Retinal toxicity during pegylated alpha-interferon therapy for chronic hepatitis C: a multifocal electroretinogram investigation

The Impact of Systemic Medications on Retinal Function

This study will provide a thorough review of systemic (and select intravitreal) medications, along with illicit drugs that are capable of causing various patterns of retinal toxicity. The diagnosis is established by taking a thorough medication and drug history, and then by pattern recognition of the clinical retinal changes and multimodal imaging features. Examples of all of these types of toxicity will be thoroughly reviewed, including agents that cause retinal pigment epithelial disruption (hydroxychloroquine, thioridazine, pentosan polysulfate sodium, dideoxyinosine), retinal vascular occlusion (quinine, oral contraceptives), cystoid macular edema/retinal edema (nicotinic acid, sulfa-containing medications, taxels, glitazones), crystalline deposition (tamoxifen, canthaxanthin, methoxyflurane), uveitis, miscellaneous, and subjective visual symptoms (digoxin, sildenafil). The impact of newer chemotherapeutics and immunotherapeutics (tyrosine kinase inhibitor, mitogen-activated protein kinase kinase, checkpoint, anaplastic lymphoma kinase, extracellular signal-regulated kinase inhibitors, and others), will also be thoroughly reviewed. The mechanism of action will be explored in detail when known. When applicable, preventive measures will be discussed, and treatment will be reviewed. Illicit drugs (cannabinoids, cocaine, heroin, methamphetamine, alkyl nitrite), will also be reviewed in terms of the potential impact on retinal function.

Host-Directed Antiviral Therapy

Antiviral drugs have traditionally been developed by directly targeting essential viral components. However, this strategy often fails due to the rapid generation of drug-resistant viruses. Recent genome-wide approaches, such as those employing small interfering RNA (siRNA) or clustered regularly interspaced short palindromic repeats (CRISPR) or those using small molecule chemical inhibitors targeting the cellular "kinome," have been used successfully to identify cellular factors that can support virus replication. Since some of these cellular factors are critical for virus replication, but are dispensable for the host, they can serve as novel targets for antiviral drug development. In addition, potentiation of immune responses, regulation of cytokine storms, and modulation of epigenetic changes upon virus infections are also feasible approaches to control infections. Because it is less likely that viruses will mutate to replace missing cellular functions, the chance of generating drug-resistant mutants with host-targeted inhibitor approaches is minimized. However, drug resistance against some host-directed agents can, in fact, occur under certain circumstances, such as long-term selection pressure of a host-directed antiviral agent that can allow the virus the opportunity to adapt to use an alternate host factor or to alter its affinity toward the target that confers resistance. This review describes novel approaches for antiviral drug development with a focus on host-directed therapies and the potential mechanisms that may account for the acquisition of antiviral drug resistance against host-directed agents.

Retinal vascular complications associated with interferon-ribavirin therapy for chronic hepatitis C: A population-based study

PURPOSE

To investigate the incidence of retinal vascular complications and risk factors in patients with chronic hepatitis C receiving interferon-ribavirin therapy in Taiwan.

METHODS

By using the Taiwan National Health Insurance Research Database, we compared the incidence of retinal vascular complications between patients receiving and not receiving interferon-ribavirin treatment. The exposure and nonexposure groups were randomly 1:1 frequency-matched according to age, sex, income, urbanization level, hypertension, and diabetes. Incidence of each retinal vascular complication and hazard ratios were assessed in the follow-up evaluation.

RESULTS

Of the sample of 4736 patients, a total of 182 patients (3.84%) developed retinopathy during the follow-up period, of which 110 patients (4.65%) received interferon-ribavirin therapy and 72 patients (3.04%) did not receive interferon-ribavirin therapy. After multivariate adjustments, the risk of retinopathy during the follow-up period was 1.533 (95% confidence interval [CI], 1.139-2.064; P = .0048) times higher in patients receiving interferon-ribavirin therapy than in those in the comparison cohort not receiving the therapy. Patients with hypertension compared with those without it (adjusted hazard ratio, 1.530; 95% CI, 1.069-2.135; P = .0125) also had an increased risk of retinopathy.

