional antiviral therapy that improved with oral valganciclovir treatment.

METHODS

Retrospective case series of 4 patients with HSV keratitis treated with oral valganciclovir between March 2016 and June 2018.

RESULTS

We reviewed the records of 4 patients with recurrent epithelial HSV keratitis. Three patients were on antiviral prophylaxis because of a history of HSV keratitis. All patients were on oral acyclovir, valacyclovir, and/or famciclovir treatment with/without topical antiviral therapy for 4 to 6 months for prophylaxis and/or recurrent dendriform epithelial keratitis. While 3 patients had recurrent episodes during their active prophylaxis with oral antiviral therapies, one patient had a recurrence after she discontinued her oral prophylactic antiviral therapy due to recurrent self-reported allergic reactions. The patients presented with recurrent dendriform epithelial keratitis despite conventional antiviral therapy. We initiated oral valganciclovir 900 mg twice a day for 10 days as a treatment dose, followed by 900 mg daily for prophylaxis. The corneal epithelium subsequently healed within the first 2 weeks in all patients. The mean follow-up time for patients on valganciclovir prophylaxis was 8 months (range: 6-12 months), and none of the patients presented with any further recurrences.

CONCLUSIONS

In case of treatment-related side effects or failure with conventional antiviral therapies, oral valganciclovir may present an alternative for the treatment and prophylaxis of HSV keratitis.

Conditional reprogrammed human limbal epithelial cells represent a novel in vitro cell model for drug responses

In this study, we established human limbal epithelial cells (LECs) from normal limbal tissues by using Conditional Reprogramming (CR) technology (refer to CR-LEC cells in this study). We have successfully established CR-LEC cell strains from three human donors (3 out of 3), and normal rabbits (2 out of 2) and pig (1 out of 1) as well. CR-LEC cells sustained a continuous and stable proliferation status with a normal karyotype, normal response to DNA damage, well-defined structured spheres in matrigel 3D culture. Responses of CR-LEC cells to IFN α2b, Ganciclovir and 5-Fluorouracil were different, suggesting that these drugs had different toxicities to these cells as expected. More important, there was no significant difference of responses to drugs between early and late passages of CR-LEC cells (p>0.05), indicating CR-LEC cells can serve a stable normal human cell model for toxicity assessment. Toxicity tests with monolayer cultures of CR-LEC cells were measured by staining the F-actin and Dsg-1 expression. Toxicity of three drugs at LD50 concentration resulted in a gradually increased destruction of monolayer, which is, in accordance with the irritation grade of three drugs on human cornea epithelium. Therefore, CR-LEC cells provide a novel and reliable in vitro physiological cell model for corneal toxicity assessment.

Ganciclovir

Ganciclovir is synthetic nucleoside analog of guanine closely related to acyclovir but has greater activity against cytomegalovirus. This comprehensive profile on ganciclovir starts with a description of the drug: nomenclature, formulae, chemical structure, elemental composition, and appearance. The uses and application of the drug are explained. The methods that were used for the preparation of ganciclovir are described and their respective schemes are outlined. The methods which were used for the physical characterization of the dug are: ionization constant, solubility, X-ray powder diffraction pattern, crystal structure, melting point, and differential scanning calorimetry. The chapter contains the spectra of the drug: ultraviolet spectrum, vibrational spectrum, nuclear magnetic resonance spectra, and the mass spectrum. The compendial methods of analysis of ganciclovir include the United States Pharmacopeia methods. Other methods of analysis that were reported in the literature include: high-performance liquid chromatography alone or with mass spectrometry, electrophoresis, spectrophotometry, voltammetry, chemiluminescence, and radioimmunoassay. Biological investigation on the drug includes: pharmacokinetics, metabolism, bioavailability, and biological analysis. Reviews on the methods used for preparation or for analysis of the drug are provided. The stability of the drug in various media and storage conditions is reported. More than 240 references are listed at the end of the chapter.

Intra-cameral level of ganciclovir gel, 0.15% following topical application for cytomegalovirus anterior segment infection: A pilot study

Purpose

To investigate the intra-cameral level of ganciclovir following topical application of ganciclovir gel, 0.15% for cytomegalovirus (CMV) anterior segment infection.

Design

Non-randomized, prospective, interventional clinical study.

Methods

Patients with active CMV anterior segment infection seen at Singapore National Eye Centre, confirmed by positive CMV real time PCR (RT-PCR) of the aqueous humor, that had not been treated with any form of ganciclovir in the preceding 1 month were recruited. They were treated with ganciclovir gel, 0.15% 1cc 5 times a day. Following 6 weeks of treatment, CMV load in the aqueous humor was measured using CMV RT-PCR and the ganciclovir drug levels in tears and aqueous humor were measured using high-performance liquid chromatography-mass spectrometry. The clinical features of the disease activity and the central corneal thickness (CCT) were recorded at the baseline and post-treatment.

