Use of human fibroblast-derived (beta) interferon in the treatment of epidemic adenovirus keratoconjunctivitis

Topical Pharmacologic Interventions Versus Active Control, Placebo, or No Treatment for Epidemic Keratoconjunctivitis: Findings From a Cochrane Systematic Review

PURPOSE

To summarize key findings from a Cochrane systematic review of the effectiveness and safety of topical pharmacologic interventions compared with active control or placebo for epidemic keratoconjunctivitis (EKC).

DESIGN

Systematic review.

METHODS

We included randomized controlled trials that compared antiseptic agents, virustatic agents, or immune-modulating topical therapies with placebo or an active control. We adhered to Cochrane methods for trial selection, data extraction, risk of bias evaluation, and data synthesis.

RESULTS

Ten randomized controlled trials with 892 participants with acute or chronic EKC were included. Eight trials compared interventions with artificial tears or saline (n = 4) or with steroids (n = 4); two 3-arm trials contributed data to both comparisons. Estimates suggested that compared with tears, after povidone-iodine (PVP-I) alone (2 studies, 409 participants) more participants with acute EKC had resolution of symptoms (risk ratio [RR] 1.15 [95% confidence interval {CI} 1.07-1.24]) and signs (RR 3.19 [95% CI 2.29-4.45]) within 10 days. In 2 trials comparing treatments with steroid alone or steroid with levofloxacin, fewer eyes treated with PVP-I or polyvinyl alcohol iodine (PVA-I) plus steroid developed subepithelial infiltrates within 21 days (RR 0.08 [95% CI 0.01-0.55]; 69 eyes). No treatment was shown to improve resolution of infiltrates.

CONCLUSIONS

Low- to very low-level certainty of evidence suggested that PVP-I or PVA-I with steroid may confer some benefit in acute EKC, but imprecision from small sample sizes, the potential risk of bias from inadequate reporting or trial design, and variability in participant selection, outcome measurement, and reporting limit the amount and quality of evidence.

Topical pharmacologic interventions versus placebo for epidemic keratoconjunctivitis

BACKGROUND

Viruses cause about 80% of all cases of acute conjunctivitis. Human adenoviruses are believed to account for 65% to 90% of cases of viral conjunctivitis, or 20% to 75% of all causes of infectious keratoconjunctivitis worldwide. Epidemic keratoconjunctivitis (EKC) is a highly contagious subset of adenoviral conjunctivitis that has been associated with large outbreaks at military installations and at medical facilities. It is accompanied by severe conjunctival inflammation, watery discharge, and light sensitivity, and can lead to chronic complications such as corneal and conjunctival scarring with discomfort and poor quality of vision. Due to a lack of consensus on the efficacy of any pharmacotherapy to alter the clinical course of EKC, no standard of care exists, therefore many clinicians offer only supportive care.

OBJECTIVES

To assess the efficacy and safety of topical pharmacological therapies versus placebo, an active control, or no treatment for adults with EKC.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, which contains the Cochrane Eyes and Vision Trials Register; 2021, Issue 4); Ovid MEDLINE; Ovid Embase; Latin American and Caribbean Health Sciences database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), with no restrictions on language or year of publication. The date of the last search was 27 April 2021.

SELECTION CRITERIA

We included randomized controlled trials in which antiseptic agents, virustatic agents, or topical immune-modulating therapy was compared with placebo, an active control, or no treatment.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