CONCLUSIONS

Interferon-ribavirin therapy was associated with a 53.3% increased risk of retinal vascular complications compared with not receiving the therapy. Regular ophthalmologic examination is essential for patients receiving interferon-ribavirin, particularly those with hypertension.

The Role of Multifocal Electroretinography in the Assessment of Drug-Induced Retinopathy: A Review of the Literature

Multifocal electroretinography (mfERG) is an objective, noninvasive examination for the assessment of visual function. It enables the stimulation of multiple retinal areas simultaneously and recording of each response independently, providing a topographic measure of retinal electrophysiological activity in the central 40-50° of the retina. A clinical application of mfERG represents the assessment of retinal toxicity associated with systemic medications. Drug-induced retinopathy represents a disease that, although not common, requires early recognition: if not detected early, it may progress and cause irreversible retinal dysfunction with subsequent visual impairment. This review aims to evaluate the use of mfERG in the assessment of retinal dysfunction associated with various systemic pharmacological agents based on the currently available literature. The most commonly recognized systemic medications affecting retinal function are included, such as chloroquine and hydroxychloroquine, vigabatrin, deferoxamine, ethambutol, interferon-α, tamoxifen, digoxin, sildenafil, canthaxanthin, amiodarone and nefazodone. The role of mfERG in the early diagnosis of retinal toxicity and the evaluation of disease severity is reviewed, as well as its clinical value in monitoring disease progression or recovery after drug cessation.

[Bilateral non-arteritic ischemic optic neuropathy during treatment of viral hepatitis C with pegylated interferon and Ribavirin]

INTRODUCTION

Hepatitis C is a serious viral infection, for which the current treatment is based on the combination of pegylated interferon (IFN) and Ribavirin(®). Ophthalmic complications observed with PEG-IFN are infrequent and of variable prognosis. They often include an ischemic retinopathy with typical cotton-wool spots, hemorrhage and retinal edema, and rarely acute non-arteritic anterior ischemic optic neuropathy as illustrated by our report.

OBSERVATION

We report the case of a 51-year-old man followed for chronic active hepatitis C, who presented in the fourth month of treatment with pegylated interferon and vidarabine with a sharp decline in visual acuity secondary to acute bilateral non-arteritic anterior ischemic optic neuropathy. The hepatitis C treatment was discontinued. His course was notable by the third week for a significant regression of papilledema with improvement in visual acuity in the right eye and no change in the left eye, remaining at counting fingers. After regressing for four years, the disease progressed to bilateral temporal optic atrophy without change in visual acuity.

CONCLUSION

Pegylated interferon and Ribavirin(®) are commonly used in the treatment of chronic hepatitis C. They are the source of various ophthalmologic complications of varied severity. The pathophysiology of this ocular toxicity currently remains hypothetical. Non-arteritic ischemic optic neuropathy is still a relatively rare complication with a poor functional prognosis, often requiring discontinuation of treatment. Thus, careful ophthalmologic monitoring before and during antiviral treatment of patients with hepatitis C appears necessary.

Interferon-associated retinopathy risk in patients with diabetes and hypertensive hepatitis C

AIM: To investigate the association of hypertension and diabetes mellitus (DM) with interferon-associated retinopathy (IAR) risk in chronic hepatitis C (CHC).

METHODS: Two investigators independently searched PubMed and Embase for eligible articles published prior to December 2013; additional studies were identified by reviewing the bibliographies. Only case-control or cohort studies that evaluated the association between hypertension and/or DM and IAR incidence in CHC patients were included. IAR was characterized by the presence of cotton-wool spots and/or retinal hemorrhage, and was defined as the primary efficacy measure. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were estimated using data extracted from papers based on random-effects models.