Results

There were 29 eyes of 29 patients, of which 23 eyes had CMV anterior uveitis and 6 eyes had CMV endotheliitis. At the end of week 6, 26 eyes had undetectable CMV titre in the aqueous humor and no anterior chamber (AC) activity. Two patients had an increased CMV titre and increased AC inflammation. Both of these patients were non-compliant with the treatment. One patient had a reduced CMV titre in the aqueous humor with minimal AC inflammation. The mean ganciclovir concentration in the aqueous humor and the tears were 17.4 ± 30.6 ng/ml and 20,420.9 ± 33,120.8 ng/ml respectively. Mean CCT was 552.2 ± 42.3 microns. There was a weak correlation between the ganciclovir concentration in the aqueous humor and CCT (Spearmen's r = + 0.42, p = 0.025). There was no significant correlation between the ganiclovir concentration in the tears and CCT (Spearmen's r = + 0.39, p = 0.11).

Conclusion

Ganciclovir levels in the aqueous humor was below the 50% inhibitory dose (ID50) for CMV replication, following topical application of the ganciclovir gel, 0.15%.

Trial registration

SingHealth Centralized Institutional Review Board, Singapore; R733/17/2010, ClinicalTrials.gov; NCT01647529.

Eyelid Molluscum Contagiosum Lesions in Two Patients with Unilateral Chronic Conjunctivitis

Molluscum contagiosum (MC) is a viral infection of the skin and mucosal tissues characterized by skin-colored or transparent round nodules with a dimple or pit in the center. The infection is caused by a DNA poxvirus called the MC virus. Although MC generally occurs in children, it has also been reported in immunocompromised and atopic patients. The virus is transmitted by skin contact or sexual intercourse. The lesions disappear spontaneously within several months in most cases. However, excision, cryotherapy, cauterization, topical chemical and antiviral agents, and/or oral cimetidine are used in refractory cases or to accelerate the healing process. Herein, we discussed the clinical findings and our treatment of two patients with unilateral chronic conjunctivitis associated with eyelid MC lesions in light of the literature.

Improved intraocular bioavailability of ganciclovir by mucoadhesive polymer based ocular microspheres: development and simulation process in Wistar rats

BACKGROUND

The poor ocular bioavailability of the conventional eye drops is due to lack of corneal permeability, nasolacrimal drainage and metabolic degradation. To overcome this issue, drug encapsulated in mucoadhesive polymer based ocular microspheres have the advantages of improved drug stability, easy administration in liquid form, diffuse rapidly and better ocular tissue internalization.

METHODS

The ganciclovir chitosan microspheres (GCM) were prepared by modified water-in-oil emulsification method. The formulation was optimized and characterized by investigating in vitro release study, release kinetics, XRD and microspheres stability. Ocular irritancy, in vivo ocular pharmacokinetic parameters and histopathology study was evaluated in Wistar rats. The use of pharmacokinetic/pharmacodynamic indices and simulation process was carried out to further ensure clinical applicability of the formulation.

RESULTS

The in vitro release study showed initial burst (nearly 50 %) in first few minutes and followed Fickian (R(2) = 0.9234, n-value = 0.2329) type of diffusion release mechanism. The XRD and stability studies showed favorable results. The Wistar rat eyes treated with GCM showed significant increase in ganciclovir AUC (~4.99-fold) and Cmax (2.69-fold) in aqueous humor compared to ganciclovir solution and delay in Tmax. The Cmax/MIC90, AUC0-24/MIC90, AUC above MIC90 and T above MIC90 were significantly higher in GCM group. The aqueous humor concentration-time profile of ganciclovir in GCM and ganciclovir solution was simulated with every 28.1 and 12.8 h, respectively. The simulated concentration-time profile shows that in duration of 75 h, the ganciclovir solution require six ocular instillations compared to three ocular instillations of the GCM formulation. The photomicrograph of GCM and ganciclovir solution treated rat retina showed normal organization and cytoarchitecture.

CONCLUSIONS

Correlating with in vitro data, the formulation showed sustained drug release along with improved intraocular bioavailability of ganciclovir in Wistar rats.

A Therapeutic Trial of Valganciclovir in Patients with Uveitis and Positive Epstein-Barr virus Early Antigen D IgG Titers

Purpose

To evaluate the effectiveness of a therapeutic trial of valganciclovir in patients with uveitis with positive Epstein-Barr virus early antigen D immunoglobulin G titers (EBV EA-D).

Methods

We performed a retrospective chart review of 14 patients at the Massachusetts Eye Research and Surgery Institution who had uveitis with positive EBV EA-D but negative studies for all other causes of uveitis and were treated with valganciclovir 450 mg twice a day or valganciclovir 900 mg twice a day between January 2010 and August 2014.

Results

Nine of 14 patients, who had presumed EBV reactivation with associated intraocular inflammation, were successfully treated with valganciclovir: 3 of these were treated with valganciclovir 450 mg twice a day and 6 were treated with valganciclovir 900 mg twice a day. Five of 14 patients failed to respond to valganciclovir with persistent inflammation after at least 2 weeks of valganciclovir therapy, and were subsequently treated with immunomodulatory therapy to control inflammation.

Conclusions

Uveitis can be caused by EBV infection/reactivation. A therapeutic trial with valganciclovir 450 mg twice a day for 1 month in patients with uveitis with positive EBV EA antibody may be beneficial.

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.