We identified 10 studies conducted in Asia, Europe, the Middle East, and North Africa with a total of 892 participants who were treated for 7 days to 6 months and followed for 7 days up to 1.5 years. Study characteristics and risk of bias In most studies participants were predominantly men (range: 44% to 90%), with an age range from 9 to 82 years. Three studies reported information on trial registration, but we found no published study protocol. The majority of trials had small sample sizes, ranging from 18 to 90 participants enrolled per study; the only exception was a trial that enrolled 350 participants. We judged most studies to be at high or unclear risk of bias across risk of bias domains. Findings We included 10 studies of 892 EKC participants and estimated combined intervention effects in analyses stratified by steroid-containing control treatment or artificial tears. Six trials contributed to the comparisons of topical interventions (povidone-iodine [PVP-I], trifluridine, ganciclovir, dexamethasone plus neomycin) with artificial tears (or saline). Very low certainty evidence from two trials comparing trifluridine or ganciclovir with artificial tears showed inconsistent effects on shortening the mean duration of cardinal symptoms or signs of EKC. Low certainty evidence based on two studies (409 participants) indicated that participants treated with PVP-I alone more often experienced resolution of symptoms (risk ratio (RR) 1.15, 95% confidence interval (CI) 1.07 to 1.24) and signs (RR 3.19, 95% CI 2.29 to 4.45) during the first week of treatment compared with those treated with artificial tears. Very low certainty evidence from two studies (77 participants) suggested that PVP-I or ganciclovir prevented the development of subepithelial infiltrates (SEI) when compared with artificial tears within 30 days of treatment (RR 0.24, 95% CI 0.10 to 0.56). Four studies compared topical interventions (tacrolimus, cyclosporin A [CsA], trifluridine, PVP-I + dexamethasone) with topical steroids, and one trial compared fluorometholone (FML) plus polyvinyl alcohol iodine (PVA-I) with FML plus levofloxacin. Evidence from one trial showed that more eyes receiving PVP-I 1.0% plus dexamethasone 0.1% had symptoms resolved by day seven compared with those receiving dexamethasone alone (RR 9.00, 95% CI 1.23 to 66.05; 52 eyes). In two trials, fewer eyes treated with PVP-I or PVA-I plus steroid developed SEI within 15 days of treatment compared with steroid alone or steroid plus levofloxacin (RR 0.08, 95% CI 0.01 to 0.55; 69 eyes). One study found that CsA was no more effective than steroid for resolving SEI within four weeks of treatment (RR 0.84, 95% CI 0.67 to 1.06; N = 88). The evidence from trials comparing topical interventions with steroids was overall of very low level certainty. Adverse effects Antiviral or antimicrobial agents plus steroid did not differ from artificial tears in terms of ocular discomfort upon instillation (RR 9.23, 95% CI 0.61 to 140.67; N = 19). CsA and tacrolimus eye drops were associated with more cases of severe ocular discomfort, and sometimes intolerance, when compared with steroids (RR 4.64, 95% CI 1.15 to 18.71; 2 studies; N = 141). Compared with steroids, tacrolimus did not increase the risk of elevated intraocular pressure (RR 0.07, 95% CI 0 to 1.13; 1 study; N = 80), while trifluridine conferred no additional risk compared to tear substitute (RR 5.50, 95% CI 0.31 to 96.49; 1 study; N = 97). Overall, bacterial superinfection was rare (one in 23 CsA users) and not associated with use of the intervention steroid (RR 3.63, 95% CI 0.15 to 84.98; N = 51). The evidence for all estimates was of low or very low certainty.

AUTHORS' CONCLUSIONS

The evidence for the seven specified outcomes was of low or very low certainty due to imprecision and high risk of bias. The evidence that antiviral agents shorten the duration of symptoms or signs when compared with artificial tears was inconclusive. Low certainty evidence suggests that PVP-I alone resolves signs and symptoms by seven days relative to artificial tears. PVP-I or PVA-I, alone or with steroid, is associated with lower risks of SEI development than artificial tears or steroid (very low certainty evidence). The currently available evidence is insufficient to determine whether any of the evaluated interventions confers an advantage over steroids or artificial tears with respect to virus eradication or its spread to initially uninvolved fellow eyes. Future updates of this review should provide evidence of high-level certainty from trials with larger sample sizes, enrollment of participants with similar durations of signs and symptoms, and validated methods to assess short- and long-term outcomes.

Treatment of viral conjunctivitis with antiviral drugs

Viral conjunctivitis is one of the most common disorders observed in ophthalmic emergency departments, yet no established treatment exists. Lately, antiviral medications have been introduced into clinical practice; however, a systematic review focusing on their use and effectiveness in the treatment of viral conjunctivitis has not been previously reported. We systemically reviewed the literature to identify studies where antiviral drugs were used to treat viral conjunctivitis. Currently, aciclovir, trifluridine and valaciclovir are commonly used as antiviral agents to treat herpesvirus infections. Cidofovir has been used successfully to treat some cases of adenoviral conjunctivitis, although toxicity has also been reported. The use of other medications, such as idoxuridine, has been minimized in clinical practice due to their high toxicity. Interestingly, most of the antiviral drugs developed are used to treat herpesvirus infections, while less progress has been made in the field of adenoviral infections. For other viral causes of conjunctivitis, no effective remedy is currently available, and treatment focuses on the relief of symptoms. Caution should be exercised when coadministering other pharmacological agents, such as corticosteroids, because of emerging adverse effects.

Systemic antiviral drugs used in ophthalmology

Over the past two decades, the recognition of viral enzymes and proteins that can serve as molecular targets of drugs has revolutionized the treatment of viral infections. Beginning with acyclovir, a number of systemically administered agents which are both relatively safe and effective for the treatment of herpetic infections and human immunodeficiency virus (HIV) infections have become widely available. Because of increased numbers of herpes virus infections, as well as the rising epidemic of HIV infections, the ophthalmologist is, more likely than ever before to be involved in the treatment of severe and frequent ocular infections caused by herpes viruses. In addition, the acute retinal necrosis (ARN) syndrome has been demonstrated to be caused by herpes viruses and a once rare retinal infection caused by cytomegalovirus is common in patients with the acquired immunodeficiency syndrome (AIDS). In this article, four systemic antiviral drugs (Vidarabine, Acyclovir, Ganciclovir, and Foscarnet) that have demonstrated usefulness in the treatment of ophthalmic disease are reviewed in detail with regard to their mechanisms, applications, effectiveness, and side effects.