RESULTS: Eight eligible studies were included in the present meta-analysis. The outcomes showed that patients with CHC and hypertension were at higher risk of IAR (48/189 vs 96/455, RR = 1.90; 95%CI: 1.15-3.15, P < 0.05). Patients with DM receiving interferon (IFN)-based therapy for CHC infection may be at higher risk for IAR (18/72 vs 60/256, RR = 1.56, 95%CI: 1.11-2.20, P < 0.05); however, the outcome was not stable. There was no significant difference in IAR risk between genotype-1-infected patients and non-genotype-1-infected patients (RR = 1.09, 95%CI: 0.64-1.87, P > 0.05). Comparable incidences of IAR were also found between patients treated with pegylated interferon (PIFN) α-2a and those treated with PIFN α-2b (RR = 0.84, 95%CI: 0.56-1.24, P > 0.05) and between patients treated with IFN α and those treated with PIFN α (RR = 1.04, 95%CI: 0.72-1.50, P > 0.05).

CONCLUSION: Patients with hypertension have a higher risk of retinopathy when receiving IFN-based therapy for CHC.

Transient visual loss in a hepatitis C patient treated with pegylated interferon alfa-2a and ribavirin

INTRODUCTION

Patients with Hepatitis C are commonly treated with combination of Pegylated Interferon alfa-2a and Ribavirin. Less than 1% of patients receiving this treatment experience very uncommon ophthalmological side effects such as optic neuropathy and vision disorder, which are usually subclinical, mild and reversible, not requiring the withdrawal of the treatment. Retinopathy is the most commonly reported ocular side effect of interferon use, usually presenting with cotton wool spots and retinal hemorrhages.

CASE PRESENTATION

We represent a case of severe retinopathy and optic neuropathy in a patient with chronic hepatitis C genotype 3a infection, treated with the combination of PEG-IFN alfa-2a (180 mkg once weekly) and Ribavirin (1200 mg daily). Bilateral visual loss of both eyes developed at 11th week of therapy and changes in retina and optic nerve were observed. Fluorescein angiography and optical coherence tomography showed bilateral anterior ischemic optic neuropathy and macular edema. Visual acuity improved 1 month and fundoscopic changes were no longer present 6 months after the urgent permanent discontinuation of PEG-IFN treatment and the pulse steroid therapy followed by a 2 week course of oral prednisone.

DISCUSSION

In case of interferon-associated retinopathy discontinuation of the therapy and treatment with high dose steroids can be beneficial. The prognosis of interferon-associated opthalmological side effects remains uncertain: in some patients visual acuity improves, other continues with poor visual outcome. Considering that, all patients should undergo ophthalmologic examination before treatment with interferon and their ophthalmological status should be monitored regularly while receiving this therapy.

Interferon-associated retinopathy during the treatment of chronic hepatitis C: a systematic review

The incidence of retinopathy in patients with chronic hepatitis C treated with interferon-based regimens has been variably reported in the literature. There is no consensus regarding ophthalmologic screening before and during treatment with interferon-based therapy. To assess the incidence of retinopathy in patients with chronic hepatitis C being treated with interferon-based regimens and estimate the rate of resolution. A systematic literature search was performed to locate all relevant publications. Pooled incidence of retinopathy was calculated in patients treated with interferon or pegylated interferon. We also estimated the rate of discontinuation of treatment and resolution after the treatment was stopped. A total of 21 studies fulfilled the inclusion criteria. The overall incidence of retinopathy using random effect model was 27.7% (95% confidence interval [CI] 20.9-34.5%). The pooled incidence of retinopathy in 10 studies that only used pegylated interferon was 20.9% (95% CI: 11.6-29.8). The incidence of retinopathy with pegylated interferon in diabetic and hypertensive patients (high-risk group) was 65.32% and 50.7%, respectively. This was significantly higher compared with the incidence of retinopathy (11.7%) in patients without these risk factors. Overall pooled estimate for the resolution of retinopathy was 87% (95% CI 75.7-98.4%). The rate of discontinuation of treatment was 6.3%. The incidence of retinopathy with pegylated interferon in patients without hypertension and diabetes is low, but the risk is higher in patients with diabetes and hypertension. Routine pretreatment fundoscopic screening may not be warranted in all patients and can be limited to the patients with these risk factors.

Pegylated interferon-associated retinopathy is frequent in hepatitis C virus patients with hypertension and justifies ophthalmologic screening

Treatment with pegylated interferon alpha (PegIFNα) and ribavirin is still regarded as the standard of care for chronic hepatitis C virus (HCV). Retinopathy has been occasionally described but prospective, longitudinal data are lacking. We investigated the frequency and clinical significance of retinopathy during therapy with PegIFNα and ribavirin in 97 consecutive HCV patients. In all, 54 (55.7%) and 43 (44.3%) patients were treated with PegIFNα 2a and PegIFNα 2b, respectively. Ophthalmologic examination was performed before therapy (baseline), at 3 and 6 months (3T and 6T, respectively) of therapy, and 3 months after the end of therapy (3ET). All patients underwent the baseline and 3T examination, 95.9% and 90.7% of patients underwent 6T and 3ET examination, respectively. Overall, 30.9% of patients developed retinopathy, as defined by the presence of cotton wool spots and/or retinal hemorrhages. Variables significantly associated with retinopathy during treatment were age (P = 0.004), metabolic syndrome (P = 0.05), hypertension (P < 0.0001), cryoglobulinemia (P = 0.05), and preexisting intraocular lesions at baseline (P = 0.01). By multivariate analysis, the only variable independently associated with PegIFNα-associated retinopathy was hypertension (hazard ratio [HR] = 4.99, 95% confidence interval [CI] 2.29-10.89). The frequency of retinopathy was significantly higher in hypertensive patients versus those without hypertension at all timepoints (18.5% versus 5.7% at baseline, P = 0.05; 48.1% versus 15.7% at 3T, P = 0.0009; 68.0% versus 19.1% at 6T, P < 0.0001; 32.0% versus 6.2%, P = 0.0005 at 3ET). In one (1.1%) hypertensive patient, who developed bilateral branch retinal vein occlusion at 6T, the therapy was discontinued. A cost analysis showed that screening for PegIFNα-associated retinopathy was cost-effective as compared with thyroid-stimulating hormone screening.

CONCLUSION

Retinopathy is frequent during treatment with PegIFNα and ribavirin, especially in hypertensive patients, who may develop serious complications. Screening for PegIFNα-associated retinopathy should be recommended for HCV patients with hypertension.

Incidence and risk factors of retinopathy in Egyptian patients with chronic hepatitis C virus treated with pegylated interferon plus ribavirin

BACKGROUND

Data are scarce on ocular complications in Egyptian patients with chronic hepatitis C treated with pegylated interferon and ribavirin therapy. The aim of this study was to investigate the development of retinal lesions induced by interferon therapy for chronic hepatitis C.

METHODS

We prospectively analyzed 84 patients with chronic hepatitis C (total 168 eyes), who underwent combination pegylated interferon and ribavirin therapy for 48 weeks. Visual acuity, color vision, and visual field were measured, and a fundus assessment was made at baseline, at 12, 24, and 48 weeks post the commencement of treatment, and at follow-up, 1 month after treatment. Past medical and ocular histories, visual symptoms, and the results of a full ophthalmologic assessment were recorded for each patient.

RESULTS

Twenty-two patients (26%) developed retinopathy. Retinal hemorrhage was observed in eight patients. Four patients complained of visual disturbance. Retinopathy disappeared in 16 patients (73%) despite the continuation of combination therapy. However, retinopathy persisted in six patients with retinal hemorrhage and three of them stopped treatment. A comparison of the clinical backgrounds between the patients with and without retinopathy showed no significant differences with regard to gender, HCV RNA level, white blood cell count, platelet count, hemoglobin level, or fibrosis score. However patients with retinopathy were of older age, had a higher prevalence of hypertension and diabetes mellitus, and more often did not respond to therapy. Multiple logistic regression analysis revealed that hypertension and diabetes were factors predicting retinopathy.

CONCLUSION

Retinopathy associated with interferon α-2a and ribavirin combination therapy tends to develop in patients of older age with hypertension and diabetes.