Comparative susceptibility of respiratory viruses to recombinant interferons-alpha 2b and -beta

Intranasal recombinant interferon-alpha 2b (rIFN-alpha 2b) protects against natural colds due to rhinoviruses, but apparently not against those caused by viruses. Because rIFN-beta serine17 (rIFN-beta ser) appears less active than rIFN-alpha 2b in preventing natural rhinovirus colds, we compared the two IFNs in two in vitro assays against selected respiratory viruses. In a yield reduction assay, both IFNs had comparable activity against rhinovirus types 39 and 1A and coronavirus 229E, which were inhibited by 90% or more at IFN concentrations of 10(-11) to 10(-10) gram of protein/ml (approximately 2-20 IU/ml). Similar activities were observed with rIFN-beta ser against rhinoviruses isolated from clinical specimens. At concentrations of 10(-9) gram protein/ml, both IFNs inhibited the growth of influenza A and parainfluenza viruses, but not of adenovirus or respiratory syncytial virus in the cell culture systems tested. Thus, the different clinical protection conferred by rIFN-alpha 2b and rIFN-beta ser in studies of natural rhinovirus colds are not accounted for by differences in their in vitro activity against these viruses, and other explanations must be found.

Topical human fibroblast interferon for acute adenoviral conjunctivitis

We conducted a prospective, randomized, double-blind, placebo-controlled clinical trial investigating the use of topical human fibroblast interferon (HuIFN-beta) 7.5 x 10(5) IU/ml, one drop 5 times daily, in the treatment of acute epidemic conjunctivitis. Of 50 patients who were initially enrolled, tear-film cultures for adenovirus were positive from 26% for type 8, 12, or 19. Based upon a quantifiable conjunctivitis severity score of 37 patients evaluated after approximately 1 week of therapy, analysis of covariance showed a statistically significant greater improvement with topical HuIFN-beta compared with placebo for affected left eyes (P = 0.02) but not for right eyes (P = 0.5), an effect that could not be adequately explained. We suggest that a higher dosage of topical HuIFN-beta may prove useful in the control of more severely affected cases. This trial provides guidelines for future investigations of interferon in the treatment and prophylaxis of adenoviral keratoconjunctivitis.

Adenovirus type 8 keratoconjunctivitis--an outbreak and its treatment with topical human fibroblast interferon

An outbreak of keratoconjunctivitis is described which involved at least 186 people; adenovirus type 8 was identified in 50 of the cases. Topical human fibroblast interferon was assessed in a double-blind, placebo-controlled study in which 34 patients participated. Seventeen of the 34 trial patients yielded adenovirus type 8; three were infected with adenovirus type 7. The outbreak was curtailed by control of infection measures: principally careful hand-washing by medical personnel between cases and by discouraging attendance of new cases at the Eye Infirmary. Consequently the trial numbers are small. In addition there was a wide interpatient variation in the severity of infection. Therefore it was not possible to make any statistically valid conclusions concerning the recovery rate of patients receiving interferon or placebo.

Interferon treatment of adenoviral conjunctivitis

We conducted a randomized, double-masked, placebo-controlled study to evaluate the efficacy of topical interferon in the treatment of adenoviral conjunctivitis. The study was designed to determine the efficacy of plasmid-derived alpha-2 interferon treatment with regard to the duration of clinical disease, virus shedding, and the occurrence of bilateral infection and subepithelial infiltrates. Interferon therapy was not found to have a statistically significant effect with regard to these factors in the 14 patients who completed 14 days of treatment in the study with interferon or a placebo. Interferon therapy was, however, associated with a tendency toward asymptomatic infection in the second eye when compared to the controls.

Intramuscular human interferon-beta injections in treatment of condylomata acuminata

A two-part study was done to assess the value of human fibroblast interferon (IFN-beta) in the treatment of condylomata acuminata. The first part was an open study of different IFN-beta preparations, which showed that intramuscular injection was the most suitable mode of administration of IFN-beta. In the double-blind placebo section 22 patients were given injections of 2 X 10(6) units IFN-beta or placebo for 10 consecutive days and followed up for 3 months. In 9 of the 11 in the IFN-beta group and 2 in the placebo group lesions disappeared from about 5 weeks after completion of the course of injections. After 3 months 8 of the non-responders were given a course of IFN-beta and all responded to treatment. None of those who had responded has had a recurrence, the disease-free period now being 12 months. Changes in (2'-5')oligo A synthetase levels in white blood cells confirm that intramuscular injections of IFN-beta produce a systemic response.

Mutagenicity studies of human fibroblast interferon (HuIFN-beta)

Human fibroblast interferon (HuIFN-beta) was studied for mutagenicity using the Ames method and in vitro cytogenetics. HuIFN-beta had no mutagenic effect on S. typhimurium (TA1535, TA1537, TA1538, TA98 and TA100) and E. coli (WP2 uvrA) at concentrations of 3, 30, 300, 3000, 30 000 or 300 000 IU/plate. In the cytogenetic study, HuIFN-beta had no clastogenic effect on human peripheral blood lymphocytes at concentrations of 3, 30, 300, 3000, or 30 000 IU/ml. These results suggest that HuIFN-beta has no mutagenic potential.