Outcome of retinopathy in chronic hepatitis C patients treated with peginterferon and ribavirin

The purpose of this study is to evaluate the incidence and outcome of retinopathy in chronic hepatitis C patients treated with peginterferon and ribavirin. A total of 74 hepatitis C patients with baseline eye exams and eye exams during therapy were included. Retinopathy was defined as development of cotton wool spots and/or intra-retinal hemorrhage. Demographics, hepatitis C viral characteristics, treatment and laboratory data, and eye exam findings were compared in groups with and without retinopathy. Retinopathy developed in 28 (38%), early in therapy. Pre-treatment eye exams did not predict risk of retinopathy. Therapy was continued in all but one; cotton wool spots resolved in 24 of 26. All nine patients with intra-retinal hemorrhage had resolution. No patient had retinopathy-related visual deterioration. Retinopathy is common with peginterferon therapy, but the outcome is favorable. Cessation of therapy for retinopathy is not warranted. Severe visual disturbances and scotomas deserve further evaluation.

[Ocular complications of hepatitis C treatment]

INTRODUCTION

Hepatitis C is a viral infection that can lead to hepatocellular carcinoma. According to current recommendations, the treatment is based on the association of pegylated interferon and ribavirin. Strict treatment criteria are available and apply for the 8,000 patients diagnosed every year in France. Ophthalmological side effects are numerous, unpredictable, and sometimes severe.

CASE REPORT

We report the case of a patient treated with an association of interferon and ribavirin for hepatitis C, who presented two periods of decreased visual acuity 4 years apart. Interferon-related toxic retinopathy was suggested for the first event, while optical neuropathy was diagnosed for the second.

CONCLUSION

Ocular complications of hepatitis C treatment with interferon and ribavirin are frequent but often benign. Our recommendations are periodic ophthalmological examinations, including visual acuity and fundus examination, before starting the treatment, at 3 months, and if necessary at 9 months.

The clinical applications of multifocal electroretinography: a systematic review

Multifocal electroretinography (mfERG) is an investigation that can simultaneously measure multiple electroretinographic responses at different retinal locations by cross-correlation techniques. mfERG therefore allows topographic mapping of retinal function in the central 40-50 degrees of the retina. The strength of mfERG lies in its ability to provide objective assessment of the central retinal function at different retinal areas within a short duration of time. Since the introduction of mfERG in 1992, mfERG has been applied in a large variety of clinical settings. This article reviews the clinical applications of mfERG based on the currently available evidence. mfERG has been found to be useful in the assessment of localized retinal dysfunction caused by various acquired or hereditary retinal disorders. The use of mfERG also enabled clinicians to objectively monitor the treatment outcomes as the changes in visual functions might not be reflected by subjective methods of assessment. By changing the stimulus, recording, and analysis parameters, investigation of specific retinal electrophysiological components can be performed topographically. Further developments and consolidations of these parameters will likely broaden the use of mfERG in the clinical setting.

Risk factors for retinopathy associated with interferon α-2b and ribavirin combination therapy in patients with chronic hepatitis C

AIM: To elucidate the frequency and risk factors for retinopathy in patients with chronic hepatitis C who are treated by interferon-ribavirin combination therapy.

METHODS: We prospectively analyzed 73 patients with histologically confirmed chronic hepatitis C, who underwent combination therapy for 24 wk. Optic fundi were examined before, and 2, 4, 12 and 24 wk after the start of combination therapy.

RESULTS: Fourteen patients (19%) developed retinopathy, which was initially diagnosed by the appearance of a cotton wool spot in 12 patients. Retinal hemorrhage was observed in 5 patients. No patient complained of visual disturbance. Retinopathy disappeared in 9 patients (64%) despite the continuation of combination therapy. However, retinopathy persisted in 5 patients with retinal hemorrhage. A comparison of the clinical background between the groups with and without retinopathy showed no significant differences in age, gender, viral genotype, RNA level, white blood cell count, platelet count, prothrombin time, complications by diabetes mellitus or hypertension, or pretreatment arteriosclerotic changes in the optic fundi. However, multiple logistic regression analysis revealed that complication by hypertension was observed with a high frequency in the group with retinopathy (P = 0.004, OR = 245.918, 95% CI = 5.6-10786.2).

CONCLUSION: Retinopathy associated with combination therapy of interferon α-2b and ribavirin tends to develop in patients with hypertension.